B-73 The Relationship Between Subjective and Objective Disinhibition in Mild Traumatic Brain Injury
Abstract Objective Veterans with mild traumatic brain injury (mTBI) frequently report cognitive difficulties, though these are not always supported by objective neuropsychological testing. The current study compared mTBI Veterans with subjective disinhibition to Veteran Controls (VC) on an objective response inhibition task while controlling for depression. Methods 53 mTBI Veterans and 31 VC with optimal effort completed a go/no-go response inhibition (RI) task and measures of subjective disinhibition (Frontal Systems Executive Behavior scale) and depression (Beck Depression Inventory-II). ANCOVAs compared RI performances of VC without cognitive complaints to (1) the total sample of mTBI Veterans and (2) to mTBI Veterans with (t-score>60; mTBI+disinhibition; n = 23) and without (t-score < 60; mTBI-disinhibition; n = 30) subjective complaints of disinhibition. Results Relative to the VC group, the mTBI Veterans endorsed significantly greater depressive symptoms (p < .001). No significant differences in RI performance were observed when the total mTBI sample was compared to VC. However, in the three group analysis, there was a significant effect of group (p = .002) controlling for depression (p = .396). Post-hoc analyses revealed the mTBI+disinhibition group performed significantly worse than the mTBI-disinhibition (p < .001) and VC (p < .001) groups; no significance differences in RI performance were observed between the mTBI-disinhibition and VC groups (p = .914). Conclusions While the larger mTBI group did not differ from VC on RI performance, mTBI Veterans with subjective disinhibition complaints evidenced poorer objective RI. Findings therefore suggest that Veterans with elevated subjective complaints may be at risk for experiencing objective cognitive difficulties. Future research is needed to elucidate the neural underpinnings of these group differences as well as clinical outcomes.