[Evaluation of the results of treatment of patients with functional dysphonia using a cepstral test]. / Otsenka rezul'tatov lecheniya patsientov s funktsional'noi disfoniei s pomoshch'yu kepstral'nogo testa.

In order to evaluate the effectiveness of the treatment in patients with functional dysphonia, the Cepstral Peak Prominence (CPP) test was used. Twenty dysphonic women aged from 18 to 47 years were under observation. The control group consisted of 20 healthy women of close age. Patients underwent 5-7 sessions electrostimulation of laryngeal muscles and phonopedic treatment, after which a complete restoration of the voice was noted. The Praat clinical program was used, installed on a Hewlett-Packard 630 laptop (Pentium B960, 2.2 GHz). A SHURE SM94 condenser microphone was used as well. In the control group, the results were as follows: M=7.49 (SD=1.26) dB. In the main group before treatment: M=5.00 (SD=1.07) dB, after treatment: M=7.95 (SD=1.34) dB. Differences in KT values in the main group before and after treatment (5.00 dB and 7.95 dB, respectively) were significant at p<0.0001. Differences in KT values in the main group before treatment (5.00 dB) and in the control group (7.49 dB) were significant at p<0.0001. Differences in KT values in the main group after treatment (7.95 dB) and in the control group (7.49 dB) were not significant at p>0.05. The study showed high sensitivity of the method. The CPP data after treatment were higher than those before treatment and did not differ from the control ones. It is concluded that CPP is a highly sensitive method for evaluating the degree of periodicity of an acoustic signal and can be used to evaluate the effectiveness of treatment in patients with functional dysphonia.

Computer-based auditory training improves second-language vowel production in spontaneous speech.

The current study examined the effectiveness of computer-based auditory training on Greek speakers' production of English vowels in read sentences and in spontaneous speech. Another group of Greek speakers served as controls. Improvement was evaluated pre- and post-training via an identification task performed by English listeners and by an acoustic analysis of vowel quality using a combined F1/F2 measure. Auditory training improved English vowel production in read sentences and in spontaneous speech for the trained group, with improvement being larger in read sentences. The results indicate that auditory training can have ecological validity since it enhances learners' production beyond the (read) sentence level.

Incongruent pitch cues are associated with increased activation and functional connectivity in the frontal areas.

Pitch plays a crucial role in music and speech perception. Pitch perception is characterized by multiple perceptual dimensions, such as pitch height and chroma. Information provided by auditory signals that are related to these perceptual dimensions can be either congruent or incongruent. To create conflicting cues for pitch perception, we modified Shepard tones by varying the pitch height and pitch chroma dimensions in either the same or opposite directions. Our behavioral data showed that most listeners judged pitch changes based on pitch chroma, instead of pitch height, when incongruent information was provided. The reliance on pitch chroma resulted in a stable percept of upward or downward pitch shift, rather than alternating between two different percepts. Across the incongruent and congruent conditions, consistent activation was found in the bilateral superior temporal and inferior frontal areas. In addition, significantly stronger activation was observed in the inferior frontal areas during the incongruent compared to congruent conditions. Enhanced functional connectivity was found between the left temporal and bilateral frontal areas in the incongruent than congruent conditions. Increased intra-hemispheric and inter-hemispheric connectivity was also observed in the frontal areas. Our results suggest the involvement of the frontal lobe in top-down and bottom-up processes to generate a stable percept of pitch change with conflicting perceptual cues.

Compensations to auditory feedback perturbations in congenitally blind and sighted speakers: Acoustic and articulatory data.

This study investigated the effects of visual deprivation on the relationship between speech perception and production by examining compensatory responses to real-time perturbations in auditory feedback. Specifically, acoustic and articulatory data were recorded while sighted and congenitally blind French speakers produced several repetitions of the vowel /ø/. At the acoustic level, blind speakers produced larger compensatory responses to altered vowels than their sighted peers. At the articulatory level, blind speakers also produced larger displacements of the upper lip, the tongue tip, and the tongue dorsum in compensatory responses. These findings suggest that blind speakers tolerate less discrepancy between actual and expected auditory feedback than sighted speakers. The study also suggests that sighted speakers have acquired more constrained somatosensory goals through the influence of visual cues perceived in face-to-face conversation, leading them to tolerate less discrepancy between expected and altered articulatory positions compared to blind speakers and thus resulting in smaller observed compensatory responses.

