Is there a cognitive impairment in MND? A survey with longitudinal data.

Twenty-nine patients affected by motor neuron disease (MND) were investigated with the Raven Progressive Matrices, a test of logical non verbal intelligence, requiring neither motor nor verbal skills. The score distribution of the MND patients did not differ from that of 321 controls. Eleven of these patients were retested after a mean interval of 8.5 months. The resulting differences in the test scores showed that their intellectual performance had not worsened over time. Even allowing for the limitations posed by the use of a single test, these data add to the evidence against systematic cognitive involvement in MND.