Evaluation of the speech motor control system in amyotrophic lateral sclerosis

Voice Onset Time in Early- and Late-Stage Amyotrophic Lateral Sclerosis

PURPOSE

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects bulbar functions including speech and voice. Voice onset time (VOT) was examined in speakers with ALS in early and late stages to explore the coordination of the articulatory and phonatory systems during speech production.

METHOD

VOT was measured in nonword /bap/ produced by speakers with early-stage ALS (n = 11), late-stage ALS (n = 6), and healthy controls (n = 13), and compared with speech performance decline (a marker of disease progression) in ALS.

RESULTS

Overall comparison of the VOT values among the three groups showed a significant difference, F(2,27) = 11.71, p < .01. Speakers in late-stage ALS displayed longer voicing lead (negative VOT) than both healthy speakers and speakers in early-stage ALS. VOT was also significantly negatively correlated with speech performance (i.e., Intelligible Speaking Rate), r(15) = .74, p < .01.

CONCLUSIONS

Speakers with more severe ALS showed greater occurrence of voicing lead and longer voicing lead. Findings show voicing precedes articulatory onset with disease progression in the production of bilabial stops, which suggests that the relative timing of coordination between the supralaryngeal structures and the phonatory system is affected in the late stage of ALS.

Comparative assessment and monitoring of deterioration of articulatory organs using subjective and objective tools among patients with amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal degenerative disease of a rapid course. In 25% of ALS sufferers, speech disorders occur as prodromal symptoms of the disease. Impaired communication affects physical health and has a negative impact on mental and emotional condition. In this study, we assessed which domains of speech are particularly affected in ALS. Subsequently, we estimated possible correlations between the ALS patients' subjective perception of their speech quality and an objective assessment of the speech organs carried out by an expert.

METHODS

The study group consisted of 63 patients with sporadic ALS. The patients were examined for articulatory functions by means of Voice Handicap Index (VHI) and the Frenchay Dysarthria Assessment (FDA).

RESULTS

On the basis of the VHI scores, the entire cohort was divided into 2 groups: group I (40 subjects) with mild speech impairment, and group II (23 subjects) displaying moderate and profound speech deficits. In an early phase of ALS, changes were typically reported in the tongue, lips and soft palate. The FDA and VHI-based measurements revealed a high, positive correlation between the objective and subjective evaluation of articulation quality.

CONCLUSIONS

Deterioration of the articulatory organs resulted in the reduction of social, physical and emotional functioning. The highly positive correlation between the VHI and FDA scales seems to indicate that the VHI questionnaire may be a reliable, self-contained tool for monitoring the course and progression of speech disorders in ALS.

TRIAL REGISTRATION

NCT02193893 .

Predicting Speech Intelligibility Decline in Amyotrophic Lateral Sclerosis Based on the Deterioration of Individual Speech Subsystems

PURPOSE

To determine the mechanisms of speech intelligibility impairment due to neurologic impairments, intelligibility decline was modeled as a function of co-occurring changes in the articulatory, resonatory, phonatory, and respiratory subsystems.

METHOD

Sixty-six individuals diagnosed with amyotrophic lateral sclerosis (ALS) were studied longitudinally. The disease-related changes in articulatory, resonatory, phonatory, and respiratory subsystems were quantified using multiple instrumental measures, which were subjected to a principal component analysis and mixed effects models to derive a set of speech subsystem predictors. A stepwise approach was used to select the best set of subsystem predictors to model the overall decline in intelligibility.

RESULTS

Intelligibility was modeled as a function of five predictors that corresponded to velocities of lip and jaw movements (articulatory), number of syllable repetitions in the alternating motion rate task (articulatory), nasal airflow (resonatory), maximum fundamental frequency (phonatory), and speech pauses (respiratory). The model accounted for 95.6% of the variance in intelligibility, among which the articulatory predictors showed the most substantial independent contribution (57.7%).

CONCLUSION

Articulatory impairments characterized by reduced velocities of lip and jaw movements and resonatory impairments characterized by increased nasal airflow served as the subsystem predictors of the longitudinal decline of speech intelligibility in ALS. Declines in maximum performance tasks such as the alternating motion rate preceded declines in intelligibility, thus serving as early predictors of bulbar dysfunction. Following the rapid decline in speech intelligibility, a precipitous decline in maximum performance tasks subsequently occurred.

