Intonation contrast in Cantonese speakers with hypokinetic dysarthria associated with Parkinson's disease

Functional data analysis of prosodic prominence in Parkinson's disease: a pilot study

This study aims to reveal dynamic changes in prosodic prominence patterns associated with Parkinson's disease (PD). To fulfill this purpose, the study proposes an exploratory methodology involving measuring a novel syllable-based prosody index (SPI) and performing functional principal component analyses (fPCAs) in a semi-automatic manner. First, SPI trajectories were collected from 31 speakers with PD before and after speech therapy and from 36 healthy controls. Then, the SPI trajectories were converted to continuous functions using B-splines. Finally, the functional SPIs were examined using fPCAs. The results showed that PD was associated with an increase of overall prominence for male speakers. The findings regarding higher prominence patterns in PD were supported by traditional phonetic measurements. For female speakers, however, there were no significant differences in prosodic prominence between speakers with PD and healthy controls. The results encourage to explore the proposed methodology also in analyses of other forms of atypical speech.

(Dys)Prosody in Parkinson's Disease: Effects of Medication and Disease Duration on Intonation and Prosodic Phrasing

The phonology of prosody has received little attention in studies of motor speech disorders. The present study investigates the phonology of intonation (nuclear contours) and speech chunking (prosodic phrasing) in Parkinson’s disease (PD) as a function of medication intake and duration of the disease. Following methods of the prosodic and intonational phonology frameworks, we examined the ability of 30 PD patients to use intonation categories and prosodic phrasing structures in ways similar to 20 healthy controls to convey similar meanings. Speech data from PD patients were collected before and after a dopaminomimetic drug intake and were phonologically analyzed in relation to nuclear contours and intonational phrasing. Besides medication, disease duration and the presence of motor fluctuations were also factors included in the analyses. Overall, PD patients showed a decreased ability to use nuclear contours and prosodic phrasing. Medication improved intonation regardless of disease duration but did not help with dysprosodic phrasing. In turn, disease duration and motor fluctuations affected phrasing patterns but had no impact on intonation. Our study demonstrated that the phonology of prosody is impaired in PD, and prosodic categories and structures may be differently affected, with implications for the understanding of PD neurophysiology and therapy.

Word segmentation based on prosody in Parkinson's Disease

While Parkinson's Disease (PD) impacts the production of prosody and may lead to dysprosody, its effect on the perception of prosody is less clear. In the current study, we investigated how people with PD (PwPD) segment continuous speech using prosodic cues. We used phonemically identical and prosodically different sequences in French. Twenty-three PwPD and 30 controls took part in the study. PwPD showed similar performance to controls (mean difference in terms of correct responses = 2%, 95% confidence interval = [-4%; 8%]). Using Bayesian statistics, our data is 3.6 times more in favour of the null model compared to the alternative model (i.e. difference between PwPD and controls). It thus seems unlikely that PD impacts the perception of prosody systematically. Furthermore, the cognitive performance of PwPD predicted their performance in our segmentation task. This suggests interesting pathways for future research on the mechanisms underlying the impact of PD on speech processing. Clinically, our findings suggest that adequate evaluation of the cognitive capacity of PwPD would help speech and language therapists in assessing speech processing skills in PwPD and in managing their speech impairments.

Acoustic and Perceptual Consequences of Speech Cues for Mandarin Speakers With Parkinson's Disease

Purpose This study investigated the effects of cueing for increased loudness and reduced speech rate on scaled intelligibility and acoustics of speech produced by Mandarin speakers with hypokinetic dysarthria due to Parkinson's disease (PD). Method Eleven speakers with PD read passages in habitual, loud, and slow speaking conditions. Fifteen listeners rated ease of understanding (EOU) of the speech samples on a visual analog scale. Effects of the cues on EOU, vocal loudness, pitch range, pause duration and frequency, articulation rate, and vowel space, as well as relationships between EOU gains and acoustic features, were analyzed. Results EOU increased significantly in the loud condition only. The loud cue resulted in increased intensity, and the slow cue resulted both in reduced articulation rate and increased pause frequency. In the loud condition, EOU increased significantly as intensity increased and vowel centralization decreased. In the slow condition, EOU tended to increase as intensity increased and vowel centralization decreased but did not reach statistical significance. Conclusion Cueing for loud speech may yield greater EOU gains than cueing for slow speech in Mandarin speakers with PD. Theoretical and clinical implications are discussed, although further investigations with more participants and a larger range of dysarthria severity are warranted.

