Impairment of emotional processing from cumulative repetitive subconcussion: Evidence from event-related potentials and sLORETA in parachuters.

Repetitive subconcussion, often overlooked due to subtle symptoms, but it can lead to cumulative neural alteration. Repetitive subconcussion, commonly arising from indirect brain trauma during sports or military activities, may affect emotional processing and cognition, yet their long-term effects are unclear. This study uses event-related potentials (ERP) and standardized low-resolution brain electromagnetic tomography (sLORETA) to assess the impact of repetitive subconcussive exposure on emotional processing in parachuters. Seventy-five parachuters, divided into low, medium, and high exposure groups based on training duration, and 25 healthy controls were recruited. Participants completed the Mini-Mental State Examination (MMSE) and Beck Depression Inventory-II (BDI-II) and viewed emotional images during EEG recording to measure late positive potential (LPP) amplitudes. sLORETA identified activation patterns in emotional processing regions. Correlation between the number of jumps and LPP amplitude and scale scores were analysed.Results: Compared to healthy controls, medium and high exposure groups exhibited reduced LPP amplitudes, indicating impaired emotional processing. sLORETA analysis revealed no differences in the low exposure group, reduced activation in BA6 for the medium group, and diminished activation in BA2, BA40, and BA46 for the high group. Jump frequency correlated negatively with LPP amplitudes and positively with BDI-II scores. The results demonstrate emotional processing impairment from repetitive subconcussion, with corresponding reductions in BA6, BA2, BA40, and BA46 activation. LPP amplitudes and activation in specific brain regions may serve as biomarkers for brain health assessment in exposed populations. This study highlights the risks of repetitive subconcussion, offering a foundation for targeted interventions.