Characterising manual dexterity, motor cortex neuroplasticity, and intracortical inhibition long after burn injury.

Abstract

Persistent motor dysfunction after burn injury may be due to altered motor cortex and corticospinal tract function. This study examined manual dexterity, motor cortex neuroplasticity, and intracortical inhibition in former burn patients 1-3 years after minor injury (<10% TBSA). Thirty former burn patients (TBSA: 0.78 ± 1.08%) and 30 non-injured controls participated. Manual dexterity was assessed using the Purdue Pegboard. Transcranial magnetic stimulation (TMS) was used to measure motor cortex excitability (motor evoked potential [MEP] amplitude) and short- and long-interval intracortical inhibition (SICI, LICI) before and after paired-associative stimulation (PAS) to induce neuroplasticity. Former burn patients performed worse than controls on the bimanual assembly subtest of the Purdue Pegboard. PAS did not induce changes in MEP amplitude but increased LICI in both burn patients and control participants. In burn patients, baseline LICI was related to bimanual performance differently than controls. These findings suggest poorer bimanual motor function persists after minor burns, and differences in the association between inhibition and bimanual dexterity between burn and control groups. Further research should explore whether targeting motor cortex inhibitory circuits can improve motor performance following burn injury.