Apraxia & Dysarthria Motor Speech Disorders

After reading last month’s excellent blog post about Apraxia of Speech, I began to reflect on memories back in graduate school, when I was first taking Neurogenic Speech Disorders and Neurogenic Language Disorders. I thought about the initial excitement I felt about preparing to learn about the myriad of neurogenic disorders including diagnosis and treatment. I remembered how overwhelmed I felt about having to learn all the medical terminology especially when it came to motor speech disorders.

These disorders affect a patient’s ability communication at home, socially and at work. When I began to work with wonderful patients and their families, the complexity of these disorders became quite clear. I began to witness first hand, the challenges and frustrations that patients and family members have during this very difficult time.

Communication during medial interactions is so important and can be daunting for patients with a diagnosis of apraxia or dysarthria. While medical staff makes every attempt to educate patients and their families, sometimes this can be difficult as there is only  limited time for most medical appointments. When patients and their family member(s) come to our clinic, we encourage questions and take the time to answer them.

The following is a resource to help understand these complex motor speech disorders.

 

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A Guide to Apraxia & Dysarthria Motor Speech Disorders

Apraxia and Dysarthria Etiologies (causes) can be acquired due to a trauma to the head, tumor, stroke or degenerative diseases of the brain.

Apraxia Types

Apraxia of Speech (AOS) (sometimes referred to as verbal apraxia or dyspraxia). Apraxia is a cortical (cortex) problem that results from a central nervous system lesion following damage to the brains left frontal lobe. Specifically; the third gyrus (ridge/fold of the surface of the brain), which is known as Broca’s Area, or Brodmann’s area 44.

Apraxia is a motor speech disorder that involves difficulty initiating and executing the movement patterns needed for speech production. With apraxia there is no paralysis, weakness, or in-coordination of the muscles, it is thought to be an impairment in the motor planning (the ability to conceive, plan and carry out the motor act) needed for speech. Apraxia effects both articulation (structures & movements to produce speech sounds) and prosody (rhythm) and may be associated with aphasia (affects ability to understand and comprehend language) and dysarthria’s (Hedge, 2010).

Types of errors with apraxia are variable. There will be a difference between a patients’ spontaneous speech production (will contain fewer errors) vs. repetition. Rote or over-learned material such as; the days of the week or months of the year are often spoken clear and fluently.

Patients will have difficulty when attempting to put their thoughts into words, due to the inability to coordinate the muscles for speech. Patients will exhibit false starts, effortful and audible groping for the right sounds and word. Numerous attempts to self-correct will be made, as patients understand that they are making errors. Substitutions are common and approximations of targeted phonemes (distinct units of sound) are made. Other errors include; transpositions, omissions, additions, repetitions or even prolongation of words. Distorted vowels and consonants are produced, while vowels tend to be easier to produce than consonants and single consonants are easier than blends. As in stuttering, final consonants are easier than those in the initial position of words.  This may occur because initial consonants are affected by anticipatory errors. Also, perhaps once an apraxic gets speech started with the production of a vowel, production continues in a more automatic fashion. Fricative [/f/, /v/, (/ð/ as in thy and /θ/ in thigh) /s/, /z/, “sh”, /z/, /ʒ-as in measure/ and /h/) and affricates (/tʃ/ = “ch”) and /dʒ/ in germ], are the most difficult phonemes for apraxics to produce. These sounds require very complex articulatory movements (McCaffrey, 2013). Their rate and rhythm will be irregular when speaking and often intervals between syllable segregation and errors in stress.

Oral apraxia will be demonstrated when non-speech volitional (a choice or a decision) movements are attempts such as attempting to being asked to pucker your lips, or puffing out your cheeks.

Childhood Apraxia of Speech (CAS) (sometimes referred to as developmental apraxia), can be congenital (present from birth-hereditary) or it can be acquired during speech development. Both congenital and acquired onsets can be idiopathic (disease or condition that arises spontaneously or the cause is unknown) or can occur in the context of complex neurodevelopmental disorders (impairments of the growth and development of the brain or central nervous system) or in association with a neurological event (Shriberg, 2010). Meaning that there isn’t a known cause for the apraxia, but it is evident that it is in planning and/or programming speech movements. (ASHA, 2007). In contrast with adults who have already developed these processes.

