Bite block vowel production in apraxia of speech

PURPOSE: This study explored vowel production and adaptation to articulatory constraints in adults with acquired apraxia of speech (AOS) plus aphasia. METHOD: Five adults with acquired AOS plus aphasia and 5 healthy control participants produced the vowels [i], [epsilon], and [ae] in four word-length conditions in unconstrained and bite block conditions. In addition to acoustic and perceptual measures of vowel productions, individually determined idealized vowels based on each participant's best performance were used to assess vowel accuracy and distinctiveness. RESULTS: Findings showed (a) clear separation of vowel formants in speakers with AOS; (b) impaired vowel production in speakers with AOS, shown by perceptual measures of vowel quality and acoustic measures of vowel accuracy and contrastivity; and (c) incomplete compensation to bite block compensation both for individuals with AOS and for healthy controls. CONCLUSIONS: Although adults with AOS were less accurate overall in vowel production than unimpaired speakers, introduction of a bite block resulted in similar patterns of decreased vowel accuracy for the two groups. Findings suggest that feedback control for vowel production is relatively intact in these individuals with AOS and aphasia. Predominant use of feedback control mechanisms is hypothesized to account for characteristic vowel deficits of the disorder.     

言语呼吸疾病的定量评估及矫治对策

本文对言语呼吸疾病的专家决策系统进行了探讨，主要从定量评估及矫治对策两方面叙述了该系统的基本构架．构成成分的基本功能．两者的关系以及发挥系统效能的途径。     

Second formant transitions in fluent speech of persistent and recovered preschool children who stutter

This study investigated frequency change and duration of the second formant (F2) transitions in perceptually fluent speech samples recorded close to stuttering onset in preschool age children. Comparisons were made among 10 children known to eventually persist in stuttering, 10 who eventually recovered from stuttering, and 10 normally fluent controls. All were enrolled in the longitudinal Stuttering Research Project at the University of Illinois. Subjects fluently repeated standard experimental sentences. The same 36 perceptually fluent target segments (syllables embedded in words) from each subject's repeated sentences were analyzed. The syllables were divided into three phonetic categories based on their initial consonant: bilabial, alveolar, and velar placement. The frequency change and duration of F2 transitions were analyzed for each of the target CV segments. F2 transition onset and offset frequencies and their interval (duration) were measured for each utterance. Data indicate that near stuttering onset, children whose stuttering eventually persisted demonstrated significantly smaller frequency change than that of the recovered group. It is suggested that the F2 transitions should continue to be investigated as a possible predictor of stuttering pathways. LEARNING OUTCOMES: (1) Readers will learn about studies regarding second formant transition related to stuttering. (2) Readers will learn about differences between children who persist in stuttering and those who recover from stuttering. (3) Readers will learn about research concerned with early identification of risk criteria in persistent stuttering.     

Macaque thresholds for detecting increases in intensity: effects of formant structure.

Macaque monkeys, like humans, are more sensitive to differences in formant frequency than to differences in the frequency of pure tones (see Sinnott et al. (1987) J. Comp. Psychol. 94, 401-415; Pfingst (1993) J. Acoust. Soc. Am. 93, 2124-2129; Prosen et al. (1990) J. Acoust. Soc. Am. 88, 2152-2158; Sinnott et al. (1985) J. Acoust. Soc. Am. 78, 1977-1985; Sinnott and Kreiter (1991) J. Acoust. Soc. Am. 89, 2421-2429; for summary, see May et al. (1996) Aud. Neurosci. 3, 135-162). In the discrimination of formant frequency, it appears that the relevant cue for macaque monkeys is relative level differences of the component frequencies (Sommers et al. (1992) J. Acoust. Soc. Am. 91, 3499-3510). To further explore the result of Sommers et al., we trained macaque monkeys (Macaca fuscata) to report detection of a change in the spectral shape of multi-component harmonic complexes. Spectral shape changes were produced by the addition of intensity increments. When the amplitude spectrum of the comparison stimulus was modeled after the /ae/ vowel sound, thresholds for detecting a change from the comparison stimulus were lowest when intensity increments were added at spectral peaks. These results parallel previous data from human subjects, suggesting that both human and monkey subjects may process vowel spectra through simultaneous comparisons of component levels across the spectrum. When the subjects were asked to detect a change from a comparison stimulus with a flat amplitude spectrum, the subjects showed sensitivity that was relatively comparable to that of human subjects tested in other investigations (e.g. Zera et al. (1993) J. Acoust. Soc. Am. 93, 3431-3441). In additional experiments, neither increasing the dynamic range of the /ae/ spectrum nor dynamically varying the amplitude of the increment during the stimulus presentation reliably affected detection thresholds.     

Diagnosis in disorders of speech development

We describe a multi-factorial model for the diagnosis of speech development disorders. The model serves as the basis for an individually designed course of therapy covering all aspects of the disorder. The separate diagnostic steps are in accordance with a classification of speech development disorders based on aetiology and pathology.     

