Straight Talk on Vocal Tremor
By Rosemary A. Lester, M.A., CCC-SLP
Tremor Talk, April 2014
Rosemary Lester was a doctoral candidate in the Department of Speech, Language, and Hearing Sciences with a minor in Neuroscience at the University of Arizona when this article was written. She received her clinical training in speech-language pathology at Indiana University and works as an SLP in Tucson, AZ.
How often do you think about how your voice sounds or how it feels when you speak? Normally, few of us think about our voices on a daily basis because speaking is usually effortless. In fact, many of us are unaware of our voices unless we have a cold and sound hoarse or we are in a noisy room and have to shout to be heard. But some people with essential tremor think about their voices all the time. They notice that their voices sound shaky when they speak. They feel that their voices are difficult to control and that speaking is tiring. These are the people who have vocal tremor, a voice disorder that affects approximately 18-30% of people with essential tremor. Fortunately, some people with vocal tremor can benefit from therapy with a speech-language pathologist (SLP) to learn how to make the voice sound less shaky and how to use less effort when speaking.
What Causes Vocal Tremor?
Many people assume that a shaky voice is caused by tremor within the larynx (the “voice box”). This is true for some people with vocal tremor. But vocal tremor can also be caused by tremor affecting the chest, abdomen, mouth, or throat. We use all of these parts of the body to speak. Before we speak, we take a breath and then we slowly release the breath to speak. We control the breath using our chest and abdominal muscles. As we release the breath, we also use muscles in the larynx to allow the vocal folds (often called the vocal cords) to vibrate and produce sound. In addition, we use muscles in the mouth and throat to shape the voice into sounds that can be understood as speech. Because muscles in all of these parts of the body are used to speak, tremor affecting any of these areas can make the voice sound shaky.
How is Vocal Tremor Treated?
The medications that are used to treat tremor affecting the arms and legs are not often effective in treating vocal tremor. But some people with vocal tremor benefit from injections of small amounts of botulinum toxin (Botox®) into the larynx. This can sometimes make the voice sound less shaky and can make it feel less difficult to speak. Unfortunately, this treatment does not help everyone with vocal tremor, and it may have some negative side effects including difficulty swallowing. For people who do benefit from Botox®, the effects are only temporary so the injections are typically repeated every few months. For these reasons, some people seek a different
treatment approach for vocal tremor that involves therapy with an SLP.
What is the Research on Therapy for Vocal Tremor?
Recent research has demonstrated that therapy can help make the voice sound more stable and make it feel easier to speak for some people with vocal tremor. But more research is needed in this area to determine who the best candidates for therapy are and what the best treatment approaches are for these individuals. Because so many muscles are used to produce voice and because essential tremor can affect many different muscles, it can be challenging to study vocal tremor in people who have essential tremor. That is one of the reasons why researchers at the University of Arizona are using computer models to simulate vocal tremor involving the different parts of the body that are used to speak. Using these models, they can isolate tremor to one part of the speech mechanism or simulate combinations of tremor affecting multiple parts of the speech mechanism. They can then make adjustments to the voice and determine which ones reduce how shaky the voice sounds to listeners. The ultimate goal is to use these findings to help determine the most effective and efficient therapeutic approaches for treating vocal tremor.
How Can I Try Therapy for Vocal Tremor?
If you think that therapy might help you, ask your doctor about a referral to an SLP who specializes in voice. You may also visit www.asha.org/findpro or call (toll free) 800.638.8255 to find an SLP in your area. To determine if you would benefit from therapy, the SLP will ask you about the changes in your voice, listen to and record your voice, and watch the way you speak. The SLP will see if tremor affects your larynx, chest, abdomen, mouth, or throat while you speak. Depending on the results of the evaluation, the SLP might teach you ways to adjust the pitch or loudness of your voice, change your breathing patterns, or alter the way you produce speech sounds. The SLP will then help you learn to use these techniques in your everyday speaking activities to improve the way your voice sounds and the way it feels when you communicate with your family, friends, and colleagues.