Cognitive impairments in advanced PD without dementia.

OBJECTIVE: To determine the nature and frequency of cognitive impairments in nondemented patients with advanced PD and their relationship to other variables potentially predictive of neuropsychological performance. METHODS: The neuropsychological performance of nondemented, nondepressed patients with idiopathic PD (n = 61) was quantified with respect to clinically available normative data. The relationship of neuropsychological measures to motor symptoms, age, years of education, disease duration, age at disease onset, disease deterioration rate, and dopaminergic therapy was assessed. RESULTS: Impairment was most frequent on measures sensitive to frontal lobe function (67% on Wisconsin Card Sorting Test number of categories, 30% on letter fluency, 30% on verbal learning). Poorer performance on multiple neuropsychological measures was related to greater overall motor abnormality (total Unified Parkinson's Disease Rating Scale score), increased bradykinesia on medication, older age, longer disease duration, and reduced education. CONCLUSIONS: Even in the absence of dementia or depression, patients with advanced PD are likely to show clinically significant impairments on neuropsychological measures sensitive to changes in dorsolateral prefrontal regions participating in cognitive basal ganglia-thalamocortical circuits.

Neuropsychological and psychiatric sequelae of pallidotomy for PD: clinical trial findings.

OBJECTIVE: To evaluate the neuropsychological and psychiatric sequelae of unilateral posterior pallidotomy for treatment of PD. METHODS: Patients with idiopathic PD completed baseline and 3- and 6-month assessments after random assignment to an immediate surgery (n = 17) or medical management (n = 16) group. RESULTS: Compared with the medical management group, the immediate surgery group with single lesions centered on the posterior internal pallidum showed superior naming and response inhibition, better verbal recall at 6 months, but greater distractibility, a tendency toward lower phonemic fluency, and a transient (3 months' only) semantic fluency deficit. The group with left lesions had more neuropsychological deficits than the group with right lesions or the medical management group, although these occurred mainly at 3 (but not 6) months. At 6 months, the patients with left lesions showed better verbal memory retention than the patients with right lesions. On most measures, the pattern of individual clinical change did not differ as a function of surgery or lesion laterality, with the exception of a higher frequency of decline in phonemic fluency in the patients with left lesions at 6 months. Although psychiatric status did not change overall, a history of depression tended to increase the risk of a depressive episode following surgery. CONCLUSIONS: Well-targeted, uncomplicated, unilateral pallidotomy does not produce overall neuropsychological or psychiatric change, although there are subtle changes on specific measures sensitive to frontal lobe function.

Event-related potential P3 change in mild Parkinson's disease.

The purpose was to determine if unmedicated, mildly affected patients with Parkinson's disease exhibited abnormality in the P3 component of the event-related potential, and whether such abnormality differed between younger and older patients. The study evaluated 10 younger (mean age = 43.7 years) and 10 older (mean age = 64.4 years) unmedicated patient volunteers diagnosed with idiopathic PD during the past 4 years and equal numbers of age-, gender-, and education-matched controls. The auditory oddball P3 was recorded, and P3 peak amplitude, peak latency, and the component score derived from principal components analysis were analysed. Neuropsychological measures focusing on frontal lobe and memory function were obtained. Although patients did not show neuropsychological deficits, they had significantly enlarged P3 amplitude measured at Cz (p < 0.01) or Pz (p < 0.01). The P3 amplitude abnormality among patients was not affected by age. Patient P3 latency was not prolonged. The results indicate that P3 amplitude may more sensitive than neuropsychological measures for detecting subtle brain dysfunction occurring early in PD. This measure has possible utility for detecting and tracking early disease. It is hypothesized that enlarged P3 amplitude reflects abnormality in use of attentional resources to compensate for brain dysfunction.