Music therapy in the cognitive and neural rehabilitation of traumatic brain injury

Traumatic brain injury (TBI) can have lifelong cognitive, emotional, and physical consequences. Music engages many cognitive, motor, and emotional functions making it a promising rehabilitation tool, but the effects of music in TBI are still largely unknown. The aim of this thesis was to explore the efficacy of neurological music therapy in the rehabilitation of moderate and severe TBI, particularly on executive functions (EF). The thesis includes three studies based on a cross-over randomized controlled trial (RCT), in which 40 participants with TBI (time since injury < 2 years) were randomized into two groups (AB/BA) to receive a 3-month neurological music therapy intervention either during the first (AB, n=20) or second (BA, n=20) half of a 6-month follow-up period. Neuropsychological and motor testing, questionnaires, and structural and functional magnetic resonance imaging (MRI) were performed at baseline and at the 3-month and 6-month stage. Results from Study I showed that general EF and set shifting improved more in the AB group than in the BA group over the first 3-month period, and the effect on general EF was maintained in the 6-month follow-up. Voxel-based morphometry analysis of the structural MRI data indicated that gray matter volume in the right inferior frontal gyrus increased significantly in both groups during the intervention versus control period, which also correlated with cognitive improvement in set shifting ability. Findings from Study II reporting the questionnaire data showed that the Behavioural Regulation Index of the Behaviour Rating Inventory of Executive Function (BRIEF-A) improved more in the AB than BA group from baseline to 3-month stage, and the effect was maintained in the 6-month follow-up. Finally, Study III explored functional connectivity patterns using resting-state functional MRI and revealed both changes towards increased and decreased functional connectivity within and between several networks. Importantly, behavioral improvements in EF correlated with resting-state functional connectivity changes within the frontoparietal network and between the default mode and sensorimotor networks. All in all, these results suggest that neurological music therapy enhances EF skills, including general EF, set shifting ability and behavioral self-regulation, after TBI and that these gains are linked to volumetric and functional neuroplastic changes in the brain. These novel findings give support to the use of music therapy in rehabilitation of moderate and severe TBI.