Magnetic resonance imaging and clinical correlates of intellectual impairment in myotonic dystrophy
S. J. Huber, J. T. Kissel, E. C. Shuttleworth, D. W. Chakeres, L. E. Clapp and M. A. Brogan
Department of Neurology, Ohio State University, Columbus 43210.
Although intellectual impairment is common in patients with myotonic
dystrophy, this aspect of the disease has received relatively little
research attention. We examined 41 patients with myotonic dystrophy using
objective neuropsychological procedures and magnetic resonance imaging. Ten
patients (24%) had severe and generalized intellectual dysfunction, while
lesser or no cognitive impairment characterized the remaining patients.
Degree of intellectual impairment was not related to neuromuscular status
or sex. Patients with severe intellectual disturbance had significantly
earlier onset of both myotonia and weakness and were more likely to inherit
the disease from their mother. Magnetic resonance imaging findings
indicated that while degree of cerebral atrophy was not related to severity
of intellectual impairment, skull thickness, focal white matter lesions,
and anterior temporal lobe abnormalities were significantly more common in
patients with severely disturbed intellect. This study reports a number of
previously unreported cerebral magnetic resonance imaging findings
associated with intellectual impairment in myotonic dystrophy, but the
etiology of these changes awaits neuropathologic examination.
