Early Measures of TBI Severity Poorly Predict Later Individual Impairment in a Rat Fluid Percussion Model

Trajectories of Global Functioning Over the 10 Years After Traumatic Brain Injury in Black Individuals: A Model System Study

OBJECTIVE

This study examined longitudinal global functioning trajectories over the 10 years after traumatic brain injury (TBI) in a group of Black individuals, and demographic and injury-related predictors of those trajectories.

DESIGN

Participants completed follow-up data collections at 1, 2, 5, and 10 years after TBI and being discharged from acute rehabilitation.

SETTING

TBI Model System (TBIMS) hospitals.

PARTICIPANTS

This study included a subsample of Black individuals (N=2523) in the TBIMS National Database who had a completed global functioning scores at 1 or more follow-up time points.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Glasgow Outcome Scale-Extended (GOS-E).

RESULTS

GOS-E scores across the full sample tended to increase slightly between years 1 and 2 and then plateaued for the successive years such that a quadratic, or U-shaped, trend best fit the data. Younger age (P<.001), higher level of education (P<.001), private insurance (P=.007), and shorter posttraumatic amnesia (PTA) duration (P<.001) were significant predictors of higher GOS-E trajectories. There was also a significant time2 × age effect (P<.001), such that younger adults improved slightly over the first 5 years and plateaued between years 5 and 10 relative to a general decline for older adults.

CONCLUSIONS

These findings suggest that age, education, insurance status, and PTA are important predictors of long-term global functional outcomes for Black individuals with TBI. Identifying baseline risk factors for Black individuals who may experience lower global functioning trajectories can inform development of targeted interventions and be a first step in working to reduce health disparities in functional outcomes in this group.

Attention Training After Moderate-to-Severe Traumatic Brain Injury in Adults: A Systematic Review

OBJECTIVE

To determine the extent and efficacy of attentional training as a form of neuropsychological rehabilitation to ameliorate attention deficits in adults with moderate-to-severe traumatic brain injury.

DATA SOURCES

Articles published in Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, PubMed, PsycINFO, Scopus, and Web of Science were searched between January 17, and February 27, 2021.

STUDY SELECTION

Two reviewers blindly assessed studies for eligibility according to the following criteria: any article evaluating the efficacy of any type of behavioral intervention that targeted attention (by means of cognitive rehabilitative, psychoeducational, or neuropsychological strategies, at either an individual or group level) in adults who had sustained a formally documented moderate-to-severe traumatic brain injury.

DATA EXTRACTION

Methodological quality of each article was blindly assessed by 2 reviewers. Data were extracted from each study, including study type, sample size, sample characteristics, summary of intervention, measures used to assess attention, statistical outcomes and results, effect size, conclusion, and limitations.

DATA SYNTHESIS

7314 articles were retrieved from databases, 4325 articles remained after duplicate removal, and finally 21 articles met eligibility criteria and were included in this review. Articles represented varied methodological quality in group or single subject design. Irrespective of the heterogeneity regarding intervention types and attentional outcome measures used across the studies, overall findings suggest that attentional gains can be made in this sample, irrespective of time since injury, age, and injury severity. Further, a growing interest in technology-based interventions is frequently used and holds promise to bettering rehabilitation efforts. However, there is still limited evidence supporting the ecological validity of attentional training interventions (eg, the transfer of treatment effects to daily activities).

CONCLUSIONS

This article plays a crucial role in informing ongoing rehabilitation practices, guiding clinicians with evidence-based strategies and shaping future research directions for more effective attentional training guidelines.

Model matters: Differential outcomes in traumatic optic neuropathy pathophysiology between blunt and blast-wave mediated head injuries

Over 3 million people in the United States live with long-term disability because of a traumatic brain injury (TBI). The purpose of this study was to characterize and compare two different animal models of TBI (blunt head trauma and blast TBI) to determine common and divergent characteristics of these models. With recent literature reviews noting the prevalence of visual system injury in animal models of TBI, coupled with clinical estimates of 50-75% of all TBI cases, we decided to assess commonalities, if they existed, through visual system injury. A unilateral (left directed) blast and repeat blast model injury with coup-contra-coup injury patterns were compared to a midline blunt injury. Injuries were induced in adult male mice to observe and quantify visual deficits. Retinal ganglion cell loss and axonal degeneration in the optic tract, superior colliculus, and lateral geniculate nuclei were examined to trace injury outcomes throughout major vision-associated areas. Optokinetic response, immunohistochemistry, and western blots were analyzed. Where a single blunt injury produces significant visual deficits a single blast injury appears to have less severe visual consequences. Visual deficits after repeat blasts are similar to a single blast. Single blast injury induces contralateral damage to the right optic chiasm and tract whereas bilateral injury follows a single blunt TBI. Repeat blast injuries are required to see degeneration patterns in downstream regions similar to the damage seen in a single blunt injury. This finding is further supported by amyloid precursor protein (APP) staining in injured cohorts. Blunt injured groups present with staining 1.2 mm ahead of the optic nerve, indicating axonal breakage closer to the optic chiasm. In blast groups, APP was identifiable in a bilateral pattern only in the geniculate nucleus. Evidence for unilateral neuronal degeneration in brain tissue with bilateral axonal ruptures are pivotal discoveries in this model differentiation. Analysis of the two injury models suggests that there is a significant difference in the histological outcomes dependent on injury type, though visual system injury is likely present in more cases than are currently diagnosed clinically.