Introduction: Cognitive complaints are common within the first weeks after mild traumatic brain injury (mTBI) and may persist for months to years in a subgroup (≈20%). Age-related cognitive decline can worsen these symptoms. However, effects of age on mTBI sequela have scarcely been investigated. 

Methods: Fifty-four patients (mean age: 37 years, range 19-64 years, 67% male) and twenty healthy controls (HCs) (mean age: 36 years, range: 18-61 years, 70% male), group-matched for age and gender were included. Functional magnetic resonance imaging (fMRI) was performed during 10 minutes rest. Independent component analysis (ICA) was used to identify resting state networks (RSNs). A multivariate approach was executed to evaluate the effects of age and gender on the RSNs in terms of the three main outcome measures: a) spatial map intensity, b) time-course spectral power, and c) functional network connectivity. 

Results: Age-related effects were identified for all three measures, indicating a) significant intensity decreases for increasing age in the default mode network (DMN), b) significant power spectral decrease within the 0-0.15 Hz range for increasing age in the DMN, frontoparietal network (FPN) and dorsal attention network (DAN), which is consistent with previous studies on healthy participants, and c) significant power spectral increase within the 0.15-0.25 Hz range for increasing age in the DMN, FPN and DAN. Additionally, a significant connectivity increase between the orbitofrontal and language networks was found for increasing age. Gender effects of smaller magnitude were found on spatial maps, with greater intensity found for males in the posterior part of the DMN, specifically within the cuneus. The significance threshold was set at p<0.05, with correction for multiple comparisons.  

Conclusions: This study on mTBI patients and healthy controls showed age- and gender-related effects on brain networks that have previously been suggested to be involved in cognitive functioning. How these effects are related to patients’ cognitive functioning in comparison to the healthy control group is still not clear and requires further investigation.

AGE AND GENDER EFFECTS ON RESTING STATE NETWORKS AFTER MILD TRAUMATIC BRAIN INJURY