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

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. 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. 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

Improved status following behavioural intervention in a case of severe dysarthria with stroke aetiology

There is little published intervention outcome literature concerning dysarthria acquired from stroke. Single case studies have the potential to provide more detailed specification and interpretation than is generally possible with larger participant numbers and are thus informative for clinicians who may deal with similar cases. Such research also contributes to the future planning of larger scale investigations. Behavioural intervention is described which was carried out with a man with severe dysarthria following stroke, beginning at seven and ending at nine months after stroke. Pre-intervention stability between five and seven months contrasted with significant improvements post-intervention on listener-rated measures of word and reading intelligibility and communication effectiveness in conversation. A range of speech analyses were undertaken (comprising of rate, pause and intonation characteristics in connected speech and phonetic transcription of single word production), with the aim of identifying components of speech which might explain the listeners’ perceptions of improvement. Pre- and post intervention changes could be detected mainly in parameters related to utterance segmentation and intonation. The basis of improvement in dysarthria following intervention is complex, both in terms of the active therapeutic dimensions and also the specific speech alterations which account for changes to intelligibility and effectiveness. Single case results are not necessarily generalisable to other cases and outcomes may be affected by participant factors and therapeutic variables, which are not readily controllable

The relationship between acoustic indices of speech motor control variability and other measures of speech performance in dysarthria

Previous studies suggested that variability indices based on information extracted from the acoustic signal are potentially useful in assessing dysarthric speech. Because of the ease of data collection, this method is especially applicable in the clinical setting. This study assessed the relationship between variability indices of sentence repetitions obtained by Functional Data Analysis with intelligibility ratings and maximum performance tasks in groups of speakers with hypokinetic dysarthria and ataxic dysarthria. The results showed significant correlations between selected parameters, which varied with dysarthria type. For the speakers with ataxic dysarthria, the variability measure mainly reflected differences in intelligibility, while for the group with hypokinetic dysarthria, there was a stronger relationship between variability indices and DDK performance. Lack of stronger correlations between variability measures and intelligibility ratings and maximum performance tasks are possibly due to heterogeneity of severity across and within speaker groups. This study provides further evidence that variability measures such as the FDA might be sensitive to speech performance of speakers with dysarthria, and can potentially differentiate between dysarthria types

Intonation in neurogenic foreign accent syndrome

Foreign accent syndrome (FAS) is a motor speech disorder in which changes to segmental as well as suprasegmental aspects lead to the perception of a foreign accent in speech. This paper focuses on one suprasegmental aspect, namely that of intonation. It provides an in-depth analysis of the intonation system of four speakers with FAS with the aim of establishing the intonational changes that have taken place as well as their underlying origin. Using the autosegmental-metrical framework of intonational analysis, four different levels of intonation, i.e. inventory, distribution, realisation and function, were examined. Results revealed that the speakers with FAS had the same structural inventory at their disposal as the control speakers, but that they differed from the latter in relation to the distribution, implementation and functional use of their inventory. In contrast to previous findings, the current results suggest that these intonational changes cannot be entirely attributed to an underlying intonation deficit but also reflect secondary manifestations of physiological constraints affecting speech support systems and compensatory strategies. These findings have implications for the debate surrounding intonational deficits in FAS, advocating a reconsideration of current assumptions regarding the underlying nature of intonation impairment in FAS

Pausing and sentence stress in children with dysarthria due to cerebral palsy

Introduction: Children with dysarthria due to cerebral palsy (CP) can experience problems manipulating intensity, fundamental frequency and duration to signal sentence stress in an utterance. Pauses have been identified as a potential additional cue for stress marking, which could compensate for this deficit. Objective: This study aimed to determine whether children use pauses to signal stress placement, and whether this differs between typically-developing children and those with CP. Methods: Six children with CP and eight typically developing children produced utterances with stress on target words in two different positions. Pauses before and after the stressed target words were analyzed in terms of number, location and duration. Results: Results showed that both groups inserted pauses into their utterances. However, neither group used pause location or duration in a systematic manner to signal the position of stressed words. Conclusions: The results suggest that pausing was not used strategically by either group to signal sentence stress. Further research is necessary to explore the value of pausing as a cue to stress marking in general and as a potential compensatory strategy for speakers with dysarthria

Defective neural motor speech mappings as a source for apraxia of speech : evidence from a quantitative neural model of speech processing

This unique resource reviews research evidence pertaining to best practice in the clinical assessment of established areas such as intelligibility and physiological functioning, as well as introducing recently developed topics such as conversational analysis, participation measures, and telehealth. In addition, new and established research methods from areas such as phonetics, kinematics, imaging, and neural modeling are reviewed in relation to their applicability and value for the study of disordered speech. Based on the broad coverage of topics and methods, the textbook represents a valuable resource for a wide ranging audience, including clinicians, researchers, as well as students with an interest in speech pathology and clinical phonetics

