Sensory system (neurological) examination o sulivan.pptx

DR.AMMAR
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ammarkhanazxc36@gmail.com
Sensory examination
By Dr,Ammar kakar
Lecturer Physiotherapy Alhamd Islamic university,Quetta.

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Sensory integration:
• If all of the sensory stimuli which enter the central nervous system were allowed to bombard the higher
centers of the brain, the individual would be rendered utterly ineffective.
• It is the brain’s task to filter, organize, and integrate a mass of sensory information so that it can be used
for the development and execution of the brain’s functions.1,
• Jean Ayers, PhD the human system is continually inundated with sensory information from a variety of
environmental inputs as well as from movement, touch, awareness of the body in space, sight, sound,
and smell.
• “In all higher order motor behaviors, the brain must correlate sensory inputs with motor outputs to
accurately assess and control the body’s interaction with the environment.
• Sensory integration is the ability of the brain to organize, interpret, and use sensory information.
• this integration provides an internal representation of the environment that informs and guides motor
responses.
• these sensory representations provide the foundation on which motor programs for purposeful
movements are planned, coordinated, and implemented.
• Ayers defined sensory integration as “the neurological process that organizes sensation from one’s own
body and from the environment and makes it possible to use the body effectively within the
environment.
• In an intact system, sensory integration occurs automatically without conscious effort

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■ SENSATION AND MOVEMENT:
• Motor learning and motor performance are inextricably linked to sensation.
• As a motor task is practiced, the individual learns to anticipate and correct or modify
movements based on sensory input organized and integrated by the central nervous
system (CNS).
• The CNS uses this information to influence movement by both feedback and
feedforward control.
• Feedback control uses sensory information received during the movement to monitor
and adjust output.
• Feedforward control is a proactive strategy that uses sensory information obtained
from experience.
• Signals are sent in advance of movement allowing for anticipatory adjustments in
postural control or movement
• The primary role of sensation in movement is to
• (1) guide selection of motor responses for effective interaction with the environment and
• (2) adapt movements and shape motor programs through feedback for corrective action.
• Sensation also provides the important function of protecting the organism from injury

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■ SENSORY INTEGRITY:
• the term somatosensation (somatosensory) refers to sensation received from the skin and musculoskeletal
system (as opposed to that from specialized senses such as sight or hearing).
• Examination of sensory function involves testing sensory integrity by determining the patient’s ability to
interpret and discriminate among incoming sensory information.
• the sensory examination is based on the premise that within the intact human system, sensory information
is taken in from the body and the environment;
• the CNS then processes and integrates the information for use in planning and organizing behavior.
• this premise is more aptly termed a theoretical construct (a concept that represents an unobservable event).
• We cannot directly observe CNS processing integration of sensory information, or the motor planning
process.
• However, our current knowledge of CNS function and motor behavior provides evidence that these
unobservable events do occur.
• We can observe impairments in motor behavior, but can only hypothesize that they truly result from faulty
sensory integration mechanisms.

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• the Guide to Physical therapist Practice defines sensory integrity as “the
intactness of cortical sensory processing, including proprioception, pallesthesia,
stereognosis, and topognosis.”
• Sensory integrity is included among the list of 24 categories of tests and
measures that may be used by physical therapists during patient examination
and is included in all practice patterns (i.e., musculoskeletal, neuromuscular,
cardiovascular/pulmonary, and integumentary).
• Box 3.1 presents examples of pathologies, impairments, activity limitations,
disabilities, risk factors, and health, wellness, and fitness needs associated with
changes in sensory integrity.
• As the CNS analyzes and uses all sensory input to identify movement errors and
initiate corrective responses, examination of sensory function typically precedes
examination of motor function.
• this sequence assists the physical therapist in differentiating the impact of
sensory impairments on motor function.

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CLINICAL INDICATIONS
• Indications for examination of sensory function are based on the history and systems review
• this includes “information provided by the patient/client, family, significant other, or caregiver; symptoms
described by the patient/client; signs observed and documented during the systems review; and information
derived from other sources and records.”
• these data may indicate the existence of pathology (or risk of pathology) resulting in sensory changes that may
impose impairments, activity limitations, participation restrictions, or disability (see Box 3.1).
• Sensory dysfunction may be associated with any pathology or injury affecting either the peripheral nervous
system (PNS) or CNS, or with a combined involvement of both systems.
• Deficits may occur at any point within the system including the sensory receptors, peripheral
nerves, spinal nerves, spinal cord nuclei and tracts, brainstem, thalamus, and
sensory cortex.
• Examples of conditions that generally demonstrate some level of sensory impairment include pathology, disease,
or injury to the peripheral nerves such as trauma (e.g., fracture) that can sever, crush, or damage a nerve;
metabolic disturbances (diabetes, hypothyroidism, alcoholism); infections (Lyme disease, leprosy, human
immunodeficiency virus [HIV]); impingement or compression (arthritis, carpal tunnel syndrome); burns; toxins
(lead, mercury, chemotherapy); and nutritional deficits (vitamin B12). Sensory impairments are also associated
with injury to nerve roots or spinal cord, cerebral vascular accident (CVA), transient ischemic attack (TIA), tumors,
multiple sclerosis (MS), and brain injury or disease.
• These examples, which are not all-inclusive, indicate the wide spectrum of injuries, disease, and pathologies that
may present with some element of sensory deficit.

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Pattern (Distribution) of Sensory Impairment:
• Examination of sensory function contributes critical information to establishing a physical therapy
diagnosis and prognosis, identifying anticipated goals and expected outcomes, and developing a POC.
• A seminal feature of the examination involves determining the pattern (specific boundaries) of sensory
involvement.
• Pattern identification is accomplished using knowledge of skin segment innervation by the dorsal roots
and peripheral nerves (Figs. 3.1 and 3.2).
• the term dermatome (or skin segment) refers to the skin area supplied by one dorsal root.
• the graphic illustration of skin segment innervation as presented in Figures 3.1 and 3.2 is referred to as a
dermatome map.
• there exist some discrepancies among published dermatome maps based on the methodologies used to
identify skin segment innervation.
• In a clinical commentary, Downs and Laporte discuss the history of dermatome mapping, including the
variations in methodologies employed, and the inconsistencies in the dermatome maps used in
education and practice.
• During the review of systems, asking the patient to carefully describe the pattern or distribution of
sensor symptoms (e.g., tingling, numbness, diminished, or absent sensation) provides the therapist with
preliminary information to help guide the examination and to assist in identifying the dermatome(s)
and nerve(s) involved.

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• Peripheral nerve injuries generally present sensory impairments that parallel the
distribution of the involved nerve and correspond to its pattern of innervation.
• For example, if a patient presents with complaints of numbness on the ulnar half
of the ring finger, the little finger, and the ulnar side of the hand, the therapist
would be alerted to carefully address ulnar nerve (C8 and T1) integrity during the
sensory examination.
• Complaints of sensory disturbances on the palmar surface of the thumb and the
palmar and distal dorsal aspects of the index, middle, and the radial half of the
ring finger would be indicative of median nerve (C6–8 and T1) involvement.
• Posterior view of skin segment innervation by dorsal roots (left) and peripheral
nerves (right).
• neuropathy (e.g., diabetes), sensory loss is often an early symptom and presents
in a glove and stocking distribution (referring to the typical involvement of the
hands and feet).
• In contrast, MS frequently presents with an unpredictable or scattered pattern of
sensory involvement.

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• Spinal cord injury (SCI) often presents with a more diffuse pattern of sensory
involvement below the lesion level that is typically bilateral, although not
necessarily symmetrical.
• Examination of sensory function following SCI provides critical data that reflect
the degree of neurological impairment.
• Together with other tests and measures, sensory data contribute to determining
the relative completeness of the injury, the existence of zones of partial
preservation (areas distal to a complete lesion that retain partial innervation),
symmetry or asymmetry of the lesion, and the presence of sacral sensation
below the neurological level of lesion (a defining feature of an incomplete lesion).

