Training of Reaching in Stroke Survivors With Severe and Chronic Upper Limb Paresis Using a Novel Nonrobotic Device: A Randomized Clinical Trial

Background and Purpose—Severe upper limb paresis is a major contributor to disability after stroke. This study investigated the efficacy of a new nonrobotic training device, the Sensorimotor Active Rehabilitation Training (SMART) Arm, that was used with or without electromyography-triggered electrical stimulation of triceps brachii to augment elbow extension, permitting stroke survivors with severe paresis to practice a constrained reaching task.

Methods—A single-blind, randomized clinical trial was conducted with 42 stroke survivors with severe and chronic paresis. Thirty-three participants completed the study, of whom 10 received training using the SMART Arm with electromyography-triggered electrical stimulation, 13 received training using the SMART Arm alone, and 10 received no intervention (control). Training consisted of 12 1-hour sessions over 4 weeks. The primary outcome measure was “upper arm function,” item 6 of the Motor Assessment Scale. Secondary outcome measures included impairment measures; triceps muscle strength, reaching force, modified Ashworth scale; and activity measures: reaching distance and Motor Assessment Scale. Assessments were administered before (0 weeks) and after training (4 weeks) and at 2 months follow-up (12 weeks).

Results—Both SMART Arm groups demonstrated significant improvements in all impairment and activity measures after training and at follow-up. There was no significant difference between these 2 groups. There was no change in the control group.

Conclusions—Our findings indicate that training of reaching using the SMART Arm can reduce impairment and improve activity in stroke survivors with severe and chronic upper limb paresis, highlighting the benefits of intensive task-oriented practice, even in the context of severe paresis.

Training-induced changes in the pattern of triceps to biceps activation during reaching tasks after chronic and severe stroke

This exploratory study was undertaken to investigate the mechanisms that contributed to improvements in upper limb function following a novel training program. Surface electromyography (EMG) was used to examine training-induced changes in the pattern of triceps and biceps activation during reaching tasks in stroke survivors with severe paresis in the chronic stage of recovery. The EMG data were obtained in the context of a single blind randomised clinical trial conducted with 42 stroke survivors with minimal upper limb muscle activity and who were more than 6 months post-stroke. Of the 33 participants who completed the study, 10 received training of reaching using a non-robotic upper limb training device, the SMART Arm, with EMG triggered functional electrical stimulation (EMG-stim), 13 received training of reaching using the SMART Arm alone, and 10 received no intervention. Each intervention group engaged in 12 1-h training sessions over a 4-week period. Clinical and laboratory measures of upper limb function were administered prior to training (0 weeks), at completion (4 weeks) and 2 months (12 weeks) after training. The primary outcome measure was 'upper arm function' which is Item 6 of the Motor Assessment Scale (MAS). Laboratory measures consisted of two multijoint reaching tasks to assess 'maximum isometric force' and 'maximum distance reached'. Surface EMG was used to monitor triceps brachii and biceps brachii during the two reaching tasks. To provide a comparison with normal values, seven healthy adults were tested on one of the reaching tasks according to the same procedure. Study findings demonstrated a statistically significant improvement in upper limb function for stroke participants in the two training groups compared to those who received no training however no difference was found between the two training groups. For the reaching tasks, all stroke participants, when compared to normal healthy adults, exhibited lower triceps and biceps activation and a lower ratio of triceps to biceps activation. Following training, stroke participants demonstrated increased triceps activation and an increased ratio of triceps to biceps activation for the task that was trained. Better performance was associated with greater triceps activation and a higher ratio of triceps to biceps activation. The findings suggest that increased activation of triceps as an agonist and an improved coordination between triceps and biceps could have mediated the observed changes in arm function. The changes in EMG activity were small relative to the changes in arm function indicating that factors, such as the contribution of other muscles of reaching, may also be implicated.

Training-induced modifications of corticospinal reactivity in severely affected stroke survivors

When permitted access to the appropriate forms of rehabilitation, many severely affected stroke survivors demonstrate a capacity for upper limb functional recovery well in excess of that formerly considered possible. Yet, the mechanisms through which improvements in arm function occur in such profoundly impaired individuals remain poorly understood. An exploratory study was undertaken to investigate the capacity for brain plasticity and functional adaptation, in response to 12-h training of reaching using the SMART Arm device, in a group of severely affected stroke survivors with chronic upper limb paresis. Twenty-eight stroke survivors were enroled. Eleven healthy adults provided normative data. To assess the integrity of ipsilateral and contralateral corticospinal pathways, transcranial magnetic stimulation was applied to evoke responses in triceps brachii during an elbow extension task. When present, contralateral motor-evoked potentials (MEPs) were delayed and reduced in amplitude compared to those obtained in healthy adults. Following training, contralateral responses were more prevalent and their average onset latency was reduced. There were no reliable changes in ipsilateral MEPs. Stroke survivors who exhibited contralateral MEPs prior to training achieved higher levels of arm function and exhibited greater improvements in performance than those who did not initially exhibit contralateral responses. Furthermore, decreases in the onset latency of contralateral MEPs were positively related to improvements in arm function. Our findings demonstrate that when severely impaired stroke survivors are provided with an appropriate rehabilitation modality, modifications of corticospinal reactivity occur in association with sustained improvements in upper limb function.

SMART Arm with outcome-triggered electrical stimulation:a pilot randomized clinical trial

The SMART (SensoriMotor Active Rehabilitation Training) Arm is a nonrobotic device designed to allow stroke survivors with severe paresis to practice reaching. It can be used with or without outcome-triggered electrical stimulation (OT-stim) to augment movement. The aim of this study was to evaluate the efficacy of SMART Arm training when used with or without OT-stim, in addition to usual care, as compared with usual care alone during inpatient rehabilitation.