PATTERNS OF COGNITIVE IMPAIRMENT IN RELAPSING-REMITTING MULTIPLE-SCLEROSIS AND THEIR RELATIONSHIP TO NEUROPATHOLOGY ON MAGNETIC-RESONANCE IMAGES

Several reviews (J. M. Peyser & C. M. Poser, 1986; S. M. Rao, 1986) ha ve suggested that multiple sclerosis (MS) results in cognitive impairm ent in learning and memory, abstract reasoning, information-processing efficiency, and often visual-spatial ability. MS patients may undergo idiosyncratic cognitive changes dependent on the site of white matter lesions. In the present study, researchers used cluster analysis on t he neuropsychological data from a group of mildly disabled relapsing-r emitting MS patients (n = 177) and a well-matched control group (n = 8 9). In those MS patients identified with unequivocal cognitive impairm ent, the majority clustered into groups with a specific deficit in 1 o r 2 areas of cognitive functioning, with normal performance in others. On magnetic resonance imaging, an association was obtained between 2 lesion sites and 2 cognitive tests. Impairment in visual-spatial abili ty, as assessed by the Benton Visual Retention Test, was associated wi th lesions in the genu of the corpus callosum (CC) and with more lesio ns throughout the CC. Impaired performance on Paired Associates, a tes t of learning and memory, was associated with a lesion in the deep whi te matter of the left parietal lobe. The findings support the hypothes is that MS results in multiple patterns of cognitive impairment that d epend on the individual placement of white matter lesions.