Oromotor Nonverbal Performance and Speech Motor Control: Theory and Review of Empirical Evidence.

This position paper offers a perspective on the long-standing debate concerning the role of oromotor, nonverbal gestures in understanding typical and disordered speech motor control secondary to neurological disease. Oromotor nonverbal tasks are employed routinely in clinical and research settings, but a coherent rationale for their use is needed. The use of oromotor nonverbal performance to diagnose disease or dysarthria type, versus specific aspects of speech production deficits that contribute to loss of speech intelligibility, is argued to be an important part of the debate.

Formant Trajectory Patterns of American English /l/ Produced by Adults and Children.

Purpose Most acoustic and articulatory studies on /l/ have focused on either duration, formant frequencies, or tongue shape during the constriction interval. Only a limited set of data exists for the transition characteristics of /l/ to and from surrounding vowels. The aim of this study was to examine second formant (F2) transition characteristics of /l/ produced by young children and adults.

Vowel reduction across tasks for male speakers of American English.

This study examined acoustic variation of vowels within speakers across speech tasks. The overarching goal of the study was to understand within-speaker variation as one index of the range of normal speech motor behavior for American English vowels. Ten male speakers of American English performed four speech tasks including citation form sentence reading with a clear-speech style (clear-speech), citation form sentence reading (citation), passage reading (reading), and conversational speech (conversation).

Relationship between tongue positions and formant frequencies in female speakers.

This study examined the relationship (1) between acoustic vowel space and the corresponding tongue kinematic vowel space and (2) between formant frequencies (F1 and F2) and tongue x-y coordinates for the same time sampling point. Thirteen healthy female adults participated in this study. Electromagnetic articulography and synchronized acoustic recordings were utilized to obtain vowel acoustic and tongue kinematic data across ten speech tasks.

Predicting speech intelligibility with a multiple speech subsystems approach in children with cerebral palsy.

Purpose: Speech acoustic characteristics of children with cerebral palsy (CP) were examined with a multiple speech subsystems approach; speech intelligibility was evaluated using a prediction model in which acoustic measures were selected to represent three speech subsystems.

Method: Nine acoustic variables reflecting different subsystems, and speech intelligibility, were measured in 22 children with CP. These children included 13 with a clinical diagnosis of dysarthria (speech motor impairment [SMI] group) and 9 judged to be free of dysarthria (no SMI [NSMI] group).

Speaking rate effects on locus equation slope.

A locus equation describes a 1st order regression fit to a scatter of vowel steady-state frequency values predicting vowel onset frequency values. Locus equation coefficients are often interpreted as indices of coarticulation. Speaking rate variations with a constant consonant-vowel form are thought to induce changes in the degree of coarticulation.

Measures to Evaluate the Effects of DBS on Speech Production.

The purpose of this paper is to review and evaluate measures of speech production that could be used to document effects of Deep Brain Stimulation (DBS) on speech performance, especially in persons with Parkinson disease (PD). A small set of evaluative criteria for these measures is presented first, followed by consideration of several speech physiology and speech acoustic measures that have been studied frequently and reported on in the literature on normal speech production, and speech production affected by neuromotor disorders (dysarthria). Each measure is reviewed and evaluated against the evaluative criteria.

Speech intelligibility, speaking rate, and vowel formant characteristics in Mandarin-speaking children with cochlear implant.

The effects of the use of cochlear implant (CI) on speech intelligibility, speaking rate, and vowel formant characteristics and the relationships between speech intelligibility, speaking rate, and vowel formant characteristics for children are clinically important. The purposes of this study were to report on the comparisons for speaking rate and vowel space area, and their relationship with speech intelligibility, between 24 Mandarin-speaking children with CI and 24 age-sex-education level matched normal hearing (NH) controls. Participants were audio recorded as they read a designed Mandarin intelligibility test, repeated prolongation of each of the three point vowels /i/, /a/, and /u/ five times, and repeated each of three sentences carrying one point vowel five times.

Cross-linguistic studies of children's and adults' vowel spaces.

This study examines cross-linguistic variation in the location of shared vowels in the vowel space across five languages (Cantonese, American English, Greek, Japanese, and Korean) and three age groups (2-year-olds, 5-year-olds, and adults). The vowels /a/, /i/, and /u/ were elicited in familiar words using a word repetition task. The productions of target words were recorded and transcribed by native speakers of each language.

A kinematic description of the temporal characteristics of jaw motion for early chewing: preliminary findings.

Purpose: The purpose of this investigation was to describe age- and consistency-related changes in the temporal characteristics of chewing in typically developing children between the ages of 4 and 35 months and adults using high-resolution optically based motion capture technology.

Method: Data were collected from 60 participants (48 children, 12 adults) across 5 age ranges (beginners, 7 months, 12 months, 35 months, and adults); each age group included 12 participants. Three different food consistencies were trialed as appropriate.

Classifications of vocalic segments from articulatory kinematics: healthy controls and speakers with dysarthria.

Purpose: In this study, the authors classified vocalic segments produced by control speakers (C) and speakers with dysarthria due to amyotrophic lateral sclerosis (ALS) or Parkinson's disease (PD); classification was based on movement measures. The researchers asked the following questions: (a) Can vowels be classified on the basis of selected measures of articulatory motions? and (b) Can classification models that are constructed from control productions classify vowels produced by speakers with dysarthria that is related to ALS and PD?

