ISC Meeting Highlights: Latest Advances and Updates in Stroke Rehabilitation

March 22, 2005

ISC Meeting Highlights: Latest Advances and Updates in Stroke Rehabilitation

Modified constraint-induced therapy (CIT), mental practice, and cortical stimulation can significantly improve upper extremity function in patients receiving treatment for hemiparetic chronic stroke, according to research presented in February at the International Stroke Conference in New Orleans. Surprisingly, however, data from studies conducted at the Center for Physical Medicine and Rehabilitation at Case Western Reserve University in Cleveland revealed that although patients with chronic stroke treated with percutaneous intramuscular neuromuscular electrical stimulation (NMES) experienced pain relief, they fared no better biomechanically than controls. A British study by researchers from Northumbria Healthcare NHS Trust in Northumberland, UK, also found that surface NMES providedno benefit in acute stroke patients and, in fact, suggested the therapy might actually impede functional recovery.Two separate reports presented by researchers from the University of Cincinnati related that modified CIT and mental practice resulted in significant upper extremity functional improvement in patients with chronic stroke. After 10 weeks of the CIT protocol, which involved 3 outpatient sessions per week plus 5 hours of restraint per day for 5 days per week, 6 patients with chronic stroke significantly improved their distal motor function by an average of 7.7 points out of 57 on the Action Research Arm Test. In addition, evidence of cortical reorganization on functional MRI, in comparison with baseline scans, was seen in all patients.VALUE OF MENTAL PRACTICEBecause of concerns about potential challenges regarding compliance with the CIT protocols, the Cincinnati researchers also have been studying the therapeutic benefits of mental practice. "Too often we practice in the gym with patients, and then we send them home, and they're not as compliant as we like," said Stephen J. Page, PhD, director of research in the Department of Physical Medicine and Rehabilitation at the university, and presenter of the group's mental practice results during the conference. "Mental practice is very easy to do at home."Mental practice, which involves imagining functional movements (in this case with the affected limb), may be less familiar to practitioners who work with stroke patients than to their colleagues who work with performers. "A lot of athletes use it; a lot of musicians use it," Page said.Six patients with chronic stroke received a half hour of physical therapy followed by a half hour of mental practice twice a week for 6 weeks. The researchers found significant improvements in reaching distance and elbow extension, as well as in peak linear velocity for "reach out" (reaching for an object at the level of the olecranon) and "reach up" (at the level of the acromioclavicular joint) tests. Improved scores on the Action Research Arm and Fugl-Meyer (FM) tests also supported these kinematic measures.A more invasive option-implantation of a cortical stimulator in the hand/wrist motor cortex of the brain-shows promise for improving upper extremity function in more severely impaired patients. Researchers from the University of Illinois at Chicago implanted both an epidural electrode array and pulse generator that delivered subthreshold cortical stimulation during rehabilitation sessions in 12 patients. This group and another group of 12 control patients performed 6 weeks of intensive therapy 5 days per week for two 1.5-hour sessions per day. The researchers found greater improvement in upper extremity function, as measured by the FM test and Arm Motor Ability Test (AMAT), in the patients who received cortical stimulation than in the controls. They also found that those patients who received cortical stimulation were more likely than controls to demonstrate clinically meaningful improvement, defined as more than 3.5 points on the FM test or more than 0.2 points on the 6-point AMAT (Table). However, in the subset of patients who were most impaired (those with upper extremity FM scores less than 28), no clinical benefit was seen in either group.PERCUTANEOUS INTRAMUSCULAR NMES AND PAIN RELIEFResearchers from Case Western Reserve University reported that pain relief experienced at 12 months following percutaneous intramuscular NMES was equivalent to pain relief experienced at 6 months following the procedure in patients with chronic stroke.In an earlier study reported in the May issue of the Archives of Physical Medicine and Rehabilitation ("Intramuscular neuromuscular electric stimulation for poststroke shoulder pain: a multicenter randomized clinical trial," pages 695-704), 61 patients were randomized to 6 weeks of treatment with either intramuscular NMES or a shoulder sling. Patients in the intervention group received stimulation in the supraspinatus, posterior deltoid, middle deltoid, and trapezius for 6 hours per day. Six months after the end of treatment, 72% of those in the intervention group had improved by at least 2 points on the Brief Pain Inventory scale. In comparison, such improvement was seen in only 38% of the control group.At 1 year after the end of treatment, the same degree of pain relief was reported in 78% of patients who received intervention and in 52% of controls, reported John Chae, MD, during the conference. Chae, who is one of the principal authors of the study, is associate professor of biomedical engineering and director of stroke rehabilitation at Case Western. He added that the improvement seen in the control group from 6 months to 1 year reflects the natural recovery over time that one would expect in an untreated patient population.Despite the pain-ameliorating effects of intramuscular NMES, Chae said he and his colleagues did not observe any improvement in motor impairment, disability, pain-free range of motion, or spasticity in the treated patients compared with the controls."We're kind of in a quandary here because we thought we would be improving biomechanics, but our results do not support that," he said.A team of British investigators had hoped to show that surface NMES is effective in improving upper extremity function and reducing shoulder pain in patients with acute stroke. However, in a controlled study in which all 155 patients wore surface electrodes but only 80 received the electrical stimulation, the researchers found greater functional gains at 3 months in the control group than in the NMES group. Pain levels did not differ between the groups."Routine use of surface NMES to the proximal upper limb after acute stroke cannot be recommended," said Catherine J. Church, MBBS, MRCP, a researcher with Northumbria Healthcare NHS Trust in Northumberland, UK, who presented her group's results at the conference.---Sidebar-Surface ETMS Offers Hope for Severely ImpairedAs promising as interventions such as constraint-induced therapy (CIT) and mental practice may be, the baseline level of function required for these treatments limits the number of patients receiving treatment for stroke who can benefit. Early results from the University of Cincinnati, however, suggest that surface electromyogram-triggered neuromuscular stimulation (ETMS) may help more severely impaired patients.In severe motor impairment, 2 significant roadblocks to therapy exist, said Stephen J. Page, PhD, director of research in the Department of Physical Medicine and Rehabilitation at the university. Only about 20% of all patients being treated for stroke have the distal motor function required for most upper extremity rehabilitation exercises. In addition, it is often difficult for a patient with a flaccid limb to practice at a level that will promote plasticity. "These folks can't even practice on their own because they have no movement," Page said.With ETMS, a patient is able to see the electromyographic signals while he or she attempts to activate affected muscles, which provides important visual feedback. The stimulation device is programmed so that if a patient achieves a preset threshold electromygraphic level-even if that level alone is not enough to facilitate movement-the muscle receives enough stimulation to make the movement possible, as a reward.The researchers studied the effects of use of ETMS for a half hour per day, twice a day, 5 days a week for 8 weeks. In 16 treated patients, significant improvement in active wrist extension, from 15 degrees preintervention to 36.3 degrees postintervention, was seen; no such improvement was seen in the 15 controls. Seven of the 16 treated patients went on to successfully qualify for and complete a modified CIT protocol, Page said. "Perhaps ETMS can serve as a possible bridge to other therapies," he added.