Stroke Rehabilitation A Novel Treatment Pays Off

Stroke Rehabilitation A Novel Treatment Pays Off

In a​ landmark study, researchers at​ the​ University of​ Alabama at​ Birmingham used a​ randomized controlled trial -- the​ gold standard method for​ evaluating the​ effectiveness of​ a​ treatment -- to​ show that immobilizing the​ good arm of​ stroke patients and​ intensively exercising the​ weakened arm actually improved recovery, even when performed long after the​ stroke occurred. at​ one level, randomized controlled trials in​ the​ field of​ rehabilitation medicine have been so rare that the​ publication of​ each and​ every one should be applauded. at​ another level, the​ outcome of​ this study is​ so satisfying in​ terms of​ what we think we know about brain physiology (function) that even if​ the​ results turn out not to​ be true, they ought to​ be.

A controlled trial is​ one in​ which there is​ a​ comparison group of​ patients that is​ either untreated or​ is​ treated differently. When a​ controlled trial is​ also randomized, it​ means that upon entering the​ study, participants agree to​ be assigned to​ one group or​ the​ other based on the​ equivalent of​ a​ coin-toss. Randomization eliminates bias that might otherwise come from (knowingly or​ unknowingly) assigning more promising patients to​ one group and​ less promising patients to​ the​ other.

Publishing their results in​ the​ March 2018 online issue of​ Stroke, a​ medical journal, Edward Taub, PhD, and​ co-workers studied 21 patients treated with "constraint-induced movement therapy" (CI) and​ compared their outcomes to​ another 20 stroke patients who received placebo treatment.

In strokes a​ loss of​ circulation damages a​ portion of​ the​ brain, resulting in​ impairment of​ whatever mental or​ bodily function that part of​ the​ brain controls. Strokes often cause weakness in​ an​ arm with or​ without concurrent numbness. Strokes are the​ leading cause of​ long-term disability in​ the​ U.S.

The researchers included stroke victims in​ their study who had mild to​ moderate impairment in​ use of​ their affected arms, but excluded those with severe impairment. the​ research subjects varied widely in​ age, averaging in​ their fifties. the​ investigators selected patients whose stroke had occurred a​ minimum of​ one year earlier with an​ average interval between stroke and​ treatment of​ 4.5 years. Patients with concurrent numbness were included, but those with poor walking or​ balance were excluded, as​ were patients with excessive confusion or​ too much additional impairment caused by other medical conditions.

The CI treatment was administered over a​ 2-week span, during which the​ good arm was immobilized about 90% of​ the​ time with an​ arm-sling and​ a​ hand-splint. CI patients had 10 weekday sessions with therapists, lasting 6 hours each. During those sessions, patients received one-on-one therapy that was individualized to​ their needs and​ abilities and​ involved specific, practical tasks of​ gradually increasing difficulty. the​ therapists praised patients each time their performances improved even just slightly. By contrast, placebo-treated patients received a​ more general program of​ physical fitness, cognitive and​ relaxation exercises over the​ same schedule.

The abilities of​ CI and​ placebo-treated patients were compared in​ two main ways. in​ one, the​ research subjects were videotaped in​ the​ laboratory while attempting specific tasks like holding a​ book, picking up a​ glass and​ brushing teeth. Their performances were rated by viewers who were purposely not told which treatment the​ subject received. the​ other rating, called the​ "real world outcome," came from structured interviews of​ the​ patients and​ their caregivers concerning performance outside the​ treatment facility.

The researchers found significant improvements in​ CI-treated patients compared with both their own initial abilities and​ those of​ patients receiving placebo treatment. the​ CI patients showed a​ moderate improvement in​ their laboratory skills and​ a​ large improvement in​ use of​ the​ affected arms in​ their daily lives. Improvement was still evident 4 weeks after treatment, and​ even after 2 years in​ the​ 14 of​ 21 CI patients who could be retested at​ that time.

The researchers interpreted the​ improvement as​ due to​ two factors. the​ first factor, probably more important for​ faster gains, was in​ overcoming "learned non-use" of​ the​ weaker arm. the​ idea is​ that after a​ stroke, patients quickly learn to​ avoid using the​ weaker arm to​ a​ greater extent than its impairment might warrant, and​ CI training forces them to​ put it​ back into action. the​ second suspected factor, developing more slowly, was "neural plasticity" or​ actual rewiring of​ the​ brain. in​ neural plasticity surviving brain cells -- previously uninvolved or​ less involved in​ controlling use of​ the​ arm -- attempt to​ make up for​ the​ lost brain cells either by creating new contacts with other brain cells or​ by modifying the​ effectiveness of​ existing links.

In 1992 researchers at​ the​ Hammersmith Hospital in​ London used positron emission tomographic (PET) scans to​ examine patterns of​ brain use in​ stroke patients. PET scans are good at​ showing which parts of​ the​ brain are most engaged by specific tasks. Investigators compared PET scans in​ 10 patients who recovered from a​ stroke to​ those of​ 10 patients who never had a​ stroke. in​ this study subjects repeatedly moved one hand (which in​ the​ stroke patients was the​ affected hand) while their brains were being scanned. Compared to​ non-stroke patients, stroke patients used more areas on both sides of​ the​ brain to​ perform the​ requested movements, as​ if​ the​ surviving brain cells were trying to​ fill in​ for​ their fallen comrades.

Taub and​ collaborators at​ the​ National Institute of​ Neurological Disorders and​ Stroke used similar methods to​ compare patterns of​ brain activation in​ 9 CI-treated stroke patients with those in​ 7 less-intensively treated stroke patients. in​ this 2003 study, CI-treated patients showed a​ shift in​ the​ extent to​ which different parts of​ the​ brain participated in​ moving the​ fingers of​ the​ weakened hand. Thus, CI treatment seemed to​ modify the​ brain pathways responsible for​ the​ finger movements.

(C) 2018 by Gary Cordingley

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