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

Post-mortem evidence has shown a depletion of dopamine in the mesocortical and mesolimbic pathways in brains of Parkinson patients. Since these dopaminergic pathways have been implicated in the control of attention in animals, selective attention to visual stimuli was studied in eight patients with early Parkinson's disease (Stage I or II as defined by the Hoehn and Yahr Scale) and eight normal controls of comparable age, sex and Full Scale Intelligence Quotient. Subjects with dementia, psychiatric disease and other neurological abnormalities were excluded. The Parkinson patients were more prone to interference in the presence of distractor items than the normal controls as shown on the focussing + distraction and switching + distraction of attention paradigms on the Distractor task. There findings are not accounted for by mood, intellectual status or memory and thus may be as a result of the loss of dopamine in the mesocortico-limbic projections.
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PMID:Distractibility in early Parkinson's disease. 238 58

This paper reports two experiments which examined the effects of Parkinson's disease (PD) upon the sensorimotor mechanisms used to control prehension movements. Transport and grasp kinematics for visually-guided and memory-guided prehension movements were examined in healthy control subjects and compared against those of patients with idiopathic PD. Two research questions were addressed: (1) Are patients with PD particularly susceptible to distraction by non-relevant objects? (2) Are patients with PD especially reliant on external feedback when executing goal-directed actions? The results indicated that the patient group were no more susceptible to distraction by non-relevant objects than the control group. In contrast, the patients with PD were shown to be significantly impaired when executing memory-guided reaches. Furthermore, the deficits exhibited by the PD group on memory-guided reaches were confined solely to those markers associated with the transport component of the prehension movement. That is, while both controls and patients with PD widened their grip aperture on memory-guided trials, the magnitude of this adjustment was comparable across the two groups. The implications of these findings for theories of visuomotor processing in sufferers of PD and the control of prehension movements more generally are discussed.
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PMID:The internal control of action and Parkinson's disease: a kinematic analysis of visually-guided and memory-guided prehension movements. 758 11

In order to distinguish impairment in set-shifting in Parkinson's disease (PD) from inability to inhibit distraction by stimuli that compete for attention, 18 nondemented patients with idiopathic PD and 13 normal controls equated for age and education, were administered the Odd-Man Out (OMO) test and the Stroop Color-Word Test. PD patients were significantly impaired on the OMO test but showed no evidence of interference during the Stroop test. Analysis of error patterns during the OMO test indicated that the requirement to repeatedly switch rules, rather than the requirement to maintain steady responding between rule switches, was responsible for impaired OMO performance. It is concluded that the OMO test is fundamentally a test of set shifting, rather than a test of set maintenance in PD. In addition, analysis of a larger sample of PD patients revealed a significant positive relationship between number and severity of extrapyramidal signs and error production on the OMO, and between the latter and global mental function. These relationships were independent of each other, suggesting that impairment in set-shifting function in PD may arise from pathology of the fronto-striatal system independently of changes in cognitive ability.
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PMID:Executive function in Parkinson's disease: set-shifting or set-maintenance? 849 50

This study aimed at a contrastive analysis of coping strategies and psychosocial alterations in patients with Parkinson's disease (PD) and stroke (CVA) and their relatives. Fifty-four PD and 50 CVA patients were investigated with a standardized semistructured interview to assess the severity of psychosocial changes following illness, the Freiburg Questionnaire on Coping with Illness, the Cornell Depression Scale and instruments to assess motor impairment. Psychosocial alterations were most prominent in the professional and emotional-cognitive domains. Degree of depression correlated with familial and emotional-cognitive alterations in both patient groups. Active problem-oriented coping and distraction predominated as coping styles. Religious relief and quest for sense were significantly more important for the PD patients. Coping styles did not correlate with degrees of depression, motor impairment or psychosocial alterations.
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PMID:Coping with chronic neurological impairment: a contrastive analysis of Parkinson's disease and stroke. 902 Dec 79

There are few studies analyzing the incidence, clinical characteristics and diagnostic work-up of psychogenic tremor. We studied the clinical and electrophysiological characteristics and the associated psychopathology in a series of patients with psychogenic tremor. All patients (n = 8) diagnosed with documented or clinically established psychogenic tremor in the movement disorders section of our Department of Neurology in a two-years period were analysed. Psychogenic tremor was diagnosed in 9.5% of the patients that consulted for postural or action tremor of the upper limbs. In all cases tremor had a variable frequency and amplitude and improvement with distraction. Electrophysiological studies revealed asynchronic muscle activity and considerable variation of the dominant frequency when weight was added to the patient hands. Six patients were initially misdiagnosed of essential tremor (n = 3); Parkinson's disease (n = 1); and cerebrovascular disease (n = 2). Final psychiatric diagnoses were depression (n = 4); conversive disorder (n = 2); and malignering (n = 2). Psychogenic tremor is a relatively frequent cause of tremor in a Movement Disorders Clinic and has a characteristic clinical and electrophysiological pattern.
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PMID:[Psychogenic tremor: clinical, electrophysiologic and psychopathologic assessment]. 943 98

