Critical decline in fine motor hand movements in human aging.
BACKGROUND
Slowing of motor movements in human aging is a well-known occurrence, but its biologic basis is poorly understood. Reliable quantitation may refine observations of this phenomenon to better aid research on this entity.


METHODS
A panel equipped with timing sensors under computer control was used to measure upper extremity movement times in two groups of healthy individuals: adults younger than 60 years of age (n = 56; range, 18-58 years) and adults older than 60 years of age (n = 38; range, 61-94 years).


RESULTS
Fine motor performance was better in the dominant hand (p = 0.0007) regardless of age. Adult and aged groups differed on two basic timing measures, which reflect coarse motor and fine motor performance (p < 0.0001). There were no gender differences on either measure. There was a strong effect of task difficulty with age on coarse motor (p < 0.01) and fine motor (p < 0.0001) measures. The fine motor measure of hand performance in healthy individuals correlated in a nonlinear fashion with age for more difficult tasks (r2 = 0.63) but showed a simple linear relation for less-demanding tasks (r2 = 0.5).


CONCLUSIONS
This technique sensitively detects age-related motor performance decline in humans. There may be a critical period in late midlife when fine motor performance decline either begins or abruptly worsens.
Smith
C D
CD
Department of Neurology, Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, USA. csmith@mri.uky.edu
Umberger
G H
GH
Manning
E L
EL
Slevin
J T
JT
Wekstein
D R
DR
Schmitt
F A
FA
Markesbery
W R
WR
Zhang
Z
Z
Gerhardt
G A
GA
Kryscio
R J
RJ
Gash
D M
DM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D012044:Regression Analysis