Speech production and sensory impairment in mild Parkinson's disease.

Little is known about speech-related sensory systems and the link to speech in Parkinson's disease (PD). This study investigates auditory and somatosensory acuity and their association to speech in PD, using /s/ and /ʃ/ as speech targets. Ten adults with mild PD and ten age- and gender-matched healthy participants performed three tasks. In the auditory task, participants discriminated three aperiodic sounds acoustically modified from /s/ and /ʃ/ and differing in spectral shapes. In the tactile task, they judged the orientation of a dome-shaped grating probe gently touching their tongue tip. Measures of auditory and tactile acuity were determined based on participants' responses. For the production task, participants read a passage and eight sentences with /s/- and /ʃ/-initial words; acoustic contrast between the two sibilants was measured using difference between the average first spectral moments of /s/ and /ʃ/. The PD participants showed reduced auditory acuity of spectral sibilant contrast and reduced tactile acuity of the tongue tip. For speech production, the PD group showed smaller sibilant contrast in the sentence readings, but the difference was not statistically significant. Correlation analyses showed significant correlations between tactile acuity and sibilant contrast for the PD group, but not for auditory task.

Real-Time Control of an Articulatory-Based Speech Synthesizer for Brain Computer Interfaces.

Restoring natural speech in paralyzed and aphasic people could be achieved using a Brain-Computer Interface (BCI) controlling a speech synthesizer in real-time. To reach this goal, a prerequisite is to develop a speech synthesizer producing intelligible speech in real-time with a reasonable number of control parameters. We present here an articulatory-based speech synthesizer that can be controlled in real-time for future BCI applications. This synthesizer converts movements of the main speech articulators (tongue, jaw, velum, and lips) into intelligible speech. The articulatory-to-acoustic mapping is performed using a deep neural network (DNN) trained on electromagnetic articulography (EMA) data recorded on a reference speaker synchronously with the produced speech signal. This DNN is then used in both offline and online modes to map the position of sensors glued on different speech articulators into acoustic parameters that are further converted into an audio signal using a vocoder. In offline mode, highly intelligible speech could be obtained as assessed by perceptual evaluation performed by 12 listeners. Then, to anticipate future BCI applications, we further assessed the real-time control of the synthesizer by both the reference speaker and new speakers, in a closed-loop paradigm using EMA data recorded in real time. A short calibration period was used to compensate for differences in sensor positions and articulatory differences between new speakers and the reference speaker. We found that real-time synthesis of vowels and consonants was possible with good intelligibility. In conclusion, these results open to future speech BCI applications using such articulatory-based speech synthesizer.

Pitch perception and production in congenital amusia: Evidence from Cantonese speakers.

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.

Phonological awareness and sinusoidal amplitude modulation in phonological dislexia.

OBJECTIVE: Dyslexia is the difficulty of children in learning to read and write as results of neurological deficiencies. The objective was to test the Phonological awareness (PA) and Sinusoidal amplitude modulation (SAM) threshold in children with Phonological dyslexia (PD). METHODS: We performed a case-control, analytic, cross sectional study. We studied 14 children with PD and 14 control children from 7 to 11 years of age, by means of PA measurement and by SAM test. The mean age of dyslexic children was 8.39 years and in the control group was 8.15. RESULTS: Children with PD exhibited inadequate skills in PA, and SAM. We found significant correlations between PA and SAM at 4 Hertz frequency, and calculated regression equations that predicts between one-fourth and one-third of variance of measurements. CONCLUSION: Alterations in PA and SAM found can help to explain basis of deficient language processing exhibited by children with PD.

Phonological awareness and sinusoidal amplitude modulation in phonological dislexia / Conciencia fonológica y la modulación sinusoidal de la amplitud en la dislexia fonológica

ABSTRACT Objective Dyslexia is the difficulty of children in learning to read and write as results of neurological deficiencies. The objective was to test the Phonological awareness (PA) and Sinusoidal amplitude modulation (SAM) threshold in children with Phonological dyslexia (PD). Methods We performed a case-control, analytic, cross sectional study. We studied 14 children with PD and 14 control children from 7 to 11 years of age, by means of PA measurement and by SAM test. The mean age of dyslexic children was 8.39 years and in the control group was 8.15. Results Children with PD exhibited inadequate skills in PA, and SAM. We found significant correlations between PA and SAM at 4 Hertz frequency, and calculated regression equations that predicts between one-fourth and one-third of variance of measurements. Conclusion Alterations in PA and SAM found can help to explain basis of deficient language processing exhibited by children with PD.

