Technological Advances in Stroke Rehabilitation—High Tech Marries High Touch •
The task must be functional. Just as Nudo demonstrated, the task performed in rehabilitation must be functional and not just motor use. The learning of specific skills is required to bring about significant changes in neural connectivity. Neural plasticity and repair therefore depend on the performance of specific tasks.
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Dose matters. It is generally accepted that the correct dose of an antibiotic or blood pressure medication is important. It is also generally believed that the dose of exercise matters. In the same vein, the number of repetitions (i.e. dose of rehabilitation) appears to be crucial in driving plasticity and learning/relearning tasks. Kleim and Jones suggest that there is a critical level of rehabilitation and repetition needed for a patient to see continued improvement, and to maintain their functional gains outside of a therapy setting. It is also suggested that there is a prime window of opportunity for optimal neural plasticity, and that early intervention is crucial. Delays in therapy could lead to the development of behaviors that interfere with recovery.
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Motivation. Many physicians and therapists have followed patients who become frustrated and give up on attempting to perform functional tasks. The compensatory strategies taught to them might seem easier, but the patient fails to perform enough repetitions of a functional task. Ways are needed to motivate the patient and to engage them in tasks that have successful outcomes and rewards.
Forced Use/Constraint Therapy
A brief discussion of ‘learned non-use’ and ‘forced-use’ therapy builds upon the aforementioned concepts. Taub and Wolf presented a model in which a person who had had a stroke made unsuccessful motor attempts with their paretic extremity.4,5
This led to negative
reinforcement and suppression of the behavior. A therapist then became involved who taught compensatory motor strategies that had positive outcomes and reinforcements. Although not a functional task, the patient was able to complete the task with compensatory strategies. The less effective strategy was strengthened and the ‘potential ability’ was masked. In other words, there was a reservoir of abilities waiting to be tapped. This leads to the next logical question: how does one encourage patients with limited functional movement to perform functional tasks with multiple repetitions, particularly during the early stages of injury? The marriage of ‘high tech’ and ‘high touch’ provides a solution.
The Challenge—Flaccid Extremities, Paraplegia, and Quadriplegia
One can see how one might design tasks for patients who have enough residual function to perform functional tasks. For years, therapists have been limited in their ability to replicate functional tasks in patients with no movement or limited voluntary movement. As discussed above, it takes a certain number of repetitions of a functional task to drive neural repair. However, the range of motion of an upper extremity on a table (or a lower extremity on a mat) does not achieve this goal. This led to the development of a neuroprosthesis, which enables the patient to perform functional tasks with high repetitions, even when they have minimal voluntary movement.
Functional Electrical Stimulation
Electrical stimulation has been used for over a century to treat neural conditions. Low levels of electrical current are used to stimulate physical or bodily functions lost through nervous system impairment.
US NEUROLOGY Figure 1: The NESS H200® Hand Rehabilitation System
For years, electrodes were hooked up to single muscles or groups of muscles to facilitate increased movement. The therapist turned on the current while asking the patient to extend their wrist. This treatment operated under the idea that repeated use would strengthen the muscle. Conventional surface neuromuscular electrical stimulation (NMES) is limited by the difficulty in placing the electrodes consistently in the right places, and the failure to perform a coordinated task. What is needed is NMES that will enable the patient to perform a coordinated functional task with the critical number of repetitions (i.e. dose). The repeated movements induced by NMES will reinforce network patterns and lead to enhanced synaptic connections and neural plasticity.
Technological Advances in Upper Extremity Rehabilitation
Functional electrical stimulation (FES) enables therapists to combine NMES with task-specific training. FES can be delivered through a neuroprosthesis that allows a patient with limited or no movement to perform functional tasks over and over again. A new, noninvasive neuroprosthesis, the Bioness H200®
Hand Rehabilitation System,
provides reproducible, synchronized electrical stimulation of the flexor and extensor muscles of the affected arm so that the patient can perform a variety of functional tasks (see Figure 1). The NESS H200 is useful in promoting motor recovery not only in patients with stroke, but also in those with traumatic brain and spinal cord injury. The NESS H200 has five electrodes that come in different sizes, enabling therapists to ‘custom fit’ a patient. The electrodes are positioned over the extensor digitorum, extensor pollicis brevis, flexor digitorum superficialis, flexor pollicis longus, and thenar muscles. By customizing the size and location of the electrodes, the patient receives a consistent level of stimulation every time they use the device. The NESS H200 is programed to alternate between finger/wrist extension and finger/wrist flexion. Once the patient has been properly fitted with the NESS H200, the therapist designs a task-specific program, which might include:
• grasping, holding, and releasing large objects, such as soft Nerfballs; • • •
picking up and moving small objects on a table;
pinch grips to stack or lift, or performing overhead activities; and dressing, grooming, eating, opening bottles, and self-feeding.
One is limited only by the imagination of the therapist and the patient. The real breakthrough is that the NESS H200 meets the three crucial
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