Predicting Early Bulbar Decline in Amyotrophic Lateral Sclerosis: A Speech Subsystem Approach

Purpose. To develop a predictive model of speech loss in persons with amyotrophic lateral sclerosis (ALS) based on measures of respiratory, phonatory, articulatory, and resonatory functions that were selected using a data-mining approach. Method. Physiologic speech subsystem (respiratory, phonatory, articulatory, and resonatory) functions were evaluated longitudinally in 66 individuals with ALS using multiple instrumentation approaches including acoustic, aerodynamic, nasometeric, and kinematic. The instrumental measures of the subsystem functions were subjected to a principal component analysis and linear mixed effects models to derive a set of comprehensive predictors of bulbar dysfunction. These subsystem predictors were subjected to a Kaplan-Meier analysis to estimate the time until speech loss. Results. For a majority of participants, speech subsystem decline was detectible prior to declines in speech intelligibility and speaking rate. Among all subsystems, the articulatory and phonatory predictors were most responsive to early bulbar deterioration; and the resonatory and respiratory predictors were as responsive to bulbar decline as was speaking rate. Conclusions. The articulatory and phonatory predictors are sensitive indicators of early bulbar decline due to ALS, which has implications for predicting disease onset and progression and clinical management of ALS.

Bulbar and speech motor assessment in ALS: challenges and future directions

Bulbar motor deterioration due to amyotrophic lateral sclerosis (ALS) leads to the eventual impairment of speech and swallowing functions. Despite these devastating consequences, no standardized diagnostic procedure for assessing bulbar dysfunction in ALS exists and adequate objective markers of bulbar deterioration have not been identified. In this paper, we consider objective measures of speech motor function, which show promise for forming the basis of a comprehensive, quantitative bulbar motor assessment in ALS. These measures are based on the assessment of four speech subsystems: respiratory, phonatory, articulatory, and resonatory. The goal of this research is to design a non-invasive, comprehensive bulbar motor assessment instrument intended for early detection, monitoring of disease progression, and clinical trial application. Preliminary data from an ongoing study of bulbar motor decline are presented, which demonstrate the potential clinical efficacy of the speech subsystem approach.

Simultaneous measures of electropalatography and intraoral pressure in selected voiceless lingual consonants and consonant sequences of German

This work assessed relationships among intraoral pressure (IOP), electropalatographic (EPG) measures, and consonant sequence duration, in the following obstruents, clusters, and affricates of German: /t/, /sh/, /sht/, and /tsh/. The data showed significant correlations between IOP and percentage of articulatory contact (PC) for all speakers, whereas duration and place of articulation (measured by the EPG center of gravity) contributed less to IOP changes. Speakers differed in the strength of this relationship, possibly reflecting differences in vocal tract morphology or degree of laryngeal abduction. Single-point EPG and IOP measures in fricatives showed consistent correspondences across consonantal contexts, but the relationships for the stops were more complex and reflected positional effects. Temporal compression was observed for both members of the cluster, but only the fricative portion of the affricate. Conversely, coarticulation was observed for both the stop and fricative portion of the affricate, but only for the stop portion of the cluster, possibly reflecting biomechanical constraints. No clear differences were observed in coarticulatory resistance for stops and fricatives. These data contribute to a limited literature on articulatory-aerodynamic relationships in voiceless consonants and consonant sequences, and will provide a baseline for considering longer combinations of obstruents.

Spasmodic dysphonia symptoms as initial presentation of amyotrophic lateral sclerosis

A patient initially diagnosed with adductor-type spasmodic dysphonia was referred for botulinum toxin (Botox) injections, but found on subsequent evaluation to have amyotrophic lateral sclerosis, and therefore Botox was not administered. This unique case underscores the need to delay botulinum toxin treatments in any patient with recent onset symptoms, and to obtain thorough motor speech and voice, otolaryngologic, and neurologic evaluation in all patients prior to consideration for injection.

Differential phonatory characteristics of four women with amyotrophic lateral sclerosis

Patients with specific neural subsystem involvement are often reported to present with particular perceptual characteristics of voice. This has been true for diseases such as amyotrophic lateral sclerosis (ALS), a progressive disease in which mixed neurologic signs are present. This article reports acoustic data on the phonatory performance of four women diagnosed with ALS who had initial bulbar signs and progressive phonatory deterioration. The data presented here demonstrate that the phonatory characteristics of women with ALS are not uniform, but in fact may vary greatly from patient to patient.

Intelligibility and the acoustic characteristics of speech in amyotrophic lateral sclerosis (ALS)

The purpose of this study was to analyze the changes in specific speech parameters in 14 patients, 7 dysarthric and 7 non-dysarthric, with amyotrophic lateral sclerosis (ALS), over a 6-month period. Measurements of single word intelligibility, F2 formant trajectories (extent, duration and rate) and diadochokinetic rate showed decreased performance in dysarthric patients as compared to non-dysarthric patients at baseline. F2 transition rates of less than 4 Hz/msec were seen only in dysarthric ALS patients. A relationship between the F2 transition rate and single word intelligibility was noted for patients with moderate to high intelligibility, but at lower levels of intelligibility the F2 rate reached a plateau despite continued decline in intelligibility. Our results support the need for frequent evaluation of dysarthric ALS patients to better understand the relationship between intelligibility and the acoustic parameters of speech.