Environmental enrichment may protect against hippocampal atrophy in the chronic stages of traumatic brain injury

OBJECTIVE To examine the relationship between environmental enrichment (EE) and hippocampal atrophy in the chronic stages of moderate to severe traumatic brain injury (TBI). DESIGN Retrospective analysis of prospectively collected data; observational, within-subjects. PARTICIPANTS Patients (N = 25) with moderate to severe TBI. MEASURES Primary predictors: (1) An aggregate of self-report rating of EE (comprising hours of cognitive, physical, and social activities) at 5 months post-injury; (2) pre-injury years of education as a proxy for pre-morbid EE (or cognitive reserve). PRIMARY OUTCOME bilateral hippocampal volume change from 5 to 28 months post-injury. RESULTS As predicted, self-reported EE was significantly negatively correlated with bilateral hippocampal atrophy (p < 0.05), with greater EE associated with less atrophy from 5 to 28 months. Contrary to prediction, years of education (a proxy for cognitive reserve) was not significantly associated with atrophy. CONCLUSION Post-injury EE may serve as a buffer against hippocampal atrophy in the chronic stages of moderate-severe TBI. Clinical application of EE should be considered for optimal maintenance of neurological functioning in the chronic stages of moderate-severe TBI.