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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to investigate relationships between cognition and regional brain function, we studied 20 non-demented patients with idiopathic Parkinson's disease (PD), 21 mildly demented patients with Alzheimer's disease (AD) and 24 control subjects using cognitive testing and single photon emission computerized tomographic (SPECT) measurements of relative regional cerebral blood flow (rCBF). Neuropsychological tests were grouped into clusters reflecting frontal lobe executive abilities, perseveration, memory and visuospatial ability, with a summary score summarizing performance in all four of these spheres. SPECT imaging utilized the tracer [123I]N-isopropyl-p-iodoamphetamine with a relative measure of regional tracer uptake normalized to occipital radiotracer uptake (rCBF ratios). Patients with PD performed more poorly than controls in all cognitive domains, and were intermediate to AD patients and controls in tests of memory and overall cognitive functioning. Those PD patients who performed most poorly on neuropsychological testing showed lowest rCBF ratios in left and right temporal lobes. Using a stepwise multiple regression procedure, we examined patterns of correlations between cognitive clusters and predictor variables, including rCBF ratios, in the PD patients. We found that while patient age was a strong determinant of performance on the memory cluster and the summary score, dorsolateral frontal lobe perfusion and scores on a depression inventory accounted for a greater proportion of the variance of the frontal lobe and perseveration clusters than did age. These results imply that different neural mechanisms are responsible for the different aspects of cognitive decline seen in PD patients, with overall cognitive function closely related to age and temporal perfusion, while frontal lobe abilities are more linked to frontal perfusion and the presence of depression.
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PMID:Cognitive function and regional cerebral blood flow in Parkinson's disease. 160 80

The utility of the concept of 'subcortical dementia' was investigated by comparing the verbal learning and memory abilities of Parkinson's disease (PD) patients with those of Huntington's disease (HD) patients. Many similarities between the PD and HD groups emerged, including impaired immediate memory spans, inconsistency of recall across learning trials, deficient use of a semantic clustering learning strategy, elevated intrusion rates on delayed recall, impaired recognition memory performance, normal retention of information over delay periods, normal vulnerability to proactive or retroactive interference, and normal types of intrusion errors. The HD subjects, however, displayed inferior free recall, deficient improvement across learning trials, abnormal serial position recall effects, higher perseveration rates, and supranormal improvement on recognition testing compared with free recall. Implications of these results for characterizing memory deficits associated with subcortical system dysfunction are discussed.
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PMID:Are all subcortical dementias alike? Verbal learning and memory in Parkinson's and Huntington's disease patients. 214 23

Previous demonstrations that problem solving deficits may occur early in the course of Parkinson's disease (PD) have been taken to support the view that disturbances in the functioning of the frontal lobes are responsible for the initial cognitive deficits in this disease. However, no specific pattern of responding associated with poor problem solving by PD patients has been observed consistently. In an effort to clarify the nature of the problem solving deficits in PD we administered the Wisconsin Card Sorting Test (WCST) and the California Card Sorting Test (CCST), a new test which provides separate measures of concept generation, concept identification, and concept execution as well as several different measures of perseveration. On both tests PD patients of lower than normal mental status performed poorly and their patterns of performance resembled those previously described for patients with focal frontal lobe lesions, but PD patients of normal mental status performed normally. Because poor problem solving in association with increased perseverative responding was only observed for patients with global cognitive deficits these findings do not necessarily support the idea that frontal dysfunction is the principal cause of impaired cognition in PD. Although the overall pattern of results was similar for the WCST and the CCST, the CCST was more sensitive for detecting deficits than was the WCST.
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PMID:Problem solving in Parkinson's disease: comparison of performance on the Wisconsin and California Card Sorting Tests. 228 33

Previous performance on measures of frontal system function have suggested prominent orbitofrontal system damage in Alzheimer's disease, but not in Parkinson's dementia. Object alternation (OA), a task sensitive to orbitofrontal system dysfunction in non-human animals, was therefore administered to determine whether this measure would distinguish Alzheimer's from Parkinson's dementia. OA was significantly impaired in Alzheimer's disease compared to Parkinson's dementia, even though both groups were equated for severity of dementia. Although the patients with Parkinson's dementia also showed impairment on OA compared to normals, an error analysis revealed that the performance of the Alzheimer's patients, but not the Parkinson's patients, was characterized by abnormal response perseveration. The marked perseverative deficit in Alzheimer's disease may reflect orbitofrontal system dysfunction whereas the milder, and qualitatively different, deficits in Parkinson's disease may reflect dorsolateral frontal system involvement.
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PMID:Object alternation and orbitofrontal system dysfunction in Alzheimer's and Parkinson's disease. 228 9

We tested a new taxonomy of perseverative behavior consisting of three categories: (1) repetition of a previous response to a subsequent stimulus (recurrent), (2) inappropriate maintenance of a category of activity (stuck-in-set), and (3) abnormal prolongation of a current activity (continuous). Three groups of neurologically impaired subjects (with aphasia, right hemisphere damage, and Parkinson's disease) were administered tests to elicit each category of perseveration. Patients with aphasia produced significantly more recurrent perseveration than did patients with right hemisphere damage or healthy controls. Stuck-in-set perseveration was associated with dopamine system dysfunction, and continuous perseveration with right hemisphere damage. We propose a theory of perseveration dependent on anatomic, neuropsychological, and pharmacologic factors related to cerebral dominance. According to this theory, disruption of specific anatomic and pharmacologic systems produces different forms of perseveration which, in turn, underlie particular neurobehavioral disorders.
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PMID:Perseveration in behavioral neurology. 367 Jun 11

