Resumen de Music-supported therapy in the rehabilitation of motor deficits after stroke
Motor deficits of the upper extremity are present in the majority of stroke patients, having a significant impact on their autonomy and quality of life. The recovery of motor deficits after stroke mainly relies on rehabilitation, which is a patient-centred process aimed at improving and maintaining the individual’s functioning using therapeutic interventions to promote adaptive learning. Importantly, recovery will depend on the extraordinary ability of the nervous system to adapt to injury and the capacity of therapeutic interventions to induce brain reorganisation.
There are several techniques to treat the hemiparesis of the upper extremity after stroke, and recently, music-based interventions have emerged as a promising tool since they can incorporate many principles of stroke motor rehabilitation. Among them, Music-supported Therapy has been developed to enhance the motor function of the paretic upper extremity in stroke patients by playing musical instruments. Previous studies have shown that Music-supported Therapy can improve the functionality of the paretic upper extremity, promote functional neuroplastic changes and improve the mood and quality of life of subacute and chronic stroke patients. Despite these promising findings, Music-supported Therapy has not been appropriately contrasted with conventional therapy, and still, several aspects of its effectiveness remain unknown.
The main aim of this thesis was to study the effectiveness of Music-supported Therapy as a therapeutic intervention in the rehabilitation of upper extremity motor function after stroke. This thesis is composed of four studies that made use of different research designs and measurements at the neural, body functions, activity and participation level to address specific aspects that contribute to the effectiveness of Music-supported Therapy.
In Study 1, we tested the effectiveness of Music-supported Therapy in treating the hemiparesis of the upper extremity, inducing neuroplastic changes in the sensorimotor cortex and enhancing the quality of life in subacute stroke patients. We used an interventional experimental design where a group of subacute stroke patients received a four-week program of Music-supported Therapy in addition to the standard rehabilitation program. Patients were assessed before and after the treatment in an evaluation that comprised standardised clinical motor tests, an assessment of the excitability of the sensorimotor cortex with Transcranial Magnetic Stimulation and a quality of life questionnaire. In addition to the patients’ group, a healthy group of matched controls underwent the same evaluation. The results of this study revealed that subacute stroke patients improved their motor function after the therapy and that this improvement was accompanied by changes in the excitability of the sensorimotor cortex and cortical motor map reorganisation. Furthermore, patients reported having a better quality of life after the treatment.
The aim of Study 2 was to test the effectiveness of adding Music-supported Therapy to a standard rehabilitation program for subacute stroke patients. A randomised controlled trial was conducted in which patients were randomised into a Music-supported Therapy group or a conventional therapy group in addition to the standard rehabilitation program. Before and after four weeks of treatment, motor and cognitive functions, mood, and quality of life of patients were evaluated. A follow-up evaluation was performed at three months to test the retention of motor gains. Both groups significantly improved their motor function, and no differences between groups were found, indicating that Music-supported Therapy as an add-on treatment was not superior to conventional therapies for motor recovery. The only difference between groups was observed in the language domain for the quality of life. Further analysis revealed that patients treated with Music-supported Therapy improved their rate of verbal learning, reported less fatigue and negative emotions and experienced a better quality of life after the treatment. Importantly, the patient’s intrinsic motivation to engage in musical activities was associated with better motor improvement in the Music-supported Therapy group.
In Study 3, a subsample of Study 2 was evaluated with a structural and functional Magnetic Resonance Imaging protocol before and after the intervention. This study aimed to characterise the lesions and white matter damage of patients, test the relationship between corticospinal tract integrity and motor recovery and explore the mechanisms of brain plasticity induced by Music-supported Therapy in subacute stroke patients compared to conventional therapy. Patients in both groups of training presented lesions mainly at the subcortical level, and no differences were found in white matter damage between groups. We did not find any association between the proportion of disconnection of the corticospinal tract and motor improvement. The results of the functional imaging part of the study revealed that patients in the Music-supported Therapy group showed greater activations of the middle and superior temporal gyri and insula in the affected hemisphere during a motor task after the training.
In Study 4, we conducted a single-case design to explore the progression of motor improvements throughout the Music-supported Therapy sessions, examine the effects of a second period of training, study the retention of motor gains over time and investigate the generalisation of motor improvements to activities of daily living. A reversal design (ABAB) was implemented in a chronic stroke patient where no treatment was provided in the A periods, and a four-week program of Music-supported Therapy was applied in the B periods. Each period was comprised of four weeks, and an extensive evaluation of the motor function using clinical motor tests and three-dimensional (3D) movement analysis was performed weekly. During the Music-supported Therapy periods, a keyboard task was recorded daily to study the patient’s musical task performance. A follow-up evaluation was performed three months after the second Music-supported Therapy period. Improvements were observed during the first sessions in the keyboard task, but functional motor gains were noticeable only at the end of the first treatment and during the second treatment period. These improvements were maintained in the follow-up evaluation. This study evidenced that gradual and continuous motor improvements are possible with the repeated application of Music-supported Therapy. Fast-acquisition in specific motor abilities was observed at the beginning of the Music-supported Therapy sessions, but generalisation of these improvements to other motor tasks took place at the end of the training or when another treatment period was provided.
Taken together, the results of this thesis show that Music-supported Therapy is an effective intervention in the rehabilitation of upper extremity function after stroke. Music-supported Therapy reduces the motor deficits and improves the functionality of the upper extremity in the same manner as conventional therapy, with gains that are generalised to activities of daily living and maintained over time. Moreover, patients treated with Music-supported Therapy have better language abilities, less fatigue and negative emotions, and greater quality of life than those patients treated only with conventional therapy. The pleasure experienced in musical activities is correlated with motor gains in patients treated with Music-supported Therapy, pointing out the importance of motivation in motor skill learning and stroke rehabilitation. Moreover, Music-supported Therapy promotes similar plastic changes than conventional therapy, inducing cortical motor map reorganisation and excitability changes in the sensorimotor cortex in stroke patients although further research is needed to pinpoint the neural plastic changes promoted by the therapy.
