These comments are based on this article, Neuroplasticity as a proposed mechanism for the efficacy of optometric vision therapy and rehabilitation, written by Dr. Julia Huang.
In the past 10 years, constraint-induced (CI) movement therapy has become the treatment of choice for patients with an upper-extremity hemiparesis after a stroke. CI therapy involves forcing the patient to use the paretic arm by restraining the non-impaired arm for several hours everyday. The patient must be actively engaged in various task-oriented activities which are made more difficult as improvement is noted. These patients make marked improvements in motor function AND quality-of-life. These improvements in function correlate with changes in the brain. Research studies have shown increases in gray matter in both sensory and motor areas, on both sides of the brain. CI therapy is based on reversing “learned non-use,” which was first described in animal studies. Monkeys are able to recover function of affected limbs following surgical destruction of selected nerves, when the non-affected limb is tied down.
More traditional occupational and physical therapy focus on teaching the use of the unaffected limb to do all the work. These studies demonstrate why this approach is ineffective at enabling a patient to RECOVER movement and function of the affected limb. The need for assistive devices, braces, and wheelchairs is lessening because CI therapy induces changes in brain structure that result in improvements in movement and function.
These principles of CI therapy are now finding their way into other rehabilitative modalities, such as speech therapy. By preventing patients from using compensatory strategies such as pointing and gesturing, and condensing 30 hours of therapy into an intensive 2 week program, patients are making significant improvements in language functions. The scientific community is beginning to embrace the concept that rehabilitation of motor, sensory and cognitive impairments can ALTER brain STRUCTURE and result in the recovery of FUNCTION. The neuroplasticity of the human brain can be invoked without regard to the age of the patient, or the severity or duration of the loss of function.
Developmental optometrists have been using these same principles for ages, most notably in the treatment of amblyopia. By patching the non-affected eye for several hours per day, the patient is forced to learn to use the amblyopic eye. Therapy includes the addition of a series of task-oriented activities which are made more difficult as improvements are noted. Reversing “learned non-use” occurs in patients of all ages, by strengthening synaptic connections and inducing cortical reorganization. The induction of neuroplasticity in the treatment of amblyopia uses the same principles as other rehabilitation specialists: repetition, motivation, loading, multi-sensory integration and feedback. The only difference is that developmental optometrists were utilizing these principles clinically before they were validated by recent research. Yes I’ve been there and done that!
Recent research from the Pediatric Eye Disease Investigator Group (PEDIG) has provided the evidence of the benefits of patching or pharmacological penalization with atropine in the treatment of amblyopia. The addition of near activities to a patching regimen has also been shown to be effective. Now, in addition to having been there and done that, I am here, as the research proves that the clinical practices I use every day are evidence-based. As a result, I will continue to think beyond the limitations imposed by current research and push the envelope to do more to help my patients improve their quality of life. I will wait patiently for the science to catch up to my clinical practice. I love my job.