Neuropsychological study of 12 patients with pure degenerative cerebellar disease

Introduction. The cerebellum has been traditionally associated with motor control learning and performance. However since 1970 a growing body of clinical and experimental evidences has suggested that the cerebellum may be involved in nonmotor cognitive functions as well. Objective. To explore the presence of eventual cognitive impairment in nondemented patients with isolated degenerative cerebellar diseases. Patients and methods. Twelve patients with the diagnosis of selective degenerative cerebellar disorders, either inherited or sporadic, were selected (mean age: 40.42 +/- 13.49 years; mean education level: 9.92 +/- 3.99 years; duration of illness: 12.13 +/- 11.27 years, MMSE: 26.75 +/- 1.5) and evaluated through a standardized neuropsychological tests battery. Normalized Z scores were estimated and compared against 0, employing the t test for one sample. Results. Significant cognitive deficits were found in the following domains: executive, visuo-spatial, memory and attention functions. Performance on the Wisconsin test showed a significative number of perseverative errors. Memory deficits included verbal learning and free recall difficulties, with good recognition of the material presented. Conclusions. The findings of this study are consistent with the role of the cerebellum as modulator of mental functions. The cognitive deficits resulting from cerebellar pathology may be related with the disruption of cerebello-cortical conexions involving a complex network which includes the prefrontal region, suggesting that the cerebellum may process cortical information coming from different areas linked with the control of cognition.