Rhythmic performance in hypokinetic dysarthria: Relationship between reading, spontaneous speech and diadochokinetic tasks

•We investigated speech rhythm in people with Parkinson’s Disease (PwPD) and controls. •Even mildly affected PwPD differed from controls in their rhythmic performance. •PwPD showed less difference between reading and spontaneous speech. •Spontaneous speech highlighted more differences between speakers than reading. •DDK performance did not relate to rhythmic behaviour in connected speech.

A Cross-Language Study of Acoustic Predictors of Speech Intelligibility in Individuals With Parkinson's Disease

PURPOSE

The present study aimed to compare acoustic models of speech intelligibility in individuals with the same disease (Parkinson's disease [PD]) and presumably similar underlying neuropathologies but with different native languages (American English [AE] and Korean).

METHOD

A total of 48 speakers from the 4 speaker groups (AE speakers with PD, Korean speakers with PD, healthy English speakers, and healthy Korean speakers) were asked to read a paragraph in their native languages. Four acoustic variables were analyzed: acoustic vowel space, voice onset time contrast scores, normalized pairwise variability index, and articulation rate. Speech intelligibility scores were obtained from scaled estimates of sentences extracted from the paragraph.

RESULTS

The findings indicated that the multiple regression models of speech intelligibility were different in Korean and AE, even with the same set of predictor variables and with speakers matched on speech intelligibility across languages. Analysis of the descriptive data for the acoustic variables showed the expected compression of the vowel space in speakers with PD in both languages, lower normalized pairwise variability index scores in Korean compared with AE, and no differences within or across language in articulation rate.

CONCLUSIONS

The results indicate that the basis of an intelligibility deficit in dysarthria is likely to depend on the native language of the speaker and listener. Additional research is required to explore other potential predictor variables, as well as additional language comparisons to pursue cross-linguistic considerations in classification and diagnosis of dysarthria types.

Children's and adults' perception of questions and statements from terminal fundamental frequency contours

The present study compared children's and adults' identification and discrimination of declarative questions and statements on the basis of terminal cues alone. Children (8-11 years, n = 41) and adults (n = 21) judged utterances as statements or questions from sentences with natural statement and question endings and with manipulated endings that featured intermediate fundamental frequency (F₀) values. The same adults and a different sample of children (n = 22) were also tested on their discrimination of the utterances. Children's judgments shifted more gradually across categories than those of adults, but their category boundaries were comparable. In the discrimination task, adults found cross-boundary comparisons more salient than within-boundary comparisons. Adults' performance on the identification and discrimination tasks is consistent with but not definitive regarding categorical perception of statements and questions. Children, by contrast, discriminated the cross-boundary comparisons no better than other comparisons. The findings indicate age-related sharpening in the perception of statements and questions based on terminal F₀ cues and the gradual emergence of distinct perceptual categories.

Dysarthria in individuals with Parkinson's disease: a protocol for a binational, cross-sectional, case-controlled study in French and European Portuguese (FraLusoPark)

INTRODUCTION

Individuals with Parkinson's disease (PD) have to deal with several aspects of voice and speech decline and thus alteration of communication ability during the course of the disease. Among these communication impairments, 3 major challenges include: (1) dysarthria, consisting of orofacial motor dysfunction and dysprosody, which is linked to the neurodegenerative processes; (2) effects of the pharmacological treatment, which vary according to the disease stage; and (3) particular speech modifications that may be language-specific, that is, dependent on the language spoken by the patients. The main objective of the FraLusoPark project is to provide a thorough evaluation of changes in PD speech as a result of pharmacological treatment and disease duration in 2 different languages (French vs European Portuguese).

