A psychometric study of chronic cerebellar stimulation in man

Groups of patients with intractable epilepsy or spasticity of varying etiologies underwent psychological testing before and during chronic cerebellar cortex stimulation, a neurosurgical technique designed for the relief of these symptoms. The battery of psychological tests permitted a standardized assessment of intellectual, memory, and perceptual functions. Other behavioral dimensions were assessed through structured interviews. No apparent declines in higher integrative functions followed shorter or longer term cerebellar stimulation. In contrast, stimulated patients tended to show increments in tests of recent memory and verbal output beyond that of unoperated comparison groups. Subjective reports of increased "alertness" and reduced depression and anxiety were also frequently given. Psychological and neural factors may both contribute to the observed behavioral alterations. It was concluded that the cerebellum participates in behavioral functions by modifying cortical and subcortical mechanisms relevant to integrative behavior and emotions. Specific hypotheses were presented.