Apraxia of speech is a disorder that affects a person’s ability to guide the movements of their articulators to produce speech. It can occur in children or adults, and individuals with the disorder are commonly classified into three categories: those with childhood apraxia of speech, stroke or trauma-induced apraxia of speech, or progressive apraxia of speech due to neurodegeneration. The condition is difficult to diagnose, and current diagnostic efforts are limited by the absence of a gold standard diagnostic test or clear diagnostic procedures. These diagnostic limitations impact both research being conducted on the disorder and the ability of clinicians to optimally treat individuals with apraxia of speech.

In the Speech and Language Recovery Laboratory at MRRI, Marja-Liisa Mailend, PhD, is investigating the cognitive mechanism of apraxia of speech to improve assessment and differential diagnosis of the disorder. She is an author on two posters that will be presented at the upcoming 2024 Motor Speech Conference in San Diego, CA, February 21-24. Research for both posters was done in collaboration with Katarina Haley, PhD, CCC-SLP, and Adam Jacks, PhD, CCC-SLP, from the University of North Carolina at Chapel Hill.

In their first poster, Drs. Mailend, Haley, and Jacks completed an important early step in addressing issues surrounding the diagnosis of apraxia of speech without a gold standard test for the disorder. This project involved a literature review of recent research on apraxia of speech in the past five years. Their findings indicated that the differential diagnosis in most of these studies was based on clinical judgments that were not standardized and could be susceptible to bias. They suggest that future research in this area should acknowledge the limitations of diagnosing apraxia of speech in the absence of a gold standard, and aim to reduce bias in the diagnostic procedures by way of converging evidence.

In their second poster, Drs. Mailend, Haley, and Jacks further examined the Apraxia of Speech Rating Scale, an instrument that was developed to standardize how researchers and clinicians diagnose apraxia of speech. The validity of this rating scale has not yet been firmly established for diagnosing apraxia of speech in individuals who do not have a neurodegenerative disease, and more work is necessary to confirm its reliability. Drs. Mailend, Haley, and Jacks were interested in further clarifying the Apraxia of Speech Rating Scale so that it can serve as a valid and reliable scale for diagnosing apraxia of speech in people after stroke. Based on their findings in independently applying the scale to sample videos and audio clips, they proposed refined operational definitions and updated procedures to augment the published guidelines for the scale. These refined definitions and procedures can now be used to formally test the reliability of the Apraxia of Speech Rating Scale in a stroke population.

“I’m really looking forward to sharing our recent work at the Motor Speech Conference this year. One thing that makes this conference unique in the field is that it brings together motor speech researchers whose work focuses on adults with motor speech conditions, as well as scientists who study motor speech in children,” explained Dr. Mailend. “My work bridges these two populations, and there are many benefits to thinking about the bigger picture — how our findings and the methods we develop in childhood apraxia of speech may be relevant for apraxia speech in adults and vice versa,” Dr. Mailend continued.

Dr. Mailend’s presentations at the Motor Speech Conference will provide an excellent opportunity to highlight her expertise as an early-career independent investigator, connect with current and prospective collaborators, and get feedback from other experts in the field.