As an undergraduate at the University of Iowa, I worked part-time as a home health aide. One of my regular clients was "John," a retired dentist and former big band leader from the 30s who was fighting Parkinson's disease.
John didn't have the "resting tremor" most commonly associated with the disease. In fact, he often complained that the doctors got it wrong.
"Look!" he said, holding his hand steady, "No tremors."
John spent his days in the TV room, eating meals, watching TV, reading, talking with his wife, and receiving visitors. Then, at night, he walked across the length of the house to his bedroom.
But this posed a problem.
The walk required that John walk from a carpeted surface, to a smooth wood-floored foyer, back to carpet. Not easy for someone with Parkinson's disease. John often "froze" and "got stuck" before moving from one surface to the next. The visual change seemed to distract him and it was difficult for him to move smoothly from one floor-type to the next. As the disease progressed and John got weaker, he would freeze more often, whether the surface changed or not. What should have taken a couple minutes instead took 10-15.
John was a musician and he loved Sousa. I forget whose idea it was (I think it was John's), but one day I started singing "Stars and Stripes Forever." In the music, there's a brief 4-bar introduction before the main melody starts. While I sang that introduction, John would start marching in place to the beat. Once the melody started, we'd be off!
I'd sing Sousa as John marched down to his bedroom. And guess what happened? No freezing. Smooth steps. Easy transitions from carpet to wood and back again. Less time to get to the bedroom. It was amazing.
I never knew why this worked until I started my graduate training at Colorado State University. It turns out that our motor system entrains to a rhythmic pulse. Think about it. If you are walking down the street and "hearing" a song in your head, you're walking to the beat. You don't realize you're doing it. It's natural and it's unconscious.
A steady rhythmic pulse acts as an external timekeeper for our motor system. It helps to structure and organize how we move. This is especially true to movements that are inherently rhythmic--walking, for example. A typical walking pattern is steady and predictable. Left - Right - Left - Right - Left - Right. If you play music with a strong, steady beat, your body will want to walk to that beat.
Our motor system is very sensitive to an auditory input. This sensitivity starts early. A story came out just yesterday about researchers in England who found that babies as young as 5 months move to music.
Zentner and his colleagues studied children aged 5 months to 2 years. They videotaped the babies listening to classical music, rhythmic beats, and speech, then had professional dancers analyze the movements to see how well they matched the music. The researchers found that babies moved their bodies to music much more often than to speech. The babies also smiled more frequently when their dancing matched the music.
We don't yet know why our bodies are sensitive to moving to music, but the implications are exciting. Rhythm can be used to help train the motor systems of people with neurological impairments: Parkinson's, stroke, autism, Huntington's, cerebral palsy, and a host of other disorders.
And sometimes it's just fun. Like watching baby Cory dance to Beyonce's "All the Single Ladies":