Altered Sensorimotor Neuroplasticity in Subacute Patients with Non-Severe Burn Injury

Abstract

Background Burn injuries affect the central nervous system, and evidence suggests they induce changes in cortical excitability related to motor dysfunction. The current study investigated markers of neuroplasticity in the motor cortex and motor performance in the subacute period following burn injury. Methods Thirty-four patients with a non-severe burn injury (total body surface area: 1.0 ± 2.0%; 16 females; age: 46.0 ± 14.0 years) participated in a longitudinal study with assessments ranging from ~1 to ~17 weeks post-injury. Transcranial magnetic stimulation (TMS) was used to evaluate motor cortex excitability and short- and long-intracortical inhibition (SICI; LICI) before and after application of paired associative stimulation (PAS) to induce neuroplasticity. Motor performance was assessed using the Purdue Pegboard. Results Patients showed improvements in bilateral motor performance from ~3 to ~6 weeks post-injury. PAS did not induce any change in net motor cortex excitability or SICI but increased LICI, which was greatest ~6 weeks post-injury. Adjusted modelling showed that greater PAS-induced increase in LICI was associated with better bilateral motor performance, suggesting an association between PAS-induced neuroplasticity of long-acting inhibitory circuits in the primary motor cortex and motor function following burn injury. Discussion These findings highlight a potential role for neuroplasticity of inhibitory circuits in the motor cortex in recovery of motor function following burn injury. Conclusion The data provide a neurophysiological basis to test whether targeting inhibitory networks in the subacute period after burn injury can enhance or expedite functional recovery.