Comparison of Intelligibility Measures for Adults With Parkinson's Disease, Adults With Multiple Sclerosis, and Healthy Controls

Abstract

Purpose This study obtained judgments of sentence intelligibility using orthographic transcription for comparison with previously reported intelligibility judgments obtained using a visual analog scale (VAS) for individuals with Parkinson's disease and multiple sclerosis and healthy controls (K. Tjaden, J. E. Sussman, & G. E. Wilding, 2014). Method Speakers read Harvard sentences in habitual, clear, loud, and slow conditions. Sentence stimuli were equated for peak intensity and mixed with multitalker babble. A total of 50 listeners orthographically transcribed sentences. Procedures were identical to those for a VAS reported in Tjaden, Sussman, and Wilding (2014). Results The percent correct scores from transcription were significantly higher in magnitude than the VAS scores. Multivariate linear modeling indicated that the pattern of findings for transcription and VAS was virtually the same with respect to differences among groups and speaking conditions. Correlation analyses further indicated a moderately strong, positive relationship between the two metrics. The majority of these correlations were significant. Last, intrajudge and interjudge listener reliability metrics for the two intelligibility tasks were comparable. Conclusion Results suggest that there may be instances when the less time-consuming VAS task may be a viable substitute for an orthographic transcription task when documenting intelligibility in mild dysarthria.

Minimally Detectable Change and Minimal Clinically Important Difference of a Decline in Sentence Intelligibility and Speaking Rate for Individuals With Amyotrophic Lateral Sclerosis

“…Additionally, because the MDC is typically calculated using test-retest reliability, presumably from a single judge using the same metric on two occasions, we explored intralistener reliability, a single judge using the same metric on one occasion, as a corollary. Several authors have previously reported the intralistener reliability on the orthographic transcription of dysarthric speech with correlation coefficients ranging from 0.58 to 1.00 (M = 0.80, SD = 0.13; Tjaden, Kain, & Lam, 2014) and from 0.32 to 0.88 (M = 0.66, SD = 0.13; Stipancic, Tjaden, & Wilding, 2016). However, in these two studies, listeners were presented stimuli that were mixed with multitalker babble.…”

Internally Versus Externally Cued Speech in Parkinson's Disease and Cerebellar Disease

“…A 100-point visual analogue scale (VAS) was used for listener ratings; this method has previously been used to rate dysarthric speech (Spencer, Morgan, & Blond, 2009) and was recently found to be correlated with speech intelligibility (Stipancic, Tjaden, & Wilding, 2016). The VAS was displayed on the screen and could be used by the experimenter when providing task directions.…”

A Comparative Study of Auditory-Perceptual Speech Measures for the Early Detection of Mild Speech Impairments

“…For instance, transcription is considered to yield better listener reliability than scaling by some researchers, 14,24,25 but not others. 11 In one study, relatively inexperienced listeners had high intrarater reliability, but only satisfactory interrater reliability when asked to identify deviant perceptual dimensions for dysarthriatype classification. 26 On closer examination, interrater reliability was found to be higher for certain dimensions like imprecise consonants and fast rate than other dimensions.…”

“…10 Additionally, orthographic transcription and the subsequent intelligibility calculation can be time consuming. 11 Scaling is less labor intensive and has been studied in comparison to traditional intelligibility transcription as a way to obtain more specific information about the speech deficit through subsystem-based severity estimates, which helps localize impairment and provide therapy targets. Specifically, using direct magnitude estimation, VAS, or an equal interval scale, listeners are asked to judge speech impairment severity based on certain salient perceptual features, for example, imprecise articulation 12 and hypernasality.…”

“…Either way, scaled severity estimates are likely to provide subsystemspecific impressions of speech loss that are otherwise unobtainable from traditional intelligibility transcription. 4 Studies comparing transcription and scaling paradigms to assess dysarthric speech have produced conflicting findings, with studies that found no significant differences between transcription-based intelligibility estimates and scaled estimates of intelligibility, 11 as well as no differences between scaled estimates of intelligibility and scaled speech severity. 12 Contrastingly, other studies show that scaled severity estimates are sensitive to aspects of dysarthria not captured by transcription.…”