Faculty Bibliography

Research Objectives: Processing speed (PS) deficits are among the most common neuropsychological (NP) deficits following traumatic brain injury (TBI). These objective deficits may lead to subjective feelings of being flooded and overwhelmed or that things happen too quickly that one can no longer keep up with cognitive demands made by external events. This subjective experience of slowed PS has been proposed to underlie symptoms of emotional reactivity (ER), such as, tension, frustration, and irritability, which in turn may exacerbate cognitive complaints. The aim of this study was to evaluate the role of objective PS deficits in ER and cognitive/somatic postconcussive symptoms (PCS) following mild TBI (mTBI). Design: Correlational/regression analyses examining objective PS measures, ER, and somatic/cognitive PCS. Setting: Large academic medical center. Participants: Adults with mTBI (n = 31), 52% female, primarily White (74%), average age of 35.8, with 16.1 years of education. Interventions: N/A. Main Outcome Measure(s): Standard TBI outcome battery, 6,7 addressing (a) objective NP impairments, (b) psychological status, and (c) PCS. ER was assessed using z-score composite of relevant self-report items. Results: Objective PS measures were significantly related to ER. ER explained a significant 33% of variance in somatic/cognitive PCS, Beta = -.62, t (29) = -3.15, p =.004, over and above variance explained directly by PS, Beta = -.07, t (29) = -.38, ns. Conclusions: ER is directly related to objective PS deficits. In addition, ER is a significant predictor of somatic/cognitive PCS, whereas objective PS measures are not directly related to PCS. Emotional reactions to the experience of objective cognitive slowing warrant further investigation as a predictor of those at risk for prolonged PCS. Further examination of ER as a predictor of PCS may lead to more accurate assessment/prognosis following mTBI

Objective(s): To determine if relationship between heart rate variability/ HRV and problem-solving is moderated by positive affect. Design: Quasi-experimental. Setting: Community-based structured day program. Participants: Thirteen individuals, aged 23-63 years with severe, chronic brain injury (13-40 years post-onset). Interventions: HRV biofeedback. Main Outcome Measure(s): PANAS positive affect/PANAS-PA; category test/CT; HRV- index (coherence ratio/CR). Results: Bivariate regression using HRV-CR to predict CT revealed moderately-large effect size, with trend towards significance, p=.085, ES(r) =.50. Similar overall interaction effect was observed when PANAS-PA was added as moderator, p=.07, ES (R²) =.23. Johnson Neyman technique revealed that when PANAS-PA was low, coherence did not have significant relationship with improvements in CT. However, when PANAS-PA was >5.79 above the mean (>36.64), the effect of coherence was in the expected negative direction (lower scores in CT reflect better performance) and significant, with large effect size, p<.05, ES(r) >.60. Conclusions: Published studies demonstrate significant association between problem-solving and HRV (Thayer, 2006; Porges, 2001). This sample demonstrated moderate-to-large main effect for HRV, which did not reach statistical significance. Taking into account levels of positive affect clarified the relationship and revealed that the effect of HRV on problem-solving was larged and statistically significantd when positive affect was high. The significant role of PANAS-PA in moderating problem solving performance is consistent with literature which found positive affect increases mental flexibility, creativity, and coping behaviors (Ashby, 1999; Damasio & Carvalho, 2013). Results are conceptually congruent with contemporary problem-solving cognitive rehabilitation models (e.g., Rath et al., 2011) and consistent with Shewchuk et al.'s (2000) study of healthy adults where negative problem-orientationdbeliefs and attitudes about one's own problem-solving abilitydimpeded objective performance on CT. These findings have important implications for addressing affect and problem-orientation in cognitive rehabilitation; dispositions to harbor pessimism about self might impede motivation for/attainment of meaningful, goal-directed behavior

This article describes a study using heart rate variability (HRV) biofeedback to treat emotional dysregulation in 13 individuals with severe chronic brain injury. Measures included HRV indices, tests of attention and problem solving, and informant reports of behavioral regulation. Results demonstrated that individuals with severe brain injury were able to learn HRV biofeedback and increase coherence between the parasympathetic and sympathetic nervous systems. Individuals who attained the greatest coherence were rated as being able to best regulate their emotions and behavior.