Jordan R. Green

A diagnostic marker for childhood apraxia of speech: the coefficient of variation ratio

Terms such as isochrony, syllable segregation, scanning speech and staccato‐like rhythmic quality have been used to characterize the temporal regularity that may be a core feature of apraxia of speech. The present report describes a procedure to quantify temporal regularity in children with suspected apraxia of speech (sAOS). Conversational speech samples from 15 such children, together with samples from 30 3–6‐year‐old children with normal speech acquisition and 30 3–6‐year‐old children with moderate to severe speech delay of unknown origin, were selected from an audio archive. Signal processing routines were developed to identify and measure the duration of speech and pause events in 24 utterances from the speech samples of each of the 75 speakers. A value termed the coefficient of variation expressed the normalized variability in the durations of each participants speech events and pause events within each utterance. A metric termed the coefficient of variation ratio, derived by dividing the coefficient of variation for pause events by the coefficient of variation for speech events, expressed a speakers relative temporal variation in the two domains. The 15 children with sAOS had higher coefficient of variation ratios than the 30 children in each of the two comparison groups, indicating that the children with sAOS had proportionally more variation in the duration of pause events and/or less variation in the duration of speech events. Findings are interpreted as supporting the view that a constraint in speech timing is a core feature of the praxis disorder that defines a developmental form of apraxia of speech.

Tongue-surface movement patterns during speech and swallowing.

The tongue has been frequently characterized as being composed of several functionally independent articulators. The question of functional regionality within the tongue was examined by quantifying the strength of coupling among four different tongue locations across a large number of consonantal contexts and participants. Tongue behavior during swallowing was also described. Vertical displacements of pellets affixed to the tongue were extracted from the x-ray microbeam database. Forty-six participants recited 20 vowel-consonant-vowel (VCV) combinations and swallowed 10 ccs of water. Tongue-surface movement patterns were quantitatively described by computing the covariance between the vertical time-histories of all possible pellet pairs. Phonemic differentiation in vertical tongue motions was observed as coupling varied predictably across pellet pairs with place of articulation. Moreover, tongue displacements for speech and swallowing clustered into distinct groups based on their coupling profiles. Functional independence of anterior tongue regions was evidenced by a wide range of movement coupling relations between anterior tongue pellets. The strengths and weaknesses of the covariance-based analysis for characterizing tongue movement are considered.

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

Abstract 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.

The development of jaw motion for mastication

The developmental course of early chewing has rarely been studied, although such knowledge is essential for understanding childhood feeding and swallowing disorders. The goal of this investigation was to quantitatively describe age- and consistency-related changes in jaw kinematics during early chewing development. An optical-motion tracking system was used to record jaw movements during chewing in 3-dimensions in 11 typically-developing participants longitudinally from 9-30 months of age. Age related changes in jaw movement were described for both puree and regular consistencies. The findings demonstrated that the development of rotary jaw motion, jaw motion speed, and management of consistency upgrades are protracted across the first two years of life. Young children did not differentiate their jaw closing speeds for puree and regular consistencies until 18-24 months of age, at which age the speed of movement was significantly slower for the puree than for the regular consistency. Horizontal jaw closing speed decreased significantly with age for the puree consistency, but not for the regular consistency. The emergence of a rotary chew pattern was not observed at the ages studied.

Kinematics of disease progression in bulbar ALS

UNLABELLED The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech performance such as speaking rate and speech intelligibility. Movements of the lip and jaw were quantified with respect to their size speed, and duration. The data revealed several changes in lip and jaw movement that coincided with ALS progression. In two out of three speakers, the changes in measures of path distance and speed anticipated the drop in speech intelligibility by approximately 3 months. With disease progression, increases in movement duration coincided with declines in speech intelligibility. Overall, the movement measures appeared to be sensitive to disease progression in ALS. LEARNING OUTCOMES By the end of the manuscript, the reader should be able to: (1) describe the changes that occur in articulatory movements of the jaw and lower lip in ALS; (2) understand the relationship between physiologic measures of movement and speech intelligibility and speaking rate; (3) identify critical points in the disease progression and understand which quantitative measures reveal the state of the bulbar system at these time points.

Tongue Movements and Their Acoustic Consequences in Amyotrophic Lateral Sclerosis

Objective: The relations between acoustic measures and their articulatory bases have rarely been tested in dysarthria but are important for diagnostic and treatment purposes. We tested the association between acoustic measures of F2 range and F2 slope with kinematic measures of tongue movement displacement and speed in individuals with amyotrophic lateral sclerosis (ALS) and healthy controls speaking at normal and slow rates. Relations between acoustic and kinematic measures and speech intelligibility were examined. Results: As healthy controls reduced their speaking rate, their F2 slopes and movement speeds decreased. In talkers with ALS, acoustic and kinematic variables were associated with changes in speaking rate, characteristic of disease progression. Participants with slow rate had shallower F2 slopes and slower movement speeds than those with normal rate. Relations between F2 range and tongue displacement were weaker. F2 slope, displacement, and duration were correlated with speech intelligibility most consistently. Conclusion: Findings suggested that F2 slope is a useful marker for tracking disease progression in ALS. F2 slope reflects changes in tongue function with disease progression and is linked to speech intelligibility. Changes in movement speed, however, might be the earliest sign of disease in the tongue.

