The diagnostic utility of patient-report and speech-language pathologists' ratings for detecting the early onset of bulbar symptoms due to ALS

OBJECTIVE

This study aimed to determine the diagnostic utility of clinician speech ratings and patient self-report for detecting early bulbar changes associated with amyotrophic lateral sclerosis (ALS), compared to instrumentation-based speech measures.

METHODS

Thirty-six individuals with ALS and 17 healthy control participants were included. Patients' awareness of early bulbar motor involvement was assessed using self-reported scores on the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R). Clinicians' detection of early bulbar motor involvement was assessed through perceptual speech ratings by two experienced speech-language pathologists. Participants with ALS were grouped as 'bulbar pre-symptomatic' or 'bulbar symptomatic' based on self-report and clinician ratings, and compared to healthy controls on six instrumentation-based speech measures. ROC analysis was used to compare the sensitivity and specificity of perceptual and instrumentation-based measures for detecting bulbar changes in pre-symptomatic individuals.

RESULTS

Early bulbar changes that were documented using instrumentation-based measures were undetected by both patients and clinicians. ROC analyses indicated that instrumentation-based measures outperformed clinicians' scaled severity ratings, and that percent pause time was the best measure for differentiating healthy controls from bulbar pre-symptomatic individuals with ALS.

CONCLUSIONS

Findings suggested that instrumentation-based measures of speech may be necessary for early detection of bulbar changes due to ALS.

The Effects of Lip-Closure Exercise on Lip Strength and Function Following Full Facial Transplantation: A Case Report

PURPOSE

Facial transplantation is a relatively new option for individuals with severe facial disfigurements. Clinical case studies on existing patients indicate many instances of persistent facial motor impairment for facial expression, speech, and swallowing. These preliminary findings motivate additional research on the impact of lip-strengthening exercises following facial transplantation.

METHOD

In this study, we assessed the efficacy of an 8-week, biofeedback-driven, lip closure-strengthening exercise program in a single patient 1-year status post-full facial transplantation. Exercise was at 60% of peak strength. Outcome measures included instrumental measures of lip strength and mobility, clinical measures of speech, and patient-reported outcomes in feeding and facial expression.

RESULTS

Results revealed improvements in labial strength, speed of lip movement, and range of motion during speech. A 3-point improvement in sentence speech intelligibility was also observed following strength-training exercise. The patient reported improvements in her ability to drink from a straw and communicate via facial expression.

CONCLUSION

These preliminary findings motivate additional research on the efficacy of lip-strengthening exercises following facial transplantation.

Speech Inconsistency in Children With Childhood Apraxia of Speech, Language Impairment, and Speech Delay: Depends on the Stimuli

PURPOSE

The current research sought to determine (a) if speech inconsistency is a core feature of childhood apraxia of speech (CAS) or if it is driven by comorbid language impairment that affects a large subset of children with CAS and (b) if speech inconsistency is a sensitive and specific diagnostic marker that can differentiate between CAS and speech delay.

METHOD

Participants included 48 children ranging between 4;7 to 17;8 (years;months) with CAS (n = 10), CAS + language impairment (n = 10), speech delay (n = 10), language impairment (n = 9), or typical development (n = 9). Speech inconsistency was assessed at phonemic and token-to-token levels using a variety of stimuli.

RESULTS

Children with CAS and CAS + language impairment performed equivalently on all inconsistency assessments. Children with language impairment evidenced high levels of speech inconsistency on the phrase "buy Bobby a puppy." Token-to-token inconsistency of monosyllabic words and the phrase "buy Bobby a puppy" was sensitive and specific in differentiating children with CAS and speech delay, whereas inconsistency calculated on other stimuli (e.g., multisyllabic words) was less efficacious in differentiating between these disorders.

CONCLUSIONS

Speech inconsistency is a core feature of CAS and is efficacious in differentiating between children with CAS and speech delay; however, sensitivity and specificity are stimuli dependent.

