April 26, 2011 News

Apraxia: Research and Resources

Research 

Script Training for Apraxia 

A study in the February 2011 issue of the Journal of Speech-Language Pathology indicates that script training—a functional treatment that has been successful for individuals with aphasia—may also be effective for individuals with apraxia of speech (AOS).

In the study, principles of motor learning were incorporated into training to promote long-term retention of scripts. Three individuals with AOS completed script training. A multiple-baseline, across-behaviors design examined acquisition of client-selected scripts. Errors and speaking rates also were analyzed. Random practice and delayed feedback were incorporated into training to promote motor learning. Probes for long-term retention were elicited up to six months after treatment.

All three clients successfully acquired their scripts, and probes demonstrated script retention six months after treatment. Errors generally decreased, but remained variable even during maintenance and retention probes. Speaking rate increased for two of the participants but also remained variable.

The researchers conclude that script training was successful and functional for clients with AOS. The clients reported increased confidence, speaking ease, and speech naturalness. Although the scripts did not become errorless, clients retained their scripts and reported using them frequently. The effect of the principles of motor learning on the long-term retention of scripts exhibited by participants, however, must be determined through future research.

Hypometabolism Patterns Refine AOS, Aphasia Variants

A study in Archives of Neurology indicates that patterns of hypometabolism on fluorodeoxyglucose F18 positron emission tomography (FDG-PET) in patients with progressive apraxia of speech (PAS) and primary progressive aphasia (PPA) variants may help further refine current classification of the disorders.

Researchers identified 24 patients who had FDG-PET and PAS or PPA who were evaluated by a speech-language pathologist. Patterns of hypometabolism were independently classified by two raters blinded to clinical data. Three SLPs reclassified all patients into 1 of 7 operationally defined categories of PAS and PPA blinded to FDG-PET data.

Of the 24 patients in the study, nine had nonfluent speech output; 14, fluent speech; and one was unclassifiable. Twenty-one patients showed FDG hypometabolism; the remaining three did not. Among the patients showing hypometabolism, eight had a prerolandic pattern of which seven had nonfluent speech including progressive nonfluent aphasia (n = 3), PAS (n = 1), and mixed nonfluent aphasia/apraxia of speech (n = 3); the other patient had PPA unclassifiable. The remaining 13 had a postrolandic pattern, all with fluent speech (P < .001), including logopenic progressive aphasia (n = 6), progressive fluent aphasia (n = 6), and semantic dementia (n = 1). Patterns of hypometabolism differed between the nonfluent variants and between the fluent variants, including progressive fluent aphasia.

Patterns of FDG-PET hypometabolism support the clinical categorizations of fluency, the distinction of apraxia of speech from progressive nonfluent aphasia, and the designation of a progressive fluent aphasia category. 

Lingual Movement in Apraxia

Speakers with apraxia of speech (AOS) show evidence of reduced anticipatory lingual movement, which can have a significant impact on absolute speech timing. Using electromagnetic articulography (EMA) and electropalatography (EPG), researchers recorded tongue-tip movement and tongue-to-palate contact patterns for three speakers with AOS and five speakers without AOS while the speakers said "a scarlet" and "a sergeant." Anticipatory lingual movement and speech timing were analyzed and tongue-tip displacement was calculated from the onset of release to the end of release to provide an indication of anticipatory lingual movement.

The EMA results indicated that two participants with AOS exhibited reduced anticipatory lingual movement (i.e., greater tongue-tip displacement) during repetitions of "sergeant." However, all speakers produced a comparable tongue-tip displacement to that produced by the control group during the release of /l/ in "scarlet." The EPG results indicated that absolute duration was significantly prolonged during the final syllables of both stimuli for each of the apraxic speakers. For more information, visit the University of Queensland website.

Resources

ASHA's apraxia resources webpage contains links to a variety of helpful resources, including:

ASHA Policies and Reports 

  • Childhood Apraxia of Speech (position statement, technical report)
  • Preferred Practice Patterns for the Profession of Speech-Language Pathology
  • Augmentative and Alternative Communication
  • Roles and Responsibilities of Speech-Language Pathologists With Respect to Augmentative and Alternative Communication (position statement, technical report)

Articles in The ASHA Leader 

  • "Getting Health Plans to Pay for Pediatric Verbal Apraxia"
  • "Michigan Insurer Rules on Childhood Apraxia of Speech"
  • "Treatment for Childhood Apraxia of Speech"

ASHA Special Interest Groups

  • Special Interest Group 2 (Neurophysiology and Neurogenic Speech and Language Disorders)

Professional Development Opportunities 

  • Acquired Apraxia of Speech: Evidence-Based Intervention
  • Progressive Apraxia of Speech as a Sign of Motor Neuron Disease
  • Perspectives in the Assessment of Children's Speech
  • Speech Sound Disorders and Treatment Outcomes
  • Intervention Strategies for Severe Disabilities

Consumer Information

  • Apraxia of speech in adults
  • Childhood apraxia of speech
  • Additional resources
  • Phonemic inventories across languages
  • Multicultural resources

  

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