Ideomotor apraxia in Huntington's disease
P. A. Shelton and D. S. Knopman
Section of Neurology, University of Manitoba, Winnipeg, Canada.
The pattern of movement errors in ideomotor apraxia suggests an abnormality
in selection and sequencing of component movements. Individuals with
Huntington's disease were evaluated prospectively for the presence of
apraxia, and aspects of motor and cognitive function were correlated with
apraxic errors. Based on a conservative apraxia rating, ideomotor apraxia
occurred in three (33%) of nine patients with a mean duration of disease of
10.4 years. Only two (22%) individuals made no apraxic errors, however, and
the group as a whole made apraxic errors in 26% of movements. Apraxia was
associated with errors in imitation of nonsymbolic movements but not with
errors in recognition of gestures. It correlated significantly with
duration of disease and with progressive abnormalities of posture but not
with other individual aspects of elementary motor or cognitive function.
These associations indicate that apraxia in Huntington's disease may be due
primarily to involvement of subcortical motor structures rather than
cerebral cortex.
