SY1.6. Therapeutic application of transcranial magnetic stimulation in stroke

Abstract

Hundreds of studies have investigated the possible benefits of non-invasive brain stimulation techniques for promoting recovery and outcomes after stroke. Most of these have applied suppressive forms of transcranial magnetic and direct current stimulation to contralesional motor cortex, based on the interhemispheric imbalance model. This model posits that the contralesional primary motor cortex is hyperexcitable after stroke and excessively inhibits the ipsilesional primary motor cortex via transcallosal projections. The assumption is that reorganisation and recovery in the ipsilesional hemisphere can be promoted by reducing the excitability of contralesional hemisphere, to reduce its transcallosal inhibition of the ipsilesional hemisphere. However, this general strategy doesn’t reliably improve motor performance, and non-invasive brain stimulation techniques have not translated to routine clinical care. This presentation will identify the limitations of previous work, and draw from more recent studies that prompt a re-think of the interhemispheric imbalance model, and the role of interhemispheric inhibition in motor control. Deepening our understanding of interhemispheric interactions after stroke may enable more personalised therapeutic applications of transcranial stimulation to promote recovery and improve outcomes.