Advancement in Texture in Early Complementary Feeding and the Relevance to Developmental Outcomes

A child's transition to independent eating is a protracted process that progresses over the course of many years. Although major health agencies, such as the World Health Organization, now offer clear guidance when to begin introducing solids, advice about how to safely transition to progressively challenging foods is varied and comes from a staggering number of sources. The resulting conflicting views have promoted parental confusion and anxiety about what foods are appropriate and when to advance to new textures. Efforts to develop science-based recommendations for complementary feeding include research on the development of chewing motor skills. Chewing development is an essential aspect of feeding readiness that is often overlooked by agencies developing recommendations for complementary feeding, and little is known about the development of chewing motor skills and how children learn to accommodate foods with varying textures. Such information is essential for designing developmentally appropriate foods, minimizing food aversions, providing caregivers science-based guidance regarding the safety and appropriateness of new foods, and identifying children at risk for choking or feeding impairments.

Slowed articulation rate is a sensitive diagnostic marker for identifying non-fluent primary progressive aphasia

BACKGROUND

Primary progressive aphasia (PPA) is a neurodegenerative aphasic syndrome with three distinct clinical variants: non-fluent (nfvPPA), logopenic (lvPPA), and semantic (svPPA). Speech (non-) fluency is a key diagnostic marker used to aid identification of the clinical variants, and researchers have been actively developing diagnostic tools to assess speech fluency. Current approaches reveal coarse differences in fluency between subgroups, but often fail to clearly differentiate nfvPPA from the variably fluent lvPPA. More robust subtype differentiation may be possible with finer-grained measures of fluency.

AIMS

We sought to identify the quantitative measures of speech rate-including articulation rate and pausing measures-that best differentiated PPA subtypes, specifically the non-fluent group (nfvPPA) from the more fluent groups (lvPPA, svPPA). The diagnostic accuracy of the quantitative speech rate variables was compared to that of a speech fluency impairment rating made by clinicians.

METHODS AND PROCEDURES

Automatic estimates of pause and speech segment durations and rate measures were derived from connected speech samples of participants with PPA (N=38; 11 nfvPPA, 14 lvPPA, 13 svPPA) and healthy age-matched controls (N=8). Clinician ratings of fluency impairment were made using a previously validated clinician rating scale developed specifically for use in PPA. Receiver operating characteristic (ROC) analyses enabled a quantification of diagnostic accuracy.

OUTCOMES AND RESULTS

Among the quantitative measures, articulation rate was the most effective for differentiating between nfvPPA and the more fluent lvPPA and svPPA groups. The diagnostic accuracy of both speech and articulation rate measures was markedly better than that of the clinician rating scale, and articulation rate was the best classifier overall. Area under the curve (AUC) values for articulation rate were good to excellent for identifying nfvPPA from both svPPA (AUC=.96) and lvPPA (AUC=.86). Cross-validation of accuracy results for articulation rate showed good generalizability outside the training dataset.

CONCLUSIONS

Results provide empirical support for (1) the efficacy of quantitative assessments of speech fluency and (2) a distinct non-fluent PPA subtype characterized, at least in part, by an underlying disturbance in speech motor control. The trend toward improved classifier performance for quantitative rate measures demonstrates the potential for a more accurate and reliable approach to subtyping in the fluency domain, and suggests that articulation rate may be a useful input variable as part of a multi-dimensional clinical subtyping approach.

Speech Movement Measures as Markers of Bulbar Disease in Amyotrophic Lateral Sclerosis

PURPOSE

The goal of this study was to identify the effects of amyotrophic lateral sclerosis (ALS) on tongue and jaw control, both cross-sectionally and longitudinally. The data were examined in the context of their utility as a diagnostic marker of bulbar disease.

METHOD

Tongue and jaw movements were recorded cross-sectionally (n = 33 individuals with ALS, 13 controls) and longitudinally (n = 10 individuals with ALS) using a three-dimensional electromagnetic articulography system during the production of the sentence Buy Bobby a puppy. The movements were examined for evidence of changes in size, speed, and duration and with respect to disease severity and time in the study.

RESULTS

Maximum speed of tongue movements and movement durations were significantly different only at an advanced stage of bulbar ALS compared with the healthy control group. The longitudinal analysis revealed a reduction in tongue movement size and speed with time at early stages of disease, which was not seen cross-sectionally. As speaking rate declined, tongue movements decreased in maximum speed, whereas jaw movements increased in maximum speed.

