PubMed Health⌕ Search

Biomedical subjects

N Schiavetti

Publications and source records attributed to N Schiavetti.

At least 19 recordsLinked to original sources
PubMed1998

Effect of fingerspelling task on temporal characteristics and perceived naturalness of speech in simultaneous communication.

This study investigated the effect of fingerspelling task length on temporal characteristics and perceived naturalness of speech produced during simultaneous communication. Stimulus words at four levels of fingerspelling task length were embedded in a sentence that was spoken and produced with simultaneous communication. Five temporal measures were calculated from acoustic recordings, and perceived speech naturalness was rated by a panel of listeners using a 9-point scale. Results indicated significant differences in temporal measures and naturalness ratings between the speech and simultaneous communication conditions and among levels of fingerspelling task length. Speech produced during simultaneous communication was rated as less natural and demonstrated increased interword interval, diphthong, word, and sentence durations. Regression analysis indicated significant correlations between temporal measures and perceived speech naturalness, and analysis of variance showed significant increases in segmental and interword interval durations and perceived speech unnaturalness as fingerspelling task length increased. These results are discussed in relation to previous findings regarding production and perception characteristics of speech that is altered in temporal parameters by a variety of conditions.

Communication↗
PubMed1996

Voice onset time in speech produced during simultaneous communication.

This study investigated speaking rate and voice onset time (VOT) in speech produced during simultaneous communication (SC) by speakers with normal hearing. Stimulus words initiated with voiced and voiceless plosives were embedded in a sentence that was spoken and produced with SC. VOT measures were calculated from acoustic recordings and results indicated significant differences between speech-only and SC conditions, with speech produced during SC demonstrating both slower speaking rate and increased VOT of voiceless consonants. VOTs produced during both SC and speech-only conditions followed English voicing rules and varied appropriately with place of articulation. The somewhat enlarged voicing contrast during SC was consistent with previous findings regarding the influence of rate changes on the temporal fine structure of speech (Miller, 1987) and was similar to the voicing contrast results reported for clear speech by Picheny, Durlach, and Braida (1986).

Communication↗
PubMed1995

Temporal characteristics of speech in simultaneous communication.

The purpose of this investigation was twofold: (a) to determine if there are changes in specific temporal characteristics of speech that occur during simultaneous communication, and (b) to determine if known temporal rules of spoken English are disrupted during simultaneous communication. Ten speakers uttered sentences consisting of a carrier phrase and experimental CVC words under conditions of: (a) speech, (b) speech combined with signed English, and (c) speech combined with signed English for every word except the CVC word that was fingerspelled. The temporal features investigated included: (a) sentence duration, (b) experimental CVC word duration, (c) vowel duration in experimental CVC words, (d) pause duration before and after experimental CVC words, and (e) consonantal effects on vowel duration. Results indicated that for all durational measures, the speech/sign/fingerspelling condition was longest, followed by the speech/sign condition, with the speech condition being shortest: It was also found that for all three speaking conditions, vowels were longer in duration when preceding voiced consonants than vowels preceding their voiceless cognates, and that a low vowel was longer in duration than a high vowel. These findings indicate that speakers consistently reduced their rate of speech when using simultaneous communication, but did not violate these specific temporal rules of English important for consonant and vowel perception.

Humans↗
PubMed1994

Psychophysical analysis of audiovisual judgments of speech naturalness of nonstutterers and stutterers.

The purpose of this study was to determine through psychophysical comparison of scaling data whether speech naturalness judgments of stutterers and nonstutterers from audiovisual recordings form a prothetic or a metathetic continuum. Comparison of direct magnitude estimation and equal-appearing interval scale data indicated that speech naturalness forms a metathetic continuum when observers judge audiovisual recordings, suggesting that either scaling procedure is valid for the quantification of this dimension. Ease of use, an existing body of comparative data from different clinics, and somewhat better reliability favor the interval scaling procedure.

Humans↗
PubMed1992

The use of artificial neural networks to estimate speech intelligibility from acoustic variables: a preliminary analysis.

