CRYOGENIC SURGERY IN THE GERIATRIC PATIENT*

Patterns of psychological function before, after unilateral, and after bilateral thalamic surgery

Visual-perceptual, verbal, and short-term retention tests were administered to unilaterally operated, bilaterally operated, and unoperated parkinsonian patients. Principal component factor analyses derived for each group yielded 4 factors regardless of treatment condition. Similarities between groups pointed to consistency and overlapping among factor patterns obtaining in the presence or absence of subcortical surgery. Variations among factor structures suggested that unoperated patients are characterized by a gross, wholistic approach to perceptual-cognitive tasks. Bilaterally operated individuals show more concern with detail and specific aspects in their perceptual-cognitive style. Unilateral brain operates occupy an intermediate position. Implications for behavioral activation and the relevance of diffuse bilateral subcortical systems were emphasized.