CONCLUSIONS

Longitudinal analyses of sentence-level kinematic data show their sensitivity to early bulbar impairment. A change in articulatory kinematics can serve as a useful diagnostic marker for bulbar ALS and to track bulbar disease progression in a clinical setting.

Predicting Intelligible Speaking Rate in Individuals with Amyotrophic Lateral Sclerosis from a Small Number of Speech Acoustic and Articulatory Samples

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurological disease that affects the speech motor functions, resulting in dysarthria, a motor speech disorder. Speech and articulation deterioration is an indicator of the disease progression of ALS; timely monitoring of the disease progression is critical for clinical management of these patients. This paper investigated machine prediction of intelligible speaking rate of nine individuals with ALS based on a small number of speech acoustic and articulatory samples. Two feature selection techniques - decision tree and gradient boosting - were used with support vector regression for predicting the intelligible speaking rate. Experimental results demonstrated the feasibility of predicting intelligible speaking rate from only a small number of speech samples. Furthermore, adding articulatory features to acoustic features improved prediction performance, when decision tree was used as the feature selection technique.

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.

An Optimal Set of Flesh Points on Tongue and Lips for Speech-Movement Classification

PURPOSE

The authors sought to determine an optimal set of flesh points on the tongue and lips for classifying speech movements.

METHOD

The authors used electromagnetic articulographs (Carstens AG500 and NDI Wave) to record tongue and lip movements from 13 healthy talkers who articulated 8 vowels, 11 consonants, a phonetically balanced set of words, and a set of short phrases during the recording. We used a machine-learning classifier (support-vector machine) to classify the speech stimuli on the basis of articulatory movements. We then compared classification accuracies of the flesh-point combinations to determine an optimal set of sensors.

RESULTS

When data from the 4 sensors (T1: the vicinity between the tongue tip and tongue blade; T4: the tongue-body back; UL: the upper lip; and LL: the lower lip) were combined, phoneme and word classifications were most accurate and were comparable with the full set (including T2: the tongue-body front; and T3: the tongue-body front).

CONCLUSION

We identified a 4-sensor set--that is, T1, T4, UL, LL--that yielded a classification accuracy (91%-95%) equivalent to that using all 6 sensors. These findings provide an empirical basis for selecting sensors and their locations for scientific and emerging clinical applications that incorporate articulatory movements.

Validation of Clinical Observations of Mastication in Persons with ALS

Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease that can result in difficulties with mastication leading to malnutrition, choking or aspiration, and reduced quality of life. When evaluating mastication, clinicians primarily observe spatial and temporal aspects of jaw motion. The reliability and validity of clinical observations for detecting jaw movement abnormalities is unknown. The purpose of this study is to determine the reliability and validity of clinician-based ratings of chewing performance in neuro-typical controls and persons with varying degrees of chewing impairments due to ALS. Adults chewed a solid food consistency while full-face video were recorded along with jaw kinematic data using a 3D optical motion capture system. Five experienced speech-language pathologists watched the videos and rated the spatial and temporal aspects of chewing performance. The jaw kinematic data served as the gold-standard for validating the clinicians' ratings. Results showed that the clinician-based rating of temporal aspects of chewing performance had strong inter-rater reliability and correlated well with comparable kinematic measures. In contrast, the reliability of rating the spatial and spatiotemporal aspects of chewing (i.e., range of motion of the jaw, consistency of the chewing pattern) was mixed. Specifically, ratings of range of motion were at best only moderately reliable. Ratings of chewing movement consistency were reliable but only weakly correlated with comparable measures of jaw kinematics. These findings suggest that clinician ratings of temporal aspects of chewing are appropriate for clinical use, whereas ratings of the spatial and spatiotemporal aspects of chewing may not be reliable or valid.

Profiling Speech and Pausing in Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD)

Objective

This study examines reading aloud in patients with amyotrophic lateral sclerosis (ALS) and those with frontotemporal dementia (FTD) in order to determine whether differences in patterns of speaking and pausing exist between patients with primary motor vs. primary cognitive-linguistic deficits, and in contrast to healthy controls.

