Purpose Perceptual training is a listener-targeted means for improving intelligibility of dysarthric speech. Recent work has shown that training with one talker generalizes to a novel talker of the same sex and that the magnitude of benefit is maximized when the talkers are perceptually similar. The current study expands previous findings by investigating whether perceptual training effects generalize between talkers of different sex. Method Forty new listeners were recruited for this study and completed a pretest, familiarization, and posttest perceptual training paradigm. Historical data collected using the same three-phase protocol were included in the data analysis. All listeners were exposed to the same talker with dysarthria during the pretest and posttest phases. For the familiarization phase, listeners were exposed to one of four talkers with dysarthria, differing in sex and level of perceptual similarity to the test talker or a control talker. During the testing phases, listener transcribed phrases produced by the test talker with dysarthria. Listener transcriptions were then used to calculate a percent words correct intelligibility score. Results Multiple linear regression analysis revealed that intelligibility at posttest was not predicted by sex of the training talker. Consistent with earlier work, the magnitude of intelligibility gain was greater when the familiarization and test talkers were perceptually similar. Additional analyses revealed greater between-listeners variability in the dissimilar conditions as compared to the similar conditions. Conclusions Learning as a result of perceptual training with one talker with dysarthria generalized to another talker regardless of sex. In addition, listeners trained with perceptually similar talkers had greater and more consistent intelligibility improvement. Together, these results add to previous evidence demonstrating that learning generalizes to novel talkers with dysarthria and that perceptual training is suitable for many listeners.

This study examined the reliability and validity of speech-language pathologists’ (SLP) estimations of speech intelligibility in dysarthria, including a visual analog scale (VAS) method and a percent estimation method commonly used in clinical settings. Speech samples from 20 speakers with dysarthria of varying etiologies were used to collect orthographic transcriptions from naïve listeners n=70 and VAS ratings and percent estimations of intelligibility from SLPs n=21. Intra- and interrater reliability for the two SLP intelligibility measures were evaluated, and the relationship between these measures was assessed. Finally, linear regression was used to evaluate the relationship between the naïve listeners’ orthographic transcription scores and the two SLP intelligibility measures. The results indicated that the intrarater reliability for both SLP intelligibility measures was strong, and the interrater reliability between the SLP ratings was moderate to excellent. A moderate positive relationship between SLPs’ VAS ratings and percent estimations was also observed. Finally, both SLPs’ percent estimations and VAS ratings were predictive of naïve listeners’ orthographic transcription scores, with SLPs’ percent estimations being the strongest predictor. In conclusion, the average SLP percent estimations and VAS ratings are valid and reliable intelligibility measures. However, the validity and reliability of these measures vary between SLPs.

Purpose: This study sought to determine if alternative vowel space area (VSA) measures (i.e., novel trajectory-based measures: vowel space hull area and vowel space density) predicted speech intelligibility to the same extent as two traditional vowel measures (i.e., token-based measures: VSA and corner dispersion) in speakers with dysarthria. Additionally, this study examined if the strength of the relationship between acoustic vowel measures and intelligibility differed based on how intelligibility was measured (i.e., orthographic transcriptions [OTs] and visual analog scale [VAS] ratings). Method: The Grandfather Passage was read aloud by 40 speakers with dysarthria of varying etiologies, including Parkinson's disease ( n = 10), amyotrophic lateral sclerosis ( n = 10), Huntington's disease ( n = 10), and cerebellar ataxia ( n = 10). Token- and trajectory-based acoustic vowel measures were calculated from the passage. Naïve listeners ( N = 140) were recruited via crowdsourcing to provide OTs and VAS intelligibility ratings. Hierarchical linear regression models were created to model OTs and VAS intelligibility ratings using the acoustic vowel measures as predictors. Results: Traditional VSA was the sole significant predictor of speech intelligibility for both the OTs ( R 2 = .259) and VAS ( R 2 = .236) models. In contrast, the trajectory-based measures were not significant predictors of intelligibility. Additionally, the OTs and VAS intelligibility ratings conveyed similar information. Conclusions: The findings suggest that traditional token-based vowel measures better predict intelligibility than trajectory-based measures. Additionally, the findings suggest that VAS methods are comparable to OT methods for estimating speech intelligibility for research purposes.

Purpose: To examine the predictive value of a selection of acoustic vowel measures for predicting intelligibility (i.e., measured using both orthographic transcriptions [OT] and visual analog scale [VAS] ratings) in speakers with dysarthria. The following questions were posed: (1) How well do trajectory-based and token-based vowel space measures predict intelligibility? And (2) does the relationship between vowel measures and intelligibility differ based on the type of intelligibility measurement (i.e., OT vs. VAS ratings)?Method: The Grandfather Passage was read aloud by forty speakers with dysarthria of varying etiologies, including Parkinson's disease (n = 10), amyotrophic lateral sclerosis (n = 10), Huntington's disease (n = 10), and cerebellar ataxia (n = 10). Token-based (i.e., acoustic vowel space area [VSA], corner dispersion) and trajectory-based (i.e., VSA hull area, and vowel space density [VSD]) acoustic vowel measures were calculated. Naïve listeners (N = 140) were recruited via crowdsourcing to provide OT and VAS intelligibility ratings. Hierarchical linear regression models were created to model OT and VAS ratings of intelligibility using the acoustic vowel measures as predictors.Results: Traditional VSA was the sole significant predictor of speech intelligibility for both the OT and VAS models. In contrast, the trajectory-based measures were not significant predictors of intelligibility. Additionally, the OT and VAS intelligibility ratings conveyed similar information.Conclusions: The findings suggest that traditional token-based vowel measures better predict intelligibility than trajectory-based measures. Additionally, the findings suggest that VAS methods are comparable to OT methods for estimating speech intelligibility for research purposes.

The current study examined the reliability and validity of speech-language pathologists’ (SLP) estimations of speech intelligibility in dysarthria, including a visual analog scale (VAS) method and a percent estimation method commonly used in clinical settings. Speech samples from 20 speakers with dysarthria were used to collect orthographic transcriptions from naïve listeners (n=70) and VAS ratings and percent estimations of intelligibility from SLPs (n=21). Intra- and interrater reliability for the two SLP intelligibility measures were evaluated, and the relationship between these measures was assessed. Finally, linear regression was used to evaluate the relationship between the naïve listeners’ orthographic transcription scores and the two SLP intelligibility measures. The results indicated the intrarater agreement for both the SLP intelligibility measures was high, and the interrater agreement between the SLP ratings was moderate to excellent. Additionally, a moderate positive relationship between SLPs’ VAS ratings and percent estimations was observed. Finally, both SLPs’ percent estimations and VAS ratings were predictive of naïve listeners’ orthographic transcription scores, with SLPs’ percent estimations being the strongest predictor. In conclusion, the aggregate SLP intelligibility estimations and VAS ratings are valid and reliable measures for estimating intelligibility. However, the validity and reliability of these measures vary between SLPs.