Precision grip in chronic stroke patients : evaluation and rehabilitation

This thesis aims to advance the evaluation and rehabilitation of precision grip in chronic stroke patients. Stroke is a leading cause of permanent deficits worldwide, and fine manipulation skills are often disturbed in the paretic hand. The evaluation of predictive and reactive control in this population highlighted deficits in the paretic hand under both conditions. Patients also displayed a significant decrease in digital dexterity and an increase in the time taken to lift the manipulandum with the paretic hand compared with the non-paretic hand and control subjects. A specific rhythmic bilateral grip-lift task oriented therapy undertaken three times per week for 8 weeks did not modify grip-lift task parameters, digital dexterity, manual ability or subjects’ satisfaction with their participation in activities of daily living. Patients’ perceptions of increased ease and fluency of manipulation after therapy was not measured through these evaluations. The suggestion of changes in cortical activity related to the task led us to develop a fMRI compatible manipulandum and concomitant EMG recording setup. With a specific evaluation protocol, this proved to be accurate at least in healthy adults. Nevertheless, there are limitations to the fMRI method. Two of them are the subjects’ supine position and the restriction of their view of the manipulated object during image acquisition. These parameters have been shown to influence grip-lift task performance in healthy adults. There is a strong recommendation to consider position and view during rehabilitation and to assess the patient under the same conditions during fMRI. The literature also recommends adding at least one further brain mapping technique to complete the evaluation. In conclusion, chronic stroke subjects have manipulation disabilities that should be considered for rehabilitation. There is a strong need to combine structure and function specific evaluation in determining which type of therapy is appropriate for each patient in terms of functional recovery level, cortical lesion site and cortical excitability.