Question
My son is now in 4th grade and despite having had speech therapy for severe articulation problems from the time he was in preschool to first grade, he continues to be at times incomprehensible. He is extremely bright (actually gifted in math and science),
Answer
Aidan sounds like a very likeable and gifted child, who has worked for several years on his speech. It must be frustrating for him and for you to realize that despite his effort and family support, he is still having difficulty being understood by others. To complicate matters, he is also in the process of correcting his overbite. There may be a relationship between his speech, eating and the overbite, which I will address in the second part of my answer to your questions. I would like to begin by discussing his history of severe articulation problems, residual sound errors, and word finding issues. I will offer two potential explanations to these characteristics. Then I will address the oral motor aspects of your question.
When children learn the sounds of their language during the first 2 years, they use the models they hear from others to produce words that have high functionality, such as bottle, night-night, and mama. All of the sounds in these words may not occur right away, but each child gradually learns more words and more sounds as he grows. By about age three, most children use sentences and are intelligible to family and friends. During this process, the child stores sounds and words through creating phonological codes in memory. That is, the sounds of the words are stored in long term memory so that the words can be retrieved as whole units, when they are needed. If the child doesn't speak the words with correct sounds, these phonological codes for words may not be stored accurately. Thus, when the child wants to produce the words he knows, word finding problems may occur and the production of the words that are retrieved may be inaccurate. This phenomenon tends to occur especially on words that have a level of complexity in terms of the presence of several syllables or highly complex consonant arrangements. A word such as "helicopter" is an example of a four syllable word with several consonants that are different from each other. Aidan may be experiencing word finding problems due to his retrieval of early and inaccurate phonological codes for his stored words. An alternative explanation is that he is having trouble accessing information, but his history of severe articulation problems leads me to suspect that phonological coding is contributing to his difficulties. You did not mention whether he had or has challenges in reading or spelling. If so, these difficulties may also stem from this problem. The good news is that there are many activities that can be practiced to improve phonological coding, storage, and retrieval strategies.
There is another explanation for the severe articulation problems noted during the preschool years followed by degrees of unintelligibility even now in the fourth grade. There is a motor-based speech production problem called Childhood Apraxia of Speech. Children with CAS have a great deal of difficulty learning new sounds and putting sounds in combinations to make words. The muscles in the structures for speech are not impaired. Rather, it is the selection and sequencing of the sounds (motor planning) that appears to interfere with sound and word production success. Words that have several syllables and complex sound arrangements are quite difficult for the child to produce. The child might look like he is experiencing word finding problems, when in fact the problem may be in the motor planning necessary to produce the particular word. The same word may be produced accurately in one instance but not in other, often depending on the complexity of other words in the phrase. Children who have CAS may also have motor planning issues during eating with exaggerated or uncoordinated movements. Again, these characteristics are not due to muscle impairment, but rather are due to difficulty with sequencing and coordinating movements. Intervention for CAS is typically intensive and the focus is on gaining flexibility in the combinations of syllables and consonants to produce accurate words.
The second issue that you described is continued difficulty with the /r/ and presumably the /l/ sounds. Many children, who have severe articulation problems in their early years, have what is known as residual errors. That is, while most other sounds become normalized through development either with or without intervention, some sounds do not normalize, even despite intensive therapy. The sounds /r/ and /l/ are often culprits. These sounds require a high degree of precision. It is not uncommon for children to compensate for their difficulty with producing the sound by using the lips in an attempt to approximate the sounds. Thus, lip-rounding during an attempt at /r/ will result in a /w/-like sound. Lip-rounding during an attempt at /l/ will also result in a /w/-like sound. In words, different vowels that occur before the /r/ or /l/ can alter the sound drastically because of the different tongue configuration required. Intervention may be more successful if each vowel + /r/ or /l/ is worked on separately. For example, words that have the "ar" sound (car) are used, then a different combination, such as "or" (for) is introduced.
The third issue that you describe for Aidan is his severe over bite. It is possible that this condition is related to open mouth breathing where the tongue is carried forward in the mouth during the resting position, rather than behind the teeth with the mouth closed. Prolonged periods of the forward tongue carriage may cause the over bite malocclusion. Mouth breathing may indicate an upper respiratory condition such as enlarged tonsils or adenoids or an obstruction in the nasal cavity. Either of these conditions can make breathing through the nose difficult, thus mouth breathing occurs. Orthodontia is typically successful for changing the over bite occlusion, but if a forward tongue carriage persists (tongue thrust), the orthodontic changes may be temporary. An evaluation to rule out tongue thrust is recommended. Myofunctional intervention is often used in combination with orthodontia and can result in correction of the tongue placement and the development of a mature swallow. It should also be noted that a forward tongue carriage may influence the production of the /r/, which is considered as a sound made through tongue positioning toward the back of the mouth. Intervention aimed at elimination of forward tongue posturing may enhance intervention for accurate production of the /r/.
Here are some hypotheses regarding your final questions "What exactly is his pathology? One or more of these hypotheses may explain the several aspects of your concerns.
- Aidan has a phonological processing disorder that impairs his ability to store and retrieve the phonological codes for the accurate production of speech sounds in words effecting his intelligibility and word finding.
- Aidan has a motor-based planning disorder (Childhood Apraxia of Speech) that is interfering with his ability to use complex syllable structures to produce words in discourse. This motor planning problem also effects eating.
- Aidan has a residual articulation disorder.
- Aidan has a tongue thrust that is contributing to the presence of his overbite, his eating and swallowing patterns, and may be a factor in his residual errors.
Dr. Kathleen Fahey has 30 years experience as a speech-language pathologist. She is a full professor and teaches undergraduate and graduate courses in Audiology and Speech-Language Sciences at the University of Northern Colorado. Her areas of expertise include phonological development and disorders, normal language development, school-age language and literacy, and professional issues including recruitment and retention of SLPs.