Interrater Reliability and Concurrent Validity for the Apraxia of Speech Rating Scale 3.0: Application With Persons With Acquired Apraxia of Speech and Aphasia.

Purpose This investigation was designed to provide interrater reliability data for the Apraxia of Speech Rating Scale 3.0 (ASRS 3.0; Strand, Duffy, Clark, & Josephs, 2014 ). Importantly, ratings were completed by investigators who were not involved with the ASRS development. Another aim was to evaluate the relationship of the ASRS 3.0 total score to word intelligibility. Method Two investigators independently completed ASRS 3.0 ratings for 28 participants with chronic apraxia of speech and aphasia. Intelligibility scores were obtained for all participants. Results Consistency of ratings for each feature and total score of the ASRS 3.0 was measured using intraclass correlation coefficients. Twelve of 13 intraclass correlation coefficients for feature ratings reached significance; clinical meaningfulness ranged from poor to excellent. Interrater reliability for the total scores was excellent. Similarly, absolute difference of ratings was minimal for the total scores, but varied across the 13 feature ratings. Correlations between the intelligibility scores and ASRS 3.0 total score were moderate to strong. Conclusion The total ASRS 3.0 score may be viewed as a reliable indicator of prevalence of apraxia of speech features. Although there was good to acceptable correspondence in ratings of the majority of the individual features, additional operationalization of rating procedures may be needed to improve interrater reliability for a few features.