Relation of neuropsychological and magnetic resonance findings in amyotrophic lateral sclerosis: evidence for subgroups

The relationship between neuropsychological impairments and changes in cranial MR images was investigated in a group of 74 consecutive patients with the sporadic form of amyotrophic lateral sclerosis (ALS). Neuropsychological tests included measures of frontal lobe function, memory, intelligence, and attention. Compared with a control group, a significant impairment of the ALS group emerged for the areas of visual attention, inhibition of response alternatives, visual memory, and word generation. These neuropsychological impairments did not show a relation to clinical status of the patients. Likewise, MR parameters derived by computer assisted planimetric analysis showed a ventricular enlargement and parenchymal atrophy in the ALS group compared with age-matched controls. When ALS patients were assigned to two subgroups differing on the basis of the neuropsychological tests by cluster-analysis the cluster with the significant impairment also showed a pronounced change for the MR-parameters while the subgroup showed essentially normal neuropsychological performance. This pattern suggests that subgroups of ALS with differential impairment of neuropsychological functions can be defined.