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■ AGE-RELATED SENSORY CHANGES
• Alterations in sensory function occur with normal aging and should be clearly differentiated
from those associated with specific illness, disease, or pathology.
• In recent years there has been a gradual expansion of interest in and information about the
causes and consequences of agerelated sensory changes.
• this has been evident through the large and expanding body of literature devoted to the
neuroscience of aging and its impact on function and quality of life of older adults.
• the topics addressed are specific age-related changes in vision, hearing, and the
somatosensory system; treatment, prevalence, and risk factor information; as well as the role
of public policy and public health in addressing age-related sensory loss
• Healthy People 2020, published by the U.S. Department of Health and Human Services,
presents a comprehensive health promotion and wellness agenda for the second decade of the
21st century. he overarching goals of Healthy People 2020 are to
• (1) attain high-quality, longer lives free of preventable disease, disability, injury, and premature
death;
• (2) achieve health equity, eliminate disparities, and improve the health of all groups;
• (3) create social and physical environments that promote good health for all; and
• (4) promote quality of life, healthy development, and healthy behaviors across all life stages.

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• Decreased acuity of many sensations occurs and is considered a characteristic finding with aging.36-40 he exact morphology of
diminished sensation with age has not been completely established.
• Over the lifespan neurons are replaced at a declining rate and this may account for the decline of average weight of the brain
with aging.
• Although a feature of Alzheimer’s disease, normal aging does not produce a significant loss in the number of cortical neurons.
• Other changes in the brain include degeneration of neurons with presence of replacement gliosis, lipid accumulation in the
neurons, loss of myelin, and development of neurofibrils (masses of small, tangled fibrils) and plaques on the cells.
• there is also a decrease in the number of enzymes responsible for synthesis of dopamine, norepinephrine, and to a lesser
degree acetylcholine, as well as depletion of the neuronal dendrites in the aging brain.
• Electrophysiological studies have identified a gradual reduction in conduction velocity of sensory nerves with advancing
age,45-47 and this may reflect degenerative changes in myelin sheaths or loss or reduction in size of sensory axons.
• Evoked potentials provide a quantitative measure of sensory function and have been found to decrease in amplitude with
age.49
• A reduction in the number of Meissner’s corpuscles has also been identified.
• these corpuscles, responsible for touch detection, are limited to hairless areas, and become sparse, take on an irregular
distribution, and vary in size and shape with age.
• Age-related changes in morphology and decreased concentrations of Pacinian corpuscles, responsive to rapid tissue
movement (e.g., vibration), have also been reported.
• Degenerative changes in myelin have been documented in both the central and peripheral nervous systems.
• In a review of the literature on the effects of normal aging on myelin and nerve fibers, Peters40 suggests that
• (1) age-associated cognitive decline is more likely due to widespread damage to myelin sheaths of cortical neuron axons than to actual loss of
these neurons and
• (2) the resulting changes in conduction velocity alter the normal timing of neuronal circuits

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• .a decrease in the distance between the nodes of Ranvier has been associated with advancing age.
• This finding may be related to a slowing of salutatory conduction identified by some authors.
• Destruction of myelin sheaths has been linked to a reduced expression of primary myelin proteins,
axonal atrophy, and to reduced expression and axonal transport of cytoskeletal proteins.
• As compared to younger subjects, lower sensory nerve conduction velocities have been documented
for both the median, and sural nerves in older subjects.
• Although not an exhaustive list, other documented age-related sensory changes include altered
postural stability and control, diminished response to tactile stimuli, reduced vibratory and
proprioceptive acuity, decreased cutaneous temperature thresholds and two-point discrimination, and
altered ability to adapt sensorimotor responses to task demands.
• These changes frequently appear in the presence of age-related visual or hearing losses that impair
compensatory capabilities.
• In addition, some medications may further influence the distortion of sensory input.
• this combination of sensory impairments may pose a variety of activity limitations for the elderly
individual such as postural instability, exaggerated body sway, balance problems, wide-based gait,
diminished fine motor coordination, tendency to drop items held in the hand, and difficulty in
recognizing body positions in space.
• Box 3.2 Evidence Summary provides an overview of research exploring age-related sensory changes.

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■ PRELIMINARY CONSIDERATIONS
• Accuracy of data from examination of sensory function relies on the patient’s
ability to respond to application of multiple somatosensory stimuli.
• Use of several easily administered preliminary tests will provide sufficient data to
determine the patient’s ability to concentrate on, and respond to, the battery of
sensory test items. the two general categories of preliminary tests include the
patient’s
• (1) arousal level, attention span, orientation, and cognition; and
• (2) memory, hearing, and visual acuity.
• these preliminary tests are typically considered with sensory involvement associated with
CNS lesions.

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• Arousal, Attention, Orientation, and Cognition A necessary first step is to
determine the patient’s arousal level for participation in the test protocol.
• Arousal is the physiological readiness of the human system for
activity.
• It is described by using traditionally accepted key terms and definitions to identify
the patient’s level of consciousness.
• these terms include alert, lethargic, obtunded, stupor, and coma and represent a
continuum of physiological readiness for activity; they are defined as follows:
• • Alert. the patient is awake and attentive to normal levels of
stimulation. Interactions with the therapist are normal and
appropriate.
• • Lethargic. the patient appears drowsy and may fall asleep if not stimulated in
some way. Interactions with the therapist may get diverted. Patient may have
difficulty in focusing or maintaining attention on a question or task.
• • Obtunded. the patient is difficult to arouse from a somnolent state and is
frequently confused when awake. Repeated stimulation is required to maintain
consciousness. Interactions with the therapist may be largely unproductive.

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• • Stupor (semicoma). the patient responds only to strong, generally noxious stimuli and
returns to the unconscious state when stimulation is stopped. When aroused, the patient is
unable to interact with the therapist.
• • Coma (deep coma). the patient cannot be aroused by any type of stimulation. Reflex motor
responses may or may not be seen.
• Reliable information about the integrity of the somatosensory system can be obtained from
patients who are alert. Reliability is proportionally reduced in patients with lethargy and
nonexistent in patients who are obtunded, stuporous, or comatose.
• Attention is selective awareness of the environment or responsiveness to a stimulus or task
without being distracted by other stimuli.
• Attention can be examined by asking the patient to repeat items on a progressively more
challenging list.
• these repetition tasks can begin with two or three items and gradually progress to longer lists.
• For example, the patient might be asked to repeat a series of numbers, letters, or words.
• Another approach to examining attention is to ask the patient to spell words backwards (e.g.,
book, fork, bottle, garden). he task can be made more challenging by using progressively longer
words. Individuals with a high attention span will be able to perform the task.
• Attention deficits will be apparent when the order of letters is confused.

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Orientation:
• refers to the patient’s awareness of time, person, and place.
• In medical record documentation the results of this mental status
screening are often abbreviated “oriented × 3,” referring to the three
parameters of time, person, and place.
• If a patient is not fully oriented to one or more domains, the notation
would read “oriented × 2 (time)” or “oriented × 1 (time, place).”
• With partial orientation entries, it is customary to include the domains of
disorientation within parentheses. Box 3.3 presents sample questions for
examining orientation.