Design

136 participants were included in the study: 33 controls, 85 patients with ALS, and 18 patients with either the behavioural variant of FTD (FTD-BV) or progressive nonfluent aphasia (FTD-PNFA). Participants with ALS were further divided into 4 non-overlapping subgroups—mild, respiratory, bulbar (with oral-motor deficit) and bulbar-respiratory—based on the presence and severity of motor bulbar or respiratory signs. All participants read a passage aloud. Custom-made software was used to perform speech and pause analyses, and this provided measures of speaking and articulatory rates, duration of speech, and number and duration of pauses. These measures were statistically compared in different subgroups of patients.

Results

The results revealed clear differences between patient groups and healthy controls on the passage reading task. A speech-based motor function measure (i.e., articulatory rate) was able to distinguish patients with bulbar ALS or FTD-PNFA from those with respiratory ALS or FTD-BV. Distinguishing the disordered groups proved challenging based on the pausing measures.

Conclusions and Relevance

This study demonstrated the use of speech measures in the identification of those with an oral-motor deficit, and showed the usefulness of performing a relatively simple reading test to assess speech versus pause behaviors across the ALS—FTD disease continuum. The findings also suggest that motor speech assessment should be performed as part of the diagnostic workup for patients with FTD.

Tongue electrical impedance in amyotrophic lateral sclerosis modeled using the finite element method

OBJECTIVE

Electrical impedance myography (EIM) of the tongue has demonstrated alterations in patients with amyotrophic lateral sclerosis (ALS) compared to normal subjects. Whether these differences are due to reduced tongue size or diseased-associated alterations in the electrical characteristics of intrinsic tongue muscles is uncertain.

METHODS

We employed computer simulations using the finite element method, inputting data from healthy and ALS mouse muscle, to help answer that question, comparing our modeled results to human data.

RESULTS

The models revealed that much of the electrical current flows superficially in the tongue and that tongue thickness only begins to have a major impact on the measured impedance when substantial atrophy is present. Modeled values paralleled the human tongue data.

CONCLUSIONS

These findings suggest that the observed changes in tongue impedance in ALS are mainly due to alterations in the electrical properties of the tongue and are not a mere consequence of tongue volume loss.

SIGNIFICANCE

Further development of EIM for evaluation of bulbar dysfunction in ALS may provide useful information on drug efficacy and could serve as a biomarker in future clinical trials.

The role of candidate-gene CNTNAP2 in childhood apraxia of speech and specific language impairment

Childhood apraxia of speech (CAS) is a debilitating pediatric speech disorder characterized by varying symptom profiles, comorbid deficits, and limited response to intervention. Specific Language Impairment (SLI) is an inherited pediatric language disorder characterized by delayed and/or disordered oral language skills including impaired semantics, syntax, and discourse. To date, the genes associated with CAS and SLI are not fully characterized. In the current study, we evaluated behavioral and genetic profiles of seven children with CAS and eight children with SLI, while ensuring all children were free of comorbid impairments. Deletions within CNTNAP2 were found in two children with CAS but not in any of the children with SLI. These children exhibited average to high performance on language and word reading assessments in spite of poor articulation scores. These findings suggest that genetic variation within CNTNAP2 may be related to speech production deficits.

Evidence for the multiple hits genetic theory for inherited language impairment: a case study

Communication disorders have complex genetic origins, with constellations of relevant gene markers that vary across individuals. Some genetic variants are present in healthy individuals as well as those affected by developmental disorders. Growing evidence suggests that some variants may increase susceptibility to these disorders in the presence of other pathogenic gene mutations. In the current study, we describe eight children with specific language impairment and four of these children had a copy number variant in one of these potential susceptibility regions on chromosome 15. Three of these four children also had variants in other genes previously associated with language impairment. Our data support the theory that 15q11.2 is a susceptibility region for developmental disorders, specifically language impairment.

Electrical impedance myography in the evaluation of the tongue musculature in amyotrophic lateral sclerosis

INTRODUCTION

Electrical impedance myography (EIM) quantifies muscle health and is used as a biomarker of muscle abnormalities in neurogenic and myopathic diseases. EIM has yet to be evaluated in the tongue musculature in patients with amyotrophic lateral sclerosis (ALS), who often show clinical bulbar signs.

METHODS

The lingual musculature of 19 subjects with motor neuron disease and 21 normal participants was assessed using EIM, strength and endurance testing, and clinical assessment.

