Motor dysfunction in mildly demented AD individuals without extrapyramidal signs.
BACKGROUND
Although not as prominent as cognitive decline, motor dysfunction occurs in AD, particularly in the later stages of the disease.


OBJECTIVE
To determine whether early-stage AD is also characterized by motor impairment.


METHODS
We examined very mildly (Clinical Dementia Rating [CDR] 0.5) and mildly (CDR 1) demented AD individuals in comparison with healthy elderly control individuals (CDR 0) on a variety of nonmotor cognitive and psychomotor measures and on four motor measures (gait velocity, finger tapping, reaction time, movement time). To minimize the possibility of extrapyramidal dysfunction contaminating the groups, only individuals who were clinically free of extrapyramidal signs were included in the study.


RESULTS
Mildly demented AD individuals were slowed on all motor measures except for finger tapping. No evidence of motor dysfunction was found in the very mildly demented AD group. As expected, both AD groups were impaired on the nonmotor cognitive and psychomotor tests.


CONCLUSIONS
These results indicate that AD alone, in the absence of clinically confirmed extrapyramidal dysfunction, is associated with motor slowing in a stage-dependent manner. It remains to be determined whether this motor slowing represents a general characteristic of mild AD or indicates other neuropathology such as PD or the Lewy body variant of AD.
Goldman
W P
WP
Department of Neurology, Alzheimer's Disease Research Center, Washington University, St. Louis, MO 63110, USA.
Baty
J D
JD
Buckles
V D
VD
Sahrmann
S
S
Morris
J C
JC
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D009069:Movement Disorders / Q000503:physiopathology*; D009483:Neuropsychological Tests; D011930:Reaction Time