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

A tapping test in which the tasks required a synchronous response to a periodic sound signal by the finger tapping was performed by 27 normal subjects and 146 patients with Parkinson's disease. Some patients could not maintain a synchronous response at a critical frequency of 2.5 or 5 Hz (taps per second) and showed a hastened tapping of 5 6 Hz, independent of the input signal frequencies, i.e., the 'hastening phenomenon.' The other patients and normal subjects could respond synchronously up to 5 7 Hz. Autocorrelational analysis of the sequential tapping intervals suggested that the synchronized response was performed by a feedback control with the input signal as target except at 2.5 and 5 Hz, whereas the hastened tapping of patients was a random process. The frequency-dependence of the error in the tapping was interpreted as representing an intrinsic oscillation in the central nervous system, which would be masked in normal subjects but released in patients with Parkinson's disease. Around 2.5 or 5 Hz the error or response becomes so large that some patients can no longer maintain the synchronized response and show a hastened tapping due to this intrinsic oscillation.
Percept Mot Skills 1978 Feb
PMID:Disturbances of rhythm formation in patients with Parkinson's disease: part I. Characteristics of tapping response to the periodic signals. 64 99

The origin of the characteristic disturbances of rhythm formation in patients with Parkinson's disease (the hastening phenomenon) was discussed, using a second-order system of the periodic response. The input signal was regarded as a pulse series of a Dirac function. The output process of the system had maximal errors of response at input frequencies of f = omega0/n (n = 1, 2, . . .), where omega0 was the intrinsic frequency of the system. Damping coefficient epsilon represented a function of an inhibitor against these maximal errors and the errors diverged to infinity when epsilon = 0. The solution of this forced oscillation system indicated that the intrinsic oscillation of the system has a possibility to be excited at these critical frequencies f = omega/n. Inferred from data on the tapping test, the frequency of an intrinsic oscillation was 5 Hz in the central nervous system, then the critical frequencies were predicted 5/n = 5, 2.5, . . . Hz. On the tapping test the errors of response become maximum around 2.5 and 5 Hz (taps per second), and their peak heights increased from the minimum in well trained normal subjects to the maximum in patients. An inhibitory mechanism against the maximal error would function well, i.e. epsilon greater than 0, in normal subjects but so insufficiently (epsilon leads to 0) in patients that the excited intrinsic oscillation would control their response directly. Thus some patients could no longer maintain a synchronous tapping response at 2.5 Hz or 5 Hz and showed a hastened tapping of 5 6 Hz independent of the signal frequency.
Percept Mot Skills 1978 Feb
PMID:Disturbances of rhythm formation in patients with Parkinson's disease: part II. a forced oscillation model. 64

The 18 patients diagnosed with Parkinson's disease were individually administered the Rorschach test. They showed less Dd%, more S%, more FC, and slightly more M responses than Japanese normal adults. These findings suggest the following personality characteristics of Parkinsonians: they are reserved, self-reliant, over-control emotionality in their inner lives, and like going their own ways. They have good common sense.
Percept Mot Skills 1981 Apr
PMID:Personality characteristics of Parkinson's disease. 725 47

Reaction time in normal subjects is known to increase in a log-linear fashion relative to the number of alternative choices. However, this relationship (formalized as "Hick's law") has received limited investigation in populations with neurological cognitive impairment. The present study used timed sorting of standard playing cards to test Hick's law for 20 young control subjects, and 20 each of age-matched elderly subjects with Alzheimer disease, Parkinson disease, and no cognitive abnormalities. Although Parkinson patients were slowest in the simple tasks of dealing out the cards and sorting by color, Alzheimer patients showed the greatest slowing for the more cognitively complex conditions of sorting by suit and rank of the cards. The performance of all four groups followed Hick's law in displaying a significant linear relationship between response time and log2 of the number of choices. These findings suggest that, although limitations of information-processing speed in Alzheimer and Parkinson disease affected choice response time, there may be sparing of fundamental cognitive organization in these disorders.
Percept Mot Skills 1993 Aug
PMID:Application of Hick's law of response speed in Alzheimer and Parkinson diseases. 836 25

Walking patterns and rhythmic movement of the fingers were examined in a total of 1,134 male and female community residents 65 years of age and over. Walking patterns were characterized according to the ratio of step length divided by step rate (cadence), called the Walk Ratio, during level walking at preferred and maximum speeds. The walking pattern tended to change according to age; older subjects walked with shorter steps (smaller Walk Ratio). Rhythmic movement was examined using the finger-tapping test in time to the sound of a 4-Hz metronome. Hastened tapping or finger festination, in which the subject tapped faster than requested (constant error of 3 msec. and over in the intertap interval), was characteristic of aging; 16.8% of the subjects exhibited finger festination and the occurrence increased with age, especially among those in their eighties (29.3%). Finger festination was accompanied by walking patterns with an increased step rate, or a smaller Walk Ratio. These characteristics of aging were discussed as similar to extrapyramidal symptoms of walking and rhythm production in patients with Parkinson's disease.
Percept Mot Skills 1996 Apr
PMID:Walking patterns and finger rhythm of older adults. 872 13

