Clinicians and parents commonly observe that practice and repetition facilitate progress in therapy for childhood apraxia of speech. Why is this aspect of treatment more important in children who have apraxia, than for children who’s primary deficit is in language or phonology? The answer lies in the fact that children with apraxia of speech primarily exhibit deficits in planning and executing movement. The researchers in the area of cognitive motor learning have taught us a great deal about how skilled movement is acquired and how we can facilitate new motor learning. Motor learning involves acquiring the ability for producing skilled actions, and occurs through practice. The researchers who study cognitive motor learning have done numerous experiments that show that limb movement practice is influenced by a variety of factors, and have demonstrated a number of principles of motor learning that can be used as guides for planning treatment for speech production.
One of the most robust variables that affect motor learning is the necessity for repetitive practice. That is why it is recommended that children with apraxia receive therapy frequently for shorter sessions versus less frequently for longer sessions. It is much better to schedule a child for two half-hour sessions rather than one session lasting an hour, or even four 20 minute sessions versus two one hour sessions. Clinicians also work to maximize the number of practice trials per session, by keeping reinforcements quick, using novel fun activities that involve continued practice with the target utterances. Other factors that influence practice include how practice is organized. This falls under the principle of mass vs. distributed practice. It is recommended that for children with severe motor planning impairment, the number of target utterances remain small (5 to 6). That allows enough mass practice for success (motor performance), yet brings in some distributed practice that facilitates motor learning (generalization). As the child improves motor planning ability, the stimulus list is gradually increased. Types and schedules of feedback have also been shown to facilitate both motor performance and motor learning. Early in therapy, more immediate feedback facilitates motor performance, but may not facilitate motor learning or generalization. Therefore, providing less frequent and less immediate feedback as the child improves accuracy is recommended. Finally, it is important to vary rate. Slowing rate improves movement accuracy, but can lead to deficits in prosody, or the natural rhythm of speech. Frequently clinicians will start with slower movement practice, gradually increasing rate to normal, and gradually varying prosody with continued repetitions.
While the literature in cognitive motor learning has been very helpful to speech pathologists who work with apraxic children, clinical research needs to be directed at how the principles of motor learning influence the acquisition of speech motor planning and execution, especially in children with motor planning deficits.
(Dr. Strand is a consultant in the Department of Neurology, Division of Speech Pathology, at the Mayo Clinic in Rochester, Minnesota, and Associate Professor in the Mayo Medical School. Her primary research and clinical interests have been in Neurologic Communication Disorders, especially developmental and acquired apraxia of speech, dysarthria, and neurologic voice disorders. She has published articles and chapters regarding the clinical management of motor speech disorders in children, including treatment efficacy. Dr. Strand is co-editor of the recent book (1999), Clinical Management of Motor Speech Disorders of Children. She lectures frequently throughout the country on childhood apraxia and motor speech disorders in both children and adults. Dr. Strand is a member of the Childhood Apraxia of Speech Association’s Professional Advisory Board.)