METHODS AND ANALYSIS

Individuals with PD are enrolled in the study in France (N=60) and Portugal (N=60). Their global motor disability and orofacial motor functions is assessed with specific clinical rating scales, without (OFF) and with (ON) pharmacological treatment. 2 groups of 60 healthy age-matched volunteers provide the reference for between-group comparisons. Along with the clinical examinations, several speech tasks are recorded to obtain acoustic and perceptual measures. Patient-reported outcome measures are used to assess the psychosocial impact of dysarthria on quality of life.

ETHICS AND DISSEMINATION

The study has been approved by the local responsible committees on human experimentation and is conducted in accordance with the ethical standards. A valuable large-scale database of speech recordings and metadata from patients with PD in France and Portugal will be constructed. Results will be disseminated in several articles in peer-reviewed journals and in conference presentations. Recommendations on how to assess speech and voice disorders in individuals with PD to monitor the progression and management of symptoms will be provided.

TRIAL REGISTRATION NUMBER

NCT02753192, Pre-results.

The Relationship Between Speech Production and Speech Perception Deficits in Parkinson's Disease

PURPOSE

This study investigated the possible relationship between hypokinetic speech production and speech intensity perception in patients with Parkinson's disease (PD).

METHOD

Participants included 14 patients with idiopathic PD and 14 matched healthy controls (HCs) with normal hearing and cognition. First, speech production was objectified through a standardized speech intelligibility assessment, acoustic analysis, and speech intensity measurements. Second, an overall estimation task and an intensity estimation task were addressed to evaluate overall speech perception and speech intensity perception, respectively. Finally, correlation analysis was performed between the speech characteristics of the overall estimation task and the corresponding acoustic analysis. The interaction between speech production and speech intensity perception was investigated by an intensity imitation task.

RESULTS

Acoustic analysis and speech intensity measurements demonstrated significant differences in speech production between patients with PD and the HCs. A different pattern in the auditory perception of speech and speech intensity was found in the PD group.

CONCLUSIONS

Auditory perceptual deficits may influence speech production in patients with PD. The present results suggest a disturbed auditory perception related to an automatic monitoring deficit in PD.

The effect of intensive speech rate and intonation therapy on intelligibility in Parkinson's disease

PURPOSE

Most studies on treatment of prosody in individuals with dysarthria due to Parkinson's disease are based on intensive treatment of loudness. The present study investigates the effect of intensive treatment of speech rate and intonation on the intelligibility of individuals with dysarthria due to Parkinson's disease.

METHODS

A one group pretest-posttest design was used to compare intelligibility, speech rate, and intonation before and after treatment. Participants included eleven Dutch-speaking individuals with predominantly moderate dysarthria due to Parkinson's disease, who received five one-hour treatment sessions per week during three weeks. Treatment focused on lowering speech rate and magnifying the phrase final intonation contrast between statements and questions. Intelligibility was perceptually assessed using a standardized sentence intelligibility test. Speech rate was automatically assessed during the sentence intelligibility test as well as during a passage reading task and a storytelling task. Intonation was perceptually assessed using a sentence reading task and a sentence repetition task, and also acoustically analyzed in terms of maximum fundamental frequency.

RESULTS

After treatment, there was a significant improvement of sentence intelligibility (effect size .83), a significant increase of pause frequency during the passage reading task, a significant improvement of correct listener identification of statements and questions, and a significant increase of the maximum fundamental frequency in the final syllable of questions during both intonation tasks.

CONCLUSION

The findings suggest that participants were more intelligible and more able to manipulate pause frequency and statement-question intonation after treatment. However, the relationship between the change in intelligibility on the one hand and the changes in speech rate and intonation on the other hand is not yet fully understood. Results are nuanced in the light of the operated research design.

LEARNING OUTCOMES

The reader will be able to: (1) describe the effect of intensive speech rate and intonation treatment on intelligibility of speakers with dysarthria due to PD, (2) describe the effect of intensive speech rate treatment on rate manipulation by speakers with dysarthria due to PD, and (3) describe the effect of intensive intonation treatment on manipulation of the phrase final intonation contrast between statements and questions by speakers with dysarthria due to PD.

