Assessment of neuroprosthetic hand grasp by combined force and position tracking

Visual pursuit tracking tasks developed to quantitatively assess neuroprosthetic hand grasp systems are discussed. The tests evaluate patient control of the hand grasp and measure the system input-output relationships which can be used to identify nonlinearities, deadbands, and inappropriate slopes in these relationships. Subjects track using the combined force and position outputs of the hand grasp. The feasibility of combined tracking was evaluated using three normal subjects. Two of the subjects performed significantly better at position tracking than at force or combined tracking. The third subject´s position tracking was not significantly better than force tracking. All three performed significantly better at force tracking than at combined tracking