Pathological association and dissociation of functional systems in multiple sclerosis and Huntington's disease

This study examined pathological associations and dissociations of functional cognitive systems in patients with multiple sclerosis and Huntington's disease. Using the subtests of the WAIS-R, two motor tests, and the word fluency test, the intertest correlations showed distinct patterns. In comparison to normals, the two clinical groups exhibited a greater degree of association among the tests. Subsequently, word fluency performance was predicted from these tests. For the normals, the overall predictive power was quite low (7%). For the MS group, the predictive power rose to 28%. For the HD group, the predictive power was 50%. These results suggest that pathological association of functional systems may be a marker of brain dysfunction and that the affected systems may be delineated by these methods.