How does the familiar music affect gait?
One of the most frustrating symptoms of Parkinson’s disease (PD) is difficulty initiating and controlling footsteps. Gait in patients with PD is characterized by small steps, slow walking rate, difficulty initiating gait, and freezing. Although medication may help these symptoms the benefits for gait can decrease over time. Thus, many clinicians advise physical therapy as a supplement to medication.
Rhythmic auditory stimulation (RAS) is an emerging method of gait rehabilitation that capitalizes on the rewarding properties of music. During a session, patients synchronize footsteps to a metronome or musical beats. Although RAS with music can ameliorate gait abnormalities (as mentioned previously here), outcomes vary, possibly because music properties, such as groove or familiarity, differ across interventions.
Rhythmic auditory stimulation (RAS) is an emerging method of gait rehabilitation that capitalizes on the rewarding properties of music. During a session, patients synchronize footsteps to a metronome or musical beats. Although RAS with music can ameliorate gait abnormalities (as mentioned previously here), outcomes vary, possibly because music properties, such as groove or familiarity, differ across interventions.
What did we look at? |
To optimize future interventions, we looked at the:
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How might familiarity play a role?
The more familiar you are with a song, the more familiar you are with its beat structure. This may reduce the cognitive demands of synchronizing movements to the beat. Previous work has shown that strides are faster and less variable when cognitive demands are low (see review by Al-Yahya, 2011), patients who are unfamiliar with the selected song may have more cognitive demand and benefit less from music-based RAS than patients who are familiar with the selected song. Also, familiarity with a song might lead to greater enjoyment of RAS by modulating reward mechanisms. Repeated exposure to unfamiliar music has been shown (here) to increase movement vigor due to the way music increases pleasure or reward. Therefore in this study, we also increased music familiarity using repeated exposure.
We predicted that...
- Greater familiarity with music will elicit better synchronization performance and faster, less variable strides.
- Faster strides (i.e., greater stride velocity) can be achieved via longer stride length and/or briefer stride times.
Procedure
17 healthy volunteers participated in this study, and a typical gait test session would look like this:
*note: for this particular experiment, during the repeated exposure task,
each participant listened to the songs for 2 minutes
*note: for this particular experiment, during the repeated exposure task,
each participant listened to the songs for 2 minutes
- Un-cued Walking: to obtain their cadence, participants would walk at their comfortable walking rate without any auditory cuing
- Ratings Task: participants listened to our library of songs and rated them on familiarity, groove, enjoyment, and beat salience
- Cued Walking: participants completed 10 walking trials based on the 5 conditions:
- High-Familiarity, High Groove Songs
- High-Familiarity, Low Groove Songs
- Low-Familiarity, High Groove Songs
- Low-Familiarity, Low Groove Songs
- Metronome
- Repeated Exposure Task: participants listened to their walking playlist again
- Cued Walking: participants completed another 10 walking trials to reassess their gait
Results
Synchronization Performance.
Interbeat and interstep intervals were calculated and then compared to assess the deviation between the beats of the music and the steps of the participant.
For tempo-matching accuracy, lower scores of mean deviation indicate better performance. Overall, familiar music elicited better tempo-matching accuracy. This difference was more evident during gait assessment after repeated exposure (run 2) versus initial exposure (run 1).
For tempo-matching variability (right panel), lower scores show less variable performance. Repeated exposure significantly reduced tempo-matching variability.
Interbeat and interstep intervals were calculated and then compared to assess the deviation between the beats of the music and the steps of the participant.
For tempo-matching accuracy, lower scores of mean deviation indicate better performance. Overall, familiar music elicited better tempo-matching accuracy. This difference was more evident during gait assessment after repeated exposure (run 2) versus initial exposure (run 1).
For tempo-matching variability (right panel), lower scores show less variable performance. Repeated exposure significantly reduced tempo-matching variability.
*note: asterisks indicate significant differences between conditions. Comparisons between conditions are not significant unless otherwise indicated. Error bars represent standard error of the mean.