Disruptions in the reach-to-grasp actions of Parkinson's patients

Abstract

Previous research has shown that Parkinson's-disease (PD) patients produce irregular movement paths during a rapid arm pointing task. The aim of this study was to investigate the movement paths of PD patients during a prehensile action to objects requiring different levels of precision. Thus, we sought to determine if movement-accuracy requirements affect the control of movement path. Thirteen PD patients and 13 age-matched controls served as participants. In addition to having prolonged movement times, PD patients showed differences in the kinematic patterns of the transport and grasp components. For the transport component, relative time to maximum deceleration and relative time to maximum elbow velocity occurred earlier for the PD patients than the controls. Analyses of wrist paths indicated that, when accuracy requirements were increased, patients produced paths that appeared more segmented than controls. For PD patients, reaches to a small object resulted in wrist paths that were significantly less smooth, as reflected by higher jerk values, and were less continuous, as indicated by larger standard deviations in curvature. A temporal analysis of movement-initiation patterns in the vertical and horizontal planes indicated that control participants had a minimal offset between initial movement in the vertical plane and initial movement in the horizontal plane regardless of accuracy constraints. However, PD patients had a significantly longer interval between initial movement in the vertical plane and subsequent movement in the horizontal plane when reaching to the small object. Higher accuracy constraints also resulted in PD patients achieving relative time to maximum elbow velocity significantly earlier than controls. For the grasp component, PD patients produced movement patterns in which the amplitude of and relative time to maximum aperture were less sensitive to object size. In addition, patients exhibited greater variability in the time to maximum aperture. Additional analyses of the grasp component indicated that control participants exhibited a stable position, relative to object location, in which aperture began to close. Conversely, PD patients showed little consistency in where aperture began to close with respect to object location. Irregularities in the transport component suggest that PD patients have a reduced capability to precisely coordinate joint segments, particularly under high accuracy requirements. Variability in where aperture began to close and disruptions in transport-grasp coordination suggests that the basal-ganglia dysfunction, as exhibited in PD, affects the specification of these movement parameters used to produce a consistent pattern of coordination between prehensile components.

The impact of subthalamic deep brain stimulation on bradykinesia of proximal and distal upper limb muscles in Parkinson's disease

“…For reach-to-grasp movements in PD patients a slowing of hand transport and a discoordination between hand transport and grasp formation with a pronounced delay of the onset of the grasp opening has been documented [8][9][10]21]. Interestingly, we found that STN-DBS shortened the time of peak grasp aperture in relation to the time of hand transport and thus normalized the temporal coupling between the reach and grasp components of the reach-to-grasp task in PD.…”

“…However, in clinical practice examination of distal movements of the arm and hand is often used to assess the severity of bradykinesia in PD [5]. Given the lack of sufficient clinical measures to judge upon the differential effectiveness of treatment on the bradykinesia of proximal and distal muscles of the arm and hand in PD, kinematic motion analysis may bridge that gap providing a sensitive tool to investigate dexterity in tasks relevant in daily life [8][9][10]. Schenk and colleagues investigated the effects of bilateral DBS of the internal globus pallidum on a reachto-grasp movement in PD [12].…”

“…Kinematic movement analysis has been shown to be a sensitive tool for both the diagnosis of impaired dexterity in PD [8,9] and the evaluation of treatment regimen [10][11][12]. Earlier studies have documented a slowing of the reach component and a delay of the onset of the grasp-aperture component in PD [8][9][10][11]. In contrast, the proper adjustment of both reaching and grasping for objects are typically unaffected by the disease [10].…”

“…For example, when reaching to grasp an object we use more proximal arm muscles for hand transport and more distal muscles of the forearm to shape our grasp according to the object properties [7]. Kinematic movement analysis has been shown to be a sensitive tool for both the diagnosis of impaired dexterity in PD [8,9] and the evaluation of treatment regimen [10][11][12]. Earlier studies have documented a slowing of the reach component and a delay of the onset of the grasp-aperture component in PD [8][9][10][11].…”

Methods for Measuring Swallowing Pressure Variability Using High-Resolution Manometry

“…Movement variability is also critical for responding to permutations in the environment and producing on-line corrections [44,50,51]. On the other hand, pathologically increased movement variability has been characterized in many neurologic conditions, including Parkinson disease [52][53][54][55][56], stroke [39,57], dystonia [41,58], developmental coordination disorder [59,60], and cerebral palsy [61,62], to name a few.…”