In AOS, which type of error is more likely to vary across attempts?

• A. Consistent phoneme substitutions across attempts.
• B. Phoneme substitutions and distortions that vary between attempts.
• C. Pure rate errors with no articulatory changes.
• D. Phoneme substitutions that are fixed across attempts.

Answer: (B)

In apraxia of speech, motor planning problems lead to changes in how a word is produced from one attempt to the next. Because the planned sequence of movements isn’t reliably accessible, phoneme substitutions and distortions can vary between attempts on the same target. This trial-to-trial variability is a hallmark of AOS, which is why the statement describing substitutions and distortions that differ across attempts is the best fit. In contrast, descriptions of consistent substitutions, pure rate errors with no articulatory changes, or fixed substitutions across attempts don’t reflect this unstable, variable pattern seen in many individuals with AOS.