Method: Nineteen C, 7 PD, and 8 ALS speakers participated in this study. The severity of dysarthria varied across individuals and between the 2 disorder groups.

An acoustic study of the relationships among neurologic disease, dysarthria type, and severity of dysarthria.

Purpose: This study examined acoustic predictors of speech intelligibility in speakers with several types of dysarthria secondary to different diseases and conducted classification analysis solely by acoustic measures according to 3 variables (disease, speech severity, and dysarthria type).

Method: Speech recordings from 107 speakers with dysarthria due to Parkinson's disease, stroke, traumatic brain injury, and multiple system atrophy were used for acoustic analysis and for perceptual judgment of speech intelligibility. Acoustic analysis included 8 segmental/suprasegmental features: 2nd formant frequency slope, articulation rate, voiceless interval duration, 1st moment analysis for fricatives, vowel space, F0, intensity range, and Pairwise Variability Index.

Statistical models of F2 slope in relation to severity of dysarthria.

Objective: This study investigated the distribution of second-formant (F2) slopes in a relatively large number of speakers with dysarthria associated with two different underlying diseases.

Patients And Methods: Forty speakers with dysarthria (20 with Parkinson's disease, PD; 20 with stroke) and 5 control speakers without a history of neurological disease were asked to repeat six words (coat, hail, sigh, shoot, row and wax) 10 times. Acoustic analysis was performed to derive F2 slope, and speech intelligibility data were collected using a direct magnitude estimate technique to examine its relationship to F2 slope.

Articulatory movements during vowels in speakers with dysarthria and healthy controls.

Purpose: This study compared movement characteristics of markers attached to the jaw, lower lip, tongue blade, and dorsum during production of selected English vowels by normal speakers and speakers with dysarthria due to amyotrophic lateral sclerosis (ALS) or Parkinson disease (PD). The study asked the following questions: (a) Are movement measures different for healthy controls and speakers with ALS or PD, and (b) Are articulatory profiles comparable for speakers with ALS and speakers with PD?

Method: Nineteen healthy controls and 15 speakers with dysarthria participated in this study. The severity of dysarthria varied across individuals and between the 2 disorder groups.

Special Panel Session: Driving Critical Initiatives in Motor Speech.

The following report is a summary of the Special Panel Session, entitled, "Driving Critical Initiatives in Motor Speech," that was conducted at the Conference on Motor Speech, March 2008, in Monterey California. Don Finan (Program Chair for Speech Motor Control) and Julie Liss (Program Chair for Motor Speech Disorders) invited four distinguished scientists (Drs. Gary Weismer, Steven Barlow, Anne Smith, and John Caviness) to share, briefly, their opinions and views on selected topics.

Two cases of foreign accent syndrome: an acoustic-phonetic description.

This paper presents an acoustic-phonetic description of two American English speakers with foreign accent syndrome (FAS). Speech samples were collected from both speakers. Acoustic measurements of voice onset time, vowel duration, first and second formant frequency analysis, fundamental frequency (F0), and consonantal duration were performed.

Interspeaker variation in habitual speaking rate: additional evidence.

Purpose: The purpose of the present study was to test the hypothesis that talkers previously classified by Y.-C. Tsao and G.

Philosophy of research in motor speech disorders.

The primary objective of this position paper is to assess the theoretical and empirical support that exists for the Mayo Clinic view of motor speech disorders in general, and for oromotor, nonverbal tasks as a window to speech production processes in particular. Literature both in support of and against the Mayo clinic view and the associated use of oromotor, nonverbal tasks, is reviewed, along with literature from normal speech production and neurophysiology. This literature is organized and analysed to show that theoretical and experimental support for the Mayo view is weak at best, and that the frequent appeal to oromotor, nonverbal tasks is misguided.

The effect of intertalker speech rate variation on acoustic vowel space.

The present study aimed to examine the size of the acoustic vowel space in talkers who had previously been identified as having slow and fast habitual speaking rates [Tsao, Y.-C. and Weismer, G.

Breath-group intelligibility in dysarthria: characteristics and underlying correlates.

Purpose: This study was designed to determine whether within-speaker fluctuations in speech intelligibility occurred among speakers with dysarthria who produced a reading passage, and, if they did, whether selected linguistic and acoustic variables predicted the variations in speech intelligibility.

Method: Participants with dysarthria included a total of 10 persons with Parkinson's disease and amyotrophic lateral sclerosis; a control group of 10 neurologically normal speakers was also studied. Each participant read a passage that was subsequently separated into consecutive breath groups for estimates of individual breath group intelligibility.

Production and perception of mandarin tone in adults with cerebral palsy.

The primary objective of the present study was to document tone production and intelligibility deficits in Mandarin-speaking persons with cerebral palsy (CP). Spastic, athetoid, and mixed types of CP were studied, along with a control group, to investigate the possibility of tone production and intelligibility deficits that were differentially affected by type of CP. Speakers produced a 78-word list that included contrasts for all four Mandarin tones.

Alternating motion rate as an index of speech motor disorder in traumatic brain injury.

The task of syllable alternating motion rate (AMR) (also called diadochokinesis) is suitable for examining speech disorders of varying degrees of severity and in individuals with varying levels of linguistic and cognitive ability. However, very limited information on this task has been published for subjects with traumatic brain injury (TBI). This study is a quantitative and qualitative acoustic analysis of AMR in seven subjects with TBI.