Music has the ability to go deep and move us. We have all been on the dance floor when “our jam” comes on and you just have to pick up the pace and move with the music. You had no choice. Contemplate that for a moment, why is that? Why does it feel so good to match your movements to the beat? Let’s dive in…
We will use the research study: Interactions between auditory and dorsal premotor cortex during
synchronization to musical rhythms, by Joyce L. Chen, Robert J. Zatorre, Virginia B. Penhune, 2006 in NeuroImage to explain the premise. (open source!)
To start off- some background information on
the known effects of synchronized music rhythms:
Auditory cues can induce changes in movement speed and coordination and they perform better than visual cues, particularly in repetitive lower extremity movements. There is no prior music knowledge / skill needed for this to occur (amazing & fantastic!).
Defining some generalized music terms: (my apologies to music theorist and composer Dr. Mark Dancigers, PhD, MM for this superficial glance…) The Rhythm: the organization of the sound. This includes temporal factors, which induce meaning, via the time between beats forming a pattern. The Beat: the basic unit of keeping time which allows us to perceive the rhythm. During a beat, the primary stimulus is the ‘Tactus’ or emphasis. The tactus can be created by an accent. The Accent: an increase in sound intensity or duration. This amplifies context of sounds and relationships of the on/off input. Accent often occur with the tactus which brings attention to the rhythm’s meter (think simultaneous guitar-pluck + bass-pluck + drum-kick + hi-hat… it’s what you’re nodding your head to). The Meter: smaller, time based unit of the beat. Temporal factors help make events predictable. A predictable time produces expectation and this anticipation allows tapping to the beat (for example). If there is no anticpiation we are forever a millisecond behind, waiting to react to the sound. Temporality again reinforces the beat, meter and tactus. Auditory-Motor actions occur, the authors propose, via perception of the Meter and the Tactus.
That all sounds pretty complicated, but our brains do it all quite beautifully (even damaged brains). Follow me through some neural explanations and you’ll understand how this relates to your patient.
As is familiar, the Temporal Lobe is maximally involved in auditory processes. (seen below)
Of course, association areas are importantly active as well. (seen below)
During auditory motor action the ipsilateral Cerebellum lights up, Sensorimotor areas get involved in tactile feedback from a tapping foot, the Prefrontal Cotrex and Premotor areas are used in selection and production of response, the Supplimentary Motor area organizes sensory input and Superior Temporal Gyrus is active associating. A neural symphony of activity indeed!
So the referenced above study illustrated that:
“As the metric saliency of the rhythms increased, beats that were louder were reproduced as longer in tap duration, an effect not seen when the pattern of accentuation had no metric structure.”
In other words, increased decibel and increased metric structure produced increased synchronicity. Yes many areas light-up, but certain areas varied with tactus/accent manipulation. Those areas were: Left planum temporale, Right posterior Superior Temporal Gyrus (pSTG) and the Bilateral dorsal premotor cortex (dPMC). Areas that were active but did not covary with manipulation were the bilateral pSTG, primary motor cortex, thalamus, and cerebellum lobule V.
Information during auditory-motor action is carried through the Dorsal Auditory Pathway. This will become important in a minute. Information travels from the STG to the parietal lobe (association) then to the dPMC… see below.
Solid arrows indicate ascending projections from auditory cortex, while dashed arrows indicate reciprocal projections back to the auditory cortex. AC, auditory cortex; AL/CL, anterolateral/caudolateral superior temporal gyrus; CS, central sulcus; IFC, inferior frontal cortex; IPL, inferior parietal lobule; PMC, premotor cortex; STS, superior temporal sulcus; The green area is the Anterior auditory pathway.
How does this relate to your patient? Well, first off, with so many areas active in the auditory movement process, if your patient has brain damage, it is likely that they did not damage all of these auditory-motor reticulations.
“…information from posterior STG may be processed serially, feeding forward to (and feeding back from) dPMC. On the other hand, if dPMC possesses auditory response properties, analogous to the motor response properties of the posterior temporal plane (Hickok et al., 2003), then both regions could respond to auditory cues in a parallel manner.”
Additionally, in other studies there are audio-motor associations found in the Insula, which has the ability to modulate signals. Oh yes, primate studies show the Ventral Premotor Cortex has a direct-connect with the posterior auditory cortex. This connects to part of the Dorsal Auditory Pathway. We have that part too! This means that those with very low function, by our human standards, still have strong ‘animal’ pathways available to use. The research that brings us this information deals heavily with perception and consciousness, so it can get kind of deep, but music can induce motor changes and action even in those at a minimally conscious level. Research on conscious and subconscious sensorimotor synchronization can be seen here.
This all translates to: patients want to hit the beat. It can auditory stimulus can encourage heel strike at predictable times, normalizing gait, etc. Some additional reading discussing the effectiveness of all this can be found here, here (open source), here in PTJ, here .pdf for kiddos with CP… and on. Really, it is quite easy to find articles / research and it’s unanimously a good choice. It’s not magic, but it can seem like it.
Future Research: I have my own thoughts on how music may help those with Parkinson’s Disease. Why does a metronome seem to help? How do auditory cues bring about a cessation of freezing or magnetic gait? We know that the production of dopamine from the substantia nigra is reduced in these individuals. We also know that dopamine is released when we accomplish tasks, it is our reward chemical. So when we step to the beat do we get rewarded? “Good job body, way to synchronize with the meter, here’s some dopamine!” Dopamine is the problem. Create rewarding tasks to increase the likelihood of production. I believe it is biologically plausible that this is how music helps those with Parkinson’s, and also why it feels good to move with a song, and why it’s not so rewarding to miss the beat. (any neuroscientists out there want to pair up and do some research?!)
There are Licensed Music Therapists, and they are extremely valuable in treatment settings that work with brain injured patients (TBI, CVA, PD, etc). But you don’t need to be a full-on Music Therapist to give the therapeutic value of music to your patient.
So, if music makes you move, why not just straight to the source? Xiao-Xuan Yang Dancigers, international professional dancer / choreographer, has been teaching dance for years and is involved in teaching dance to people with Parkinson’s as well. Below is how music, and dance (read: movement to music!) is used in getting these individuals with Parkinson’s to move. Meeting movement expectations via dance may provide the same rewards as synchronizing to a beat.
Now, all this is quite interesting and is not as appropriate a treatment for gait as sound input. It does, however address trunk stiffness and increases healthy movement. Recommend it to your patients.
Those with brain injury have trouble interpreting your instructions and getting feedback. Music has the fascinating ability to bypass all that and provide both inspiration for movement and feedback (knowledge-of-results).
How often do you see music used during treatment? It does take a little leap of faith past your embarrassment and the willingness to step out of your comfort zone to make some noise, but it is a powerful tool. Other professionals can be a great treatment partner, and while we as PTs are movement experts and rehabilitation specialists, enlisting the concepts, help and skills of other movement facets is only going to benefit our patients. As I have mentioned before, we are not music or dance therapists, but we can use the therapeutic nature of these models to maximize the lives of those seeking care.
Bottom line: use music to synchronize movement, to normalize gait, to increase intensity and range of motion. Patients with many different types of brain injury are able to respond to this type of stimulus.
Our patient’s brains are ready to move. Inspire them to do so.