How Music Heals
By Christine Xu
Parkinson’s Disease (PD) is a neurodegenerative disease caused by the death of dopaminergic neurons, which are brain cells that release a chemical called dopamine. Because dopamine is crucial for proper motor function, PD patients have slow, unsteady gaits, tremors, rigid muscles, and impaired balance. Drug therapy is often problematic, because gait deficiencies can be resistant to medication[1]. However, neurological music therapy (NMT) can help PD patients regain their ability to initiate movements[2]. Observing patients undergoing NMT and conducting an extensive literature review, I discovered that NMT’s advantages over generic physical therapy can partly be explained by music’s ability to recruit undamaged areas of the brain to help strengthen a patient’s weakened motor areas of the brain. This phenomenon is known as neuroplasticity.
Neuroplasticity is an innate property of the brain that allows different areas of the brain to compensate for one another, to a certain degree. The compensatory nature of neuroplasticity was demonstrated in an experiment by Drs. David Hubel and Torsten Wiesel from Johns Hopkins University, in which they revealed that covering one eye of a cat led to physiological and functional changes in the visual cortex. Specifically, the brain regions associated with the uncovered eye “stole” brain area in the visual cortex from the covered eye through neural growth[3]. The result was that the uncovered eye became stronger and more sensitive to compensate for the fact that the cat had only one eye. Similarly, in PD patients, music can activate areas of the brain that compensate for the motor regions that are no longer active or functioning correctly. Music can therefore reinforce motor skills and strengthen the connections between motor areas of the brain.
One of the most basic NMT techniques is called Rhythmic Auditory Stimulation (RAS) and it was developed by Dr. Michael Thaut[4]. Witnessing RAS as an observer is quite striking. Instead of a PD patient being surrounded by a gaggle of clinicians in a generic physical therapy setting, RAS calls for one single clinician, who strums chords on a guitar as the patient places one foot in front of the other.
To perform RAS, the music therapist first measures the patient’s baseline stride tempo using a device called a metronome. Then, during the first week of therapy, the music therapist emphasizes the “beat” of a patient’s stride by playing chords on the guitar. Dr. Jessica Grahn, a cognitive neuroscientist from Western University in London, Ontario, researches music and rhythm, and she has reported on a standard protocol for RAS. The patient learns to walk in tandem with a normal beat (one matching their baseline stride), a quick beat (5-10% faster than baseline), and a fast beat (15-20% faster than baseline)[5]. Each week, the therapist increases the baseline tempo by 5-10% until the patient’s stride has returned to normal[5].
Neuroimaging studies have shown that the perception of rhythm activates structures in the brain associated with critical motor networks, such as a structure called the basal ganglia[4]. Thus, these studies support the neuroplastic basis for NMT. That is, music can strengthen undamaged, alternative neuronal pathways that already exist in the patient to compensate for neuronal damage. As a result, NMT can greatly help a PD patient improve his/her gait (e.g. by promoting longer strides, more symmetrical steps, and steadier movement)[5].
In the ten PD patients whom I have observed, the majority exhibited tremendous improvements in lengthening stride and improving balance, as well as decreases in freezing and shuffling. In Dr. Thaut’s 1996 paper, PD patients who used RAS for three weeks increased their gait velocity by 25%, stride length by 12%, and step cadence by 10%. This contrasted significantly with the group of PD patients who were not exposed to RAS; overall, their gait velocity decreased by 7%[2]. These findings support my observation that PD patients may improve their gait through music therapy.
My exploration of NMT also holds personal significance for me, because I used it to assist a PD patient very dear to my heart—my own grandfather. I traveled to China to visit him during his final days, and I used RAS to help him practice his gait. I was heartbroken when he passed away last year, but I found solace knowing that I was able to give him the most powerful kind of support that I could in his final days. I am gratified knowing that music can not only uplift and soothe, but also, it can heal.
Sources:
- Blin, O., Ferrandez, A. M., Serratrice, G. 1990. Quantitative analysis of gait in Parkinson’s patients; increased variability of stride length. Journal of The Neurological Sciences 98, 91-97.
- Thaut MH, McIntosh GC, Rice RR, Miller RA, Rathbun J, et al. (1996) Rhythmic auditory stimulation in gait training for Parkinson's disease patients. Mov Disord 11: 193–200.
- Hubel DH, Wiesel TN. Receptive fields of single neurons in the cat's striate cortex. J Physiol. 1959;587: 2721–2732.
- Thaut, M. H. Rhythm, Music and the Brain. New York and London: Taylor and Francis Group. 2005.
- Nombela, C., Hughes, L. E., Owen, A. M., and Grahn, J. A. (2013). Into the groove: can rhythm influence Parkinson’s disease? Neurosci. Biobehav. Rev. 37, 2564–2570. doi: 10.1016/j.neubiorev.2013.08.003