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Cognition:
• is defined as the process of knowing and includes both awareness and judgment.
• Nolan suggests three areas for testing cognition-dependent functions:
• (1) fund of knowledge,
• (2) calculation ability, and
• (3) proverb interpretation.
• Fund of knowledge is defined as the sum total of an individual’s learning and experience in life, which will be
highly variable and different for each patient.
• Detailed information about premorbid knowledge base is often not available.
• However, a number of general categories of information can be used to test this cognitive function.
• Sample questions might include the following:
• • Who became president after Kennedy was shot?
• • Who is the current vice president of the United States?
• • Which is more—a gallon or a liter?
• • In what country is the Great Pyramid?
• • What would you add to your food to make it sweeter?
• • In what state would you find the city of Boston?
• • What are the elements that make up water and salt?
• • Can you name a car made by General Motors?
• • Who is Charles Dickens? Calculation ability examines foundational mathematical abilities. Two associated terms are acalculia
(inability to calculate) and dyscalculia (difficulty in accomplishing calculations).

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• his cognitive screening can be administered either verbally or in written format. the patient is asked to
mentally perform a series of calculations when provided with mathematical problems.
• the test should be initiated with simple problems and progress to the more difficult.
• Adding and subtracting are generally easier than multiplication and division.
• An alternative approach is to provide written mathematical problems and ask the patient to fill in the
answer (e.g., 4 + 4 = ____; 10 + 22 = ____; 46 × 8 = ____; 13 × 7 = ____; 4 × 3 = ____; 6 × 6 = ____; and
so forth.).
• Proverb interpretation examines the patient’s ability to interpret use of words outside of their usual
context or meaning.
• this is a sophisticated cognitive function. During the screening, the patient should be asked to describe
the meaning of the proverb. Sample proverbs include the following:
• • People who live in glass houses shouldn’t throw stones.
• • A rolling stone gathers no moss.
• • A stitch in time saves nine.
• • the early bird catches the worm.
• • the dog that trots about finds the bone.
• • the empty wagon makes the most noise.
• • Every cloud has a silver lining.
• • Grass doesn’t grow on a busy street.

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Memory, Hearing, and Visual Acuity:
• Also related to the ability to respond during sensory testing is the status of the patient’s memory and hearing function as well
as visual acuity.
• Memory Both long- and short-term memory should be examined.
• Impairments of short-term memory will be the most disruptive to collecting sensory information owing to patient difficulties
in remembering and following directions.
• Long-term (remote) memory can be examined by requesting information
• on date
• place of birth
• number of siblings,
• date of marriage
• schools attended
• historical facts.
• Short-term memory can be addressed by verbally providing the patient with a series of words or numbers.
• For example, a series of words might include “car, book, cup”
• use of numbers could include a seven digit list;
• a short sentence could also be used to test short-term memory.
• To ensure understanding of the task, the patient should repeat the sequence immediately.
• Individuals with normal memory function should be able to recall the list 5 minutes9 later and at least two of the items from
the list after 30 minutes.6

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Hearing:
• Observing the patient’s response to conversation can provide a gross
assessment of hearing.
• Note should be made of how alterations in voice volume and tone
influence patient response.

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Visual Acuity:
• A gross visual examination can be made by use of a standard Snellen chart
mounted on the wall or visual acuity cards for use at bedside.
• If the patient uses corrective lenses, they should be worn during testing and
should be clean.
• Visual acuity is typically recorded at 20 feet (6 m) from the Snellen chart
(standard eye chart).
• his distance (20 feet [6 m]) is then placed over the size of the type the
individual is able to read comfortably.
• For example, on a continuum of visual acuity 20/20 is considered excellent
and 20/200 is considered poor acuity.9

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• peripheral field vision can be examined by sitting directly in front of the
patient with outstretched arms.
• the index fingers should be extended and gradually brought toward the
midline of the patient’s face.
• the patient is asked to identify when the therapist’s approaching finger is
first seen.
• Differences between right and left visual field should be noted carefully.
• Depth perception may be grossly checked by holding two pencils or fingers
(one behind the other) directly in front of the patient.
• the patient is asked to touch or grasp the foreground object

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• Because tests of sensory integrity require a verbal response to the stimulus,
patients with arousal, attention, orientation, cognitive, or short-term
memory impairments generally cannot be accurately tested.
• However, impairments in vision, hearing, or speech will not adversely affect
test results if appropriate adaptations are made in providing instructions and
indicating responses (e.g., signaling with either one or two fingers during tests
for two-point discrimination, pointing to an area of stimulus contact,
mimicking joint position sense or awareness of movement with the
contralateral extremity, or object identification by selecting from a group of
items during tests for stereo gnosis).

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CLASSIFICATION OF THE SENSORY SYSTEM
• Several different schemes have been proposed for categorizing the
sensory system.
• Among the more common is classification by the type (or location) of
receptors and the spinal pathway mediating information to higher
centers.
• Sensory Receptors Sensory receptors (sensory nerve endings) are
located at the distal end of an afferent nerve fiber.
• Once stimulated, they give rise to perception of a specific sensation.

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• Sensory receptors are highly sensitive to the type of stimulus for which they were designed (termed receptor
specificity).
• this specificity of nerve fiber sensitivity to a single modality of sensation is called the labeled line principle.
• this means that individual tactile sensations are perceived when specific types of receptors are stimulated.
• For example, in response to touch, selective activation of Merkel’s discs and Ruffini endings generate the sensation
of steady pressure in the cutaneous area above the active receptors.
• It should be noted that the term modality has a specific meaning within the context of sensation.
• Modality “defines a general class of stimulus, determined by the type of energy transmitted by the stimulus and the
receptors specialized to sense that energy.”
• Each type of sensation perceived (e.g., vision, hearing, taste, touch, smell, pain, temperature, proprioception) is
referred to as a modality of sensation.
• the three divisions of sensory receptors include those that mediate the
• (1) superficial,
• (2) deep, and
• (3) combined (cortical) sensations.
• Superficial Sensation Exteroceptors are responsible for the superficial sensations.
• they receive stimuli from the external environment via the skin and subcutaneous tissue.
• Exteroceptors are responsible for the perception of pain, temperature, light touch, and pressure.
• Deep Sensation Proprioceptors are responsible for the deep sensations.
• these receptors receive stimuli from muscles, tendons, ligaments, joints, and fascia, and are responsible for position
sense68 and awareness of joints at rest, movement awareness (kinesthesia), and vibration

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• Spinal Pathways Sensations also have been classified according to the system by
which they are mediated to higher centers.
• Sensations are mediated by either the anterolateral spinothalamic system or
the dorsal column-medial lemniscal system.
• Anterolateral Spinothalamic this system initiates self-protective
reactions and responds to stimuli that are potentially harmful
• It contains
• slow-conducting fibers of small diameter
• some of which are unmyelinated
• The system is concerned with transmission of
• thermal
• nociceptive information,
• mediates pain,
• Temperature
• crudely localized touch, tickle,
• itch, and sexual sensations.

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• Dorsal Column–Medial Lemniscal System The dorsal column is
the system involved with responses to more discriminative sensations.
• It contains
• fast-conducting fibers of large diameter
• with greater myelination.
• This system mediates the sensations
• of discriminative touch
• pressure sensations,
• vibration,
• movement,
• position sense
• awareness of joints at rest.
•The two systems are interdependent and integrated so
as to function together.