Characterizing intonation deficit in motor speech disorders: an autosegmental-metrical analysis of spontaneous speech in hypokinetic dysarthria, ataxic dysarthria, and foreign accent syndrome

PURPOSE

The autosegmental-metrical (AM) framework represents an established methodology for intonational analysis in unimpaired speaker populations but has found little application in describing intonation in motor speech disorders (MSDs). This study compared the intonation patterns of unimpaired participants (CON) and those with Parkinson's disease (PD), ataxic dysarthria (AT), and foreign accent syndrome (FAS) to evaluate the approach's potential for distinguishing types of MSDs from each other and from unimpaired speech.

METHOD

Spontaneous speech from 8 PD, 8 AT, 4 FAS, and 10 CON speakers were analyzed in relation to inventory and prevalence of pitch patterns, accentuation, and phrasing. Acoustic-phonetic baseline measures (maximum-phonation-duration, speech rate, and F0-variability) were also performed.

RESULTS

The analyses yielded differences between MSD and CON groups and between the clinical groups in regard to prevalence, accentuation, and phrasing. AT and FAS speakers used more rising and high pitch accents than PD and CON speakers. The AT group used the highest number of pitch accents per phrase, and all 3 MSD groups produced significantly shorter phrases than the CON group.

CONCLUSIONS

The study succeeded in differentiating MSDs on the basis of intonational performances by using the AM approach, thus, demonstrating its potential for charting intonational profiles in clinical populations.

The use of analogy in speech motor performance

The acoustic correlates of pitch variation were examined in 40 participants who received analogy instructions or explicit instructions that required them to modulate their intonation during speech production. First, using focus group methodology, professional speech-language pathologists were asked to identify analogies that best described minimum pitch variation (monotone), moderate pitch variation (normal intonation), and maximum pitch variation (exaggerated intonation) in speech. The focus group established that an appropriate pitch variation metaphor may be related to imagery of "waves at sea", with minimum pitch variation represented by a flat calm sea, moderate pitch variation represented by a moderate sea, and maximum pitch variation represented by a choppy sea. Forty adult participants without speech impairments were asked to read aloud a standard paragraph using their habitual pitch variation (control condition). They were then allocated randomly to an analogy or an explicit instruction group and were asked to read aloud different paragraphs with minimum, moderate, or maximum pitch variations. Results revealed that acoustic correlates of pitch variation (standard deviation of fundamental frequency, SDF0) were not different for the control condition, or moderate and maximum pitch variation conditions in the two groups. However, the analogy instruction was significantly more effective than the explicit instruction for inducing minimum pitch variation. Analysis of participants in each group who showed higher than normal pitch variation in the control condition (>.5 SD above the group SDF0) revealed that the analogy instruction was more effective than the explicit instruction in the minimum variation condition. It was concluded that analogy instructions may be a useful tool in speech rehabilitation.

Assessment of prosodic communicative efficiency in Parkinson's disease as judged by professional listeners

This study examines the impact of Parkinson's disease (PD) on communicative efficiency conveyed through prosody. A new assessment method for evaluating productive prosodic skills in Dutch speaking dysarthric patients was devised and tested on 36 individuals (18 controls, 18 PD patients). Three professional listeners judged the intended meanings in four communicative functions of Dutch prosody: Boundary Marking, Focus, Sentence Typing, and Emotional Prosody. Each function was tested through reading and imitation. Interrater agreement was calculated. Results indicated that healthy speakers, compared to PD patients, performed significantly better on imitation of Boundary Marking, Focus, and Sentence Typing. PD patients with a moderate or severe dysarthria performed significantly worse on imitation of Focus than on reading of Focus. No significant differences were found for Emotional Prosody. Judges agreed well on all tasks except Emotional Prosody. Future research will focus on elaborating the assessment and on developing a therapy programme paralleling the assessment.