While acquired apraxia and childhood apraxia of speech have similar speech characteristics, the fundamental difference is with CAS is the age in which it presents. Speech typically develop as an infant progressing from cooing, babbling, words, phrases to finally sentences between 3-4 years of age. This developmental process is interactive involving not only sensory and motor control but perception and psycholinguistic (psychological and neurobiological factors on how we acquire, use, comprehend and produce language) processes. For children with CAS this process is somehow interrupted.

Dysarthria

Dysarthria is a term used to describe neurological speech disorder of movement and/or muscular control. This is due to damage of either the central nervous system (consists of brain and spinal cord) or the peripheral nervous system (consists of nerves outside the brain and spinal cord). The neural pathway that sends signals between the brain and muscles for motor movements of speech is interrupted. Types of are classified by injury site within the nervous system and by speech characteristics.

The types of errors in dysarthria is different from those of patients with apraxia. There is no time when speech errors are not present. Errors in dysarthria are consistent and predictable. Speech sound errors will occur under all speaking tasks and will not change. They will include distorted errors and omissions of sounds.

Dysarthria Types

Flaccid dysarthria: characterized by muscular weakness with recovery after rest. Typically weakness progresses along with low muscle tone, possible twitching of muscles. Symptoms do vary by type of injury.  Respiration, speech and swallowing can be impacted.

Spastic dysarthria: characterized by weakness, reduced range and slowness of movement. Symptoms include slow effortful speech, fatigue, hypernasality, drooling, dysphagia (trouble swallowing), and difficulty controlling emotional expression.

Ataxic dysarthria: characterized by difficulties with body position and walking, tremor, reduced muscle tone and range of movement. “Drunken-like” effortful speech , with difficulty coordinating respiration difficulty with the oral phase of swallowing and  fatigue are common.

Hypokinetic dysarthria: characterized by resting tremor, rigidity, slow and reduced range of movement, and posture abnormalities. Symptoms of weak voice, fast rate of speech, fatigue, drooling and swallowing difficulties.

Unilateral upper motor neuron: characterized by Babinski reflex (the big toe remains extended or extends itself when the sole of the foot is stimulated, abnormal except in young infants) on the affected side. Weakness, low tone appear first but transition into spasms strong reflexes and increased tone. Symptoms of fatigue, unintelligible, slow rate of speech, drooling, with chewing and swallowing difficulties.

Mixed: damage to different areas of the nervous system or from multiple lesions, caused by various diseases such as multiple sclerosis, multiple strokes, and ALS. Characteristics depend on the combination of dysarthria.

Treatment Considerations

Apraxia and Dysarthria treatments will vary dependent upon the individual patient’s needs. Factors such as severity, etiology, coexisting problems including patients’ ability and motivation are considered.

Dysarthria therapy is strictly compensatory (learning techniques to help increase clear speech), due to the severed motor pathways, which cannot be repaired.

Apraxia therapy works on retraining to create neuronal connections to improve the planning, sequencing, and coordination of musle movements for speech production.

Childhood Apraxia of Speech works on creating neuronal connections typically involving movement patterns vs. sound patterns.

A Speech Language Pathologist will evaluate, discuss treatment options and goals specific to each unique individual’s needs.

Communication Tips

As frustrating as it may be for you, remember your loved one is struggling as well. Patience is the key. Remember to look at the person when they talk, reducing background noise and distractions. Allow plenty of time for a response, eliminating stress and anxiety that can further impede communication. Avoid correcting errors or finishing sentences unless you have discussed this and the patient prefers your help. Otherwise it can cause resentment. Honesty is best.  If you do not understand on the first try, paraphrase what you did understand and ask for clarification. Saying you did understand when you did not causes frustration.

AnneMarie Finn MS CF-SLP

Resources and Support

References:

  • Childhood Apraxia of Speech (2007) Retrieved June 27, 2014, from http://www.asha.org/
  • Duffy, J.R. (2003) Motor speech disorders: substrates, differential diagnosis, and management (3rd ed.). St. Louis, Mo.: Elsevier Mosby.
  • Hedge, M.N., & Davis, D. (2010) Clinical methods and practicum in speech-language pathology (5th ed.).  Clifton Park, NY: Delmar Cengage Learning.
  • McCarthy, P. (2013) Neuropathologies of Swallowing and Speech. Retrieved April, 7 2016 from  http://www.csuchico.edu/~pmccaffrey//syllabi/SPPA342/342unit15.html.
  • Yorkston, K.M. (2010) Management of motor speech disorders in children and adults, (3rd ed.). Austin,  Tex.: Pro-Ed.

 

 

 

 

 

 

 

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