Motor Speech Disorders

Motor speech difficulties impact the ability to perform the movements or gestures required for clear speech production. The most common Motor Speech Disorders are Childhood Apraxia of Speech and Dysarthria.

Motor Speech Disorders

Motor speech disorder (MSD) refers to a subset of speech sound disorders that includes articulation impairment (sometimes categorized as a motor speech difficulty), Childhood Apraxia of Speech (CAS) and Childhood dysarthria [MCleod & Baker, 2017]. Motor speech difficulties impact the ability to perform the movements or gestures required for clear speech production. MSDs encompass problems with one or more processes needed to produce speech, such as planning the speech motor pattern and executing the motor plan - including respiration (i.e., coordination of the lungs and associated muscles), phonation (i.e., coordination of the muscles of the larynx, including vocal cords), resonance (i.e., airflow through nose or mouth) and articulation (i.e., movements of the tongue, lips and law). These conditions affect the intricate process of formulating and articulating speech, which in turn can impact effective communication, socialization, and academic success [9]. With an in-depth understanding of these disorders and their symptoms, diagnoses, and treatments, we can better support children in overcoming these challenges.

Childhood Apraxia of Speech (CAS)

Childhood Apraxia of Speech, often abbreviated as CAS, is a neurological motor speech disorder. It creates a disconnect between what a child wishes to express and their ability to coordinate the muscular actions required to form the corresponding speech sounds [2][7].

CAS manifests itself through a variety of symptoms, which may differ between children depending on their age, the severity of the disorder, and other individual factors. Some commonly observed symptoms include [8]:

  • Delayed onset of first words: Children with CAS often start speaking later than their peers, and this delay may become noticeable as they reach their developmental milestones without beginning to speak.

  • Limited vocabulary: Children with CAS may struggle to add new words to their spoken vocabulary, often resulting in a more limited repertoire of words compared to their peers.

  • Difficulty forming sounds: Forming different consonant or vowel sounds can be challenging for these children, as they may have difficulties transitioning from one sound to another in fluid speech.

  • Inconsistent pronunciation: A child with CAS may pronounce the same word differently each time they attempt it. This inconsistency can cause confusion for the listener and frustration for the child.

  • Difficulty imitating sounds and words: Due to the motor planning difficulties associated with CAS, these children often struggle to mimic sounds and words they hear in their environment.

speech therapist works with young child

CAS Diagnosis

Diagnosing CAS requires a comprehensive evaluation by a speech-language pathologist (SLP). This professional will conduct a detailed assessment of the child's expressive and receptive language skills, their speech sound inventory, and examine their ability to coordinate oral movements for speech production [4][7].

Interventions for CAS

Treatment for CAS is tailored to each child's unique needs, with the overarching goal of improving their speech abilities and overall communication skills. The child will work closely with an SLP to achieve these goals [3]. There are several evidence-based approaches to working with children with CAS. All of these approaches will emphasize the Principles of Motor Learning. No matter which approach is used, the SLP will support the child to master the correct mouth movements for different speech sounds, specifically focusing on sound sequences or words that are of particular importance for that child (e.g., their name). We will always build from their strengths - sounds and sequences they already use successfully - and grow from there.

Childhood Dysarthria

Dysarthria is a motor speech disorder that arises due to weakness, slow movement, or lack of movement in the muscles involved in speech. These muscles, located in the mouth, face, and respiratory system, can be affected due to a stroke or other brain injury [3][6].

Identifying the Symptoms of Dysarthria

Dysarthria presents with several symptoms that can affect a child's speech in different ways [1]. The most common symptoms include:

  • Slurred or mumbled speech: The speech of children with dysarthria may be unclear and hard to understand due to slurred or mumbled pronunciation.

  • Changes in speech pace and rhythm: Dysarthria can lead to abnormally slow or rapid speech, both of which can make communication difficult. They may also exhibit speech that is broken into short, choppy segments, punctuated by several pauses, as opposed to fluid, complete sentences.

  • Fluctuating speech volume: Children with this disorder might speak either too softly or too loudly without intending to, making it hard for others to comprehend their speech.

  • Altered voice quality: A child's voice may become hoarse, harsh, strained, breathy, nasal, robotic, or monotone due to dysarthria.

Treating Dysarthria: A Multi-pronged Approach

Treatment for dysarthria is tailored to each child's unique needs, depending on the cause, type, and severity of the disorder [3]. Treatment commonly includes:

Muscle strengthening exercises: These exercises aim to enhance the strength and coordination of the muscles involved in speech. This would only be a part of the treatment plan if and when it is supported by a collaborating Occupational Therapist or Physical Therapist. In the case of dysarthria, as with many speech and language challenges, it is important for the SLP to be collaborating with the child’s healthcare team.

Breath control exercises: These exercises can help children with dysarthria better control their breath while speaking, improving the fluency and clarity of their speech.

Speech rhythm and pacing exercises: Through these exercises, children can develop a more regular and understandable speech rhythm, making it easier for others to follow their speech.

Conclusion

Motor speech disorders such as CAS and dysarthria can significantly impact a child's ability to communicate, learn, and socialize. However, with early diagnosis and the implementation of appropriate intervention strategies led by a speech-language pathologist, children can make significant improvements in their speech abilities and overall communication skills. For those invested in the growth and development of children – parents, educators, healthcare providers – gaining a comprehensive understanding of these disorders is an important first step in offering meaningful support.

FAQs

  • The cause of Childhood Apraxia of Speech is usually unknown. Sometimes, apraxia of speech can be the result of stoke or brain injury.

    Sometimes, CAS is referred to as “develpmental apraxia”, which may intend to describe it as something from birth, not being attributed to any event or in jury. CAS is sometimes attributed to a co-occuring genetic disorder or syndrome, but this is not always the case.

  • An oral mechanism exam, also known as an OME, is often conducted as part of an assssment by a speech therapist. This exam observes the strength and range of motion of the tongue, lips and jaw. It also looks at the structures of the mouth (e.g., the palate, tonsils, dentition), breath support, and various movements of the tongue, lips and jaw that are important for speech. It can also identify if a child has difficulties performing movements intentionally, or if they struggle with certain sequences of movement, which is common for children with motor speech disorders.

    If your speech therapist is conducting an OME with your child, don’t be afraid to ask questions! They will likely ask you questions regarding your child’s sleep habits (e.g., snoring, mouth breathing), allergies, feeding habits (e.g., are they a particularly slow eater?), or history of ear infections.

  • Children with motor speech disorders may also have co-ocurring difficulties with delayed language. This means they may benefit from support with learning new vocabulary, expanding their sentence structure, using appropriate grammar, or telling clear stories.

    In addition to assessing your child’s speech sound development, an SLP can assess their receptive and expressive language development in order to identify appropriate goals for them to focus on.

Links & Resources Motor Speech Disorders

  • For SLPs: Dynamic Temporal and Tactile Cueing (DTTC)

    DTTC is an evidence-based approach for working with children with Childhood Apraxia of Speech. There are free courses available for SLPs to learn how to implement DTTC in their prcatice.

    Dr. Edythe Strand

  • Therapy Videos & Education

    Amy Graham from Graham Speech Therapy specializes in treating speech sound disorders, including motor speech disorders. On her instagram page @grahamspeechtherapy, you’ll find tons of education and resources to learn more about working on these goals with children. She posts regular videos of therapy sessions which are helpful for seeing how she implements her strategies and approaches. She also has highlights saved of many topics, including the Principle of Motor Learning, which is important for SLPs working with children with motor speech disorders.

Related Articles - Motor Speech Disorders