Motor dysfunction in mild cognitive impairment and the risk of incident Alzheimer disease.
BACKGROUND
Little is known about motor function in mild cognitive impairment (MCI) and its relation to the risk of Alzheimer disease (AD).


OBJECTIVE
To examine motor function in persons with MCI and its relation to risk of AD.


METHODS
Longitudinal cohort study.


METHODS
More than 40 Catholic religious orders across the United States.


METHODS
We studied 816 older Catholic clergy members from the Religious Orders Study. At the baseline evaluation, they were classified as having no cognitive impairment (n = 558), MCI (n = 198), or dementia (n = 60).


METHODS
Motor function was assessed at baseline using performance-based measures of upper and lower extremity function and a modified version of the motor section of the Unified Parkinson's Disease Rating Scale, from which previously established measures of parkinsonian signs were derived. Clinical evaluations for dementia and AD were repeated annually for up to 10 years. All analyses controlled for age, sex, educational level, and possession of at least 1 apolipoprotein E epsilon4 allele.


RESULTS
At baseline, individuals with MCI had impaired motor function relative to those without cognitive impairment and superior motor function vs those with dementia. Among those with MCI, baseline levels of lower extremity motor performance, parkinsonian gait, and bradykinesia were inversely related to risk of AD, even after controlling for clinical stroke. Thus, a person with impaired lower limb performance or parkinsonian gait (10th percentile) was 2 to 3 times more likely to develop AD than a person with good lower limb function (90th percentile).


CONCLUSIONS
Persons with MCI also have impaired motor function, and the degree of impairment in lower extremity function is related to the risk of AD.
Aggarwal
Neelum T
NT
Rush Alzheimer's Disease Center, Rush Institute for Healthy Aging, Rush University Medical Center, Chicago, IL 60612, USA. neelum_t_aggarwal@rsh.net
Wilson
Robert S
RS
Beck
Todd L
TL
Bienias
Julia L
JL
Bennett
David A
DA
D000367:Age Factors; D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000235:genetics; D053327:Apolipoprotein E4 / Q000235:genetics; D002977:Clergy / Q000706:statistics & numerical data; D003072:Cognition Disorders / Q000150:complications* / Q000453:epidemiology* / Q000235:genetics; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D004493:Education; D005260:Female; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009069:Movement Disorders / Q000453:epidemiology* / Q000209:etiology*; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology; D012307:Risk Factors; D012737:Sex Factors; D014481:United States / Q000453:epidemiology
D053327:Apolipoprotein E4