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■ TYPES OF SENSORY RECEPTORS:
• the sensory receptors frequently are divided according to their structural design and
the type of stimulus to which they preferentially respond.
• these divisions include
• (1) mechanoreceptors, which respond to mechanical deformation of the receptor or
surrounding area;
• (2) thermoreceptors, which respond to changes in temperature;
• (3) nociceptors, which respond to noxious stimuli and result in the perception of pain;
• (4) chemoreceptors, which respond to chemical substances and are responsible for
taste, smell, oxygen levels in arterial blood, carbon dioxide concentration, and
osmolality (concentration gradient) of body fluids; and
• (5) photic (electromagnetic) receptors, which respond to light within the visible
spectrum

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• The perception of pain is not limited to stimuli received from nociceptors,
because other types of receptors and nerve fibers contribute to this
sensation.
• High intensities of stimuli to any type of receptor may be perceived as pain
(e.g., extreme heat or cold and high intensity mechanical deformation).
• the general classification of sensory receptors is presented in Box 3.4.
• Note that this list also includes the receptors responsible for electromagnetic
(visual) and chemical stimuli

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Cutaneous Receptors:
• Cutaneous sensory receptors are located at the terminal portion of the afferent
fiber.
• these include free nerve endings, hair follicle endings, Merkel’s discs, Ruffini
endings, Krause’s end-bulbs, Meissner’s corpuscles, and Pacinian corpuscles.
• the density of these sensory receptors varies for different areas of the body.
• For example, there are many more tactile receptors in the fingertips than in the
back
• these areas of higher receptor density correspondingly display a higher cortical
representation in somatic sensory area I.
• Receptor density is a particularly important consideration in interpreting the results
of a sensory examination for a given body surface.
• Figure 3.3 illustrates the cutaneous sensory receptors and their respective locations
within the various layers of skin

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• Free Nerve Endings these receptors are found throughout the body.
• Stimulation of free nerve endings result in the perception of pain, temperature, touch, pressure, tickle, and itch sensations.
• Hair Follicle Endings (Hair End-Organs) At the base of each hair follicle a free nerve ending is entwined. he combination of the hair
follicle and its nerve provides a sensitive receptor.
• these receptors are sensitive to mechanical movement and touch.
• Merkel’s Discs these touch receptors are located below the epidermis in hairless smooth (glabrous) skin with a high density in the
fingertips. they are sensitive to low-intensity touch, as well as to the velocity of touch, and respond to constant indentation of the skin
(pressure).
• They provide for the ability to perceive continuous contact of objects against the skin and are believed to play an important role in both two-
point discrimination and localization of touch.
• Merkel’s discs are also believed to contribute to recognition of texture.
• Ruffini Endings Located in the deeper layers of the dermis, these encapsulated endings are involved with the perception of touch and
pressure.
• they are slowly adapting and particularly important in signaling continuous skin deformation such as tension or stretch; they are also found in
joint capsules and assist with joint position sense.
• Krause’s End-Bulb The function of these bulbous encapsulated nerve endings is not clearly understood.
• They are located in the dermis and conjunctiva of the eye.
• They are believed to be low threshold mechanical receptors that may play a contributing role in the perception of touch and pressure.
• Meissner’s Corpuscles Located in the dermis, these encapsulated nerve endings contain many branching nerve filaments within the
capsule.
• they are low-threshold, rapidly adapting and in high concentration in the fingertips, lips, and toes, areas that require high levels of
discrimination. hese receptors play an important role in discriminative touch (e.g., recognition of texture) and movement of objects over skin
• Pacinian Corpuscles these receptors are located in the subcutaneous tissue layer of the skin and in deep tissues of the body (including
tendons and soft tissues around joints). hey are stimulated by rapid movement of tissue and are quickly adapting. hey play a significant role in
the perception of deep touch and vibration.

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Deep Sensory Receptors:
• The deep sensory receptors are located in muscles, tendons, and joints and include both muscle and joint receptors.
• they are concerned primarily with posture, position sense, proprioception, muscle tone, and
speed and direction of movement.
• the deep sensory receptors include the muscle spindle, Golgi tendon organs, free nerve endings,
Pacinian corpuscles, and joint receptors.
• Muscle Receptors
• Muscle Spindles
• the muscle spindle fibers (intrafusal fibers) lie in a parallel arrangement to the muscle fibers (extrafusal fibers).
• they monitor changes in muscle length (Ia and II spindle afferent endings) as well as velocity (Ia ending) of these changes.
• the muscle spindle plays a vital role in position and movement sense and in motor learning.
• Golgi Tendon Organs
• These receptors are located in series at both the proximal and distal tendinous insertions of the muscle.
• The Golgi tendon organs function to monitor tension within the muscle.
• They also provide a protective mechanism by preventing structural damage to the muscle in situations of extreme tension.
• This is accomplished by inhibition of the contracting muscle and facilitation of the antagonist.
• Free Nerve Endings
• these receptors are within the fascia of the muscle.
• they are believed to respond to pain and pressure.
• Pacinian Corpuscles:
• Located within the fascia of the muscle, these receptors respond to vibratory stimuli and deep pressure.

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Muscle Receptors
• Muscle Spindles
• the muscle spindle fibers (intrafusal fibers) lie in a parallel arrangement to the muscle fibers (extrafusal
fibers).
• they monitor changes in muscle length (Ia and II spindle afferent endings) as well as velocity (Ia ending)
of these changes.
• the muscle spindle plays a vital role in position and movement sense and in motor learning.
• Golgi Tendon Organs
• These receptors are located in series at both the proximal and distal tendinous insertions of the muscle.
• The Golgi tendon organs function to monitor tension within the muscle.
• They also provide a protective mechanism by preventing structural damage to the muscle in situations of
extreme tension.
• This is accomplished by inhibition of the contracting muscle and facilitation of the antagonist.
• these receptors are within the fascia of the muscle.
• they are believed to respond to pain and pressure.
• Pacinian Corpuscles:
• Located within the fascia of the muscle, these receptors respond to vibratory stimuli and deep pressure.

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Joint Receptors:
• Golgi-Type Endings
• These receptors are located in the ligaments, and function to detect the rate of
joint movement.
• Found in the joint capsule and ligaments, these receptors are believed to respond
to pain and crude awareness of joint motion.
• Ruffini Endings
• Located in the joint capsule and ligaments, Ruffini endings are responsible for the
direction and velocity of joint movement.
• Paciniform Endings
• These receptors are found in the joint capsule and primarily monitor rapid joint
movements.

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■ PATHWAYS FOR TRANSMISSION OF
SOMATIC SENSORY SIGNALS:
• Somatic sensory information enters the spinal cord through the dorsal roots.
• Sensory signals are then carried to higher centers via ascending pathways from one of two
systems:
1. the anterolateral spinothalamic system
2. dorsal column–medial lemniscal system.
• Anterolateral Spinothalamic Pathway
• the spinothalamic tracts are diffuse pathways concerned with non discriminative sensations
such as pain, temperature, tickle, itch, and sexual sensations.
• this system is activated primarily by mechanoreceptors, thermoreceptors,
and nociceptors,
• composed of afferent fibers that are small diameter and slowly conducting.
• Sensory signals transmitted by this system do not require discrete localization of signal source
or precise gradations in intensity.

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• After originating in the dorsal roots, the fibers of the spinothalamic
pathway immediately cross and ascend up the spinal cord through
the medulla, pons, and midbrain to the ventroposterolateral (VPL)
nucleus of the thalamus (Fig. 3.4).
• Axons of the VPL neurons project to the somatosensory cortex via
the internal capsule.
• Compared with the dorsal column–medial lemniscal system, the
anterolateral spinothalamic pathways make up a cruder, more primitive
system.
• the spinothalamic tracts are capable of transmitting a wide variety of
sensory modalities.
• However, their diffuse pattern of termination results in only crude abilities
to localize the source of a stimulus on the body surface, and poor intensity
discrimination.

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• the three major tracts of the spinothalamic system are the
• (1) anterior (ventral) spinothalamic tract, which carries the sensations of
crudely localized touch and pressure;
• (2) the lateral spinothalamic tract, which carries pain and temperature;
• (3) the spinoreticular tract, which is involved with diffuse pain sensations.

