Search

Objective: To investigate the effect of eating utensil weight on kinematic performance in people with Parkinson’s disease. Design: A counterbalanced repeated-measures design. Setting: A motor control laboratory in a university setting. Subjects: Eighteen adults with Parkinson’s disease and 18 age-matched controls. Experimental conditions: Each participant performed a food transfer task using spoons of three different weights: lightweight (35 g), control (85 g) and weighted (135 g). Kinematic variables of arm movement were derived and compared between conditions. Main measures: Kinematic variables of arm movement, including movement time, peak velocity and number of movement units. Results: Utensil weights significantly affected the movement kinematics of all participants. Both groups had fewer movement units in the lightweight condition (Parkinson’s disease group: 22.18, controls: 19.89) than in the weighted condition (Parkinson’s disease group: 22.68, controls: 21.36), suggesting smoother movement in the former condition. In addition, both groups had higher peak velocity in the lightweight than in the weighted condition. Conclusions: Our findings suggest that a lightweight utensil may facilitate smoother and higher-velocity arm movement than a weighted one in people with Parkinson’s disease.

Objective: To examine, in a dual-task paradigm, the effect of auditory stimuli on people with Parkinson's disease. Design: A counterbalanced repeated-measures design. Setting: A motor control laboratory in a university setting. Subjects: Twenty individuals with Parkinson's disease. Experimental conditions: Each participant did two experiments (marching music experiment and weather forecast experiment). In each experiment, the participant performed an upper extremity functional task as the primary task and listened to an auditory stimulus (marching music or weather forecast) as the concurrent task. Each experiment had three conditions: listening to the auditory stimulus, ignoring the auditory stimulus and no auditory stimulus. Main measures: Kinematic variables of arm movement, including movement time, peak velocity, deceleration time and number of movement units. Results: We found that performances of the participants were similar across the three conditions for the marching music experiment, but were significantly different for the weather forecast experiment. The comparison of condition effects between the two experiments indicated that the effect of weather forecast was (marginally) significantly greater than that of marching music. Conclusions: The results suggest that the type of auditory stimulus is important to the degree of interference with upper extremity performance in people with Parkinson's disease. Auditory stimuli that require semantic processing (e.g. weather forecast) may distract attention from the primary task, and thus cause a decline in performance.

Objective: To examine the effect of spoon-handle size on kinematic performance in people with Parkinson's disease. Design: A counterbalanced repeated-measures design. Setting: A motor control laboratory in a university setting. Subjects: Eighteen individuals with Parkinson's disease and 18 age-matched controls. Experimental conditions: Each participant was instructed to scoop water (simulated soup) using spoons with three different-sized handles. Main measures: Kinematic variables (movement time, peak velocity and number of movement units) of arm movement, size of hand aperture and number of fingers to grasp the spoon. Results: The movement of the participants with Parkinson's disease was faster (shorter movement time) and smoother (fewer movement units) when they used spoons with a small- or medium-sized handle than when using a spoon with a large-sized handle. In contrast, the healthy controls showed no significant differences in movement kinematics between handle sizes. Moreover, the participants with Parkinson's disease had a significantly smaller hand aperture and used more fingers to hold the spoons than the controls did. Conclusions: These results suggest that, for people with Parkinson's disease, a small-to-medium-sized handle is more suitable than a large-sized built-up handle.

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 reversalshift 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.

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.

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 over-all 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.

The precueing paradigm developed by Posner has been used to examine visuospatial shifting of attention. In the current study, we modified such a paradigm so that it could be studied in nonvisuospatial domains and its component processes of disengagement, movement, and engagement could be analyzed in a similar fashion to the visuospatial domains. 14 patients with Parkinson's disease and 14 normal controls matched for age, sex, handedness, and years of education served as subjects. The speed of shifting attention was measured using the cost and benefit analysis. Analyses showed an over-all slowness in reaction time of patients with Parkinson's disease compared to the control group but without a concomitant slowness to engage, shift, and disengage their attention.