Speech not only consists of the words we say, but how we say them. That “how” is what is called prosody: the pitch, loudness, and timing of speech.
The term prosody comes from the Greek word prosōidia meaning “song” or “melody.” Therefore, prosody is often viewed as the melody of speech. Without prosody, our speech would sound robotic, and could even be hard to understand.
The meaning of our words can change based on how we say them. When we talk, we stress certain words by raising our pitch, saying them louder, and stretching out the words. When we stress words like this, we are conveying certain meanings, such as making a correction or introducing a new topic. Because of prosody, people can also tell whether we are asking a question (“You know Nina?”) or making a statement (“You know Nina!”).
Lastly, prosody helps us express emotion in our speech and convey our own unique speaking style. Every person has a unique way of talking. Because of prosody, we can tell when someone is happy, angry, sad, or bored. Before the days of cell phones and caller IDs, a person could call a family’s landline and tell who was talking based on their voice and speaking style alone. That unique speaking style is prosody. These subtle but important changes in pitch, loudness, and timing shape the meaning of our speech and how it is interpreted.
What commonly happens to prosody in ataxia?
Neurological conditions such as ataxia, Parkinson’s Disease, and Amyotrophic Lateral Sclerosis frequently result in what is called dysarthria: a neurological impairment in the execution of speech. There are unique dysarthria characteristics for each neurological condition. Dysarthria in ataxia, termed “ataxic dysarthria” by speech-language pathologists, is uniquely characterized by variable prosody.
Variable prosody means that prosody is not consistent during speech, but rather varies, sometimes unpredictably. For example, sometimes people talk louder at the start of the phrase, called “explosive loudness.” Other times, people may raise and lower their pitch more than what is typical while talking. Lastly, it is common that the timing of words and pauses between words is inconsistent.
Prosodic impairments in ataxia range from mild to severe and can impact how the speaker’s message is interpreted. Some people with ataxia have reported that people think they are angry when they are not because they are speaking too loudly. Other people say they are often misinterpreted, potentially because of stressing the wrong word while talking. Impaired prosody can also significantly impact the quality of life if the speaker does not like how their speech sounds post-diagnosis.
Prosody is likely impaired in ataxia due to damage to the parts of the cerebellum which coordinate breath control and vocal fold vibration, as well as send signals to modify our voice based on how we hear out voice through auditory feedback.
How can prosody be improved?
Research is still being completed to find effective therapies for improving prosody in ataxia. There is currently no gold standard for treatment. The main recommendation is to seek a referral for an evaluation by a speech-language pathologist to determine your own unique prosodic difficulties, and what may be causing them.
For example, if you have explosive loudness bursts while talking, it may be beneficial to work on improved breath control while speaking. This could include learning the effective amount of air to inhale before speaking and how to better control exhalation. If you have difficulty controlling pitch while talking, potential treatment goals could focus on improved breath control, vocal fold closure, and the use of visual feedback to track changes in pitch.
If you would like to learn more about prosody, take a look at these resources by Mango Languages.
Snapshot Written by: Allison Hilger, PhD, CCC-SLP
Edited by: Celeste Suart, PhD