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Dorsal Column–Medial Lemniscal Pathway:
• this system is responsible for the transmission of discriminative sensations received from specialized
mechanoreceptors.
• Sensory modalities that require fine gradations of intensity and precise localization on the body surface are mediated by
this system.
• Sensations transmitted by the dorsal column–medial lemniscal pathway include discriminative touch,
stereognosis, tactile pressure, barognosis, graphesthesia, recognition of texture,
kinesthesia, two-point discrimination, proprioception, and vibration.
• this system is composed of large, myelinated, rapidly conducting fibers.
• After entering the dorsal column the fibers ascend to the medulla and synapse with the dorsal column nuclei
(nuclei gracilis and cuneatus).
• From here they cross to the opposite side and pass up to the thalamus through bilateral pathways called the
medial lemnisci.
• Each medial lemniscus terminates in the ventral posterolateral thalamus.
• From the thalamus, third-order neurons project to the somatic sensory cortex.
• Projection to sensory association areas in the cortex allows for the perception and interpretation of the
combined cortical sensations (Fig. 3.5).Table 3.1 presents a comparison of the most salient features of each ascending
pathway

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SOMATOSENSORY CORTEX:
• The most complex processing of sensory information occurs in the somatosensory cortex,
which is divided into three main divisions:
• primary somatosensory cortex (S-I),
• secondary somatosensory cortex (S-II),
• and posterior parietal cortex (Fig. 3.6A).
• the primary somatosensory (S-I) area occupies a lateral strip called the postcentral
gyrus (posterior to the central sulcus) and includes four distinct areas:
• Brodmann’s areas 3a, 3b, 1, and 2.
• S-I neurons identify the location of stimuli as well as discern the size, shape, and texture of
objects.
• At the superior aspect of the lateral sulcus is the secondary somatosensory
cortex (S-II), which is innervated by neurons from S-I.
• S-II projects to the insular cortex that innervatesthe temporal lobe, believed important in
tactile memory.

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• the posterior parietal lobe is behind S-I and consists of areas 5 and 7.
• Area 5 integrates= tactile input from mechanoreceptors of the skin with
proprioceptive input from muscles and joints.
• Area 7 integrates =stereognostic and visual information from visual, tactile,
and proprioceptive input.
• these processing areas analyze and integrate somatosensory information and
contribute to motor performance by
• (1) determining the initial position required before a movement occurs,
• (2) error detection as movement occurs, and
• (3) identification of movement outcomes, which helps to shape learning.

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The sensory homunculus:
• (somatotopic map) represents a cross-sectional view through the postcentral gyrus and
identifies the relative size of the cortex devoted to specific body parts (Fig. 3.6B).
• Note that certain areas of the body are exaggerated such as the hand, face, and
mouth owing to greater innervation density of the skin.
• The relative size of body parts represents both the density of sensory input from the
body region as well as the importance of sensory information from the area as it relates
to function.
• For example, the relative size of the foot is reflective of its importance in
locomotion; the relative size of the index finger reflects its role in fine motor
skills.
• In contrast, cortical areas for the trunk and back are small, implying a lower receptor
density and reduced role in sensory perception related to function.
• Using two-point discrimination as an example, Bear et al74 provide an extraordinary
illustration of how our ability to perceive a stimulus varies remarkably across the body
• Two-point discrimination varies at least twentyfold across the body.

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■ SCREENING:
• An important component of physical therapy intervention is to accurately and
efficiently meet individual patient needs.
• Together with information from the history and review of systems,
screenings assist the therapist in proficiently identifying the needed tests and
measures and setting priorities within the examination process.
• Screenings consist of a series of brief tests that provide the therapist an “overview”
of the system of interest (e.g., musculoskeletal, neuromuscular).
• Within this context, screenings are conducted to
• • Determine the need for further or more detailed examination
• • Determine in a timely manner if referral to another health care practitioner is
warranted
• • Focus the search for the origin of symptoms to a specific location or body part
• • Identify system-related impairments that contribute to activity limitations or
disability

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• To perform a sensory screening, several easily tested (i.e., requiring little or
no specialized equipment) modalities of sensation are selected.
• It is important to select modalities from each of the general categories of
sensations. For example, the therapist might
• select pain and light touch (superficial),
• kinesthesia and vibration (deep),
• and two-point discrimination or stereognosis (combined)
• Sensory screening is performed by using the selected modalities to test
randomly over somewhat large surface areas.
• For example, several applications of each stimulus might be distributed
over the upper and lower extremities and trunk.
• the information gathered informs the therapist’s decision making.

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• For example, if sensory impairments are identified it may
• (1) indicate the need for more detailed testing,
• (2) help narrow the origin of symptoms, or
• (3) provide insight into the cause of activity limitations.
• As mentioned earlier, screening tests for mental status (arousal, attention,
orientation, cognition, and memory), vision, and hearing acuity should be
performed prior to the sensory examination

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■ SCREENING:
• Within this context, screenings are conducted to:
• • Determine the need for further or more detailed examination
• • Determine in a timely manner if referral to another health care practitioner is
warranted
• • Focus the search for the origin of symptoms to a specific location or body part
• • Identify system-related impairments that contribute to activity limitations or disability

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PREPARATION FOR ADMINISTERING THE
SENSORY EXAMINATION
• Before initiating the examination of sensory function,
1. the testing environment should be identified and prepared,
2. needed equipment gathered,
3. consideration given to patient preparation (i.e., what information
and instruction will be provided).

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Testing Environment:
• the sensory examination should be administered in a quiet, well-lighted
area.
• Depending on the number of body areas to be tested, either a sitting or
recumbent position may be used.
• If full body testing is indicated, both prone and supine positions will be
required and use of a treatment table is recommended to allow
examination of each side of the body.
• Equipment To perform a sensory examination the following equipment
and materials are used:

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• 1. Pain.
• A large-headed safety pin or a large paper clip that has one segment bent open (providing one
sharp and one dull end).
• the sharp end of the instrument should not be sharp enough to risk puncturing the skin.
• If a large-headed safety pin is used, the sharp end may be further blunted by a light sanding.
• Commercially available single-use protected neurological pins may also be used (Fig. 3.7).
• 2. Temperature.
• Two standard laboratory test tubes with stoppers.
• Tip Therm is an early detection tool for identification of changes in thermal perception
designed for monitoring polyneuropathy associated with diabetes (F

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• 3. Light touch.
• A camel-hair brush, a piece of cotton, or a tissue.
• 4. Vibration.
• Tuning fork and earphones (if available, to reduce auditory clues).
• Tuning forks are made of steel or magnesium alloy and grossly resemble a two-pronged fork.
• When the tines are stuck against a surface (usually the palm of the examiner’s hand) the fork
resonates at a specific pitch (e.g., 128, 256, or 512 Hz) determined by the length of the two U-
shaped prongs (tines).
• 5. Stereognosis
• (object recognition). A variety of small, commonly used articles such as a comb, fork, paper clip,
key, marble, coin, pencil, and so forth.
• 6. Two-point discrimination.
• Several instruments are available to measure two-point discrimination.
• A two-point discrimination aesthesiometer (Fig. 3.9) is a small handheld instrument designed to
measure the shortest distance that two points of contact on the skin can be distinguished.
• It consists of a small ruler with one stationary and one moveable (sliding) tip coated with vinyl.
• The vinyl coverings help to minimize the impact of temperature on perception of contact.
• Some instruments also have a third tip allowing ease of alternating from two points to a single
point of contact during testing.
• If used on an uneven body surface, care should be taken not to allow the “ruler” portion of the
instrument to make contact with the skin.

