Addressing Diagnostic Challenges in Acquired Apraxia of Speech: A Preliminary Study to Inform Curriculum Development

Acquired apraxia of speech (AOS) frequently co-occurs with aphasia and/or dysarthria, complicating accurate and reliable diagnosis for speech-language pathologists (SLPs). To address this challenge, this preliminary study explored the diagnostic processes and decision making of SLPs during recorded evaluations of persons with aphasia with potential co-occurring AOS and/or dysarthria, with the ultimate goal of informing the development of a training curriculum to improve diagnostic accuracy.

Eight licensed SLPs participated and viewed recorded videos of eight individuals with aphasia and potential motor speech impairments. Stimuli included the spoken language subtests of Western Aphasia Battery-Revised and a standard motor speech exam. After viewing, SLPs were asked to complete the Apraxia of Speech Rating Scale (ASRS) and two questionnaires focusing on the diagnostic processes.

The majority of SLPs reported limited confidence in diagnosing AOS. Among the perceptual features evaluated, prosodic elements (segmentation, slow rate) and groping were most frequently identified and ranked as salient. Interrater reliability, measured using Cohen's kappa statistic (range: -1.0 to 1.9), indicated poor agreement overall. The total ASRS rating reliability was -.049 (none to slight disagreement), with individual item reliability ranging from -.045 (none to slight disagreement) to .390 (fair agreement).

These findings highlight substantial variability in clinician judgments and underscore the challenge of reliably diagnosing AOS in the presence of co-occurring aphasia and/or dysarthria. Future directions include the development of specialized training programs to improve diagnostic accuracy and clinician confidence.