Phonological and phonetic marking of information status in Foreign Accent Syndrome

This study investigated the phonological and phonetic markers of information status (givenness) in speakers with foreign accent syndrome (FAS) and healthy controls (CON). A speech production experiment explored the ability of 4 speakers with FAS (2 male, 2 female; M=56 years) and 4 CON participants (2 male, 2 female; M=55 years) to signal new and given information within a set of short sentences. The data were examined in relation to the use of the phonetic parameters F0, intensity and duration as well as phonological categories, i.e. pitch accents and de-accentuation, using the autosegmental-metrical (AM) framework of intonational analysis. Both speaker groups employed all 3 phonetic parameters to differentiate between new and given information although the FAS group used these markers to a smaller extent. Groups also differed regarding the use of phonological markers, with speakers with FAS placing pitch accents on given information instead of de-accenting these elements. The fact that speakers with FAS marked givenness similarly to control speakers at the phonetic level, but failed to do so using phonological categories highlights the importance of assessing both phonetic as well as phonological features to gain information about the functional use of intonation in clinical populations

Cognitive impairment in Parkinson's disease : is it a unified phenomenon?

Parkinson's disease (PD) has long been associated with dementia. This has been found to correlate with participant age, age at onset of PD and severity of PD. In addition, a large corpus of research points to the fact that participants with, as well as without, dementia can be impaired in a variety of cognitive tasks. Among these, set-shifting and dual-tasking skills have received particular focus. Most studies report that a reduction in attentional resources can lead to problems with these tasks. However, none have been able to determine exactly which systems are involved in these skills and which neurological impairments underlie the observed cognitive deficits. The current study set out to investigate how performance on tasks requiring set-shifting and dual tasking related to each other, as well as overall measures of cognition gained across a variety of tasks. Fifteen participants with PD and 12 control participants underwent screening tests for dementia, as well as specific tests to assess attention, set-shifting and dual tasking. The results indicate that set-shifting ability correlated well with other measures of cognitive performance, whereas dualtasking skills did not. This could suggest that set-shifting and dual tasking are not necessarily controlled by the same process, or that a particular process is involved to different degrees. In addition, many participants showed individual performance variations and dissociations between tasks that were not necessarily evident from the statistical analysis. This indicates that it can be difficult to make assumptions on overall cognitive performance from specific tasks and vice versa. This observation has implications for clinical practice as well as research methodology

The effects of delayed and frequency shifted feedback on speakers with Parkinson disease

Delayed auditory feedback (DAF) has been assessed as a rate reduction and intelligibility enhancing tool in patients with Parkinson disease (PD) for some time. However, there are contradictory results in the literature regarding the success of this device. Also, little is known about the effects of DAF on speech other than influences on speech rate and intelligibility. Frequency shifted feedback (FSF) is known to produce more natural sounding speech than DAF and to improve the fluency of persons who stutter. However, there are currently no studies reporting how PD speakers perform under FSF. The aim of this study was to investigate the effects of both types of altered feedback on the speech of PD and control participants on a broad range of measures. The performance of 16 PD speakers and 11 control speakers in a reading task under DAF, FSF, and no altered feedback (NAF) are reported here. The results showed that all groups responded to altered feedback in a similar way and showed a prominent reduction of speech rate. The conditions evoked changes in pause frequency (increases), loudness levels (increases), pitch variation (increases), and intelligibility and naturalness (decreases) for all or some of the groups. Few effects could be observed on articulation/pause time ratio, pause duration, pitch range, and speech rhythm. Previous reports on differences in susceptibility of PD speaker to altered feedback were confirmed, and some speakers benefited from the system despite the negative group results for intelligibility and naturalness. In general, FSF resulted in performance closer to the NAF state than to DAF on all variables, and for those PD speakers who benefited from altered feedback, the FSF condition evoked the greatest improvement

Temporal and spatial variability in speakers with Parkinson's Disease and Friedreich's Ataxia

Speech variability in groups of speakers with Parkinson's disease (PD) and with Friedreich's ataxia was compared with healthy controls. Speakers repeated the same phrase 20 times at one of two rates (fast or habitual). A non-linear analysis of variability was performed which used some of the principles behind the spatio-temporal index (STI). The STI usually employs variation in lip displacement over repetitions of the same utterance and a linear analysis of such signals is conducted to represent the combined variation in spatial and temporal control. When working with patients, audio measures (here we used speech energy) are preferred over kinematics ones as they are minimally disruptive to speech. Non-linear methods allow spatial variability to be estimated separately from temporal variability. The results are tentatively interpreted as showing that PD speakers were distinguished from healthy control speakers in spatial variability and ataxic speakers were distinguished from controls in temporal variability. These findings are consistent with the speech symptoms reported for these disorders. We conclude that the non-linear analysis using the speech energy measure is worth investigating further as it is potentially revealing of the differences underlying these two pathologies