Assessment of Childhood Apraxia of Speech: A Review/Tutorial of Objective Measurement Techniques.

Background With respect to the clinical criteria for diagnosing childhood apraxia of speech (commonly defined as a disorder of speech motor planning and/or programming), research has made important progress in recent years. Three segmental and suprasegmental speech characteristics-error inconsistency, lengthened and disrupted coarticulation, and inappropriate prosody-have gained wide acceptance in the literature for purposes of participant selection. However, little research has sought to empirically test the diagnostic validity of these features. One major obstacle to such empirical study is the fact that none of these features is stated in operationalized terms. Purpose This tutorial provides a structured overview of perceptual, acoustic, and articulatory measurement procedures that have been used or could be used to operationalize and assess these 3 core characteristics. Methodological details are reviewed for each procedure, along with a short overview of research results reported in the literature. Conclusion The 3 types of measurement procedures should be seen as complementary. Some characteristics are better suited to be described at the perceptual level (especially phonemic errors and prosody), others at the acoustic level (especially phonetic distortions, coarticulation, and prosody), and still others at the kinematic level (especially coarticulation, stability, and gestural coordination). The type of data collected determines, to a large extent, the interpretation that can be given regarding the underlying deficit. Comprehensive studies are needed that include more than 1 diagnostic feature and more than 1 type of measurement procedure.

Quantitative assessment of interutterance stability: application to dysarthria.

PURPOSE: Following recent attempts to quantify articulatory impairment in speech, the present study evaluates the usefulness of a novel measure of motor stability to characterize dysarthria. METHOD: The study included 8 speakers with ataxic dysarthria (AD), 16 speakers with hypokinetic dysarthria (HD) as a result of Parkinson's disease, and 24 unimpaired control participants. Each participant performed a series of sentence repetitions under habitual, fast, and slow speaking rate conditions. An algorithm to measure utterance-to-utterance spectro-temporal variation (UUV; Cummins, 2009) was used. Speech rate and intelligibility were also measured. RESULTS: UUV scores were significantly correlated with perceptually based intelligibility scores. There were significant differences in UUV between control speakers and the AD but not the HD groups, presumably because of differences in intelligibility in the samples used and not because of differences in pathology. Habitual speaking rate did not correlate with UUV scores. All speaker groups had greater UUV levels in the slow conditions compared with habitual and fast speaking rates. CONCLUSIONS: UUV results were consistent with those of other variability indices and thus appear to capture motor control issues in a similar way. The results suggest that the UUV could be developed into an easy-to-use clinical tool that could function as a valid and reliable assessment and outcome measure.