A. Blythe LaGasse; Influence of an External Rhythm on Oral Motor Control in
Children and Adults, Journal of Music Therapy, Volume 50, Issue 1, 1
March 2013, Pages 6–24, https://doi.org/10.1093/jmt/50.1.6
One of the most undeniable elements of music is rhythm. Everyone experiences rhythm; whether it is through hearing it within music or feeling it through vibrations. Rhythm is also one of the most undeniable elements of our bodies. As humans we are rhythmic beings. From our heartbeat, blinking, walking, and to the way our breathing patterns changes, we operate with rhythm. This is something that excited me about music and how it impacts the body. Therefore, when I came across the article, Influences of an External Rhythm on Oral Motor Control in Children and Adults by LaGasse, I knew it would be an interesting and informative read.
Before jumping into all the technical details of this study, I will briefly discuss something the author references throughout the article, which is the concept of entrainment. Entrainment is basically our body’s ability to sync up with external rhythms, pulses or beats (LaGasse, 2013). We entrain to the rhythms around us all the time, but we are not always aware of it. A simple example of this could be tapping your foot to a familiar song, or beginning to walking in sync with someone you are walking next to. Our bodies are often able to anticipate as well as reproduce what is heard and felt around them through entrainment. It is important to preface with this, because the author goes on to discuss motor movements of the upper and lower extremities, as well as oral motor movements and how they relate to entrainment.
Rhythm in music therapy is one of our most valuable tools, especially with individuals that have neurological disabilities. Within my practice at The George Center, rhythmic auditory stimulation is used regularly to support and facilitate patients with motor and speech goals. Sometimes all it takes is tapping on the shoulder of a client while they vocalize. Other times entire interventions are centered around helping a patient entrain to a slower beat so that they can slow down their body enough to have success in later exercises. Body percussion throughout a song, or playing rhythm sticks are some way that this is implemented musically.
LaGasse touches on how rhythmic auditory cues have been supported in the field through research. Rhythm is beneficial in promoting the development of motor speech, which is an individual's ability to plan, control, coordinate, and produce speech. LaGasse also compares the limb motor responses to oral motor responses. This is important to note because just like our arms and legs entrain to rhythm, so can our mouth. The oral motor system is complex, but has much less research to support rhythmic impact within therapy. Therefore, this study in 2013 opened a door for others to continue researching the entrainment phenomenon in relation to oral motor movements.
The study focused on 26 children and adults ages ranging from 7 to 35 years old with no history of speech, language, or hearing impairments. The method used to measure kinematic (movement) data in these individuals was Peak Motus, a 3-camera system. The camera recorded markers that were placed on three points of the oral motor area, the upper lip (UL), lower lip (LL), and the mental protuberance of the mandible (J) (LaGasse, 2013). Digital cameras were also set up so that 60 samples would be taken per second. A metronome positioned in the same location near each patient, was used to produce the auditory stimulus, which was set at 60 decibels. The participants were asked to repeat the syllable /pa/ at a comfortable pace during one trial. This trial tracked oral performance at a self-selected tempo. Participants were instructed to produce the same /pa/ syllable with an external auditory stimulus provided through a metronome set to the beat of their previously self-selected tempo. The participants were also asked to produce the syllable with a faster tempo, at a 10% increase from their original preferred tempo. The trials were done in varying orders through random selection. This was done to decrease any effects due to learning or fatigue amongst the participants (LaGasse, 2013).
After the trials were completed, measurements were made to compare levels of entrainment. This was done through the use of program data, which measured movement and the amount of time between beats, as well as the distance between UL and LL during syllable production (LaGasse, 2013). In short, the technology used measured each individual’s oral movements in length, time, and distance to come up with an overall average for the subject. This was done for all 26 participants.
The results of this study were particularly interesting to me because they were calculated using such a raw element of music. Individuals were solely provided a computer-generated tempo to entrain to! This is cool because they had no melody or otherwise motivating musical theme to listen to, it was simply a constant “beep” that created the steady beat. For the synchronization aspect of the study, no significant differences were shown amongst children and adults. Asynchrony, which means the individual produced sound before the beat, was recorded for all groups, but was a result of anticipatory responses in all cases. However, these instances were milliseconds off of the beat (LaGasse, 2013).
This study supported movement data with graphs for all participants, which were especially interesting to view, as they created a picture of each movement. They were successful in measuring all participants through this method, which is exciting because this research will be able to be repeated in the future! This method proved to be a reliable way of tracking oral motor movements in individuals. When comparing oral motor synchronization to the same strategies done for limbs, LaGasse reported some slight differences among errors recorded. Overall, the data recorded was exciting to view and compare amongst children and adults.
As I reach the halfway point of my internship at The George Center, I can honestly say that the approaches I am being taught can be supported with this type of research. There is not a day that goes by that I am not reminded to, “let the music be your co-therapist” or to “use the rhythm”. Words like “entrainment”, “anticipation”, and “support” are constantly woven into the teaching of approaches being applied in the treatment setting. One clinical example of this would be using percussion, like drumming, with patients as a primer activity to get their body in sync with the beat of a song. Following this, I continue to play the guitar rhythmically to support them while we sing a song together. After the client is singing, I can fade out singing with them and use the rhythmic playing to cue responses. With clients that have speech and oral motor difficulties, techniques like this have proven to work very well. I am continuing to learn how to better manipulate and use the elements of music to elicit positive responses from each client. Rhythm is a major part of this beautiful process!