Neuropsychological mechanisms of dementia in Alzheimer's and Parkinson's diseases were compared using a tactile discrimination learning paradigm adopted from animal models. There were two components to the task: tactile original learning (TOL), which is sensitive to parietal lobe damage in nonhuman primates; and tactile reversal of original learning (TRL), a measure of perseveration. The patients with Alzheimer's disease were significantly impaired on TOL compared with demented patients with Parkinson's disease, even though both groups were equated for severity of dementia. On TRL, the patients with Alzheimer's disease and demented patients with Parkinson's disease were both significantly impaired, but the patients with Alzheimer's disease showed significantly more perseverative errors. The mechanisms underlying TOL and TRL deficits may serve to differentiate Alzheimer's from Parkinson's dementia, and may involve selective parietal system lesions.
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PMID:Tactile discrimination learning deficits in Alzheimer's and Parkinson's diseases. 382 95

Schizophrenics and controls were compared on a computerized test of attentional set-shifting which provides a componential analysis of the Wisconsin Card Sort Test and has previously been shown to be sensitive to frontal lobe dysfunction and Parkinson's disease. The main test was of extra-dimensional shifting where subjects are required to shift response to an alternative perceptual dimension. In one condition, termed 'perseveration', subjects are required to shift to a novel dimension and ignore the previously relevant one. In the other condition, termed 'learned irrelevance', subjects are required to shift to the previously irrelevant dimension and ignore a novel one. Chronic medicated schizophrenics (N = 32) show a highly significant impairment on the perseveration but not the learned irrelevance condition, as compared to normal age and IQ matched controls (N = 24). This was true even of a subgroup of patients with preserved IQ. The impairments in attentional set-shifting failed to correlate with patients' scores on the Mini-Mental State Examination (mean; S.D. 26.8; 1.8) or with scores on a test of recognition memory. These results provide evidence for a specific deficit in a set-shifting test of executive function and support a hypothesis of frontostriatal dysfunction in schizophrenia.
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PMID:Neuropsychological evidence for frontostriatal dysfunction in schizophrenia. 748 Apr 41

Difficulties in shifting of cognitive sets and perseverative behaviour have been shown to be part of the neuropsychology of Parkinson's disease, possibly due to frontal dysfunction. We have tested perseverative motor behaviour by assessing ability to generate random movement sequences in 15 patients with Parkinson's disease using the Breidt Perseveration Test Device (PTD). In this experiment subjects are instructed to press one of nine buttons arranged randomly on a metal board without use of systematic or repetitive strategies. The speed of this task that comprises 150 consecutive presses is determined by an acoustic go-signal appearing at 1 Hz frequency. Results were compared with 14 age-matched controls. Patients performance was impaired with intrusion of unwanted systematic strategies suggesting a decreased ability of Parkinson patients to generate random movement sequences.
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PMID:Perseverative motor behaviour in Parkinson's disease. 793 63

Tests which assess the ability to shift cognitive set modelled after the Wisconsin Card Sorting Test are particularly sensitive to impairments in patients with Parkinson's disease as well as in patients with frontal lobe damage. However, the underlying mechanisms responsible for the similar deficits observed in the two patient groups are not well understood and may not be identical. For example, an apparent deficit in set-shifting ability may reflect either an impairment in the ability to shift from a perceptual dimension which has previously commanded attention (i.e. 'perseveration'), or in the ability to shift to an alternative perceptual dimension which has previously been irrelevant (i.e. 'learned irrelevance'). In this study, the performance of both medicated and non-medicated patients with Parkinson's disease were compared with a group of neurosurgical patients with localized excisions of the frontal lobes on a novel task designed to assess the relative contribution of 'perseveration' and 'learned irrelevance' to impaired set-shifting ability. Patients with frontal lobe damage were worse than controls in their ability to shift attention from a previously relevant stimulus dimension. Medicated patients with Parkinson's disease were worse at shifting to a previously irrelevant dimension. In contrast to both groups, nonmedicated patients with Parkinson's disease were impaired in both conditions. These results suggest that the gross set-shifting deficits reported in both frontal lobe patients and patients with Parkinson's disease may involve fundamentally different, though related, cognitive processes, and that these may be differentially affected by medication. Specifically, L-dopa therapy may protect Parkinson's disease patients from preservation of attention to a formerly relevant stimulus dimension.
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PMID:Contrasting mechanisms of impaired attentional set-shifting in patients with frontal lobe damage or Parkinson's disease. 822 Oct 53

The generative naming ability (verbal fluency) of 88 idiopathic Parkinson disease (PD) patients was evaluated and compared to that of 21 Alzheimer disease (AD) patients and 43 normal age- and education-matched normal control subjects. The PD patients were classified according to whether they scored within the normal range on the Mini-Mental State Examination (MMSE), a score of 27 or higher, or in the abnormal range, a score of 26 or lower. Semantic and letter generative naming tasks were administered to assess verbal fluency. Results of the study provide evidence that letter category naming is inherently more difficult than semantic category naming; that age significantly affects generative naming; that PD patients with normal MMSE scores were significantly inferior to normal control subjects in generative naming even after the effects of age and mental status are controlled; that PD patients with non-normal MMSE scores performed like AD patients after controlling for the effects of age and mental status; and, that ideational perseveration is the most common type of error response for all subject groups.
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PMID:Generative naming in Parkinson disease patients. 835 8


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