In a sample of 46 children aged 4 to 7 years with Autism Spectrum Disorder (ASD) and intelligible speech, there was no statistical support for the hypothesis of concomitant Childhood Apraxia of Speech (CAS). Perceptual and acoustic measures of participants' speech, prosody, and voice were compared with data from 40 typically-developing children, 13 preschool children with Speech Delay, and 15 participants aged 5 to 49 years with CAS in neurogenetic disorders. Speech Delay and Speech Errors, respectively, were modestly and substantially more prevalent in participants with ASD than reported population estimates. Double dissociations in speech, prosody, and voice impairments in ASD were interpreted as consistent with a speech attunement framework, rather than with the motor speech impairments that define CAS. Key Words: apraxia, dyspraxia, motor speech disorder, speech sound disorder A continuing question about persons with Autism Spectrum Disorder (ASD) is whether reported diminished abilities in gross, fine, and oral motor control are causally associated with reported deficits in speech acquisition and performance. The classification term for the speech deficit in question, recently adapted by the American Speech-Language-Hearing Association (ASHA;2007a, 2007b, is Childhood Apraxia of Speech (CAS). Medical literatures and speech literatures in other countries continue to prefer several other classificatory terms for this disorder, including dyspraxia and developmental verbal dyspraxia. "Childhood" apraxia of speech differentiates congenital and early acquired forms of apraxia of speech from adult acquired forms, but creates a nosological problem because childhood apraxia of speech generally persists into adulthood. We will use the ASHA (2007a) recommended term-CAS.The strong form of the hypothesis in the title of this paper, hereafter, the 'CAS-ASD' hypothesis, is that CAS is a sufficient cause of lack of speech development in at least some children classified as nonverbal ASD. The weak form of the CAS-ASD hypothesis is that CAS contributes to the inappropriate speech, prosody, and/or voice features reported in some children and adults with verbal ASD. Although the present report addresses only the weak form of the hypotheses, the conceptual framework and implications for treatment NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript apply to both forms of the hypothesis. Forthcoming research addresses the strong form of the hypothesis. The following sections provide (a) rationales for the CAS-ASD hypothesis, (b) an overview of idiopathic speech sound disorders, and (c) a summary of speech, prosody, and voice findings in verbal ASD. Rationales for the CAS-ASD HypothesisThe American Speech-Language-Hearing Association Position Statement recommends the following definition of CAS:Childhood apraxia of speech (CAS) is a neurological childhood (pediatric) speech sound disorder in which the precision and consistency of movements underlying speech are impaired in the absence of neuromuscula...

We present results obtained with new instrumental methods for the acoustic analysis of prosody to evaluate prosody production by children with Autism Spectrum Disorder (ASD) and Typical Development (TD). Two tasks elicit focal stress, one in a vocal imitation paradigm, the other in a picture-description paradigm; a third task also uses a vocal imitation paradigm, and requires repeating stress patterns of two-syllable nonsense words. The instrumental methods differentiated significantly between the ASD and TD groups in all but the focal stress imitation task. The methods also showed smaller differences in the two vocal imitation tasks than in the picture-description task, as was predicted. In fact, in the nonsense word stress repetition task, the instrumental methods showed better performance for the ASD group. The methods also revealed that the acoustic features that predict auditory-perceptual judgment are not the same as those that differentiate between groups. Specifically, a key difference between the groups appears to be a difference in the balance between the various prosodic cues, such as pitch, amplitude, and duration, and not necessarily a difference in the strength or clarity with which prosodic contrasts are expressed

Assessment of prosody is important for diagnosis and remediation of speech and language disorders, for diagnosis of neurological conditions, and for foreign language instruction. Current assessment is largely auditory-perceptual, which has obvious drawbacks; however, automation of assessment faces numerous obstacles. We propose methods for automatically assessing production of lexical stress, focus, phrasing, pragmatic style, and vocal affect. Speech was analyzed from children in six tasks designed to elicit specific prosodic contrasts. The methods involve dynamic and global features, using spectral, fundamental frequency, and temporal information. The automatically computed scores were validated against mean scores from judges who, in all but one task, listened to "prosodic minimal pairs" of recordings, each pair containing two utterances from the same child with approximately the same phonemic material but differing on a specific prosodic dimension, such as stress. The judges identified the prosodic categories of the two utterances and rated the strength of their contrast. For almost all tasks, we found that the automated scores correlated with the mean scores approximately as well as the judges' individual scores. Real-time scores assigned during examination -as is fairly typical in speech assessment -correlated substantially less than the automated scores with the mean scores.

We present results obtained with new instrumental methods for the acoustic analysis of prosody to evaluate prosody production by children with Autism Spectrum Disorder (ASD) and Typical Development (TD). Two tasks elicit focal stress, one in a vocal imitation paradigm, the other in a picture-description paradigm; a third task also uses a vocal imitation paradigm, and requires repeating stress patterns of two-syllable nonsense words. The instrumental methods differentiated significantly between the ASD and TD groups in all but the focal stress imitation task. The methods also showed smaller differences in the two vocal imitation tasks than in the picturedescription task, as was predicted. In fact, in the nonsense word stress repetition task, the instrumental methods showed better performance for the ASD group. The methods also revealed that the acoustic features that predict auditory-perceptual judgment are not the same as those that differentiate between groups. Specifically, a key difference between the groups appears to be a difference in the balance between the various prosodic cues, such as pitch, amplitude, and duration, and not necessarily a difference in the strength or clarity with which prosodic contrasts are expressed Verbal communication has two aspects: What is said and how it is said. The latter refers to prosody, defined as the use of acoustic features of speech to complement, highlight, or modify the meaning of what is said. Among the best known of these features are fundamental frequency (F 0 , or, informally, pitch), duration (e.g., Klatt, 1976), and intensity (e.g., Fry, 1955); less known is spectral balance, which is a correlate of, for example, oral aperture and breathiness (e.g., Sluijter, Shattuck-Hufnagel, Stevens, & van Heuven, 1995;Campbell & Beckman, 1997;Sluijter, van Heuven, & Pacilly, 1997; van Santen & Niu, 2003;Miao, Niu, Klabbers, & van Santen, 2006). Exactly which acoustic features are involved in prosody and how they interact is an intrinsically complex issue that still is only partially understood. First, prosodic features tend to be used jointly. For example, the end of a phrase is typically signaled in the final one or two syllables by slowing down, lowering pitch, decreasing intensity, and increasing breathiness. Second, speakers may compensate for making less use of one feature by making more use of another feature ("cue trading";Beach, 1991). Thus, at the end of a phrase some speakers may slow down more than others, but increase breathiness less. Third, while in certain cases (e.g., affective prosody) global features such as average loudness or pitch range are useful descriptors, in other cases (e.g., Address: DR JAN P. H. VAN NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript contrastive stress) subtle details of the dynamic patterns of these features, such as pitch peak timing (e.g., Post, d'Imperio, & Gussenhoven, 2007), are important.Prosody plays a crucial role in an individual's communicative competence and socialemotional reciproci...

No abstract

No abstract

Dimensionality reduction and feature selection is an important aspect of electroencephalography based event related potential detection systems such as brain computer interfaces. In our study, a predefined sequence of letters was presented to subjects in a Rapid Serial Visual Presentation (RSVP) paradigm. EEG data were collected and analyzed offline. A linear discriminant analysis (LDA) classifier was designed as the ERP (Event Related Potential) detector for its simplicity. Different dimensionality reduction and feature selection methods were applied and compared in a greedy wrapper framework. Experimental results showed that PCA with the first 10 principal components for each channel performed best and could be used in both online and offline systems.

No abstract