COGNITIVE AND MEMORY DEFICITS IN UNTREATED PARKINSONS-DISEASE AND AMYOTROPHIC-LATERAL-SCLEROSIS PATIENTS - A COMPARATIVE-STUDY

We investigated the profile of cognitive and memory deficits of 22 Par kinson's disease (PD), 24 amyotrophic lateral sclerosis (ALS) patients and 26 age-matched controls. The patients were at the early phase of the disease and untreated. The ALS patients exhibited deficits in simp le visuoperceptual functions and in complex visuoperceptual reasoning (Digit Symbol and Block Design tests), whereas the PD patients showed deficits only in simple visuoperceptual functions. Moreover, both ALS and PD patients had impairment in tasks requiring set shifting from on e reaction to another that may suggest frontal lobe dysfunction. The A LS and PD patients also showed impairment in the task of learning a wo rd list with effort-demanding organization of the material to be remem bered. However, preserved delayed recall of logical passages suggests that memory, per se, is not impaired in ALS or in PD. The patterns of errors in a test of recognition of learned words imply, at least parti ally, different underlying deficits in the two diseases. An inability to inhibit irrelevant information may contribute to memory impairment in ALS patients, whereas the memory deficit in PD may derive from lowe red motivation or initiating behaviour.