Below is a recursive version of this function.
<?php
function array_change_key_case_recursive($input, $case = null){
if(!is_array($input)){
trigger_error("Invalid input array '{$array}'",E_USER_NOTICE); exit;
}
if(null === $case){
$case = CASE_LOWER;
}
if(!in_array($case, array(CASE_UPPER, CASE_LOWER))){
trigger_error("Case parameter '{$case}' is invalid.", E_USER_NOTICE); exit;
}
$input = array_change_key_case($input, $case);
foreach($input as $key=>$array){
if(is_array($array)){
$input[$key] = array_change_key_case_recursive($array, $case);
}
}
return $input;
}
?>