A comparison of the functional connectome in mild traumatic brain injury and post-traumatic stress disorder

Association of mild traumatic brain injury, post-traumatic stress disorder, and other comorbidities on photosensitivity

SIGNIFICANCE

Photosensitivity is common after mild traumatic brain injury. However, this study demonstrates that photosensitivity is also impacted by common comorbidities that often occur with mild traumatic brain injury. Understanding how physical and psychological traumas impact photosensitivity can help improve provider care to trauma survivors and guide novel therapeutic interventions.

PURPOSE

This study aimed to characterize the association between mild traumatic brain injury and common comorbidities on photosensitivity in post-9/11 veterans.

METHODS

Existing data from the Translational Research Center for TBI and Stress Disorders cohort study were analyzed including traumatic brain injury history and post-traumatic stress disorder clinical diagnostic interviews; sleep quality, anxiety, and depression symptoms self-report questionnaires; and photosensitivity severity self-report from the Neurobehavioral Symptom Inventory. Analysis of covariance and multiple ordinal regression models were used to assess associations between mild traumatic brain injury and common comorbidities with photosensitivity severity.

RESULTS

Six hundred forty-one post-9/11 veterans were included in this study. An initial analysis showed that both mild traumatic brain injury and current post-traumatic stress disorder diagnosis were independently associated with higher photosensitivity ratings compared with veterans without either condition, with no interaction observed between these two conditions. Results of the ordinal regression models demonstrated positive associations between degree of photosensitivity and the number of mild traumatic brain injuries during military service and current post-traumatic stress disorder symptom severity, particularly hyperarousal symptoms, even when controlling for other factors. In addition, the degree of sleep disturbances and current anxiety symptoms were both positively associated with photosensitivity ratings, whereas depression symptoms, age, and sex were not.

CONCLUSIONS

Repetitive mild traumatic brain injury, post-traumatic stress disorder, anxiety, and sleep disturbances were all found to significantly impact photosensitivity severity and are therefore important clinical factors that eye care providers should consider when managing veterans with a history of deployment-related trauma reporting photosensitivity symptoms.

Disentangling effects of remote mild traumatic brain injury characteristics and posttraumatic stress on processing speed and executive function in veterans

Mild traumatic brain injury (mTBI) and posttraumatic stress are prevalent in military service members and share objective and subjective cognitive symptoms, complicating recovery. We investigated the effects of remote mTBI characteristics and current posttraumatic stress symptoms on neuropsychological performance in 152 veterans with a history of remote mTBI and current cognitive concerns. Participants completed clinical neuropsychological evaluations within a Veterans Affairs Level-II TBI/Polytrauma outpatient clinic (i.e. tertiary trauma care center for US military veterans outside of a research or teaching hospital setting). Archival data analysis of mTBI injury characteristics, clinical diagnoses, scores on the Posttraumatic Stress Disorder Checklist-Military Version (PCL-M) and performance on tests of processing speed, attention and executive function was conducted. Hierarchical linear regression demonstrated that elevated PCL-M scores were associated with slower performance on trail making test (TMT) Parts A and B (p < .016). PCL-M symptoms moderated the effect of alteration of consciousness (AOC) on TMT performance, with endorsement of AOC associated with better performance, but only when PCL-M scores were high (p < .005). Follow-up mediation analyses demonstrated that PCL-M score fully mediated the relationship between AOC and TMT-A performance and partially mediated the relationship between AOC and TMT-B performance. Post-hoc analyses meant to separate the impact of processing speed on TMT-B were all non-significant. Remote mTBI characteristics, specifically AOC, were not associated with decrements in cognitive performance. Posttraumatic symptoms were associated with worse processing speed, suggesting that psychological distress and psychopathology are contributing factors in understanding and treating persistent cognitive distress following remote mTBI.

Apelin-Overexpressing Neural Stem Cells in Conjunction with a Silk Fibroin Nanofiber Scaffold for the Treatment of Traumatic Brain Injury

Traumatic brain injury (TBI), especially moderate or severe TBI, is one of the most devastating injuries to the nervous system, as the existing therapies for neurological defect repair have difficulty achieving satisfactory results. Neural stem cells (NSCs) therapy is a potentially effective treatment option, especially after specific genetic modifications and when used in combination with biomimetic biological scaffolds. In this study, tussah silk fibroin (TSF) scaffolds with interconnected nanofibrous structures were fabricated using a top-down method. We constructed the apelin-overexpressing NSCs that were cocultured with a TSF nanofiber scaffold (TSFNS) that simulated the extracellular matrix in vitro. To verify the therapeutic efficacy of engineered NSCs in vivo, we constructed TBI models and randomized the C57BL/6 mice into three groups: a control group, an NSC-ctrl group (transplantation of NSCs integrated on TSFNS), and an NSC-apelin group (transplantation of apelin-overexpressing NSCs integrated on TSFNS). The neurological functions of the model mice were evaluated in stages. Specimens were obtained 24 days after transplantation for immunohistochemistry, immunofluorescence, and western blot experiments, and statistical analysis was performed. The results showed that the combination of the TSFNS and apelin overexpression guided extension and elevated the proliferation and differentiation of NSCs both in vivo and in vitro. Moreover, the transplantation of TSFNS-NSCs-Apelin reduced lesion volume, enhanced angiogenesis, inhibited neuronal apoptosis, reduced blood-brain barrier damage, and mitigated neuroinflammation. In summary, TSFNS-NSC-Apelin therapy could build a microenvironment that is more conducive to neural repair to promote the recovery of injured neurological function.