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• the term aesthesiometeis not specific to this instrument;
• it is used to describe any number of instruments designed to examine touch
perception.
• For finer gradations in measurement (e.g., fingertips),
• small circular disks can be used to measure two-point discrimination (Fig. 3.10).
these instruments typically allow quantification of two-point discrimination
from 1 to 25 mm.
• 7. Recognition of texture.
• Samples of fabrics of various texture such as cotton, wool, burlap, or silk

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Patient Preparation:
• A full explanation of the purpose of the testing should be provided.
• the patient also should be informed that cooperation is necessary to obtain accurate
test results.
• It is of considerable importance that the patient be requested not to guess if uncertain
of the correct response
• During the examination, the patient should be in a comfortable, relaxed position.
• Preferably, the tests should be performed when the patient is well rested.
• Considering the high level of concentration required, it is not surprising that fatigue
has been noted to affect results of some sensory tests adversely.
• Note: A “trial run” or demonstration of each test should be performed just prior to
actual administration.
• this will orient the patient to the sensation being tested, what to anticipate, and what
type of response is required.
• the importance of this initial trial should not be underestimated.

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• If a practice trial is inadequately or not performed, what appears to be a sensory
impairment may in reality only be a reflection of the patient’s lack of
understanding of the testing protocol or how to respond to a stimulus.
• Some method of occluding the patient’s vision during the testing should be used
(vision should not be occluded during the explanation and demonstration).
• Visual input is prevented because it may allow for compensation of a sensory
deficit and thus decrease the accuracy of test results.
• the traditional methods of occluding vision are by use of a fabric blindfold (such
as those worn by travelers to sleep on an airplane), a small folded towel, or by
asking the patient to keep the eyes closed.
• these methods are practical in most instances.
• However, in situations of CNS dysfunction, a patient may become anxious or
disoriented if vision is occluded for a long period of time. In these situations, a
small screen or folder may be preferable as a visual barrier.
• Whatever method is used, it should be removed between the tests while
directions and demonstrations are provided.

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■ THE SENSORY EXAMINATION:
• The pattern superficial>deep>combined receptors should be examined.
• If a test indicates impairment of the superficial responses,
• some impairment of the more discriminative (deep
and combined) sensations also will be
noted and is a contraindication to
further testing (e.g., lack of touch sensation would be a
contraindication for testing stereognosis).
• that is, the primary modality of sensation (touch) must be
sufficiently intact to permit meaningful testing of cortical sensory function
(ability to identify objects placed in the hand).

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• For each sensory test, the following data should be gathered:
1. the modality tested
2. the quantity of involvement or body surface areas
affected (pattern identification)
3. the degree or severity of involvement
(e.g., absent, impaired, or delayed responses)
4. Localization of the exact boundaries of the sensory
impairment
5. The patient’s subjective feelings about changes in
sensation
6. the potential impact of sensory loss on function
(i.e., activity limitation, disability)

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• Knowledge of skin segment (dermatome) innervation by the dorsal roots and peripheral nerve
innervation (see Figs. 3.1 and 3.2) is required for making sound, accurate diagnostic and prognostic
judgments.
• they serve as critical references during testing as well as provide a framework for documenting results.
• Sensory tests are typically performed in a distal to
proximal direction.
• this progression will conserve time, particularly when dealing with localized lesions involving a single extremity,
where deficits tend to be more severe distally.
• It is generally not necessary to test every segment of each dermatome; testing general body areas
is sufficient.
• However, once a deficit area is noted, testing must become more discrete and the
exact boundaries of the impairment should be identified.
• A skin pencil may be useful to mark the boundaries of sensory change directly.
• this information should be transferred later to a sensory examination form, graphically presented
on a dermatome chart, and peripheral nerve involvement identified. Figure 3.11 presents a
sample Sensory Examination Form.
• A single documentation form applicable to the variety of patients seen in different practice
settings does not exist.
• Specialized centers or organizations have developed specific forms to examine sensory function (e.g.,
the American Spinal Injury Association (ASIA)

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However, the following are common elements of
sensory examination forms:
• (1) a dermatome chart to graphically display findings;
• (2) a grading scale
• (e.g.
• 0—absent;
• 1—impaired
• 2—normal;
• NT—not testable;
• so forth) to score patient perception of individual modalities; and
• (3) a section for narrative comments.
• Most often the dermatome charts are completed using a color code (i.e., each color represents a different sensory modality).
• the colors used to plot each sensation are then coded by the examiner directly on the form (see Fig. 3.11).
• In many instances hatch marks of varying density are used to represent gradations in sensory impairment (i.e., the closer
together, the greater the sensory impairment).
• With this method, a completely colored in area indicates no response to a given sensation.
• With varied or “spotty” sensory loss it is not uncommon that more than one dermatome chart is required to completely
depict all test findings.
• With use of several dermatome charts, the sensation(s) represented should appear in bold print at the top of each page.
• Figure 3.11 provides the foundational elements of documentation typically included for sensory examinations.
• It should be modified or expanded to meet the needs of a given population or facility.
• It is also not uncommon for therapists to included sensory testing data within the body of a narrative or progress report

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A)Superficial Sensations:
• 1) Pain Perception:
• this test is also referred to as sharp/dull discrimination and indicates function of protective sensation.
• To test pain awareness, the sharp and dull ends of a large headed safety pin, a reshaped paper clip (the
segment pulled away from the body of the paper clip provides a sharp end), or a single-use protected
neurological pin (see Fig. 3.7) are used.
• the instrument should be carefully cleaned before administering the test and disposed of
immediately afterward (owing to the protective cap on the neurological pin, cleaning is not required).
• the sharp and dull ends of the instrument are randomly applied perpendicularly to the skin.
• To avoid summation of impulses, the stimuli should not be applied too close to each other or in too rapid a
succession.
• To maintain a uniform pressure with each successive application of stimuli, the pin or reshaped paper clip
should be held firmly and the fingers allowed to “slide” down the pin or paper clip once in contact with the
skin.
• this will avoid the chance of gradually increasing pressure during application.
• the instrument used to test pain perception should be sharp enough to deflect the skin, but not puncture
it.
• Response
• the patient is asked to verbally indicate sharp or dull when a stimulus is felt.
• All areas of the body may be tested.

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2)Temperature Awareness:
• This test determines the ability to distinguish between warm and cool stimuli.
• Two test tubes with stoppers are required for this examination;
• one should be filled with warm water
• and the other with crushed ice.
• Ideal temperatures for cold are between 41°F (5°C) and 50°F (10°C) and for
warmth, between 104°F (40°C) and 113°F (45°C).
• Caution should be exercised to remain within these ranges, because exceeding these
temperatures may elicit a pain response and consequently inaccurate test results.
• The side of the test tube should be placed in contact with the skin
(as opposed to only the distal end).
• This technique provides sufficient surface area contact to determine the temperature.
• The test tubes are randomly placed in contact with the skin area to be tested.
• All skin surfaces should be tested

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Response:
• the patient is asked to reply hot or cold after each stimulus
application.

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3) Touch Awareness:
• this test determines perception of tactile touch input.
• A camel-hair brush, piece of cotton (ball or swab), or tissue is used.
• The area to be tested is lightly touched or stroked.
• Examination of finer gradations of light touch can be quantified using monofilaments (see
later section titled Quantitative Sensory Testing and Specialized Testing Instruments)
• Response
• The patient is asked to indicate when he or she recognizes that a stimulus has been applied by responding
“yes” or “now.”
• Note: A quantitative score for pain perception, temperature, and light touch awareness can be
obtained by dividing the number of correct responses by
the number of stimuli applied(normal response would be 100%).
• Also, inability to verbally communicate does not necessary preclude obtaining accurate data.
• For example, having the patient hold up one or two fingers might be used for dichotomous responses
(yes/no; hot/cold).
• Other options might include nodding the head, pointing to index cards containing printed responses;
or using hand gestures to indicate recognition of a stimulus

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4)Pressure Perception:
• the therapist’s fingertip or a double-tipped cotton swab is used to apply a firm
pressure on the skin surface.
• This pressure should be firm enough to indent the skin and to stimulate
the deep receptors.
• this test can also be administered using the thumb and fingers to squeeze the
Achilles tendon.
• Response The patient is asked to indicate when an applied stimulus is recognized
by responding “yes” or “now

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B)Deep Sensations:
• the deep sensations include kinesthesia, proprioception, and
vibration.
• Kinesthesia is the awareness of movement.
• Proprioception includes position sense and the awareness of joints at rest.
• Vibration refers to the ability to perceive rapidly oscillating or
vibratory stimuli.
• Although these sensations are closely related, they are examined individually.