Previous research has used regression analysis to attempt to predict the intelligibility of hearing-impaired speakers from acoustic speech parameters. Improvement of prediction may be achieved by the use of computerized artificial neural networks to process mathematically the acoustic input variables as part of the intelligibility process. A preliminary scheme for estimating speech intelligibility from acoustic parameters using a neural network is outlined and preliminary data illustrate its use.

Adult↗
PubMed1990

Acoustic and psychophysical dimensions of the perceived speech naturalness of nonstutterers and posttreatment stutterers.

The purpose of this study was twofold: to determine through psychophysical comparison of scaling data whether speech naturalness is a prothetic or a metathetic continuum, and to examine the relationship between selected acoustic characteristics of the speech of nonstutterers and treated stutterers and listeners' judgments of their speech naturalness. Comparison of magnitude estimation and interval scaling data indicated that speech naturalness behaves like a metathetic continuum, suggesting that either scaling procedure is valid for the quantification of this dimension. The speech of the nonstutterers was judged more natural than the speech of the treated stutterers, and a global voice onset time (VOT) measure (averaged across places of articulation) and a sentence duration measure were found to be the acoustic parameters most highly correlated with and predictive of speech naturalness. These results suggest the possibility that stuttering treatments that employ strategies like gentle voicing onset and prolonged speech may result in somewhat slower posttherapy speech patterns characterized by prolonged VOTs that could influence listeners to judge the speech as more unnatural than the speech of nonstutterers.

Adolescent↗
PubMed1990

Acoustic dimensions of hearing-impaired speakers' intelligibility: segmental and suprasegmental characteristics.

Regression and principal components analyses were employed to study the relationship between 28 segmental and suprasegmental acoustic parameters of speech production and measures of speech intelligibility for 40 severely to profoundly hearing-impaired persons in an effort to extend the findings of Metz, Samar, Schiavetti, Sitler, and Whitehead (1985). The principal components analysis derived six factors that accounted for 59% of the variance in the original 28 parameters. Consistent with the findings of Metz et al., a subsequent regression analysis using these six factors as predictor variables revealed two factors with strong predictive relationships to speech intelligibility. One factor primarily reflected segmental production processes related to the temporal and spatial differentiation of phonemes, whereas the other primarily reflected suprasegmental production processes associated with contrastive stress. However, the predictive capability of the present factor structure was somewhat reduced relative to the findings of Metz et al. (1985). Data presented indicate that the populations sampled in the two studies may have differed on one or more dimensions of subject characteristics. Considered collectively, the present findings and the findings of Metz et al. support the tractability of employing selected acoustic variables for the estimation of speech intelligibility.

Adult↗
PubMed1989

Articulatory dimensions of hearing-impaired speakers' intelligibility: evidence from a time-related aerodynamic, acoustic, and electroglottographic study.

Regression and principal components analyses were employed to study the relationship between 30 aerodynamic speech parameters and the speech intelligibility of 40 severely to profoundly hearing-impaired speakers. Regression analysis on the original 30 aerodynamic variables revealed that speech intelligibility was predicted by a cognate-pair voice onset-time difference measure and a measure of the stability of the volume-velocity rise time. Principal components analysis of the 30 independent variables derived seven factors that accounted for 84.3% of the variance in the original 30 parameters. Subsequent regression analysis using the seven factors as predictor variables revealed four factors with independent relationships to speech intelligibility. These included a factor that reflected cognate-pair voice onset-time distinctions, a factor that reflected cognate-pair peak volume-velocity distinctions, and two other factors, which reflected production stability of temporal distinctions between cognate pair members.

Adult↗
PubMed1985

Acoustic dimensions of hearing-impaired speakers' intelligibility.