RESULTS

Tongue musculature in the ALS group was characterized by significantly smaller phase (Ph) and greater resistance (R) when compared with the healthy cohort. Ph and tongue endurance were correlated in the ALS group.

CONCLUSIONS

EIM of tongue musculature could distinguish those with ALS from healthy controls. The demonstrated relationship between tongue function and Ph supports further testing of EIM of the tongue as a potential biomarker in ALS.

Longitudinal development of speech motor control: Motor and linguistic factors

Lip shape in adult talkers is primarily driven by vertical opening; however, little is known about how children converge on this highly organized and efficient lip shape pattern. This longitudinal study investigated the development of lip shape control and its relation to speech and vocabulary acquisition in 28 typically developing children between 3 months and 5 years of age. Results suggested that during infancy lip shape was characterized by horizontal spreading of the lips, but that the contribution of vertical opening increased nonmonotonically over time. This change co-occurred with gains in expressive communication. These data suggest that lip shape may represent an important marker of normal oromotor development. Future work is required to determine the functional significance of the observed changes in lip shape control for identifying children at risk for speech and language impairments.

Reliance on auditory feedback in children with childhood apraxia of speech

Children with childhood apraxia of speech (CAS) have been hypothesized to continuously monitor their speech through auditory feedback to minimize speech errors. We used an auditory masking paradigm to determine the effect of attenuating auditory feedback on speech in 30 children: 9 with CAS, 10 with speech delay, and 11 with typical development. The masking only affected the speech of children with CAS as measured by voice onset time and vowel space area. These findings provide preliminary support for greater reliance on auditory feedback among children with CAS.

LEARNING OUTCOMES

Readers of this article should be able to (i) describe the motivation for investigating the role of auditory feedback in children with CAS; (ii) report the effects of feedback attenuation on speech production in children with CAS, speech delay, and typical development, and (iii) understand how the current findings may support a feedforward program deficit in children with CAS.

Data-driven subclassification of speech sound disorders in preschool children

PURPOSE

The purpose of the study was to determine whether distinct subgroups of preschool children with speech sound disorders (SSD) could be identified using a subgroup discovery algorithm (SUBgroup discovery via Alternate Random Processes, or SUBARP). Of specific interest was finding evidence of a subgroup of SSD exhibiting performance consistent with atypical speech motor control.

METHOD

Ninety-seven preschool children with SSD completed speech and nonspeech tasks. Fifty-three kinematic, acoustic, and behavioral measures from these tasks were input to SUBARP.

RESULTS

Two distinct subgroups were identified from the larger sample. The 1st subgroup (76%; population prevalence estimate = 67.8%-84.8%) did not have characteristics that would suggest atypical speech motor control. The 2nd subgroup (10.3%; population prevalence estimate = 4.3%-16.5%) exhibited significantly higher variability in measures of articulatory kinematics and poor ability to imitate iambic lexical stress, suggesting atypical speech motor control. Both subgroups were consistent with classes of SSD in the Speech Disorders Classification System (SDCS; Shriberg et al., 2010a).

CONCLUSION

Characteristics of children in the larger subgroup were consistent with the proportionally large SDCS class termed speech delay; characteristics of children in the smaller subgroup were consistent with the SDCS subtype termed motor speech disorder-not otherwise specified. The authors identified candidate measures to identify children in each of these groups.

Speaking rate effects on articulatory pattern consistency in talkers with mild ALS

This study investigated speaking rate effects on articulatory pattern consistency in talkers with mild amyotrophic lateral sclerosis (ALS) to better understand speech rate declines during the early stages of speech deterioration. Eight talkers with mild ALS and 11 controls repeated a sentence at their typical rate, an accelerated rate, and a reduced rate. Lip and jaw movements were captured using a 3-D motion capture system. Results showed that talkers with ALS produced more consistent articulatory patterns during typical speech than did controls. Further, rate reduction resulted in diminished pattern consistency in both groups. Fast speech also elicited less consistent articulatory patterns in talkers with ALS. Controls, by contrast, tended to produce more consistent patterns during fast speech. Relatively inconsistent patterns during fast speech suggest that ALS may negatively affect articulatory control when the speech motor system operates near its performance limit. Relatively consistent patterns during typical speech indicate a successful adaption to disease-related articulatory deficits. Rate reduction does not appear to benefit articulatory stability during early stages of speech decline.

