Traumatic brain injury (TBI) is a steadily rising health concern associated with significant risk of emotional, behavioral and cognitive impairments. Cognitive memory impairment is one of the most concerning outcomes after TBI, affecting a wide range of everyday activities, social interactions and employment. Several comparative and comprehensive reviews on the effects of cognitive interventions in individuals with TBI have been conducted but usually with a qualitative rather than quantitative approach. Thus, evidence synthesis of the effects of TBI interventions on memory difficulties is limited.

In this meta-analysis, we examined the memory-remediating effects of internal and external interventions, injury severity and the interaction of both factors for patients with TBI.

Data were extracted from studies published between 1980 and 2020 that used objective memory measures (computerized or pencil-and-paper), and multiple meta-analyses were conducted to compare effectiveness across these interventions. Publication bias was assessed, as was quality of evidence using the Cochrane Risk of Bias tool for randomized controlled studies. Our final meta-analysis included 16 studies of 17 interventions classified into 3 categories: internal, external and mixed.

Mixed interventions demonstrated the highest average effect size for memory difficulties (Morris d=0.79). An evaluation of injury severity yielded 2 categories: mild-moderate and moderate-severe. Analyses demonstrated a homogenous medium effect size of improvement across injury severity, with moderate-severe injury with the largest average effect size (Morris d=0.65). Further evaluation of injury severity interaction with intervention type revealed a mediating effect for both factors, demonstrating the largest effect size for mixed interventions with moderate-severe injury (Morris d=0.81).

This study highlights the effectiveness of memory remediation interventions on memory impairment after TBI. A wide range of interventions are more effective because they address individual variability for severity and memory deficits. The study further supports and expands existing intervention standards and guidelines.