Regression and principal components analyses were employed to study the relationship between three measures of speech intelligibility and 12 segmental, prosodic, and hearing ability parameters in 20 severely to profoundly hearing-impaired speakers. Regression analyses on the original 12 parameters revealed that cognate pair voice onset time differences and mean sentence duration strongly predicted speech intelligibility based on readings of isolated word and contextual speech material. A principal components analysis derived four factors that accounted for the majority of the variance in the original 12 parameters. Subsequent regression analyses using the four factors as predictor variables revealed two factors with strong relationships to the speech intelligibility measures. One factor primarily reflected segmental production processes related to the temporal and spatial differentiation of phonemes, whereas the other factor reflected prosodic features and production stability. These results are consistent with prior research that suggests independent primary and secondary roles for segmental and prosodic speech characteristics, respectively, in determining intelligibility in severely to profoundly hearing-impaired speakers.

Adult↗
PubMed1984

Prediction of contextual speech intelligibility from isolated word intelligibility measures.

The purpose of this study was to evaluate the efficacy of two nonlinear formulae posited by Boothroyd (1978) for prediction of contextual intelligibility from measures of isolated word intelligibility with four different sets of speech intelligibility data. Both of Boothroyd's formulae, Pc = 1 - (1 - Pi)2 and Pc = 1 - (1 - Pi)1.5 (1 + Pi), provided excellent fit of measured contextual intelligibility with predicted contextual intelligibility for all sets of data. Attempts to improve correlation coefficients between measured and predicted contextual intelligibility by iterating Boothroyd's suggested exponents did not significantly improve the predictive ability of the original formulae.

Deafness↗
PubMed1983

Contextual effects in the measurement of hearing-impaired speakers' intelligibility.

Previous research has indicated that hearing-impaired speakers' intelligibility scores are better when sentences are used than when word lists are used as speech material in word identification tests. The speech intelligibility of 20 hearing-impaired speakers was measured with word identification tests using isolated words (W-22 monosyllables) and words in sentence context (CID sentences). Analysis of individual speakers' intelligibility data revealed that sentence intelligibility scores were higher than word intelligibility scores only for the better speakers and that no differences were apparent between sentence and single-word intelligibility for the poorer speakers. These findings agree with the results of research with normal speech degraded in intelligibility by noise or filtering and indicate that an interaction may exist between context and overall intelligibility in which only speech that has a certain degree of overall intelligibility may show further intelligibility improvement with increased contextual clues.

Adult↗
PubMed1983

Direct magnitude estimation and interval scaling of stuttering severity.

The appropriateness of direct magnitude estimation and interval scaling for assessing stuttering severity was investigated by determining whether the continuum of the stutterers' judged severity was prothetic or metathetic. As operationally defined by Stevens, prothetic continua show a curvilinear relation between magnitude estimates and interval scale values of the same set of stimuli, whereas metathetic continua show a linear relation between these scale values. The stuttering severity of 20 stutterers was scaled by three groups of 15 listeners who used interval scaling, direct magnitude estimation with standard/modulus, and direct magnitude estimation without standard/modulus. The results indicated that the two sets of direct magnitude estimation scale values were related to the interval scale values in the curvilinear fashion that is typical of prothetic continua. These findings suggest that direct magnitude estimation is preferable to interval scaling for measuring stuttering severity.

Adult↗
PubMed1981

Construct validity of direct magnitude estimation and interval scaling of speech intelligibility: evidence from a study of the hearing impaired.

The appropriateness of direct magnitude estimation and interval scaling procedures for assessing the speech intelligibility of hearing-impaired adults was investigated by determining whether the continuum of the talkers' intelligibility was prothetic or metathetic. The intelligibility of 20 hearing-impaired talkers was scaled by 20 listeners using direct magnitude estimation and by 20 listeners using interval scaling. The two sets of scaling data were related in the curvilinear fashion that is typical of prothetic continua, indicating better construct validity for direct magnitude estimation than for interval scaling of speech intelligibility.

Analysis of Variance↗
PubMed1975

Morphological inflections of children with normal and impaired articulation.

Twenty articulation-impaired Kindergarten children and 20 peers with normal articulation were compared on their use of morphological rules with the nonsense material of the Berry-Talbott Test. The results indicated that there were no significant differences between the two groups, although about one quarter of the articulation-impaired subjects did not perform as well as the normal articulation subjects on the overall task.

Articulation Disorders↗