by Emily MacPherson
I’ve been told a few times, by wise professors, that the best way to understand how to treat a disease is to understand it’s etiology. So to understand NMT’s efficacy in assisting movement (more specifically gait) in people with Parkinson’s disease (PD), we must first understand what is happening under the surface.
According to Nombela, Hughes, Owen & Grahn (2013) the loop between the basal ganglia portion of the brain and the supplementary motor area (SMA) is what produces healthy motor performance in people. This loop requires an internal cue that acts as a conductor of sorts. The symphony needs a person standing in front of them indicating the tempo and cueing entrances, emotions, dynamics, etc. to make the notes on the pages of the music sing. If the conductor decides to take a long coffee break, the symphony would still be able to play- but would the product be as smooth and beautiful without him or her? Would they begin together or keep the correct tempo within the group? (For the sake of this analogy the correct answer is no.) In a person with PD, “this internal cue is impaired, delayed or missing,” (Nombela et al., 2013). Just like we imagined the struggles of the symphony deprived of it’s conductor, without the internal cue working correctly, initiation and timing of movements are difficult and we see the resulting irregular stride length, step rate, and freezing that are a notorious part of PD.
Maybe you’re thinking, “So if the internal cues are broken or missing, why don’t we provide external cues?” Yes! External cues are an excellent way to replace the internal cues necessary to conduct the loop. To bring the point home, auditory external cueing in the form of Rhythmic Auditory Stimulation (RAS) is exactly what an NMT is providing during gait training with a person with PD. This is possible because, “rhythm activates the neural circuits involved in motor processing,” (Nombela et al., 2013).
While we know that the rhythm is the most important function of RAS, and a steady rhythm can be provided by a metronome, the inability of a metronome to identify patient responses and adjust accordingly to them is what makes a trained Neurologic Music Therapist so important. In addition, de Dreu, Kwakkel, and van Wegen’s chapter in Handbook of Neurologic Music Therapy tells us when RAS is implemented utilizing music, rhythmic cues are delivered while also providing, “a cultural and motivational context,” (p. 69, 2014). The researched benefits of RAS in people with PD include improved walking velocity and step length when combined with gait training (de Dreu, Kwakkel, & van Wegen. 2014), reduction of shape variability in the lower leg muscles –more specifically the medial gastrocnemius and tibialis anterior muscles (Miller, Thaut, McIntosh, & Rice. 1996), and reduction of the attentional cost of walking (Baker, Rochester, & Nieuwboer. 2008), just to name a few.
In case you are saying to yourself now, “Well that sounds nice, but what about when the NMT stops playing the auditory stimulus and goes home? Are they back to square one?” Nope. Research has shown us that participating in an optimally-dosed RAS and gait training program produces incredible carryover and in fact, can last up to three weeks(de Dreu, Kwakkel, & van Wegen. p. 84)!
The only question left to ask yourself now is, “Where can I find the nearest Neurologic Music Therapist?” MedRhythms has a team ready to go!
Baker, K., Rochester, L., & Nieuwboer, A. (2008). The effect of cues on gait variability: Reducing the attentional cost of walking in people with Parkinson’s disease. Parkinsonism and Related Disorders. 14, 314-320. doi: 10.1016/j.parkreldis.2007.09.008
de Dreu, M. Kwakkel, G., & van Wegen, E. (2014). Rhythmic Auditory Stimulation (RAS) in gait rehabilitation for patients with Parkinson’s disease: A research perspective. In M. Thaut, & V. Hoemberg (Eds.), Handbook of Neurologic Music Therapy (pp. 69-93). Oxford, UK: Oxford University Press.
Miller, R. A., Thaut, M. H., McIntosh, G. C., & Rice, R. R. (1996). Components of EMG symmetry and variability in parkinsonian and healthy elderly gait. Electroencephalography and Clinical Neurophysiology. 101, 1-7.
Nombela, C., Hughes, L. E., Owen, A. M., & Grahn, J. A. (2013). Into the groove: Can rhythm influence Parkinson’ disease? Neuroscience and Behavioral Reviews. http://dx.doi.org/10.1016/j.neubiorev.2013.08.003