Orienting attention to visual stimuli was studied in 13 patients with Parkinson's disease whose responses were compared to those of a matched control group using a cued reaction-time task which measured cost and benefit effects of orienting of attention. Both groups were screened to exclude dementia, psychiatric disease, and other neurological abnormalities. Although Parkinson patients showed overall slow mean reaction time, responses showed a pattern of cost and benefit effects similar to that of the control group. The results suggested that Parkinson patients are not impaired on visuospatial orienting of attention on this task.
Percept Mot Skills 1996 Jun
PMID:Visuospatial orienting of attention in Parkinson's disease. 882 95

Research into Parkinson's disease has made much use of the precuing paradigm developed by Posner to examine patients' ability to shift visuospatial attention. The majority of studies indicate that patients with Parkinson's disease have significantly reduced shift costs when compared with normal controls. This reduction in costs is ascribed to abnormal maintenance of attention resulting from Parkinson's disease. We know that visual attention is not directed to spatial locations alone but that it may also be directed to object representations. To date, however, it has not been clear whether the reduced shift costs apparent in Parkinson's disease patients are evident only on spatial locations or on both spatial locations and object representations. Therefore, in the current study we have adopted a new technique with a view to studying both location-based and object-based attentional components within the same paradigm. Our results with 17 patients with Parkinson's disease suggest, at least in the early stages, patients do not show deficits in maintenance of attention to the miscued source of stimulation as reflected in their normal magnitude of cuing effect related to shifting between locations and between objects. 14 normal persons were control subjects.
Percept Mot Skills 1997 Dec
PMID:Object-based and location-based shifting of attention in Parkinson's disease. 945 Feb 86

Visuospatial discrimination was evaluated longitudinally in 45 patients with idiopathic Parkinson's disease. 47 normal matched subjects served as controls. Visuospatial discrimination was assessed by means of a picture test with complex superimposed objects (Poppelreuter's test) at the beginning of the study as well as three years later. At initial evaluation the group with Parkinson's disease identified fewer objects than the control group and made more errors. Relations between performance on the visuospatial discrimination task and the main parameters of the disease were not statistically significant. At reevaluation, three years later on the same task, performance by the group with Parkinson's disease deteriorated. Longitudinal assessment of motor symptoms showed that disease progressed during the study period in 35 patients. Comparison of motor deterioration with performance on the visuospatial discrimination task showed no statistically significant relationship.
Percept Mot Skills 1998 Feb
PMID:A longitudinal study of visuospatial discrimination in parkinsonian patients. 953 Jul 27

Hallucinations, sensory perceptions without environmental stimuli, occur as simple experiences of auditory, gustatory, olfactory, tactile, or visual phenomena as well as mixed- or complex experiences of more than one simple phenomenon. The nature of the hallucination assists localization, differential diagnosis, and treatment planning. In particular, the presence of persistent visual hallucinations of persons with Parkinson's disease predicts dementia, rapid deterioration, permanent nursing home placement, and death. Hallucinations in persons with Alzheimer's disease are often associated with serious behavioral problems and predict a rapid cognitive decline. Theories of the etiology of hallucinations include (1) stimulation, e.g., neurochemical, electrical, seizure, and ephaptic, and (2) inhibition, e.g., destruction of normally inhibitory functions, resulting in disinhibition as in the Charles Bonnet and phantom limb syndromes. Functional neuroimaging procedures suggest anatomical associations for hallucinations. While hallucinations may be a symptom of medical, neurologic, and psychiatric disorders, they may also occur in a wide range of human experiences.
Percept Mot Skills 1998 Jun
PMID:Hallucinations. 965 80

Two experiments were designed to investigate effects of cueing upon aptitude for shifting by patients with Parkinson's disease. Subjects executed in alternation two different components of a task set over successive items in a list. We compared the costs of shifting when the stimulus ensemble remained constant from trial to trial ("uniform" lists), with the case in which a change of stimulus ensemble cued each shift of task ("mixed" lists). Shift costs with mixed lists were significantly smaller than those with uniform lists (Exp. 1, ns = 12). This suggests that patients with Parkinson's disease can benefit from cues about the stimulus ensemble in performing tasks. Patients' shifting performance was different from that of controls only in a reversal-shift condition of the previously consistent stimulus-response mappings (Exp. 2, ns = 12). This result suggests that patients with Parkinson's disease suffer from a specific but not a general deficit in ability to shift.
Percept Mot Skills 1998 Dec
PMID:A specific shifting deficit in Parkinson's disease: a reversal shift of consistent stimulus-response mappings. 988 83


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