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Kinesthesia awareness :
• this test examines awareness of movement.
• the extremity or joint(s) is moved passively through a relatively small range of
motion (ROM).
• Small increments in ROM are used as joint receptors fire at specific points throughout
the range.
• the therapist should identify the range of movement being examined (e.g., initial,
mid-, or terminal range).
• a trial run or demonstration of the procedure should be performed
•Response
• The patient is asked to describe verbally the direction (up, down, in, out, and so forth) and range
of movement in terms previously discussed with the therapist while the extremity is in motion.
• The patient may also respond by simultaneously duplicating the movement with the
contralateral extremity.

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2)Proprioceptive Awareness:
• This test examines joint position sense and the awareness of joints at rest.
• The extremity or joint(s) is moved through a ROM and held in a static position.
• Again, small increments of range are used.
• The words selected to identify the range of movement examined should be identified to
the patient during the practice trial (e.g., initial, mid-, or terminal range).
• As with kinesthesia, caution should be used with hand placements to avoid
excessive tactile stimulation.
• Response While the extremity or joint(s) is held in a static position by the therapist, the
patient is asked to describe the position verbally or to duplicate the position of the
extremity or joint(s) with the contralateral extremity (position matching).
• This test may also be performed unilaterally using the same extremity or joint(s);
• first held in position by the examiner,
• then returned to resting position, followed by active duplication of position by patient using the
same limb.

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3)Vibration Perception:
• this test requires a tuning fork that vibrates at 128 Hz.
• the ability to perceive a vibratory stimulus is tested by placing the base of a
vibrating tuning fork on a bony prominence (such as the sternum, elbow, or
ankle).
• the tuning fork base (the “handle” of the fork) is held between the examiner’s thumb
and index finger
• without making contact with the tines.
• The tines are then briskly hit against the open palm of the examiner’s opposite hand to
initiate the vibration.
• Care must be taken not to touch the tines, as this will stop the vibration.
• the base of the fork in then placed over a bony prominence.
• If vibration sensation is intact, the patient will perceive the vibration.
• If there is impairment, the patient will be unable to distinguish between a vibrating and
non vibrating tuning fork.

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• Therefore, there should be a random application of vibrating and non-
vibrating stimuli.
• Auditory clues can pose a challenge in obtaining accurate test results.
• Typically it is easy to hear the sound of the tines making vigorous contact with the
examiner’s hand to initiate the vibration.
• If the sound is not heard, it provides an easy indicator to the patient that
the next application will be non-vibrating.
• To minimize this effect, the vibration can be initiated for every stimulus application;
however, when a non-vibrating stimulus is desired, brief contact of the therapist’s
fingers on the tines will stop the vibration prior to placement on the skin.
• This, though, does not solve the problem of the auditory cues generated during
application of a vibrating stimulus.
• The best solution is use of sound occlusive earphones (the type worn by airport ground
workers).
• Unfortunately, such earphones are seldom available in a clinic setting.
• Response :
• The patient is asked to respond by verbally identifying or otherwise indicating if the stimulus
is vibrating or non-vibrating each time the fork makes contact.

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C)Combined Cortical Sensations:
• 1) Stereognosis :
• Perception his test determines the ability to recognize the form of objects by
touch (stereognosis).
• A variety of small, easily obtainable, and culturally familiar objects of differing size and
shape are required (e.g., keys, coins, combs, safety pins, pencils, and so forth).
• A single object is placed in the hand, the patient manipulates the object, and then
identifies the item verbally.
• The patient should be allowed to handle several sample test items during the
explanation and demonstration of the procedure.
• The patient is asked to name the object verbally.
• For patients with speech impairments, sensory testing shields can be used (Fig. 3.12).
Alternatively, the item manipulated can be identified from a group of images
presented after each test.

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2)Tactile Localization
• This test determines the ability to localize touch sensation on the skin (topognosis).
• the patient is asked to identify the specific point of application of a touch stimulus (e.g., tip
of ring finger, lateral malleus, and so forth) and not simply the perception of being touched.
• Tactile localization is typically not tested in isolation and frequently examined in
combination with similar tests such as pressure perception or touch awareness.
• Using a cotton swap or fingertip, the therapist touches different skin surfaces.
• After each application of a stimulus the patient is given time to respond.
• Response the patient is asked to identify the location of the stimuli by pointing to the area or
by verbal description.
• the patient’s eyes may be open during the response component of this test.
• The distance between the application of the stimulus and the site indicated by the patient
can be measured and recorded.
• Accuracy of localization over Various parts of the body may be compared to determine the
relative sensitivity of different areas.

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3) Two-Point Discrimination:
• This test determines the ability to perceive two points applied to the skin
simultaneously.
• It is a measure of the smallest distance between two stimuli (applied
simultaneously and with equal pressure) that can still be perceived as two
distinct stimuli.
• Two-point discrimination values vary for different individuals and body parts.
• As this sensory function is most refined in the distal upper extremities, this is the
typical site for testing. It is believed to contribute to precision grip movements
and instrumental activities of daily living (IADL).

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• As mentioned earlier, the aesthesiometer (see Fig. 3.9) and the circular two-
point discriminator are among the most common devices used for
measurement.
• Two reshaped paper clips can also be used; however, this requires the
assistance of a second examiner to measure the distance between the two
points using a small ruler.
• During the test procedure the two tips of the instrument are applied to the
skin simultaneously with tips spread apart.
• To increase the validity of the test, it is appropriate to alternate the application
of two stimuli with the random application of only a single stimulus (the
purpose of the third tip on some aesthesiometers).
• With each successive application, the two tips are gradually brought closer
together until the stimuli are perceived as one. he smallest distance between
the stimuli that is still perceived as two distinct points is measured.
• Response :
• The patient is asked to identify the perception of “one” or “two” stimuli.

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4)Double Simultaneous Stimulation:
• this test determines the ability to perceive simultaneous touch stimuli (double
simultaneous stimulation [DSS]).
• the therapist simultaneously (and with equal pressure)touches:
• (1) identical locations on opposite sides of the body,
• (2) proximally and distally on opposite sides of the body, and/or
• (3) proximal and distal locations on the same side of the body.
• The term extinction phenomenon is used to describe a situation in which only the
proximal stimulus is perceived, with “extinction” of the distal.
•Response
• The patient verbally states when he or she perceives a touch stimulus and the number of
stimuli felt.

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Note:
• However, these tests are usually not performed if stereognosis and
two-point discrimination are found to be intact
• Several additional tests for the combined (cortical) sensations include
1. graphesthesia (traced finger identification),
2. recognition of texture,
3. barognosis (recognition of weight).

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5) Graphesthesia:
• (Traced Figure Identification) This test determines the ability to recognize letters,
numbers, or designs “written” on the skin.
• Using a fingertip or the eraser end of a pencil, a series of letters, numbers, or shapes
is traced on the palm of the patient’s hand.
• During the practice trial, agreement should be reached about the orientation of the
tracings. (For example, the bottom of the traced figures will always be oriented toward
the base of the patient’s hand [wrist].)
• Between each separate drawing the palm should be gently wiped with a soft cloth to
clearly indicate a change in figures to the patient.
• This test is also a useful substitute for stereognosis when paralysis prevents grasping
an object.
• Response
• The patient is asked to identify verbally the figures drawn on the skin.
• For patients with speech or language impairments, the figures can be selected (pointed to) from a
series of line drawings.

