Executive function and gait in older adults with cognitive impairment.
BACKGROUND
Cognitive impairment has been shown to predict falls risk in older adults. The ability to step accurately is necessary to safely traverse challenging terrain conditions such as uneven or slippery surfaces. However, it is unclear how well persons with cognitive impairment can step accurately to avoid such hazards and what specific aspects of cognition predict stepping ability in different patient populations.


METHODS
Healthy older adults (NC), patients with Mild Cognitive Impairment with only memory impairment (MCI-EF) or memory and executive function impairments (MCI+EF) and early Alzheimer's patients (AD) were timed as they performed a stepping accuracy test with increasing cognitive demand (Walking Trail-Making Test; W-TMT), which required stepping on instrumented targets with either increasing sequential numbers (W-TMT A) or alternating sequential numbers and letters (W-TMT B).


RESULTS
After accounting for age and baseline walking speed, the AD and MCI+EF groups were significantly slower than the NC and MCI-EF groups on the task with the highest cognitive demand, W-TMT B (interaction effect F = 6.781, p <.0001). No group differences were noted on the W-TMT A task that was less cognitively demanding. Neuropsychological measures of executive functioning were associated with slower W-TMT B performance, whereas memory, visual attention and visual spatial skills were not (adjusted R(2) = 0.42).


CONCLUSIONS
Executive function is important for stepping performance, particularly under more complex environmental conditions.
Persad
Carol C
CC
Department of Psychiatry, University of Michigan, Ann Arbor, MI 48105, USA. cpersad@umich.edu
Jones
Joshua L
JL
Ashton-Miller
James A
JA
Alexander
Neil B
NB
Giordani
Bruno
B
D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology; D003072:Cognition Disorders / Q000503:physiopathology*; D005260:Female; D005684:Gait / Q000502:physiology*; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000503:physiopathology; D008875:Middle Aged; D009483:Neuropsychological Tests