Apraxia of Speech: Perceptual Analysis of Bisyllabic Word Productions Across Repeated Sampling Occasions

摘要

Early apraxia of speech (AOS) research depicted errors as being unpredictable resulting in a number of different error types on repeated productions of the same stimuli. However, recent research has suggested errors may not be variable, but there are limited data regarding variability over time (i.e., more than one sampling occasion). Additionally, the influence of conditions of stimulus presentation (i.e., blocked vs. random) on sound errors remains uncertain. The purpose of this investigation was to examine variability of sound errors in 11 individuals with AOS and aphasia. The effects of repeated sampling and method of speech elicitation on the variability of error types using narrow phonetic transcription were of particular interest. Twenty-eight bisyllabic words comprising 7 target phonemes in the initial position (/h, f, m, d, s, r, n/) served as stimuli. On three occasions over a 7-day period, stimuli were elicited under two conditions: blocked presentation (blocked by sound) and randomized presentation. Findings revealed a similar overall percentage of errors for the group in both conditions across the three sampling times. The dominant error type across all target phonemes was distortions. However, the dominant error type varied among target phonemes and appeared to be influenced by number of errors.