Effect of vowel environment on fricative consonant duration in speech produced during simultaneous communication

This study investigated the effect of vowel environment on fricative consonant duration in contextual speech produced during simultaneous communication (SC). Previous studies (Schwartz, 1969) of vowel influences on consonant duration supported the notion of anticipatory scanning, in which final vowel targets influence the duration of preceding fricative consonants. Ten normal-hearing, experienced sign language users recorded palatal and alveolar fricatives produced in four vowel environments in contextual sentences under SC and speech-only (SO) conditions. Results indicated longer sentence durations for SC than for SO, and significant effects of vowel context on fricative consonant duration in contextual speech in both SC and SO conditions that revealed similar anticipatory scanning effects as seen in previous studies. These data confirm previous research indicating that the temporal alterations produced by simultaneous communication do not involve violations of the temporal rules of English speech.     

小儿言语障碍原因分析

目的探讨小儿言语障碍的原因.方法对9岁以下162例言语障碍的小儿行ABR和40Hz AERP检查,部分患儿经儿科及精神科医师会诊.结果耳聋129例(79.6%),智力低下13例(8%).结论聋是小儿言语障碍的主要原因,但除了听力障碍外,还应考虑其他致病因素.     

Stability and composition of functional synergies for speech movements in children with developmental speech disorders

The aim of this study was to investigate the consistency and composition of functional synergies for speech movements in children with developmental speech disorders. Kinematic data were collected on the reiterated productions of syllables spa (/spa?/) and paas (/pa?s/) by 10 6- to 9-year-olds with developmental speech disorders (five with speech sound disorder [SSD] and five with subtype childhood apraxia of speech [CAS]) and six normally speaking children using electro-magnetic midsagittal articulography (EMMA).Results showed a higher variability of tongue tip movement trajectories and a larger contribution of the lower lip relative to the jaw in oral closures for the five children with CAS compared to normally developing controls, indicating that functional synergies for speech movements in children with CAS may be both delayed and less stable. Furthermore, the SSD group showed a composition of tongue tip movements that is different from both CAS and controls. These results suggest that the differences in speech motor characteristics between SSD and subtype CAS are qualitative rather than quantitative. At the same time, the results suggest that both SSD and subtype CAS increase movement amplitude as an adaptive strategy to increase articulatory stability.Although in direct comparison no exclusive characteristics were found to differentiate subtype CAS from the group of children with SSD and from normally developing children, these preliminary results are promising for quantifying the role of speech motor processes in childhood speech sound disorders.Learning outcomes: The reader will be able to: (1) describe the development of speech motor control and explain the role of functional synergies/coordinative structures; (2) explain the measurement of the stability and composition of speech movements; (3) identify the difficulties in studying disordered speech motor development; (4) describe the differences in speech motor characteristics between SSD and subtype CAS; (5) describe the potential role of motor control strategies in developmental speech disorders.     

Precursors to speech in infancy: the prediction of speech and language disorders.

During the canonical stage of infant babbling, infants produce well-formed syllables, often in reduplicated sequences such as "bababa." Although nearly all infants with normal hearing begin the canonical stage by 10 months of age, a few are delayed, and these infants may be of special interest. Recent studies indicate that late onset of canonical babbling may be a predictor of disorders. A simple screening procedure that focuses on canonical babbling was used to evaluate over 3400 infants at risk who were about 10 months of age. Among infants who showed late onset of canonical babbling, fewer than half had been previously diagnosed as having a significant medical problem that might have accounted for the delay. A follow-up study indicated that infants with delayed canonical babbling had smaller production vocabularies at 18, 24, and 30 months than did infants in the control group. The results suggest that late onset of canonical babbling, a factor that can be monitored effectively through an interview with a parent, can predict delay in the onset of speech production.     

Relationship between speech motor control and speech intelligibility in children with speech sound disorders

The current study was undertaken to investigate the impact of speech motor issues on the speech intelligibility of children with moderate to severe speech sound disorders (SSD) within the context of the PROMPT intervention approach. The word-level Children's Speech Intelligibility Measure (CSIM), the sentence-level Beginner's Intelligibility Test (BIT) and tests of speech motor control and articulation proficiency were administered to 12 children (3:11 to 6:7 years) before and after PROMPT therapy. PROMPT treatment was provided for 45 min twice a week for 8 weeks. Twenty-four naïve adult listeners aged 22–46 years judged the intelligibility of the words and sentences. For CSIM, each time a recorded word was played to the listeners they were asked to look at a list of 12 words (multiple-choice format) and circle the word while for BIT sentences, the listeners were asked to write down everything they heard. Words correctly circled (CSIM) or transcribed (BIT) were averaged across three naïve judges to calculate percentage speech intelligibility. Speech intelligibility at both the word and sentence level was significantly correlated with speech motor control, but not articulatory proficiency. Further, the severity of speech motor planning and sequencing issues may potentially be a limiting factor in connected speech intelligibility and highlights the need to target these issues early and directly in treatment.