The impact of lesion laterality on neuropsychological change following posterior pallidotomy: A review of current findings

This paper reviews seven studies evaluating the impact of lesion laterality on the neuropsychological sequelae of posterior pallidotomy for treatment of Parkinson's disease. Left lesions of the internal globus palllidus (GPI) were associated with subtle deficits on measures sensitive to frontal lobe function. The findings of a randomized clinical trial including a patient control group indicated that many of these deficits were transient, resolvi ng by 6 months following surgery. Right GPI lesions were not consistently a ssociated with neuropsychological deficit, except in one study that include d a significant proportion of demented patients. It is hypothesized that wh en neuropsychological decline is present following surgery, this reflects i mpingement of posterior GPI lesions into proximal regions such as anterior GPi or the external pallidum that participate in cognitive basal ganglia-th alamocortical circuits. The findings from neuroimaging will be important fo r elucidating the relationship between lesion locus and neuropsychological sequelae. (C) 2000 Academic Press.