The prevalence of stroke increases in the ageing population entailing an enormous economic and societal burden. This has raised the need for motivating, effective and easily applicable rehabilitation tools to enhance recovery and neuroplasticity. Music is an important source of enjoyment and well-being across life and it provides a multidomain stimulus that is both pleasant and rewarding, and engages the brain extensively. Previous evidence suggests that daily music listening can enhance cognitive recovery and mood and induce functional and structural neuroplasticity changes after stroke. Songs may also function as a verbal learning aid in healthy subjects. The aim of this thesis was to further explore the specific role of vocal (sung) music as a tool to aid verbal learning and long-term recovery after stroke. In Studies I and II, stroke patients (N = 31) performed a verbal learning task where novel narrative stories were presented in both spoken and sung formats, and underwent MRI at acute and 6-month post-stroke stages. Study I showed that stroke patients, especially those with mild aphasia, learned and recalled the stories better when they were presented in sung than spoken format at the 6-month stage. Exploring the cognitive and neural mechanisms underlying this effect, Study II further showed that non-aphasic patients exhibited more stable recall, indicated by reduced serial position effects, whereas aphasic patients showed a larger recency effect and enhanced chunking in the sung than spoken task. Diffusion tensor imaging and voxel-based morphometry results indicated that these effects were coupled with greater volume of the left arcuate fasciculus in non-aphasics, and with greater volume of the right inferior fronto-occipital fasciculus and grey matter in a bilateral network of temporal, frontal, and parietal regions in aphasics. In Study III, data was pooled from two randomized controlled trials where stroke patients (N = 83) received an intervention involving daily listening to self-selected vocal music, instrumental music, or audiobooks during the first three months after stroke. The recovery was assessed with neuropsychological tests and a mood questionnaire at acute, 3-month and 6-month stages, and structural MRI and functional MRI (fMRI) at acute and 6-month stages. Compared to audiobooks, listening to music enhanced the recovery of language skills and verbal memory and reduced negative mood. Vocal music had the strongest rehabilitative effect on both language and verbal memory, and the positive effects of music listening on language recovery were seen especially in patients with aphasia. Results from voxel-based morphometry and resting-state, and task-based fMRI analyses showed that vocal music listening selectively increased grey matter volume in left temporal areas and functional connectivity in the default mode network from acute to 6-month stage. The findings of the present thesis provide further evidence that listening to vocal music is a useful tool to support cognitive and emotional recovery after stroke and to enhance early language recovery in aphasia. The rehabilitative effects are driven by both structural and functional plasticity changes in temporoparietal networks, which are crucial for emotional processing, language and memory.
|Status||Publicerad - 2020|
|MoE-publikationstyp||G5 Doktorsavhandling (artikel)|
Bibliografisk informationM1 - 90 s. + liitteet
- 515 Psykologi