Victims of electrical injury (EI) often experience injuries to the peripheral nervous system and neuromuscular damage that may diminish motor function, such as flexibility/dexterity. These difficulties may continue after rehabilitation due to the reorganization of muscle afferent projections during peripheral nerve regeneration. Therefore, understanding how patients with a history of thermal burn injuries perform on motoric measures is necessary to explain the impact neuromuscular damage has on both motor and non-motor tests of cognition. However, no studies have examined the impact of motor functioning on cognition in patients who experienced thermal and electrical injuries compared to an electrical shock injury. This study explored the impact of motor dysfunction and psychiatric distress measured by depression severity on psychomotor speed and executive test performances among EI patients with and without thermal burn injuries.

This cross-sectional study consisted of EI patients undergoing an outpatient neuropsychological evaluation, including tests of motor dexterity (Grooved Pegboard [GP]), psychomotor speed (Wechsler Adult Intelligence Scale-IV Coding, Trail Making Test [TMT] Part A), and executive functioning (Stroop Color and Word Test [SCWT] Color-Word trial, TMT Part B). The sample was 83% male and 17% female, 88% White, 3% Black, 5% Hispanic, and 2% other race/ethnicity, with a mean age of 43.9 years (SD=11.36), mean education of 12.9 years (SD=2.05), and mean depression severity of 20.05 (SD=12.59) on the Beck Depression Inventory-II (BDI-II). Exclusion criteria were: 1) injury history of moderate-to-severe head trauma, 2) >2 performance validity test failures, and 3) any amputation of the upper extremity. Regression analyses included GP T-Scores for dominant hand and BDI-II total score as independent variables and neuropsychological normative test data as dependent variables.

Among validly performing patients with EI (n=86), regression analyses revealed GP performance accounted for significant variance (R2 =.153-.169) on all neuropsychological measures. Among EI patients with burn injuries (n=50), regression analyses revealed GP performance accounted for significant variance (R2 =.197-.266) on all neuropsychological measures. Among EI patients without burn injuries (n=36), analyses revealed that neither GP performance nor BDI-II severity accounted for significant variance across the neurocognitive tests (R2=.056-.142). Furthermore, among EI patients with burn injuries and the total sample, regression analyses revealed depression severity negatively predicted GP performance (R2 =.099-.13), however, in patients without burn injuries, depression did not predict GP performance (R2 =.052).

Overall, results showed that GP performance is a significant predictor of neurocognitive performance on both motor and non-motor measures in EI patients with burn injuries. Therefore, among EI patients with burn injuries, GP performance may have potential utility as an early indicator of injury severity, considering that it predicts neuropsychological test performance on measures of psychomotor speed and executive functioning. Lastly, depression predicted GP performance within the burn injury sample illustrating that psychological distress may negatively impact motor functionality.