Neuropsychological Studies of Mild Traumatic Brain Injury: A Meta-Analytic Review of Research Since 1995

Abstract

A meta-analysis conducted by Binder, Rohling and Larrabee established a relationship between mild traumatic brain injury (TBI) and small reductions in cognitive functioning in individuals assessed more than 3 months post-injury. As a follow-up, this study summarized similar research that (1) was published since the previous meta-analysis, and (2) included data collected at any stage post-injury. An extensive literature search revealed 17 suitable studies from which effect sizes were aggregated. The overall effect size was g = 0.32, p < .001. Speed of processing measures had the largest effect, g = 0.47, p < .001. The merging of post-acute effect sizes with those reported in Binder et al.'s review yielded a nonsignificant result, g = 0.11. Time since injury was found to be a significant moderator variable, with effect sizes tending to zero with increasing time post injury.

Neuropsychology and clinical neuroscience of persistent post-concussive syndrome

“…Belanger et al (2005) perPersistent post-concussive syndromeformed a meta-analysis of 39 studies involving 1463 cases of mTBI assessing clinical neuropsychological test findings. Their findings were similar to what has also been described by Binder et al (1997), Frencham et al (2005), and Schretlen & Shapiro (2003), implicating short-term, but not necessarily long-term neuropsychological effects, except for those cases who were in litigation, where either "stable or worsening of cognitive functioning over time (p. 215) was observed." Mooney et al (2005), in a university based rehabilitation service, examined those with "disappointing recoveries" and observed that "in cases of poor recovery after mTBI where compensation or litigation may be a factor, most of the variance in recovery seems to be explained by depression, pain, and symptom invalidity (p. 975) ."…”

Neuropsychological Sequelae of PTSD and TBI Following War Deployment among OEF/OIF Veterans

“…Evidence clearly suggests that, for most people, the cognitive effects of mTBI resolve within days to three months post-injury (for meta-analyses see: Belanger et al, 2005;Frenchman et al, 2005;Schretlen & Shapiro, 2003). Yet, despite generally good long-term prognosis for individuals who experience a mTBI, a subset report the subjective experience of chronic cognitive deficits, especially in attention and memory (e.g., Dikmen, Machamer, Fann, & Temkin, 2010;Hartlage, Durant-Wilson, & Patch, 2001;Binder, Rohling, & Larrabee, 1997;Rimel, Giordani, Barth, Boll, & Jane, 1981).…”

“…Post-injury reductions in information processing speed have been identified as the single greatest predictor of neuropsychological functioning during the acute stages of recovery following mTBI (Frenchman, Fox, & Mayberry, 2005). In addition, attention, specifically concentration and divided attention, as well as learning/memory processes, are the primary cognitive symptoms following a concussion/mTBI (APA, 2000).…”

Traumatic Brain Injury and Executive Functioning in an Incarcerated Sample

“…As described above, these impairments typically resolve within the first three months post-injury (Frencham et al, 2005).…”

“…The findings of one meta-analysis support this view for the mild cognitive impairments that often follow mild TBI (Frencham, Fox, & Maybery, 2005). However, the remainder of individuals with mild TBI can go on to develop "persistent cognitive, emotional, behavioral, and physical impairments that extend well into the late (>1 year) period following TBI" (Arciniegas et al, 2005, p. 312).…”