In a total of 30 tremor patients (14 with Parkinson's disease, 6 with cerebellar tremor, 4 with essential tremor, 4 with psychogenic tremor, 2 with enhanced physiological tremor), tremor was electromyographically recorded before, during and after contralateral distraction tasks (tapping with the index finger or the tip of the foot, sequential flexion of the 2nd to 5th finger towards the thumb, "keyboarding", and sensory discrimination). 22 of 26 patients with organic tremors spontaneously choose a volitional tapping frequency independent from their tremor frequency. In 4 patients with psychogenic tremor, frequencies of tremor and tapping were locked (n = 3), or tremor disappeared abruptly (n = 1) when contralateral tapping was started. Contralateral "keyboarding" and sensory discrimination revealed no clear differences between organic and psychogenic tremors. Contralateral tapping in further 23 patients (22 with organic tremors and 1 with psychogenic tremor) confirmed these findings. Contralateral tapping appears as the most valid distraction task and may help to differentiate psychogenic from organic tremors.
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PMID:[Polygraphic validation of distraction tasks in clinical differential tremor diagnosis]. 983 78

Monitoring systems enable the long-term registration of tremor in patients with Parkinson's disease This method is useful in the objective measurement of tremor during the course of treatments. Indeed, the symptoms of tremor as well as the aggravating and attenuating influences can be observed under real-life conditions. The methodology of data recording and analysis, described in previous investigations, was extended to automatically detect body position and certain movement patterns with calibrated 4-channel accelerometry. The main purpose of the present investigation was to apply this refined and extended methodology to patients in a clinical rehabilitation program, and to examine its practability with respect to the results of the treatment and the patients' compliance. The methodology was tested on 30 patients (17 male, 13 female) with Parkinson's disease. The mean age was 64.8 years (s = 8.9). The Hoehn-Yahr index ranged from 1 to 3 (m = 2.3, s = 0.7) and the overall UPDRS scale between 10 and 74 (m = 42.9, s = 18.1). The data recording included: (1) the registration of tremor under standardised conditions of rest and postural tremor test with and without distraction; (2) a standard protocol to obtain reference values for body position and movement; and (3) the 24-hr monitoring. 21 patients could be recorded a second time, on average 18 days after the first recording. Between the two registrations, patients received individually tailored drug treatment supplemented with specific activating physiotherapy, ergotherapy measures, and individual psychotherapeutic counseling. Changes between first and second recording were evident for the three tremor variables, but significant only for the 24-hr ambulatory monitoring. The between and within-subjects correlations of the tremor variables were rather low except the correlations between occurrence and amplitude (between-subjects. 87; within-subjects. 67). Conditions of rest and postural tremor test showed a correlation with corresponding segments of the ambulatory monitoring of about. 50 for the tremor occurrence. The best prediction of the day-time monitoring was made by the tremor tests with distraction, whereas the night segment was best predicted by the standard protocol.
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PMID:Tremor in Parkinson's disease: 24-hr monitoring with calibrated accelerometry. 1512 53

Catalepsy tests performed in rodents treated with drugs that interfere with dopaminergic transmission have been widely used for the screening of drugs with therapeutic potential in the treatment of Parkinson's disease. The basic method for measuring catalepsy intensity is the "standard" bar test. We present here an easy to use microcontroller-based automatic system for recording bar test experiments. The design is simple, compact, and has a low cost. Recording intervals and total experimental time can be programmed within a wide range of values. The resulting catalepsy times are stored, and up to five simultaneous experiments can be recorded. A standard personal computer interface is included. The automated system also permits the elimination of human error associated with factors such as fatigue, distraction, and data transcription, occurring during manual recording. Furthermore, a uniform criterion for timing the cataleptic condition can be achieved. Correlation values between the results obtained with the automated system and those reported by two independent observers ranged between 0.88 and 0.99 (P<0.0001; three treatments, nine animals, 144 catalepsy time measurements).
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PMID:A novel automated rat catalepsy bar test system based on a RISC microcontroller. 1593 23

Focused attention can be compromised by the neurodegenerative processes associated with both healthy aging and Parkinson's disease (PD). Deficits in ignoring distractors with reflexive or overlearned response links have been attributed to impaired inhibition. The current research assessed whether similar deficits occur for distractors with recently learned arbitrary response associations, for which sensorimotor transformations are far less automatic and therefore considerably easier to resist. We used a selective attention task that evaluated distractibility and the use of distractor inhibition within the same context. The task involved stimuli that were arbitrarily assigned to responses based on a rule learned during the testing session. Performance showed that distraction increased with both healthy aging and PD. Moreover, these increases in distraction were accompanied by decreases in overt evidence of distractor inhibition, which appear to reflect at least in part a failure of reactive inhibition. Comparison of the deficits in the two groups indicates that the key difference reflects severity, rather than distinct symptoms, suggesting that they stem from neural changes associated with both aging and PD. These results demonstrate that aging- and PD-related hyper-distractibility and impaired inhibition during focused attention affect stimuli without prepotent response links, which implicates dopaminergic networks in the strategic control of arbitrary visuomotor transformations.
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PMID:Distractibility with advancing age and Parkinson's disease. 1939 71

We investigated the role of dopamine in working memory by examining effects of withdrawing dopaminergic medication in patients with Parkinson's disease. Resistance to distraction during a delayed response task was abnormally enhanced in Parkinson's disease patients OFF medication relative to controls. Conversely, performance on a backward digit span test was impaired in these same Parkinson's disease patients OFF medication. Dopaminergic medication reinstated susceptibility to distraction and backward digit span performance, so that performance of Parkinson's disease patients ON medication did not differ from that of controls. We hypothesize that the enhanced distractor resistance and impaired backward digit span in Parkinson's disease reflects low dopamine levels in the striatum, and perhaps upregulated frontal dopamine levels. Dopaminergic medication may reinstate distractibility by normalizing the balance between striatal and prefrontal dopamine transmission.
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PMID:Enhanced frontal function in Parkinson's disease. 1999 71


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