Neural correlates of cognitive decline in ALS: an fNIRS study of the prefrontal cortex

Functional near infrared spectroscopy (fNIRS) is a clinically feasible functional neuroimaging modality for detecting early cortical changes due to neurodegenerative diseases that affect cognition. The objective of this preliminary investigation was to test for reduced prefrontal activity in persons with cognitive impairments due to amyotrophic lateral sclerosis (ALS). Participants were required to complete two N-back working memory tasks of increasing complexity during fNIRS recordings. Five participants with ALS and age- and gender-matched healthy participants comprised the experimental and control groups, respectively. Significant reductions in prefrontal oxygenation levels were observed for the left and right hemispheres in the ALS group compared to the control group. Reduced prefrontal activation despite intact behavioral performance for a working memory task may suggest early neuroanatomical, neurophysiological and/or compensatory mechanisms in affected individuals. The fNIRS-derived oxygenation measure shows promise as a sensitive neural marker to identify early neuropsychological impairments due to ALS.

Articulatory distinctiveness of vowels and consonants: a data-driven approach

PURPOSE

To quantify the articulatory distinctiveness of 8 major English vowels and 11 English consonants based on tongue and lip movement time series data using a data-driven approach.

METHOD

Tongue and lip movements of 8 vowels and 11 consonants from 10 healthy talkers were collected. First, classification accuracies were obtained using 2 complementary approaches: (a) Procrustes analysis and (b) a support vector machine. Procrustes distance was then used to measure the articulatory distinctiveness among vowels and consonants. Finally, the distance (distinctiveness) matrices of different vowel pairs and consonant pairs were used to derive articulatory vowel and consonant spaces using multidimensional scaling.

RESULTS

Vowel classification accuracies of 91.67% and 89.05% and consonant classification accuracies of 91.37% and 88.94% were obtained using Procrustes analysis and a support vector machine, respectively. Articulatory vowel and consonant spaces were derived based on the pairwise Procrustes distances.

CONCLUSIONS

The articulatory vowel space derived in this study resembled the long-standing descriptive articulatory vowel space defined by tongue height and advancement. The articulatory consonant space was consistent with feature-based classification of English consonants. The derived articulatory vowel and consonant spaces may have clinical implications, including serving as an objective measure of the severity of articulatory impairment.

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.

Speech in ALS: Longitudinal Changes in Lips and Jaw Movements and Vowel Acoustics

PURPOSE

The goal of this exploratory study was to investigate longitudinally the changes in facial kinematics, vowel formant frequencies, and speech intelligibility in individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). This study was motivated by the need to understand articulatory and acoustic changes with disease progression and their subsequent effect on deterioration of speech in ALS.

METHOD

Lip and jaw movements and vowel acoustics were obtained for four individuals with bulbar ALS during four consecutive recording sessions with an average interval of three months between recordings. Participants read target words embedded into sentences at a comfortable speaking rate. Maximum vertical and horizontal mouth opening and maximum jaw displacements were obtained during corner vowels. First and second formant frequencies were measured for each vowel. Speech intelligibility and speaking rate score were obtained for each session as well.

RESULTS

Transient, non-vowel-specific changes in kinematics of the jaw and lips were observed. Kinematic changes often preceded changes in vowel acoustics and speech intelligibility.

CONCLUSIONS

Nonlinear changes in speech kinematics should be considered in evaluation of the disease effects on jaw and lip musculature. Kinematic measures might be most suitable for early detection of changes associated with bulbar ALS.

Increases in cognitive and linguistic processing primarily account for increases in speaking rate with age

Age-related increases of speaking rate are not fully understood, but have been attributed to gains in biologic factors and learned skills that support speech production. This study investigated developmental changes in speaking rate and articulatory kinematics of participants aged 4 (N = 7), 7 (N = 10), 10 (N = 9), 13 (N = 7), 16 (N = 9) years, and young adults (N = 11) in speaking tasks varying in task demands. Speaking rate increased with age, with decreases in pauses and articulator displacements but not increases in articulator movement speed. Movement speed did not appear to constrain the speaking. Rather, age-related increases in speaking rate are due to gains in cognitive and linguistic processing and speech motor control.