What are Motor Speech Disorders

What Are Motor Speech Disorders?

Myra Huffman¹, Shelley Velleman²

             Most people who have been diagnosed with 7q11.23 duplication syndrome experience some kind of oral-motor and/or motor speech difficulties.  What does that mean? “Motor speech disorder” is a term used by speech-language pathologists, physicians, and researchers for classifying a group of speech sound production disorders. As a group, these disorders result from difficulty with movement control and involve nervous system activity occurring before or during the act of speaking. Motor speech disorders are usually classified into two subgroups, apraxia of speech and the dysarthrias.

            The general classification dysarthria is given for various speech disorders that disrupt the ability to execute (carry out) speech movements appropriately. They are due to difficulties with controlling the muscles. The movement difficulty can affect one or several aspects of speech production including a) speech breathing, b) voice production, c) prosody, the melody and rhythm of speech, d) resonance such as nasality, and/or, e) clear accurate productions of speech sounds. Typically, the speech-language pathologist will suspect dysarthria when a person's speech is unclear and distorted. A full oral-motor and speech-language assessment will identify possible causes and other symptoms. Careful attention will be given to the state of the speech muscles during the act of speaking. Specific symptoms might include poor sensory awareness in the mouth area, weaker than necessary speech movements (for example, reduced strength and endurance of the tongue), restricted range of movement of the speech structures, or slower than expected speech production. Typically, dysarthric speech is consistent; the person sounds similarly unclear in different situations.

            Apraxia of speech is the term used for a speech disorder that reduces the ability to mentally plan and program the voluntary and complex movements needed for speaking. Motor planning and programming occur in the brain before someone actually speaks a particular message. The brain has to send the right commands, in the right order, for a) efficiently sequencing the sounds and syllables in a message, and b) programming the message in terms of overall rhythm, emphasis, and speaking rate. Because motor planning and programming occur before speech is produced and are affected by the situation, speech-language pathologists suspect apraxia of speech only after carefully observing the quality of speech in several kinds of speaking tasks. It is important to understand that muscle weakness is not a core feature of apraxia (although it could be present in the speech of some individuals who have both dysarthria and apraxia). The term “childhood apraxia of speech” (CAS) is used when these symptoms begin in childhood.

            Researchers have agreed that the three core features of CAS include; a) inconsistent speech errors when a word is repeated, b) choppy speech, and c) inappropriate prosody, especially poor control of stressing syllables. Other behaviors suggestive of CAS include, a) mistakes on vowel sounds, b) differences between speech that is produced purposefully compared to that which is produced automatically (such as well-known songs), c) difficulty with tasks requiring verbal imitation, d) difficulty including all the parts of the word (e.g., the final consonant, the blends, etc.) and e) not reaching speech milestones in the usual order (e.g., learning supposedly more difficult sounds before supposedly easier sounds). Apraxic speech often sounds effortful, choppy, slow, and flat.

            After thoroughly considering speech history and current behavior, the speech-language pathologist will make an appropriate diagnosis so that strategies chosen for therapy will be the most effective and efficient. Speech therapy for both conditions includes what is known from motor learning research. This research tells us that learning movements requires focused attention, certain kinds of practice, appropriate feedback, flexible use of new skills, and the ability to remember and apply what has been learned in new words or new situations. More contemporary approaches have also included what is known from cognitive learning research. This research suggests the importance of recognizing the learner as an active problem solver, making sure that learning material is meaningful and useful, providing information to more than one sense at once (for example, encouraging the person to watch and listen), and including the learner's family in the treatment program. In the beginning phase of therapy with very young children, the use of alternate communication strategies can help decrease frustration while the child learns to talk. Two forms of alternate communication are manual sign language and computerized speaking devices.  

            Overall, we learn what we practice. Therefore, to improve speech the person must practice speech; simple mouth exercises like blowing and chewing will not improve speech. Because speech is typically very difficult for children with motor speech disorders, practicing at home is very useful. You can also provide something that your child desperately needs and will rarely get in school or speech therapy: fun breaks from that hard work and loving opportunities to communicate without being judged.

¹Myra Huffman, M.S., CCC-SLP, Department of Psychological and Brain Sciences, University of Louisville, Louisville, KY

²Shelley Velleman, Ph.D., CCC-SLP, Communication Disorders, University of Massachusetts, Amherst, MA