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

Dementia and extrapyramidal signs combine in both Alzheimer's disease (AD) and Parkinson's disease (PD) to produce various degrees of clinical overlap between the two diseases. Rest tremor, positive motor response to dopaminergic drugs, bradyphrenia and disproportionate deficits in visuospatial function, dating capacity, recency discrimination, sequencing and set-shifting are specific features of PD; myoclonus, orofacial dyskinesia, aphasia and rapidly progressive global dementia favours AD. A clearer analysis of the underlying brain-behaviour relationships is necessary to advance our understanding of the origin of cognitive and motor impairment and its treatment.
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PMID:Clinical similarities and differences between Alzheimer's disease and Parkinson's disease. 331 3

Twenty-eight cases of mirror writing were seen during a period of three and a half years. These consisted of 12 patients with essential tremor, nine with Parkinson's disease, three with spino-cerebellar degeneration and four other cases. There were no cases of hemiparesis, aphasia, apraxia, agnosia or confusion. Fragmentary reversals were excluded from this study. Since essential tremor, Parkinsonian tremor and cerebellar tremor can be abolished by a stereotaxic produce applied to the thalamus, a common neural pathway via the thalamic nuclei may exist in these disorders. The existence is therefore proposed of some neural mechanism that controls the higher cerebral function of writing via the thalamus.
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PMID:The aetiology of mirror writing: a new hypothesis. 343 91

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

Histopathologic studies of the cerebral cortex, hippocampus, and three subcortical nuclei were performed in four patients with Parkinson's disease whose mental status had been evaluated by neuropsychologic testing. Clinicopathologic correlations suggest that dementia with marked visuospatial disturbance as well as severe aphasia may be associated with severe neuronal loss in subcortical nuclei, without significant numbers of plaques or tangles in the hippocampus and cerebral cortex. Furthermore, memory loss may not be consistently related to neuronal loss in the nucleus basalis of Meynert, particularly in non-Lewy body parkinsonism.
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PMID:Pathologic correlates of dementia in Parkinson's disease. 375 74

The terms "cortical" and "subcortical" dementia are controversial; however, the clinical distinction between them is real. For example, although Alzheimer's and Parkinson's disease (prototypical of cortical and subcortical dementia, respectively) share clinical features, they differ in the presence of aphasia, apraxia, and agnosia in Alzheimer's disease but not in Parkinson's dementia. We review our studies aimed at clarifying the mechanisms underlying the differences between these neurological disorders. Experimental paradigms adopted from animal models were used to study the functional anatomy and neuropsychological characteristics of Alzheimer's and Parkinson's disease. The tasks administered include delayed alternation (DA) and delayed response (DR), which are sensitive to frontal system damage, and tactile discrimination learning (TOL) and reversal (TRL) paradigms sensitive to parietal system damage. Alzheimer's patients were significantly impaired on all tasks whereas Parkinsonians with dementia were impaired only on DR and TRL. Consideration of neuroanatomical and neuropsychological mechanisms involved in DA, DR, TOL, and TRL appears to have sharpened the distinction between Alzheimer's and Parkinson's dementia. Dementia in Alzheimer's disease may involve dorsolateral frontal, orbitofrontal and parietal systems. In contrast, dementia in Parkinson's disease may involve prominent dorsolateral frontal system damage.
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PMID:Comparative neuropsychology of cortical and subcortical dementia. 379 Oct 55

The distinction between cortical and subcortical syndromes of dementia is controversial. Clinical reports suggest that subcortical syndromes (eg, Parkinson's disease) involve less severe intellectual and memory dysfunction and lack the aphasia, agnosia, and apraxia typical of the cortical dementias (eg, dementia of the Alzheimer type). A recent neuropsychological investigation using a standardized procedure failed to confirm the distinction. We examined patients with Alzheimer's disease, patients with Parkinson's disease, and normal controls by using a neuropsychological procedure specifically designed to quantitatively evaluate the proposed clinical differences. The results differentiated these dementia syndromes, and the pattern of performance was consistent with the cortical-subcortical hypothesis.
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PMID:Cortical vs subcortical dementia. Neuropsychological differences. 395 23

Subcortical dementia is a clinical syndrome characterized by slowness of mental processing, forgetfulness, impaired cognition, apathy, and depression. First recognized in progressive supranuclear palsy and Huntington's disease, the concept has been extended to account for the intellectual impairment of Parkinson's disease, Wilson's disease, spinocerebellar degenerations, idiopathic basal ganglia calcification, the lacunar state, and the dementia syndrome of depression. Disorders manifesting subcortical dementia have pathologic changes that involve primarily the thalamus, basal ganglia, and related brain-stem nuclei with relative sparing of the cerebral cortex. Recent studies of neuropsychologic deficits following focal subcortical lesions also support a role for these structures in arousal, attention, mood, motivation, language, memory, abstraction, and visuospatial skills. The clinical characteristics of subcortical dementia differ from those of dementia of Alzheimer's type where prominent cerebral cortical involvement produces aphasia, amnesia, agnosia, and apraxia.
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PMID:Subcortical dementia. Review of an emerging concept. 623 97

