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

Patients with Parkinson's disease exhibit a number. of abnormalities that seem more marked in circumstances in which stimulus and response are predictable in advance. In this article, we consider the prolonged movement onset latencies exhibited by Parkinsonian subjects in the tracking of predictable targets and in the simple reaction time (RT) task. It has been suggested that the performance impairments on both these tasks stem from a common planning deficit. We argue that the Parkinsonian tendency to refrain from predictive tracking cannot be ascribed to an inability to anticipate due to a planning deficit. The data are better accommodated by our alternative thesis that when Parkinsonians' response initiation lags behind that of normal subjects, this is a result of a strategic adaptation to an impairment of the accuracy of movements guided by an internal representation of the target. Our conclusion, that the primary impairment of predictive tracking is one of inaccurate movement execution rather than delayed response initiation, precludes postulation of the same deficit as a source of the selective prolongation of simple RT sometimes found in Parkinson's disease. Moreover, an analysis of the processing demands of the two tasks shows that the predictability that characterizes each of them is quite different in nature. Hence, the impairments in predictive tracking and simple RT tasks are unlikely to stem from a single mechanism that is defective in Parkinson's disease.
J Mot Behav 1993 Jun
PMID:Simple reaction time and predictive tracking in Parkinson's disease: do they converge on a single, fixed impairment of preparation? 1506

Auditory event-related potentials were evaluated in 45 nondemented patients with mild to moderate Parkinson's disease and 40 matched normal controls. All patients were neuropsychologically assessed by means of the Raven Colored Progressive Matrices, four subtests of the Wechsler Memory Scale (Digit Span Forward, Logical Memory, Visual Memory, Associate Learning), and the Wisconsin Card-sorting Test. The P300 component of the auditory event-related potentials was significantly prolonged in the patients with Parkinson's disease. Correlations between P300 latency and neuropsychological measures showed significant associations with lower performance on the Raven Colored Progressive Matrices and the Wisconsin Card-sorting Test. Our results indicate that for patients with mild to moderate Parkinson's disease subtle changes in cognitive abilities may be reflected as P300 prolongation.
Percept Mot Skills 2004 Jun
PMID:Auditory event-related potentials in Parkinson's disease in relation to cognitive ability. 1529 Dec 36

This study established the test-retest reliability of a seated Functional Rotation Test monitoring hand-pointing, together with head and trunk-rotation performance, in people with Parkinson's disease. An ancillary purpose was to establish the concurrent validity between the Functional Rotation Test and an electrogoniometer. 10 males with Parkinson's disease (M age=70.5 yr.; Hoehn and Yahr staging severity ranging from II to IV) were recruited. Subjects were fitted with laser-pointing devices, sat in the Functional Rotation room, and were instructed to turn actively and point to their right (or left) as far as they could comfortably manage. Tagged projections were scored (in degrees). Testing was repeated after a brief interval. Electrogoniometer projected locations were compared with Functional Rotation Test scores. Intraclass correlation coefficients (.91 to .97) indicated excellent test-retest reliability. There was also excellent agreement between electrogoniometric and Functional Rotation Test values (Intraclass correlation coefficients=.99). Thus the Functional Rotation Test provides a replicable measure of axial rotation of head, trunk, and hand-pointing in seated subjects with Parkinson's disease.
Percept Mot Skills 2004 Aug
PMID:Test-retest reliability of the seated Functional Rotation Test in people with Parkinson's disease: a preliminary study. 1544 54

The somatosensory system is vulnerable to large amounts of noise distortion. But how does the central nervous system distinguish the peripheral inputs which carry information to the brain from that which does not possess information? To address this question we studied the effect of electrical stimulation of the median nerve on tactile spatial frequency perception in healthy subjects and Parkinson's disease (PD) patients. Subjects were categorized in two groups (healthy and PD patients) and were asked to report if a test tactile frequency pattern (TFP) was the same as the reference TFP given to the other hand. In each case stimulation was either present or absent on the median nerve of the hand holding the test pattern. We observed no impairment of tactile performance in the presence of electrical stimulation of the median nerve. This result together with previous work on direct stimulation of the somatosensory relay nucleus of the thalamus in which the same result of no impairment of the tactile discrimination task was observed suggest a high degree of noise tolerance exists in the somatosensory pathway.
Somatosens Mot Res
PMID:Resistance of peripheral and sub-cortical somatosensory pathway to electrical noise. 1576

Isometric impulse frequencies associated with active tremor and force regulation were examined in 10 patients with idiopathic Parkinson's disease (PD) and in 10 older adults (OAs) who performed an isometric tracing task. The authors decoupled and analyzed the data to determine whether PD-related tremor in the thumb and in the index finger during isometric force control are related and whether PD impairs the performance of volitional force control beyond the errors contributed by tremor. After decoupling, there were clear and robust differences in PD patients' control of isometric force that could not be attributed to action-tremor error. Those errors, which occurred in the absence of movement, suggest impairment in coordinated recruitment and derecruitment of motor units during a fine-motor task.
J Mot Behav 2005 May
PMID:Quantification of manual force control and tremor. 1588 17

