The pattern of depressive symptoms varies with progression of Parkinson's disease.

Whether or not depressive symptoms increase in severity with progression of Parkinson's disease (PD) remains uncertain. Unlike previous studies, we examined whether the severity of specific features of depression (mood, self reproach, vegetative, and somatic symptoms) differ with respect to the progression of PD. Results indicated that symptoms related to both mood and self-reproach were present in the early stages of PD but did not increase in severity with advancing disease. Somatic features of depression were evident early and increased with disease progression, and vegetative symptoms were seen only in the later stages of PD. The different patterns of these depressive features with progression of PD may account in part for the variations seen in previous studies.

Neuropsychological differences between the dementias of Alzheimer's and Parkinson's diseases.

The question of whether dementia of the Alzheimer type and dementia associated with Parkinson's disease are clinically separable is controversial. We examined possible neuropsychological differences in these two patient groups matched for overall severity of dementia. Patients with dementia of the Alzheimer type had more severe impairment on measurements of memory, language, and orientation, and, unlike patients with Parkinson's disease, there was evidence of apraxia. Patients with Parkinson's disease had more severe impairment related to speed of information processing, and, unlike patients with dementia of the Alzheimer type, they also had disturbance of mood. The nature of visuospatial abnormalities also differentiated the two groups. The pattern of neuropsychological differences is consistent with the cortical-subcortical hypothesis.

Effects of anticholinergic agents on patients with tardive dyskinesia and concomitant drug-induced parkinsonism.

Twenty-five percent of 80 consecutive patients who met research criteria for persistent tardive dyskinesia (TD) were found to have an energy peak in the parkinsonian tremor band (3-6 Hz) of the frequency spectrum of their machine-measured resting hand movements in addition to the abnormalities consistent with TD (increased energy in the 0.5-3 Hz frequency spectrum). Twelve of these patients were studied again in double-blind fashion 2 hours after receiving a placebo and again 2 hours after a single 4 mg dose of trihexyphenidyl hydrochloride (HCl). Compared with the placebo condition, the trihexyphenidyl HCl markedly diminished the measured energy in the 4 Hz band and had no effect or slightly decreased the energy at all other points on the frequency spectrum. Simultaneous Abnormal Involuntary Movement Scale ratings revealed no change in the dyskinetic movements between the conditions; there was a significant subjective improvement reported by the patients following the trihexyphenidyl HCl administration. These observations indicate that electromechanical devices identify a subpopulation of TD patients who may acutely benefit from anticholinergic treatment.

Neuropsychological similarities in lateralized parkinsonism.

Parkinson's disease (PD) patients who have left or right predominance of motor symptoms may exhibit cognitive differences. Previous research found greater neuropsychological impairment in patients with both right and left motor predominance, and some found no differences. Variability in overall severity of disease among the patients studied makes evaluation of these reports difficult. We examined the possibility that neuropsychological differences may occur in different stages of disease by comparing patients with mild unilateral disease (Exp. 1) and advanced disease (Exp. 2). Results indicated that while overall cognitive impairment increased with advancing disease, the pattern of neuropsychological impairments were not different with respect to laterality of motor symptoms in either experiment.

Neuropsychological impairments associated with severity of Parkinson's disease.

Intellectual impairment and disease severity tend to parallel one another in patients with Parkinson's disease (PD), but the pattern of development of the neuropsychological impairments contributing to the overall intellectual decline is unknown. This problem was addressed by comparing neuropsychological performance in the early and later stages of PD. Impairment of recent memory, impairment of cognition, and somatic features of depression were seen early and worsened with more advanced disease. Impairment of visuospatial skills, remote memory, language, and mood were observed only in the later stages of PD. These findings suggest that neuropsychological impairments do not develop in a uniform manner with progression of PD.