Early speech motor development: Cognitive and linguistic considerations

UNLABELLED This longitudinal investigation examines developmental changes in orofacial movements occurring during the early stages of communication development. The goals were to identify developmental trends in early speech motor performance and to determine how these trends differ across orofacial behaviors thought to vary in cognitive and linguistic demands (i.e., silent spontaneous movements, babble, and first words). Movements of the lower lip and jaw were recorded using a three-dimensional motion capture system. Twenty-four infants were observed every 3 months, from 9 to 21 months of age. Jaw and lower lip speed, and lower lip range of movement increased with age. Silent spontaneous movements were consistently slower than words, whereas kinematic measures associated with babble did not differ from those associated with words. These findings suggest that speech movements may reflect linguistic and cognitive processing demands and that the continuity hypothesis between babbling and words may also be observed at the kinematic level. LEARNING OUTCOMES Readers will be able to: (1) describe the potential role of cognition and language in early speech development, (2) describe kinematic changes in the orofacial system from 9 to 21 months of age, and (3) identify the differences in kinematic characteristics for silent spontaneous orofacial movements, babbles and words between 15 to 21 months of age.

The co-emergence of cognition, language, and speech motor control in early development: A longitudinal correlation study

UNLABELLED Although the development of spoken language is dependent on the emergence of cognitive, language, and speech motor skills, knowledge about how these domains interact during the early stages of communication development is currently limited. This exploratory investigation examines the strength of associations between longitudinal changes in articulatory kinematics and development of skills in multiple domains thought to support early communication development. Twenty-four children were investigated every 3 months between the ages of 9 and 21 months. Movements of the upper lip, lower lip, and jaw were transduced using a three-dimensional motion capture system to obtain age-related changes in movement speed and range of movement. Standardized measures of cognition and language from the Battelle Developmental Inventory, 2nd edition and the MacArthur-Bates Communicative Development Inventory were also collected. Significant associations were identified between orofacial kinematic and the standardized measures of language and cognitive skills, even when age served as covariate. These findings provide preliminary evidence of interactions between cognition, language, and speech motor skills during early communication development. Further work is needed to identify and quantify causal relations among these co-emerging skills. LEARNING OUTCOMES The reader will be able to: (1) describe how cognition, language, and speech motor control may interact during speech development, (2) describe the associations between speech kinematic characteristics and measures of cognition and language.

Task Specificity in Early Oral Motor Development

This article addresses a long-standing clinical and theoretical debate regarding the potential relationship between speech and nonspeech behaviors in the developing system. The review is motivated by the high popularity of nonspeech oral motor exercises (NSOMEs), including alimentary behaviors such as chewing, in the treatment of speech disorders in young children. The similarities and differences in the behavioral characteristics, sensory requirements, and task goals for speech and nonspeech oromotor behaviors are compared. Integrated theoretical paradigms and empirical data on the development of early oromotor behaviors are discussed. Although the efficacy of NSOMEs remains empirically untested at this time, studies of typical developmental speech physiology fail to support a theoretical framework promoting the use of NSOMEs. Well-designed empirical studies are necessary, however, to establish the efficacy of NSOMEs for specific clinical population and treatment targets.

Breath Group Analysis for Reading and Spontaneous Speech in Healthy Adults

Aims: The breath group can serve as a functional unit to define temporal and fundamental frequency (f₀) features in continuous speech. These features of the breath group are determined by the physiologic, linguistic, and cognitive demands of communication. Reading and spontaneous speech are two speaking tasks that vary in these demands and are commonly used to evaluate speech performance for research and clinical applications. The purpose of this study is to examine differences between reading and spontaneous speech in the temporal and f₀ aspects of their breath groups. Methods: Sixteen participants read two passages and answered six questions while wearing a circumferentially vented mask connected to a pneumotach. The aerodynamic signal was used to identify inspiratory locations. The audio signal was used to analyze task differences in breath group structure, including temporal and f₀ components. Results: The main findings were that spontaneous speech task exhibited significantly more grammatically inappropriate breath group locations and longer breath group duration than did the passage reading task. Conclusion: The task differences in the percentage of grammatically inadequate breath group locations and in breath group duration for healthy adult speakers partly explain the differences in cognitive-linguistic load between the passage reading and spontaneous speech.