The speech of people with Parkinson's disease is often unintelligible because the speaker has limited volume and imprecisely articulated speech. The Lee Silverman Voice Treatment addresses volume by requiring a patient to exert extreme effort to adduct the vocal folds and increase volume. Little attention, however, is paid to articulation. Such patients often have perceptual difficulties which prevent them from monitoring their own volume and speech. A case study presents a method for improving volume and articulation of speech of a patient with Parkinson's disease by focusing on perceptual aspects of speech.
Percept Mot Skills 2005 Oct
PMID:Treating Parkinsonian speech: development of a feedback rating scale using a case study. 1638 3

Parkinson's disease (PD) patients can perform many daily activities, but movement deficits are evident. Those deficits may be increased when the required movement is constrained in accuracy. Variable improvements in performance with PD medication have been demonstrated, and sensitivity to task constraint has been evident in some studies. The authors quantified both specific movement deficits and improvements for PD patients in a reaching task. PD patients (N=8) both on and off medication showed a need for greater ongoing control in movements with higher task-accuracy constraints. Increased task-accuracy constraints further compromised movement timing and structure among PD patients who were off medication, suggesting that unmedicated PD patients may typically compensate by using more conscious control of movement, resulting in increased slowing and segmentation of components when higher task accuracy is required.
J Mot Behav 2006 Jan
PMID:Motor deficits in Parkinsonian reaching: dopa-sensitivity influenced by real-world task constraint. 1643 62

12 nondemented patients with Parkinson's disease (M age = 67.3) and 12 normal control participants were administered an object-based attention task that enabled examination of both negative and positive priming. Unlike previous studies in which spatial-based attention tasks were used, results of the present study indicated that the patients displayed negative and positive priming not different from those shown by controls. These results suggest that certain object-based attentional processes may not be impaired in patients with Parkinson's disease.
Percept Mot Skills 2006 Feb
PMID:Lack of impairment in patients with Parkinson's disease on an object-based negative priming task. 1667 22

Eight people with Parkinson's disease (PD), 8 age-matched older adults, and 8 young adults executed 3-dimensional rapid aiming movements to 1, 3, 5, and 7 targets. Reaction time, flight time, and time after peak velocity to the 1st target indicated that both neurologically healthy groups implemented a plan on the basis of anticipation of upcoming targets, whereas the PD group did not. One suggested reason for the PD group's deficiency in anticipatory control is the greater variability in their initial force impulse. Although the PD group scaled peak velocity and time to peak velocity similarly to the other groups, their coefficients of variation were greater, making consistent prediction of the movement outcome difficult and thus making it less advantageous to plan too far in advance. A 2nd finding was that the PD group exhibited increased slowing in time after peak velocity in the final segments of the longest sequence, whereas the other 2 groups did not. The increased slowing could be the result of a different movement strategy, increased difficulty modulating the agonist and antagonist muscle groups later in the sequence, or both. The authors conclude that people with PD use more segmented planning and control strategies than do neurologically healthy older and young adults when executing movement sequences and that the locus of increased bradykinesia in longer sequences is in the deceleration phase of movement.
J Mot Behav 2007 Mar
PMID:Planning and control of sequential rapid aiming in adults with Parkinson's disease. 1742 56

Computerized treadmill gait analysis in models of toxicant exposure and neurodegenerative disorders holds much potential for detection and therapeutic intervention in these models, and researchers must validate the technology that assists in that data collection and analysis. The present authors used a commercially available computerized gait analysis system that used (a) a motorized treadmill on retired breeder male C57BL/6J mice, (b) the toxicant-induced (1-methyl-1-, 2-, 3-, 6-tetrahydropyridine) MPTP mouse model of Parkinson's disease (PD), and (c) the superoxide dismutase 1 (SOD1) G93A transgenic mouse model of amyotrophic lateral sclerosis (ALS). The authors compared the detection of deficits by computerized treadmill gait analysis in MPTP-treated mice with inked-paw stride length and correlated these measures to dopamine (DA) loss. The authors found that the computerized treadmill gait analysis system did not distinguish MPTP-treated mice from vehicle controls, despite a nearly 90% deficit of striatal DA. In contrast, decreases in inked-paw stride length correlated strongly with DA losses in these same animals. Computerized treadmill gait analysis could neither reliably distinguish SOD1 G93A mutant mice from controls from 6 to 12 weeks of age nor detect any consistent early motor deficits in these mice. On the basis of the authors' findings, they inferred that computerized gait analysis on a motorized treadmill is not suited to measuring motor deficits in either the MPTP mouse model of PD or the SOD1 G93A mouse model of ALS.
J Mot Behav 2008 Nov
PMID:Treadmill gait analysis does not detect motor deficits in animal models of Parkinson's disease or amyotrophic lateral sclerosis. 1898 Sep 9


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