Objective: Cortical excitability is simply defined as excitability of brain tissue. It can electro physiologically be measured by transcranial magnetic stimulation (TMS). In this study, we aimed to investigate the effect of physical injuries on cortical excitability in patients diagnosed with post-traumatic stress disorder (PTSD).
Method: Thirteen PTSD patients with physical injury (injuries that disrupts the body integrity other than central and peripheral nervous system injuries that affect MEP measures; such as muscular and/or skeletal injuries) and 24 PTSD patients who did not have a physical injury were included in the study. Patient groups were compared by means of motor evoked potentials.
Results: Motor stimulation threshold was lower at physically injured patients than in patients without physical injury but the difference was not statistically significant. Measured cortical amplitudes were greater at patients with injury. In particular, the amplitudes measured from the right abductor pollicis brevis muscle (APB) and left APB were significantly greater (p<0.001). In patients with injury; right contralateral cortical silent period (CSP), the left contralateral CSP and right ipsilateral CSP were found to be shorter (p; 0.049, 0.019 and 0.003, respectively)
Conclusion: The findings of lower motor stimulation threshold and higher measured MEP amplitudes show that cortical excitability was affected more in PTSD patients with physical injuries than in patients without injury. CSP is considered as a sign of GABA dysfunction. Deterioration of the function of GABA, the main inhibitory neurotransmitter, may be the main reason for these excitability changes.