Are Cognitive Outcome and Recovery Different in Civilian Penetrating Versus Non-Penetrating Brain Injuries?

Impact of day-of-injury alcohol consumption on outcomes after traumatic brain injury: A meta-analysis

Although a known risk factor for traumatic brain injury (TBI), alcohol has been found to both promote and protect against secondary brain damage. However, it is presently unclear whether the cognitive, psychological and medical/functional outcomes of adults who have consumed alcohol prior to sustaining a TBI differ from those who have not. This meta-analysis examined the outcomes of groups that differed in terms of their day-of-injury (DOI) blood alcohol levels (BALs) by comparing positive with zero BAL (BAL⁺/BAL^-) and high with low BAL (BAL^high/BAL^low) samples. The PubMed, PsycINFO, EMBASE, and Scopus databases were searched from inception until the end of March 2015. Hedge's g effects (continuous data) and odds ratios (categorical data) were calculated for 27 studies that compared either the outcomes of BAL⁺ and BAL^- groups or BAL^high and BAL^low groups. BAL⁺ was associated with significantly poorer cognitive outcomes (overall and on general tests) and higher levels of disability, and BAL^high was associated with shorter stays in intensive care. More generally, however, most effect sizes were small to low-moderate in size, non-significant and inconsistent in their direction. Although DOI alcohol consumption increases the risk of sustaining a TBI, it is not consistently associated with better or worse outcomes, other than subtle cognitive deficits; the source of which remains to be determined.

Traumatic brain injury: guidance in a forensic context from outcome, dose-response, and response bias research

Traumatic brain injury (TBI) occurs at a high incidence, involving millions of individuals in the U.S. alone. Related to this, there are large numbers of litigants and claimants who are referred annually for forensic evaluation. In formulating opinions regarding claimed injuries, the present review advises experts to rely on two sets of information: TBI outcome and neuropsychological dose-response studies of non-litigants and non-claimants, and response bias literature that has demonstrated the relatively high risk of invalid responding among examinees referred within a secondary gain context, which in turn has resulted in the development of specific assessment methods. Regarding prospective methods for detecting possible response bias, both symptom validity tests, for measuring over-reporting of symptoms on inventories and questionnaires, and performance validity tests, for measuring insufficient effort on ability tests, are considered essential.

Methodological Issues in Longitudinal Research on Cognitive Recovery after Traumatic Brain Injury: Evidence from a Systematic Review

Background: Previous research addressing cognitive recovery after traumatic brain injury (TBI) in adults has predominately used cross-sectional methods. This systematic review examines longitudinal research into cognitive recovery in the first 2 years following moderate-to-severe TBI in adults and aims to identify apparent methodological issues with the existing literature.

Design: Systematic review of the first 2 years post-trauma.

Setting: Data were extracted from three electronic databases and manual searches of published articles until October 2012.

Participants: Two hundred and forty-two participants with severe TBI and 281 comparison participants were used to calculate effect sizes.

Results: Twenty papers met the selection criteria, with effect sizes computed from four studies. Moderate-to-large effect sizes were initially observed between the TBI and comparison groups on most measures (range: d = 0.2–2.8). Recovery continued in all five cognitive domains over the 2 years post-injury.

Conclusions: Results demonstrated that cognitive recovery was continuous throughout the first 2 years following moderate-to-severe TBI. Findings also indicated different rates of recovery for the specific cognitive domains, highlighting the heterogeneous nature of cognitive recovery after TBI. The review highlighted several methodological issues within the limited existing literature; recommendations were developed to improve the evidence base.

Characterizing discourse deficits following penetrating head injury: a preliminary model

PURPOSE

Discourse analyses have demonstrated utility for delineating subtle communication deficits following closed head injuries (CHIs). The present investigation examined the discourse performance of a large group of individuals with penetrating head injury (PHI). Performance was also compared across 6 subgroups of PHI based on lesion locale. A preliminary model of discourse production following PHI was proposed and tested.

METHOD

Story narratives were elicited from 2 groups of participants, 167 with PHI and 46 non brain-injured (NBI). Micro- and macrostructural components of each story were analyzed. Measures of memory, executive functions, and intelligence were also administered. All measures were compared across groups and PHI subgroups. The proposed model of discourse production was tested with a structural equation modeling procedure.

RESULTS

No differences for the discourse measures were noted across the six PHI subgroups. Three measures distinguished the PHI and NBI groups: narrative length, story grammar, and completeness. The proposed model of discourse production had an adequate-to-good fit with the cognitive and discourse data.

CONCLUSION

In spite of differing mechanisms of injury, the PHI group's discourse performance was consistent with what has been reported for individuals with CHI. The model tested represents a preliminary step toward understanding discourse production following traumatic brain injury.