Language and speech depend basically upon complex serial (i.e., sequential or temporally structured) neuronal events (action programs) which enable a perception of symbols and a production of meaningful words and sentences with adequate syntax and semantic content. There is evidence that action programs for speech and language, like other serial programs of the CNS, are handled specifically by the prefrontal cortex. Measurements of regional cerebral blood flow (rCBF) and metabolic rate (rCMR) support this view. Word perception, speech, reading etc. activate circumscribed areas in different patterns both in postcentral (afferent) and in precentral/prefrontal (efferent) regions of the hemisphere cortices. Most of these patterns show important symmetrical features. The classical speech cortices of Wernicke and Broca are not unconditionally activated in rCBF measurements during speech reception and production, respectively. Upper prefrontal activations are recorded during e.g. serial word production and reading, and during word perception lower prefrontal activations are seen in addition to postcentral increases of rCBF. A selective activation of prefrontal regions only, takes place during serial information processing related to cognition and ideation, including inner silent speech. In patients with cerebrovascular disorders, organic dementia, Parkinson's disease, and schizophrenia, various types of prefrontal (and other) rCBF and rCMR abnormalities may be seen. In such states different forms of "aseriality" or "dysseriality" (i.e., a defective serial programming) of speech can be recognized, which include non-fluent forms of aphasia of the Broca type, the hesitant, reduced and sometimes aprosodic speech in organic dementia and Parkinson's disease, as well as the peculiar semantic and motor disturbances of speech in schizophrenia.
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PMID:Serial aspects of language and speech related to prefrontal cortical activity. A selective review. 636 59

The capability of positron computed tomography (PCT) to delineate the substructures of the brain and its facility for accurately measuring the local tissue radioactivity concentration allow the application of tracer kinetic models for the study of local cerebral function in man. This principle and an adaptation of the 14C-deoxyglucose (DG) model of Sokoloff et al. with 18F-2-fluoro-deoxy-D-glucose (FDG) is being used at UCLA. Brookhaven National Laboratory, University of Pennsylvania, NIH, and the Massachusetts General Hospital to determine the local cerebral glucose metabolic rate (LCMRGIc) in normal man at rest and during sensory activation and the changes that occur in patients with a variety of cerebral disorders. Kinetic studies with PCT have been employed to measure the rate constants of the model in different gray and white matter structures of the brain in both normal and ischemic states. The precision of the method in normals has been shown to be about +/- 5% for 1.5-2.0 sq cm regions of the brain. Studies in normals have yielded values for hemispheric CMRGIc that are in agreement with measurement using the Kety-Schmidt technique and LCMRGIc values in agreement with values in monkeys using DG autoradiography. Studies in volunteers subjected to visual and auditory stimulation are demonstrating the potential of this technique for investigating the human brain's response to different stimuli. STudies in patients with stroke show excellent correlation between the degree, extent, and particular structures involved and the clinical symptoms. The method consistently detected hypometabolism in cortical, thalamic, and striatal tissues that were dysfunctional due to deactivation or damage but which appeared normal on x-ray CT. Studies in patients with partial epilepsy have shown hypometabolic zones that highly correlated anatomically with interictal EEG spike foci and were associated with normal x-ray CT studies in 77% of the patients studied. The studies on epilepsy at UCLA have resulted in the integration of the LCMRGIc study into the clinical workup of patients with partial epilepsy that are candidates for surgical resection of their epileptogenic focus (effective June 1979). Studies on Huntington's chorea, Parkinson's disease, aphasia, dementia, schizophrenia, and tumors are in early stage of investigation but also are providing exciting new results. Further studies are needed to determine the role of the local function information obtained with the PCT-FDG method in elucidating the basic mechanism and the potential to aid in improving the approach to medical therapy.
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PMID:Positron computed tomography studies of cerebral glucose metabolism in man: theory and application in nuclear medicine. 697 94

This article, basing on experimental analysis and clinical observations, focuses on the role of subcortical structures in memory processes. It explained terminological problems and defined terms of memory: immediate, delayed, recent, remote, declarative and procedural. The present article pointed out functional hemispheric specialization as a predicator of material-specific forms of memory. Neuroanatomical basis was revealed, especially limbic system with its connections to prefrontal, cortical and brain stem regions. Amnesic Korsakoff and Wernicke syndromes, transient global amnesia, memory loss after bilateral damage of temporal lobes and after anterior communicating artery aneurysm rupture, were also discussed. Next part exhibited current knowledge about definition of dementia which may be caused by many multi-focal brain diseases like multiinfarct (vascular) dementia, Parkinson disease, Huntington disease, and sclerosis multiplex, and compared to Alzheimer disease. Term of dementia was defined, according to Cummings and Benson, as syndrome of acquired intellectual dysfunction when three of the following mental functions are impaired: language, memory, visuospatial skills, emotion, and cognition (abstraction, calculation, judgement). There is little doubt that various subcortical diseases are characterised by similar, no specific dysfunctions of cognitive processes including: disturbed attention and concentration, slowness of mental processing, forgetfulness, personality alterations and mood disturbances as well as motivational impairment, visuospatial disturbances, absence of symptoms of cortical dysfunction such as aphasia, agnosia and apraxia and associated motor disorder. Review of the literature suggests that rapid forgetting and retrieval deficits are most often symptoms of memory deficits observed after subcortical brain injuries.
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PMID:[Neuropsychological description of memory impairment following cortical and subcortical brain injuries]. 756 22


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