Performance and speaker (3), a participant with hypokinetic dysarthria, produced highly variable intensity peaks. Finally, speaker (4) shows behaviour typical for PD in that he accelerated towards the end of the utterance despite having been quite regular initially. In addition, he also presented with reduced clarity of syllable production, particularly during the acceleration period, which is shown by the less defined gaps between syllables. Although each of the disordered speakers displayed a degree of durational variability in addition to the above features (see speaker (3) in particular), this was not sufficient to take them into the abnormal range, as control speakers were not completely regular in their repetitions either (note for example the shorter third syllable for speaker (1)). It could therefore be hypothesized that the listeners based their judgements not only on durational regularity, but might also have been influenced by other factors such as those described above, thus leading to the mismatch between perceptual results and the COV measure.4. DiscussionThis paper aimed to explore the degree to which acoustic rhythm metrics in their current form are able to reflect the nature of impairment in people with MSDs and whether their results might be Lonafarnib chemical information affected by measurement conventions, in an attempt to better understand how applicable existing rhythm metrics are to the analysis of disordered speech. The results showed that there was poor relationship between the acoustic and perceptual measures in that none of the metrics applied captured the differences between controlspeaker (1)speaker (2)rstb.royalsocietypublishing.orgspeaker (3)speaker (4)Phil. Trans. R. Soc. B 369:Figure 4. PRAAT screenshots demonstrating performance characteristics for the repetition of /pa/. (1): Control speaker; (2) and (3): speakers with ataxic dysarthria; (4): speaker with hypokinetic dysarthria. The upper window represents the waveform, the lower window shows the spectrogram with intensity (yellow peaks) and F0 levels (blue lines) superimposed. Time is displayed on the x-axis, the y-axis indicates frequency and intensity levels. The darker shades in the spectrogram represent speech, i.e. the syllable /pa/, the lighter or blank areas show the pauses between the syllables (including the closure phase for the consonant /p/). (Online version in colour.)and disordered speakers that had been identified perceptually by the listeners. There was also some suggestions that in at least some cases, certain dysarthric speech RP5264 supplement symptoms such as inappropriate duration, segmental articulation errors or changes in intensity and F0 modulation either influenced the results of the metrics directly or affected listener perception of rhythm, thus leading to the mismatch between the two types of analyses. These findings have implications for the use of acoustic-based metrics to characterize speech performance in disordered populations, suggesting that care needs to be taken in the interpretation of these results and additional analysis methods might need to be employed to arrive at a valid characterization of a speaker’s performance. The lack of differentiation between groups by the rhythm metrics in task 1 was unexpected, given that speakers had been selected on the basis that they perceptually presented with rhythmic deviance. The current findings contradict earlier studies which demonstrated good sensitivity of the investigated rhythm metrics to different types of speec.Performance and speaker (3), a participant with hypokinetic dysarthria, produced highly variable intensity peaks. Finally, speaker (4) shows behaviour typical for PD in that he accelerated towards the end of the utterance despite having been quite regular initially. In addition, he also presented with reduced clarity of syllable production, particularly during the acceleration period, which is shown by the less defined gaps between syllables. Although each of the disordered speakers displayed a degree of durational variability in addition to the above features (see speaker (3) in particular), this was not sufficient to take them into the abnormal range, as control speakers were not completely regular in their repetitions either (note for example the shorter third syllable for speaker (1)). It could therefore be hypothesized that the listeners based their judgements not only on durational regularity, but might also have been influenced by other factors such as those described above, thus leading to the mismatch between perceptual results and the COV measure.4. DiscussionThis paper aimed to explore the degree to which acoustic rhythm metrics in their current form are able to reflect the nature of impairment in people with MSDs and whether their results might be affected by measurement conventions, in an attempt to better understand how applicable existing rhythm metrics are to the analysis of disordered speech. The results showed that there was poor relationship between the acoustic and perceptual measures in that none of the metrics applied captured the differences between controlspeaker (1)speaker (2)rstb.royalsocietypublishing.orgspeaker (3)speaker (4)Phil. Trans. R. Soc. B 369:Figure 4. PRAAT screenshots demonstrating performance characteristics for the repetition of /pa/. (1): Control speaker; (2) and (3): speakers with ataxic dysarthria; (4): speaker with hypokinetic dysarthria. The upper window represents the waveform, the lower window shows the spectrogram with intensity (yellow peaks) and F0 levels (blue lines) superimposed. Time is displayed on the x-axis, the y-axis indicates frequency and intensity levels. The darker shades in the spectrogram represent speech, i.e. the syllable /pa/, the lighter or blank areas show the pauses between the syllables (including the closure phase for the consonant /p/). (Online version in colour.)and disordered speakers that had been identified perceptually by the listeners. There was also some suggestions that in at least some cases, certain dysarthric speech symptoms such as inappropriate duration, segmental articulation errors or changes in intensity and F0 modulation either influenced the results of the metrics directly or affected listener perception of rhythm, thus leading to the mismatch between the two types of analyses. These findings have implications for the use of acoustic-based metrics to characterize speech performance in disordered populations, suggesting that care needs to be taken in the interpretation of these results and additional analysis methods might need to be employed to arrive at a valid characterization of a speaker’s performance. The lack of differentiation between groups by the rhythm metrics in task 1 was unexpected, given that speakers had been selected on the basis that they perceptually presented with rhythmic deviance. The current findings contradict earlier studies which demonstrated good sensitivity of the investigated rhythm metrics to different types of speec.
