Music Stimulation for People with Disorders of Consciousness: A Scoping Review

Musical and electrical stimulation as intervention in disorder of consciousness (DOC) patients: A randomised cross-over trial

BACKGROUND

Disorders of consciousness (DOC), i.e., unresponsive wakefulness syndrome (UWS) or vegetative state (VS) and minimally conscious state (MCS), are conditions that can arise from severe brain injury, inducing widespread functional changes. Given the damaging implications resulting from these conditions, there is an increasing need for rehabilitation treatments aimed at enhancing the level of consciousness, the quality of life, and creating new recovery perspectives for the patients. Music may represent an additional rehabilitative tool in contexts where cognition and language are severely compromised, such as among DOC patients. A further type of rehabilitation strategies for DOC patients consists of Non-Invasive Brain Stimulation techniques (NIBS), including transcranial electrical stimulation (tES), affecting neural excitability and promoting brain plasticity.

OBJECTIVE

We here propose a novel rehabilitation protocol for DOC patients that combines music-based intervention and NIBS in neurological patients. The main objectives are (i) to assess the residual neuroplastic processes in DOC patients exposed to music, (ii) to determine the putative neural modulation and the clinical outcome in DOC patients of non-pharmacological strategies, i.e., tES(control condition), and music stimulation, and (iii) to evaluate the putative positive impact of this intervention on caregiver's burden and psychological distress.

METHODS

This is a randomised cross-over trial in which a total of 30 participants will be randomly allocated to one of three different combinations of conditions: (i) Music only, (ii) tES only (control condition), (iii) Music + tES. The music intervention will consist of listening to an individually tailored playlist including familiar and self-relevant music together with fixed songs; concerning NIBS, tES will be applied for 20 minutes every day, 5 times a week, for two weeks. After these stimulations two weeks of placebo treatments will follow, with sham stimulation combined with noise for other two weeks. The primary outcomes will be clinical, i.e., based on the differences in the scores obtained on the neuropsychological tests, such as Coma Recovery Scale-Revised, and neurophysiological measures as EEG, collected pre-intervention, post-intervention and post-placebo.

DISCUSSION

This study proposes a novel rehabilitation protocol for patients with DOC including a combined intervention of music and NIBS. Considering the need for rigorous longitudinal randomised controlled trials for people with severe brain injury disease, the results of this study will be highly informative for highlighting and implementing the putative beneficial role of music and NIBS in rehabilitation treatments.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05706831, registered on January 30, 2023.

Multimodal communication reported by familiar caregivers to build communication capacity in persons who are minimally conscious

PURPOSE

Limited clinical and research evidence is available to support healthcare practitioners in the communication assessment and intervention of persons who are minimally conscious. This study placed a specific focus on the multimodal communication strategies familiar caregivers of persons who are minimally conscious observed, as well as the verbal and the nonverbal communication strategies they employed to build communication capacity. This may inform clinical practice as it provides valuable autobiographical information as well as familiar stimuli that may elicit responses from persons in a minimally conscious state.

METHOD

A descriptive qualitative design employing in-depth semi-structured interviews with familiar caregivers was utilised to address the purpose of the study.

RESULT

Familiar caregivers reported that they used both nonverbal and verbal communication strategies to obtain a response from persons who are minimally conscious. These caregivers also reported that these persons appeared to rely on nonverbal communication strategies to express 36 different communication functions.

CONCLUSION

Based on the findings of this study, it is clear that caregivers can be beneficial to persons who are minimally conscious, if they are able to observe and capitalise on naturally occurring multimodal communication strategies and functions. This study emphasises that familiar caregivers respect and value the dignity of persons who are minimally conscious and want to improve their communication capacity, but often lack confidence in their own communication skills.

Functional NIRS to detect covert consciousness in neurocritical patients

OBJECTIVE

This pilot study assesses the feasibility to detect covert consciousness in clinically unresponsive patients by means of functional near infrared spectroscopy (fNIRS) in a real intensive care unit setting. We aimed to verify if the hemodynamic response to familiar music measured with fNIRS varies according to the level consciousness of the patients.

METHODS

22 neurocritical patients and 6 healthy controls were included. The experiment consisted in 3 subsequent blocks including a first resting state recording, a period of music playback and a second resting state recording. fNIRS measurement were performed on each subject with two optodes on the forehead. Main oscillatory frequencies of oxyhemoglobin signal were analyzed. Spectral changes of low frequency oscillations (LFO) between subsequent experimental blocks were used as a marker of cortical response. Cortical response was compared to the level of consciousness of the patients and their functional outcome, through validated clinical scores.

RESULTS

Cortical hemodynamic response to music on the left prefrontal brain was associated with the level of consciousness of the patients and with their clinical outcome after three months.

CONCLUSIONS

Variations in LFO spectral power measured with fNIRS may be a new marker of cortical responsiveness to detect covert consciousness in neurocritical patients. Left prefrontal cortex may play an important role in the perception of familiar music.

SIGNIFICANCE

We showed the feasibility of a simple fNIRS approach to detect cortical response in the real setting of an intensive care unit.

Psychophysiological Effects of Biographical Interventions in People With Unresponsive Wakefulness Syndrome and Minimally Conscious State

Background

Various music interventions can evoke favorable behavioral responses or physiological reactions in people with disorders of consciousness (DOC), such as coma, unresponsive wakefulness syndrome (UWS), and minimally conscious state (MCS). However, it appears that no study thus far has investigated the effects of music on the endocrine system of people with DOC.

Objective

This explorative study aimed to investigate the effects of biographical music and biographical language on the physiological and endocrine systems of people with UWS and MCS.

Method

A cohort of 20 people with DOC (10 women, 10 men; age range 19–77) received 20 min of biographical music and biographical language. Before and afterward, they were exposed to silence. Physiological and hormonal measurements were conducted before, during, and after the interventions.

Results

Paired t-tests showed a significant decrease of salivary cortisol in the condition with biographical language interventions.

Conclusion

Biographical interventions can modulate reactions in the endocrine system in people with DOC. Further studies are needed to establish whether and how individuals living with DOC show psychoneuroendocrine responses to music and other arts-based interventions.

Increase in Low-Frequency Oscillations in fNIRS as Cerebral Response to Auditory Stimulation with Familiar Music

Recognition of typical patterns of brain response to external stimuli using near-infrared spectroscopy (fNIRS) may become a gateway to detecting covert consciousness in clinically unresponsive patients. This is the first fNIRS study on the cortical hemodynamic response to favorite music using a frequency domain approach. The aim of this study was to identify a possible marker of cognitive response in healthy subjects by investigating variations in the oscillatory signal of fNIRS in the spectral regions of low-frequency (LFO) and very-low-frequency oscillations (VLFO). The experiment consisted of two periods of exposure to preferred music, preceded and followed by a resting phase. Spectral power in the LFO region increased in all the subjects after the first exposure to music and decreased again in the subsequent resting phase. After the second music exposure, the increase in LFO spectral power was less distinct. Changes in LFO spectral power were more after first music exposure and the repetition-related habituation effect strongly suggest a cerebral origin of the fNIRS signal. Recognition of typical patterns of brain response to specific environmental stimulation is a required step for the concrete validation of a fNIRS-based diagnostic tool.