Objective Traumatic brain injury (TBI) survivors often exhibit problems with executive function (EF). Language use can also impact EF test performances. We examined the effects of TBI and bilingualism/monolingualism on several EF tests. Method The sample (N = 94) consisted of 37 healthy controls (19 bilingual; 18 monolingual), 30 acute TBI participants (10 bilingual; 20 monolingual), and 27 chronic TBI participants (16 bilingual; 11 monolingual). Acute TBI participants were tested 6 months post-injury and chronic TBI participants were tested 12 months or more post-injury. Stroop Color-Word (SCW), Delis-Kaplan Executive Function System Letter Fluency (DKEFS-LF), Trail Making Test part B (TMT-B) and a EF global composite (EF-GC) were used to assess EF. All participants passed performance validity testing. 3X2 ANOVAs were conducted to determine the effect of TBI and bilingualism/monolingualism on EF performances. Results Main effects were found between groups (control and TBI groups) on SCW, p = .046, ηp² = .07, TMT-B, p = .042, ηp² = .07, and EF-GC, p = .005, ηp² = .13; the 6-month TBI group performed worse than controls on TMT-B and EF-GC. Main effects were found for bilingualism/ monolingualism on SCW, p = .012, ηp² = .07, and TMT-B, p = .034, ηp² = .05; monolingual participants performed better than bilingual participants. No significant interactions between TBI and language were found. Conclusion The TBI group underperformed on SCW, TMT-B, and EF-GC compared to controls; relative to monolinguals, bilinguals underperformed on the SCW and TMT-B only. In conclusion, our findings seem to suggest that monolinguals have better cognitive flexibility compared to bilinguals that result in better EF performances.

Objective Traumatic brain injury (TBI) survivors exhibit cognitive deficits. Language factors can also influence neurocognitive performance. We examined the effects of TBI and bilingualism/monolingualism on a test of attention and cognitive speed (i.e., Symbol Digit Modalities Test; SDMT). Method The sample (N = 98) consisted of 37 controls (19 bilingual; 18 monolingual), 34 acute TBI participants (12 bilingual; 22 monolingual), and 27 chronic TBI participants (16 bilingual; 11 monolingual). Acute TBI participants were tested 6 months post-injury; chronic TBI participants were tested 12 months or more post-injury. All participants passed performance validity testing. 3X2 ANOVAs were conducted to determine the effect of TBI and language on SDMT written and oral performance. Results A main effect was found between groups (control and TBI groups) on SDMT written, p < .001, ηp² = .19 and SDMT oral p < .001, ηp² = .16. Pairwise comparisons revealed a difference between the control group and TBI groups, with TBI groups performing worse. A main effect for bilingualism/monolingualism was not found; interaction effects emerged between TBI and bilingualism/monolingualism on SDMT written, p < .05, ηp² = .07 and SDMT oral p < .05, ηp² = .07. Conclusion TBI groups performed worse than controls on the SDMT. Relative to monolinguals with TBI, our findings suggest better cognitive recovery of verbal attention and cognitive speed in bilingual TBI participants.

Objective Traumatic brain injury (TBI) impacts neurocognitive function. Language is also known to influence test performances. We examined the relationship between TBI and monolingualism/bilingualism on verbal and design fluency tests. Method The sample (N = 74) consisted of 33 healthy controls (18 bilingual; 15 monolingual), 15 acute TBI participants (6 bilingual; 9 monolingual), and 26 chronic TBI participants (15 bilingual; 11 monolingual). Acute TBI participants were tested 6 months post-injury and chronic TBI participants were tested 12 months or more post-injury. The Delis-Kaplan Executive Function System Letter Fluency (DKEFS-LF), Category Fluency (DKEFS-CF), Category Switching Fluency (DKEFS-CSF), and global verbal fluency composite (DKEFS-GVF) scores assessed verbal fluency; DKEFS fill-dots (DKEFS-FD), empty dots (DFEFS-ED), dot switching (DKEFS-DS), and global design fluency composite (DKEFS-GDF) scores assessed design fluency; and global verbal and non-verbal fluency composite (DKEFS-GF) assessed overall fluency. 3X2 ANOVAs were conducted to evaluate the effect of monolingualism/bilingualism on fluency performance in TBI and controls. Results The groups (control and TBI groups) differed for DKEFS-LF, p = .048, ηp² = .09, DKEFS-CF, p = .000, ηp² = .21, DKEFS-GVF, p = .004, ηp² = .15, DKEFS-ED, p = .008, ηp² = .13, DKEFS-GF, p = .001, ηp² = .20, with controls outperforming TBI groups on the DKEFS-CF, DKEFS-GVF, and DKEFS-GF. Furthermore, controls outperformed acute TBI participants on the DKEFS-LF and DKEFS-ED. Main effects were found for bilingualism/monolingualism on DKEFS-CF, p = .035, ηp² = .06, with bilinguals outperforming monolinguals. No interactions were found. Conclusion The TBI group had poor verbal and design fluency in contrast controls. Unexpectedly, bilinguals outperformed monolinguals on a task of verbal category fluency. Revealing that in the present study bilinguals have better semantic verbal fluency abilities.