Cognition in aging

Cognition in Aging
Clifford Gonzales
CRNA, PhD

Cognition in Aging
• Identify cognitive functions
• List age-related changes in cognitive functions
• Identify activities promoting healthy cognitive
functions
• POCD vs POD
• Name precipitating variables of POCD
• Strategies minimizing POCD

Cognitive Functions
• Working memory
• Processing speed
• Inhibition
• Sensory system

Working Memory
• Store= 12 in; 2mmhg/in
• Processing= 12 x 2= 24 mmhg
• Store= 24mmhg
• Look at current blood pressure= 100/65 mmhg
• Retrieve the 24mmhg
• Processing= 100-24 and 65-24= 76/41
• Compare 20% threshold

Age-Related Changes
• Brain atrophy= 0.35% per year @ 50 y/o1
• Ventricular hypertrophy= 2.9% per year @ 70
y/o2
• Hippocampal atrophy= ave of <1 % (26-
82y/o)3
• Pruning of white matter

Age-Related Changes
• Mortimer JA, Snowdon DA, Markesberry WR.
Neuropsychology. 20031
• Scarmeas N, Albert SM, Manly JJ, Stern Y. J
Neurol Neurosurg Psychiatry. 20062

Cognitive Reserve Theory
Clinical
Expression
of
Cognitive
Impairment
CNS lesions
White matter lesions
Brain atrophy
Plaques & tangles
Vascular damage
Metabolic/endocrine
diseases
Injury
Influencing factors
Genes
Lifestyle factors
(education,
occupation,social,
physical, & leisure
activities)
Brain size and function
Neural network
density and complexity
Processing capacity
and efficiency
Premorbid Cognitive
ability
Other influences
on cognitive impairment
prevention
Personality
Health service delivery
and uptake
Richards M, Deary IJ. Annals of
Neurology. 20053

Healthy Cognitive Functions
Physical activity
150 min (moderate) or 75min (vigorous)
aerobic + muscle strengthening
• Decrease sympathetic stimulation
• Maintenance of brain structures4,5

Leisure Activity
• Activities more on life
satisfaction
• Productive vs
consumptive
• Effect on white matter6,7
• Associated with working
memory, episodic
memory, and processing
speed.

Socialization
• Associated with working
memory and processing
speed8

Cognitive Impairment
• Postoperative delirium- acute fluctuation of
the state of orientation and attention.
• Postoperative cognitive dysfunction- alteration
in learning, memory, abstract thinking, and
concentration after surgery.

Postoperative Cognitive Dysfunction
• Predisposing factors:
Age
Co-morbidities: presence of cognitive
impairment
• Precipitating factors
 Stress
 Cell injury

Cell Injury
• Precursors of Alzheimer’s dse
• Inflammatory
markers/receptors

Alzheimer’s Dse
Temperature
induced

Inflammatory Markers/Receptors
• Microglial activation-release of TNF-a
• NMDA receptors-protein changes
lead to spatial learning impairment

Neuroprotection vs Neurotoxicity
• Type of surgery
• Type of anesthesia
 RA vs GA
 Volatile vs intravenous
 Isoflurane vs Desflurane vs Sevoflurane
• Number of exposure to anesthesia

Type of Surgery
• Evered 2011- RCT, 644 participants

RA vs GA
• Mason 2010: systematic review with meta-analysis, 21
studies.
• Mandal 2011: RCT, 60 participants, GA vs EA.

Volatile vs Intravenous
• Chen 2014, retrospective, secondary analysis,
26,725 Taiwanese

Iso vs. Des vs. Sevo
• Ye 2013. Cell culture. Use of Iso, sevoflurane,
and propofol
• Zhang 2012. Pilot study, 15 per group,
Isoflurane, desflurane.

Reasons for Various Results
• Different neuropsychological tests
• Different design and methodology

Strategies
• Preoperative screening
• Hemodynamic monitoring- is 20% BP
threshold is applicable for older adults?
• Monitor oxygenation and ventilation
• Temperature regulation
• Use of BIS monitor

References
1. Mortimer JA, Snowdon DA, Markesberry WR. Head circumference, education, and risk of dementia: Findings from the Nun study. J Exp Psychol.
2003; 25(5): 671-679.
2. Scarmeas N, Albert SM, Manly JJ, Stern Y. Eudcation and rates of cognitive decline in incident of Alzheimer’s disease. J Neurol Neurosurg
Psychiatry. 2006; 77:308-316
3. Richards M, deary IJ. A life course approach to cognitive reserve: a model for cognitive aging and development. Annals of Neurol. 2005;58(4):617-
622
4. Colcombe SJ, Erickson KI, Raz N, et al. Aerobic fitness reduces brain tissue loss in aging humans. J Gerontol A. 2003; 58(2): 176-180
5. Erickson KI Prakash RS, Voss MW, et al. Aerobic fitness associated with hippocampal volume in elderly humans. Hippocampus. 2009; 19(10):
1030-1039.
6. N. A. Dennis and R. Cabeza, “Neuroimaging of healthy cognitive aging,” in Handbook of Aging and Cognition, F. I. M. Craik and T. A. Salthouse,
Eds., pp. 1–54, Psychology Press, New York, NY, USA, 3rd edition, 2008.
7. Sullivan EV, Pfefferbaum A, Adalsteinsson E, Swan GE, Carmelli D. Differential rates of regional brain change in callosal and
ventricular size: a 4-year longitudinal MRI study of elderly men. Cereb Cortex. 2002; 12(4): 438-45
8. Bigler ED, Blatter DD, Anderson CV, Johnson SC, Gale SD, Hopkins RO, Burnett B. Hippocampal volume in normal aging and traumatic brain injury.
AJNR. 1997; 18: 11-23.
9. Saczynski JS, Jonsdottir MK, Sigurdsson S, Eiriksdottir G, Jonsson PV, Garcia ME, et al. White matter lesions and cognitive performance: the role of
cognitively complex leisure activity. J Gerontol A Biol Sci Med Sci. 2008; 63(8): 848-854.
10. Gow AJ, Bastin ME, Phil D, Maniega SM, Hernandez V, Morris Z, Murray C, et al. Neuroprotective lifestyles and aging brain. Neurology.
2012;79(17): 1802-1808.
11. Ybarra O, Burnstein E, Winkielman P, Keller M, Mannis M, Chan E, Rodriguez J. Mental exercising through simple socializing: social interactions
promotes general cognitive functioning. Pers Soc Psychol Bull. 2008;34(2): 248-259.
12. Xiao-dong Z. Mei-hua P, Yan-shu W, Chun-sheng F. Influence of sub-anesthetic dose of ketamine and dexmedetomidine on early postoperative
cognitive dysfunction in elderly orthopedic patients under total intravenous anesthesia. Journal of Jilin University. 2013

Cognition in aging

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