Background. The mapping from muscle activation to joint torque production can be difficult to det... more Background. The mapping from muscle activation to joint torque production can be difficult to determine for the multi-articular muscles of the fingers. This relationship was examined in vivo as a function of posture in the index finger.
Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairmen... more Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairment in chronic stroke. Arch Phys Med Rehabil 2006;87:1262-9. Objective: To assess the relative contributions of several neurologic and biomechanic impairment mechanisms to overall finger and hand impairment in chronic hemiparetic stroke survivors. Design: Repeated-measures design. Setting: Clinical research laboratory. Participants: Thirty stroke survivors with chronic hemiparesis. Fifteen subjects had severe hand motor impairment and 15 had moderate impairment, as measured with the Chedoke-McMaster Stroke Assessment.
Stroke is the leading cause of permanent adult disability in the U.S., frequently resulting in ch... more Stroke is the leading cause of permanent adult disability in the U.S., frequently resulting in chronic motor impairments. Rehabilitation of the upper limb, particularly the hand, is especially important as arm and hand deficits post-stroke limit the performance of activities of daily living and, subsequently, functional independence. Hand rehabilitation is challenging due to the complexity of motor control of the hand. New instrumentation is needed to facilitate examination of the hand. Thus, a novel actuated exoskeleton for the index finger, the FingerBot, was developed to permit the study of finger kinetics and kinematics under a variety of conditions. Two such novel environments, one applying a spring-like extension torque proportional to angular displacement at each finger joint and another applying a constant extension torque at each joint, were compared in 10 stroke survivors with the FingerBot. Subjects attempted to reach targets located throughout the finger workspace. The constant extension torque assistance resulted in a greater workspace area (p pÂ
The kinematics of movement of all five digits was analyzed during reach-and-grasp tasks for a var... more The kinematics of movement of all five digits was analyzed during reach-and-grasp tasks for a variety of objects. Ten healthy subjects performed 20 trials involving the grasp of five objects of distinct size and shape. Joint angles were recorded, and digit trajectories were computed using forward kinematics. For a given subject, fingertip trajectories were consistent across trials. The different-sized objects largely produced movement along different portions of a stereotypical trajectory described by a logarithmic spiral. The spirals fit the actual finger positions with a mean error across all trials of 0.23 Ϯ 0.25 cm and accounted for over 98% of the variance in finger position. These patterns were consistent independent of initial finger posture. Subjects did not produce straight-line movements, either in Cartesian space or joint space. The direction of the thumb trajectories exhibited a greater dependence on object type than the finger trajectories, but still utilized a small percentage (Ͻ5%) of the available workspace. These results suggest that restoration of a small but specific part of the workspace could have significant impact on function following hand impairment.
Archives of Physical Medicine and Rehabilitation, 2006
Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairmen... more Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairment in chronic stroke. Arch Phys Med Rehabil 2006;87:1262-9. Objective: To assess the relative contributions of several neurologic and biomechanic impairment mechanisms to overall finger and hand impairment in chronic hemiparetic stroke survivors. Design: Repeated-measures design. Setting: Clinical research laboratory. Participants: Thirty stroke survivors with chronic hemiparesis. Fifteen subjects had severe hand motor impairment and 15 had moderate impairment, as measured with the Chedoke-McMaster Stroke Assessment.
Sign up for email alerts, and subscribe to this journal's RSS feeds at http://brain.oxfordjournal... more Sign up for email alerts, and subscribe to this journal's RSS feeds at http://brain.oxfordjournals.org image downloads
Archives of Physical Medicine and Rehabilitation, 2008
Iwamuro BT, Cruz EG, Connelly LL, Fischer HC, Kamper DG. Effect of a gravity-compensating orthosi... more Iwamuro BT, Cruz EG, Connelly LL, Fischer HC, Kamper DG. Effect of a gravity-compensating orthosis on reaching after stroke: evaluation of the Therapy Assistant WREX. Arch Phys Med Rehabil 2008;89:2121-8.
The goal of this study was to examine the characteristics of planar fingertip movements with resp... more The goal of this study was to examine the characteristics of planar fingertip movements with respect to the hand. Ten subjects with no known neuromuscular impairments performed a series of point-to-point movements with their dominant index fingertips. Subjects were instructed to move between five pairs of targets within the workspace of the index finger in each direction, for a total of ten separate movement tasks. We hypothesized that the trajectories with respect to the hand of these movements would exhibit curved paths contrary to the findings of similar hand path studies. The ratio of the path taken to the straight-line distance between the two targets was dependent upon the movement task (PP
Background. The mapping from muscle activation to joint torque production can be difficult to det... more Background. The mapping from muscle activation to joint torque production can be difficult to determine for the multi-articular muscles of the fingers. This relationship was examined in vivo as a function of posture in the index finger.
Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairmen... more Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairment in chronic stroke. Arch Phys Med Rehabil 2006;87:1262-9. Objective: To assess the relative contributions of several neurologic and biomechanic impairment mechanisms to overall finger and hand impairment in chronic hemiparetic stroke survivors. Design: Repeated-measures design. Setting: Clinical research laboratory. Participants: Thirty stroke survivors with chronic hemiparesis. Fifteen subjects had severe hand motor impairment and 15 had moderate impairment, as measured with the Chedoke-McMaster Stroke Assessment.
Stroke is the leading cause of permanent adult disability in the U.S., frequently resulting in ch... more Stroke is the leading cause of permanent adult disability in the U.S., frequently resulting in chronic motor impairments. Rehabilitation of the upper limb, particularly the hand, is especially important as arm and hand deficits post-stroke limit the performance of activities of daily living and, subsequently, functional independence. Hand rehabilitation is challenging due to the complexity of motor control of the hand. New instrumentation is needed to facilitate examination of the hand. Thus, a novel actuated exoskeleton for the index finger, the FingerBot, was developed to permit the study of finger kinetics and kinematics under a variety of conditions. Two such novel environments, one applying a spring-like extension torque proportional to angular displacement at each finger joint and another applying a constant extension torque at each joint, were compared in 10 stroke survivors with the FingerBot. Subjects attempted to reach targets located throughout the finger workspace. The constant extension torque assistance resulted in a greater workspace area (p pÂ
The kinematics of movement of all five digits was analyzed during reach-and-grasp tasks for a var... more The kinematics of movement of all five digits was analyzed during reach-and-grasp tasks for a variety of objects. Ten healthy subjects performed 20 trials involving the grasp of five objects of distinct size and shape. Joint angles were recorded, and digit trajectories were computed using forward kinematics. For a given subject, fingertip trajectories were consistent across trials. The different-sized objects largely produced movement along different portions of a stereotypical trajectory described by a logarithmic spiral. The spirals fit the actual finger positions with a mean error across all trials of 0.23 Ϯ 0.25 cm and accounted for over 98% of the variance in finger position. These patterns were consistent independent of initial finger posture. Subjects did not produce straight-line movements, either in Cartesian space or joint space. The direction of the thumb trajectories exhibited a greater dependence on object type than the finger trajectories, but still utilized a small percentage (Ͻ5%) of the available workspace. These results suggest that restoration of a small but specific part of the workspace could have significant impact on function following hand impairment.
Archives of Physical Medicine and Rehabilitation, 2006
Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairmen... more Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairment in chronic stroke. Arch Phys Med Rehabil 2006;87:1262-9. Objective: To assess the relative contributions of several neurologic and biomechanic impairment mechanisms to overall finger and hand impairment in chronic hemiparetic stroke survivors. Design: Repeated-measures design. Setting: Clinical research laboratory. Participants: Thirty stroke survivors with chronic hemiparesis. Fifteen subjects had severe hand motor impairment and 15 had moderate impairment, as measured with the Chedoke-McMaster Stroke Assessment.
Sign up for email alerts, and subscribe to this journal's RSS feeds at http://brain.oxfordjournal... more Sign up for email alerts, and subscribe to this journal's RSS feeds at http://brain.oxfordjournals.org image downloads
Archives of Physical Medicine and Rehabilitation, 2008
Iwamuro BT, Cruz EG, Connelly LL, Fischer HC, Kamper DG. Effect of a gravity-compensating orthosi... more Iwamuro BT, Cruz EG, Connelly LL, Fischer HC, Kamper DG. Effect of a gravity-compensating orthosis on reaching after stroke: evaluation of the Therapy Assistant WREX. Arch Phys Med Rehabil 2008;89:2121-8.
The goal of this study was to examine the characteristics of planar fingertip movements with resp... more The goal of this study was to examine the characteristics of planar fingertip movements with respect to the hand. Ten subjects with no known neuromuscular impairments performed a series of point-to-point movements with their dominant index fingertips. Subjects were instructed to move between five pairs of targets within the workspace of the index finger in each direction, for a total of ten separate movement tasks. We hypothesized that the trajectories with respect to the hand of these movements would exhibit curved paths contrary to the findings of similar hand path studies. The ratio of the path taken to the straight-line distance between the two targets was dependent upon the movement task (PP
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