Increasing attention is being given to intensive functional training as a means of increasing motor function in the disabled. One form of intensive training is constraint-induced movement therapy (CIMT), which aims to increase the amount and quality of upper extremity movement in children with hemiplegic cerebral palsy (CP). A number of studies have suggested that CIMT is beneficial for many individuals with CP (see CIMT fact sheet, March 2007). However, CIMT has a number of limitations, including the fact that it is potentially invasive, and it focuses exclusively on one hand impairments, which does not greatly impact functional independence and quality of life. Given recent work showing impaired coordination of both hands, a better goal of upper extremity rehabilitation would be to increase functional independence and quality of life by improving use of both hands in cooperation.
Bilateral (or bimanual training) is a new class of interventions aimed at increasing the efficiency of movement in the context of using both hands together. The brain and spinal cord underlying human dexterity are capable of considerable reorganization after damage, likely responsible for recovery of function. Pathways on the same (ipsilateral) side of the impaired upper extremity have been implicated in the control of the affected hand in CP as well as the recovery of function after stroke in adults. Thus, task recruitment of these ipsilateral pathways, such as symmetrical bilateral movements, may be beneficial. Bilateral practice may result in changes in cortical representations and excitability in the undamaged hemisphere. This reasoning has provided the basis for bilateral training protocols in adults with stroke (e.g., 1). The efficacy of bilateral training in the stroke population is not clear, although several studies report positive outcomes. However, it should be noted that most of these training protocols involve non-functional, repetitive symmetrical movements (e.g., upper extremity cycling). Such tasks are unlikely to sustain interest for sufficient periods of time in children. Thus, protocols need to be created that are child friendly.
To date, there is limited work on bilateral training in the pediatric population. One protocol, Hand-Arm Bimanual Intensive Training (HABIT) has recently been developed and tested with support from the United Cerebral Palsy Research and Education Foundation (2). HABIT takes advantage of the key element of CIMT, intensive practice, but does not involve restraint of the less affected upper extremity. Instead, it utilizes structured (part and whole) task practice embedded in bimanual play and functional activities. Task difficulty is increased by progressing the more affected hand from a passive stabilizer to an active manipulator. HABIT is performed in a day-camp setting and is based on understanding of the mechanisms of underlying hand impairments in CP, recognized benefit of treatment intensity, principles of motor learning and neuroplasticity using prototypical behaviors, goal orientation, knowledge of results, motivation and rewards.
In a small randomized trial, researchers at Teachers College, Columbia University have presented the results of a preliminary study of HABIT (3). A single-blinded randomized control study was performed to examine its efficacy in 20 children (3.5-15.5 yrs). Children were engaged in play and functional activities that provided structured bimanual practice six-hours per day for 10 days. Children who received HABIT demonstrated improved scores on the Assisting Hand Assessment and bimanual items of the Bruininks-Oseretsky Test of Motor Proficiency, increased involved extremity use measured using accelerometry and a caregiver survey, and better coordination completing a draw-opening task with two hands measured kinematically. Thus, the results from this report were encouraging.
Bimanual training is based on sound scientific principles, and in theory, should address some of the limitations of CIMT. Despite its promise, a more complete understanding of the neurological basis of hemiplegia and mechanisms of recovery are needed to fine-tune such protocols. Larger studies across a more diverse subject population with long-term follow-up are required. The appropriate age and impairment levels need to be identified and factors such as side and location of brain damage, attention span, optimal dosage and identification of key ingredients need to be considered to ultimately define the most efficacious rehabilitation strategy. Finally, the extent to which it may compliment CIMT will be of interest.
(1) Cauraugh JH, Summers JJ (2005) Neural plasticity and bilateral movements: A rehabilitation approach for chronic stroke. Prog Neurobiol:75:309-320
(2) Charles J, Gordon AM (2006) Development of Hand-Arm Bimanual Intensive Therapy (HABIT) for Improving Bimanual Coordination in Children with Hemiplegic Cerebral Palsy.
Dev Med Child Neurol 48:931-936.
(3) Charles J, Gordon AM (2006) Efficacy of Hand-Arm Intensive Bimanual Training (HABIT) on upper extremity movement in children with hemiplegic cerebral palsy. Dev Med Child Neurol 48: 24 (Supplement No. 106)