First let me give you some background on speech disorders. In my mind I separate them into three main types.
- Articulation Disorder - This is when a child has difficulty pronouncing a specific sound correctly. Often the sound is /r/, /l/, or /s/. They may have trouble with two or three sounds, but the problem is with the sounds on an individual level. Usually this kind of problem doesn’t impact their intelligibility (how easily a stranger can understand them) too much and is relatively easy to address. The therapist would work on helping the child learn to make the sound correctly first in isolation, and then at the beginning, middle, and ends of words. They’d move up to phrases and sentences. This type of problem is relatively easy to address and if the child has a sound that simply won’t respond to remediation, the consequences aren’t that severe.
- Phonological Disorder - Make a /k, k, k/ sound out loud. Now make a /g, g, g/ sound. Both of those sounds are made in the back of the mouth with the back of your tongue. Now make a /m, m, m/ sound and a /p, p, p/ sound. Both of those sounds are made in the front of your mouth with your lips. All of the consonant sounds in our language can be categorized by the place in the mouth in which they are produced and by how they are produced. Some sounds are front sounds and some are back sounds. Some sounds are stop sounds and some sounds are fricatives. Children with a phonological disorder have trouble with groups of sounds. They might take all front sounds and produce them as back sounds instead. Alternately they might take all back sounds and move them to the front. They might take sounds that are supposed to be long and drawn out like /s, sh, m/ and shorten them. You get the idea. The more patterns they have difficulty with the harder they are to understand. This type of disorder can significantly impact a child’s intelligibility and is more difficult to remediate than a simple articulation problem. When treating a child with a phonological disorder you treat the patterns rather than specific sounds. The way the SLP structures therapy will be different than with a simple articulation problem and that difference is important if you are going to see the most change in the shortest amount of time. A phonological disorder is a significant speech disorder that takes a lot of therapy to address. You can address it in a group setting particularly if you group children together who are making errors with the same phonological processes.
- Childhood Apraxia of Speech - This is a completely different kind of problem. It is not a problem with a specific sound or even with groups of sounds. This is a neurological motor planning disorder. The child knows what they want to say. The mouth is physically capable of making the sounds. The planning of the muscle movements necessary to make the sounds is what is difficult. This brings the scope of the problem to a whole different level. Now you aren’t just trying to fix the sound /s/. You’re not even trying to teach a child who is moving all their front sounds backwards to bring them back to the right place. You have to help a child learn, at the level of muscle memory, how to produce all the possible sound combinations. This is a huge task because the way the muscles have to move to produce /baa/ is different than the way they have to move to produce /bee/ . So you can’t just work on a generic /b/. Therapy needs to be designed with a motor planning approach. Targets have to be carefully chosen. Therapy needs to be focused on getting the maximum number of productions possible. Therapy usually needs to be one-on-one in order to achieve this. Ideally, you’d have therapy multiple times a week and your therapist would be teaching you how to do carry-over activities at home. You want to be (gently, of course) focused on getting your child to incorporate his target productions into his daily routine as much as possible. You want him to be using his target productions with a wide variety of people in a wide variety of situations. You want them to learn and overlearn everything so that it becomes automatic. Typically, children with CAS need a lot of therapy to show improvement. Typically, especially early on, it has a pretty big impact on intelligibility and these children are extremely frustrated. Typically a child with CAS will not progress when the therapy type is not focused on motor planning. That is why it is important to know if your young child looks like a likely candidate for CAS. You need to get the right kind of therapy and a lot of it as early as possible. Go back to this post and read the three bolded sections near the bottom for some quotes directly from ASHA or research articles that pertain to the issue of appropriate therapy for CAS.
As you can see, at least on paper, there are some pretty clear differences between the main types of speech disorders and clear differences on how to treat them. In reality, it is always more messy. It can be difficult to tell the difference between a very young child with a severe phonological disorder and a very young child with CAS. I talk about the red flags for CAS in a young child here. If your therapist is not sure, he or she may begin with more general expressive language stimulation / phonological therapy. If your child does not make progress over several months using that approach, that’s additional evidence that you may be dealing with CAS.
There is no significant disadvantage in trying an intensive motor planning approach to therapy to see if your child responds. And if your child does have CAS, research shows that it is with this approach that the most progress is made.
(Note: there are several different packaged approaches / programs of intervention designed to address apraxia that you may have heard of such as Kaufman, PROMPT, Dynamic Temporal and Tactile Cueing, etc. All of these approaches are fundamentally based on motor planning theory.)