DR.AMMAR
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5) Recognition of Texture
• This test determines the ability to differentiate among various
textures.
• Suitable textures may include cotton, wool, burlap, or silk. The items
are placed individually in the patient’s hand.
• The patient is allowed to manipulate the sample texture.
• Response
• the patient is asked to identify the individual textures as they are placed in
the hand.
• They may be identified by name (e.g., silk, cotton) or by texture (e.g., rough,
smooth).

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6) Barognosis (Recognition of Weight):
• This test determines the ability to recognize different weights.
• A set of discrimination weights consisting of small objects of the same size and
shape but of graduated weight is used (Fig. 3.13).
• The therapist may choose to place a series of different weights in the same
hand one a simultaneously, or ask the patient to use a fingertip grip to pick up
each weight.
• Response
• The patient is asked to identify the comparative weight of objects in a series (i.e., to
compare the relative weight of the object with the previous one);
• or when the objects are placed (or picked up) in both hands simultaneously the patient
is asked to compare the weight of the two objects.
• The patient responds by indicating that the object is “heavier” or “lighter. t a time, place
a different weight in each hand

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• Clinical Note:
• Impaired sensation is a contraindication to or precaution for use of
some physical agents because the end range of intensity or duration
is frequently associated with the patient’s subjective report of how
the intervention feels (i.e., patient tolerance).

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■ CRANIAL NERVE SCREENING:
• Screening tests for the cranial nerves provide information about location of
dysfunction within the brainstem as well as identification of cranial nerves that require
more detailed examination.
• Data generated may include function of muscles innervated by the cranial nerves;
visual, auditory, sensory, and gag reflex integrity; perception of taste; swallowing
characteristics; eye movements; and constriction and dilation patterns of the pupils.
• Table 3.3: provides a summary of the functional components of the cranial nerves.
• Box 3.5 presents screening tests for each cranial nerve. Impairments noted during the
screening indicate that a more comprehensive examination is warranted.
• Examination of Motor Function: Motor Control and Motor Learning, for additional
information on cranial nerve examination.

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■ QUANTITATIVE SENSORY TESTING AND
SPECIALIZED TESTING INSTRUMENTS:
• With the expanding availability of specialized testing systems and instruments,
quantitative sensory testing (QST) has gained considerable clinical and research
interest.
• This is clearly evident from the expanding body of literature on this topic.
• QST allows quantification of the level of stimuli required for perception of a sensory
modality.
• Although sufficient data are not available to predict the ultimate integration of QST
instrumentation into clinical practice, preliminary information suggests its potential
usefulness.
• this section provides a brief overview of selected QST devices and is certainly not
all-inclusive.
• the Internet provides a rich source of information on this developing technology and
instrumentation.

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TSA-II Thermal Sensory Analyzer + VSA 3000
(Medoc, Ltd., Durham, NC)
• This computer-controlled system (Fig. 3.14) is capable of generating and recording a response to
repeatable vibratory and thermal stimuli (i.e., warmth, cold, heat- or cold-induced pain).
• For testing thermal sensation, a “thermode” capable of heating or cooling is placed on the
patient’s skin (Fig. 3.15).
• The patient is asked to respond to the stimulus by pushing a response button
• A sensory threshold is recorded and a computer comparison to age-matched normative data is
generated.
• The system includes hand and foot
• (Fig. 3.16) support vibratory stimulators as well as a handheld vibrating device (see Fig 3.14).
• A variety of report formats can be generated; a sample is presented in Figure 3.17.
• Several examples of clinical applications include
• neuropathies (e.g., diabetic, metabolic, cancer),
• compression injuries, and
• pharmacological trials.
• von Frey Aesthesiometer (Somedic Sales AB, Hörby, Sweden) Monofilaments are not new to examination of
sensory function and are actually considered a classic tool

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von Frey Aesthesiometer (Somedic Sales AB,
Hörby, Sweden):
• Monofilaments are not new to examination of sensory function and are actually considered a
classic tool for measuring touch-evoked potentials (Fig. 3.18).
• they are designed to detect very small changes in touch threshold.
• The filaments are available as sets, in various sizes (i.e., thicknesses), with each mounted on a
handle.
• The force required for bending the monofilament increases from 0.026 g for the first handle
to 100 g for the last (pressure range of between 5 g/mm2 and 178 g/mm2).
• The filaments are applied individually to the patient’s skin until it bends; each filament
providing a specific amount of force (thicker filaments are used if the thinner are not
perceived).
• With vision occluded, the patient responds “yes” when a stimulus is felt.
• The filaments are held perpendicular to the skin and application is usually repeated three
times at each testing site.
• Monofilaments are frequently used in hand rehabilitation clinics;
• other examples of clinical applications include neuropathies (e.g., diabetic) and peripheral
nerve injuries.

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Touch-Test Sensory Evaluator (North Coast
Medical, Inc., Morgan Hill, CA):
• Individual monofilaments are also available in increments ranging from 0.008 to
300 g (Fig. 3.19).
• these instruments are convenient and can be carried in a pocket.
• the handle opens to a 90° angle for testing; when folded it protects the
monofilament when not in use.

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Rydel-Seiffer 64/128 Hz Graduated Tuning
Fork (US Neurologicals, Kirkland, WA):
• This quantitative tuning fork contains small scaled weights on the distal ends of
the two prongs converting it from 128 to 64 Hz (Fig. 3.20).
• The two triangles move closer together and their intersection moves upward
as the intensity of vibration decreases.
• The intensity where the patient no longer perceives the vibration is recorded
as the number adjacent to the intersection of the triangles.
• This instrument allows more sensitive and specific testing for detecting sensory
changes as compared to qualitative tuning forks and has demonstrated high
intertester and intratester reliability.

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Bio-thesiometer (Bio-Medical Instrument Co,
Newbury, OH):
• this instrument is designed to quantitatively measure threshold
perception of a vibratory stimulus (Fig. 3.22).
• the stimulus is applied using a handheld device applied to the skin.
• Intensity of stimulation can be preset or gradually increased until the
threshold is reached (or gradually lowered until no longer felt).

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Vibrameter (Somedic Sales AB, Hörby,
Sweden):
• the Vibrameter also quantitatively measures the perception of vibration (Fig
3.23).
• Standardized test points have been identified for use with this instrument.
• The test points (e.g., dorsum of the metacarpal bone of index finger, first
metatarsal, and on tibia) allow for ease of comparison and interpretation of
results.
• The sites also represent relatively long neural pathways for transmission to the
CNS.
• Stimulus is applied using the handheld device.

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SENSEBox (Somedic Sales AB, Hörby, Sweden):
• This instrument measures pain thresholds (algometer) and touch evoked
potentials (von Frey transducer).
• It determines the relationship between the intensity of controlled mechanical
stimuli and patient response.
• Handheld transducers are used to apply the stimuli (Fig. 3.24A and B).
• Patient responses are recorded using a handheld pushbutton device or a
continuous electronic visual analog scale (VAS).
• During examination, data are automatically stored in a computer database

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MSA (Modular Sensory Analyzer) hermotest
(Somedic Sales AB, Hörby, Sweden):
• the MSA Thermotest (Fig. 3.25) measures response to thermal (warm and
cold) stimuli.
• thermodes of different sizes allow testing of various anatomical locations.
• A computer interfaces using SenseLab software that sets up and runs the
Thermotest, and allows for analysis and storage of data.
• Temperatures range from 41° to 125.6°F (5° to 52°C).

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