Abstracts

Rationale: The effects of continuous therapy in individuals with chronic disability is unknown. In case of cerebral hemispherectomy there is no prospect of recruiting additional areas in the affected hemisphere and contralateral corticospinal tract is not available. This limits recovery to what the remaining ipsilateral tract can do together with the mechanisms of spinal cord that are poorly understood. We evaluated the effects of intensive therapy on motor outcomes and cortical representations in 20 individuals after right and left hemispherectomy. Age-appropriate gait, balance and walking speed scores were calculated and varied between 65 and 85% of respective scores for neurologically-intact controls. Brain imaging showed that all participants had partial overlap between M1S1 of both feet that increased following therapy. Six years later a subset of the same group has repeated therapy to investigate the resiliency of cortical remodeling noted in therapy round 1. Methods: Twenty individuals post cerebral hemispherectomy (right resection, n=8, age range 6-25 years) underwent intensive Body Weight Supported therapy to improve gait, balance and walking speed. Each participant had 30 hrs of individual therapy that included treadmill and overground training with brain imaging performed before and after therapy. The subset of this cohort underwent the repeat therapy pulse 6 years later to investigate both motor development and resiliency of cortical remodeling we documented during the first round of intervention. Results: Age-appropriate normalized scores were calculated and showed that all participants either remained on the same functional level or showed motor regression. Participants presented with significant pain issues related to uneven gait. The improvements following therapy Round 2 were much more modest than what we saw during Round 1. Motor maps seen pre-therapy showed very little overlap between affected and non-affected feet similar to what we saw during first session. In the same vein, following intervention there was more overlap between the maps and stronger activations. Conclusions: During 6 years between therapy pulses and with no physical therapy offered to our participants they regressed in their motor functional presentation. Similar to individuals with chronic disabilities our participants developed pain and emotional disturbances associated with motor activity necessary for everyday functioning. Motor representations did not show resiliency and "migrated" into their old places. We were able to see improvements and cortical remodeling following repeat therapy pulse, but results were less pronounced than what we documented the first time. We suggest that repeat therapy pulses are necessary to arrest the loss of therapy-induced gains and cortical remodeling associated with it.