Childhood apraxia of speech

Overview

Speech disorders like Childhood Apraxia of Speech (CAS) are relatively rare conditions. In individuals affected by CAS, there are difficulties in coordinating the precise movements of the lips, jaws, and tongue during speech.

In CAS, the brain encounters challenges in effectively directing the movements for speech. Even though the muscles involved in speech are not inherently weak, they struggle to form words correctly due to a problem in the brain’s ability to instruct them properly.

In order to speak fluently, the brain must generate intricate plans that guide the muscles responsible for moving the lips, jaw, and tongue. When executed correctly, these movements result in words and sounds being produced at the appropriate speed and rhythm. CAS interferes with this process.

A commonly employed approach for addressing CAS is speech therapy. Under the guidance of a speech–language pathologist, children with CAS learn and practice the correct pronunciation of words, syllables, and phrases during therapy sessions.

Symptoms

Speech symptoms in children with CAS might vary. The age of the kid and the severity of the speech issues affect the symptoms.

CAS may lead to:

• Babbling less or producing fewer vocal sounds than expected for a child between the ages of 7 and 12 months.
• Speaking for the first time later in life, usually after the ages of 12 to 18 months.
• Speak with fewer consonants and vowels.
• Making difficult–to–understand speech.
• Frequently omitting sounds during speaking.

Typically, these symptoms become noticeable in children between 18 months and 2 years of age. During this developmental stage, certain signs may suggest the presence of Childhood Apraxia of Speech (CAS). However, it’s crucial to recognize that a child initially suspected of having CAS may indeed have this speech disorder. Therefore, closely monitoring the child’s speech development is essential to determine the appropriate timing for initiating therapy.

Between the ages of two and four is often when children speak more. Symptoms that could point to CAS include:

• Mispronouncing words, like “pie” for “bye.”
• Distortions of consonant and vowels
• Pauses between syllables or words.

Many kids with CAS struggle to position their lips, tongues, and jaws in the right ways to produce sound. They might also find it difficult to transition fluidly to the following sound.

A lot of kids with CAS also struggle with language, like having a limited vocabulary or having issues with word order.

Certain symptoms might be specific to kids with CAS, which aids in the diagnosing process. But some CAS symptoms can also be found in other kinds of speech or language impairments. If a child only exhibits symptoms that are common to both CAS and other diseases, it might be challenging to diagnose CAS.

Certain characteristics aid in differentiating CAS from other kinds of speech impairments. People connected to CAS consist of:

• Trying to make the right motions for speech sounds by groping movements of the jaw, lips, or tongue.
• Vowel distortions, such as attempting to pronounce a vowel correctly yet mispronouncing it.
• Difficulty transitioning smoothly between sounds, syllables, or words.
• Difficulty mimicking simple words
• Varying in pronunciation errors when attempting to pronounce the same word twice.
• Mispronouncing words, such as saying “down” when you mean “town.”
• Stressing a word incorrectly—for example, saying “banana” as “BUH–nan–uh” rather than “buh–NAN–uh.”
• Stressing each syllable equally, for example, when saying “BUH–NAN–UH.”
• Syllable division, such as adding a pause or space between syllables.

Other speech problems that are occasionally mistaken for CAS

As there is often an overlap in symptoms between speech sound issues and Childhood Apraxia of Speech (CAS), they are frequently confused. These speech sound problems encompass conditions such as dysarthria, phonological problems, and articulation disorders.

In the case of a child dealing with an articulation or phonological disorder, the primary challenge lies in acquiring and using specific sounds correctly. Unlike CAS, these children do not face difficulties in organizing or coordinating their speech movements. It’s worth noting that articulation and phonological disorders are more common than CAS.

Speech problems related to phonology or articulation can include:

• Omitting last consonants. “Duh” or “uh” may be used by a child with CAS in place of “duck” or “up.”
• Substituting the sounds. The youngster may substitute words such as “wabbit” for “rabbit,” “tup” for “cup,” or “fum” for “thumb.”
• Making sound combinations simpler. It is possible that the child will say “ting” instead of “string” or “fog” instead of “frog.”
• Cutting off the airflow. It is possible that the child will say “tun” instead of “sun” or “doo” instead of “zoo.”

Dysarthria is a speech disorder characterized by weakened speech muscles. In individuals with dysarthria, these muscles cannot move as far, as quickly, or as forcefully as required for typical speech production, resulting in difficulty in producing speech sounds. Additionally, dysarthria can manifest as a hoarse, soft, or strained voice, and individuals with this condition may also speak slowly or slur their words.

Diagnosing Childhood Apraxia of Speech (CAS) is generally more complex than diagnosing dysarthria. Distinguishing between CAS and dysarthria can be particularly challenging when CAS is caused by damage to brain regions that affect speech coordination.

Causes

A multitude of factors may contribute to CAS. However, a reason is frequently unknown. Typically, a kid diagnosed with CAS does not exhibit any problems in the brain. 

On the other hand, injuries or illnesses of the brain might cause CAS. A stroke, infections, or traumatic brain injury are a few examples of them.

Moreover, CAS could be a symptom of a metabolic disease, syndrome, or genetic abnormality.

Another name for CAS is developmental apraxia. However, children with CAS do not outgrow CAS, nor do they produce typical developmental sound mistakes. This is not the case for kids who have developmental disorders or delayed speech, who usually develop speech and sound patterns at a slower rate than normal.

Risk factors

Variations in the FOXP2 gene appear to increase the risk of developing Childhood Apraxia of Speech (CAS) as well as other speech and language disorders. The FOXP2 gene may play a role in developing specific brain circuits and nerves related to speech and language. Researchers are actively exploring how mutations in the FOXP2 gene affect various aspects of speech, language processing, and motor coordination in the brain. Additionally, it is possible that other genes may also contribute to the development of motor speech disorders.