RESUMEN Objetivo La Dislexia es la dificultad en niños de aprender a leer y escribir como resultado de una deficiencia neurológica. Nuestro objetivo fue probar la Conciencia fonológica (CF) y la Modulación sinusoidal de la amplitud (MSA) en niños con Dislexia fonológica (DF). Métodos Realizamos un estudio analítico, transversal, de casos y controles. Estudiamos la CF y la MSA en 14 niños con DF y 14 controles de 7–11 años. La edad media de los niños con DF fue de 8.39 años y de los controles fue 8.15. Resultados Los niños con DF presentaron deficiencias en CF y en MSA. Encontramos correlaciones entre CF y MSA en la frecuencia de 4 Hertzios (Hz), calculamos ecuaciones de regresión que predijeron de un cuarto a un tercio de la varianza de las mediciones. Conclusión Las deficiencias en CF y en MSA pueden ayudar a comprender las alteraciones en el procesamiento del lenguaje presentadas por los niños con DF.

Modeling of Breathy Voice Quality Using Pitch-strength Estimates.

BACKGROUND: The characteristic voice quality of a speaker conveys important linguistic, paralinguistic, and vocal health-related information. Pitch strength refers to the salience of pitch sensation in a sound and was recently reported to be strongly correlated with the magnitude of perceived breathiness based on a small number of voice stimuli. OBJECTIVE: The current study examined the relationship between perceptual judgments of breathiness and computational estimates of pitch strength based on the Aud-SWIPE (P-NP) algorithm for a large number of voice stimuli (330 synthetic and 57 natural). METHODS AND RESULTS: Similar to the earlier study, the current results confirm a strong relationship between estimated pitch strength and listener judgments of breathiness such that low pitch-strength values are associated with voices that have high perceived breathiness. Based on this result, a model was developed for the perception of breathy voice quality using a pitch-strength estimator. Regression functions derived between the pitch-strength estimates and perceptual judgments of breathiness obtained from matching task revealed a linear relationship for a subset of the natural stimuli. We then used this function to obtain predicted breathiness values for the synthetic and the remaining natural stimuli. CONCLUSIONS: Predicted breathiness values from our model were highly correlated with the perceptual data for both types of stimuli. Systematic differences between the breathiness of natural and synthetic stimuli are discussed.

Motor-Learning-Based Adjustment of Ambulatory Feedback on Vocal Loudness for Patients With Parkinson's Disease.

OBJECTIVES: To investigate how the direct biofeedback on vocal loudness administered with a portable voice accumulator (VoxLog) should be configured, to facilitate an optimal learning outcome for individuals with Parkinson's disease (PD), on the basis of principles of motor learning. STUDY DESIGN: Methodologic development in an experimental study. METHODS: The portable voice accumulator VoxLog was worn by 20 participants with PD during habitual speech during semistructured conversations. Six different biofeedback configurations were used, in random order, to study which configuration resulted in a feedback frequency closest to 20% as recommended on the basis of previous studies. RESULTS: Activation of feedback when the wearer speaks below a threshold level of 3 dB below the speaker's mean voice sound level in habitual speech combined with an activation time of 500 ms resulted in a mean feedback frequency of 21.2%. CONCLUSIONS: Settings regarding threshold and activation time based on the results from this study are recommended to achieve an optimal learning outcome when administering biofeedback on vocal loudness for individuals with PD using portable voice accumulators.

Comparison of Two Perceptual Methods for the Evaluation of Vowel Perturbation Produced by Jitter.

OBJECTIVES: To explore perceptual evaluation of jitter produced by fundamental frequency (F0) variation in a sustained vowel /a/, using two different methods. One is based on listener's internal references and the other is based on external references provided by the experimenter. METHODS: We used two methods: one is magnitude estimation-converging limits (ME-CL), which is close to the standard approach used by speech therapists when they use numerical estimations and their own standards, and other is intramodal matching procedure (IMP), where each matched stimulus is to be compared with a fixed-set matching stimuli. Systematic variations were introduced in vowel /a/ by Linear Prediction Coding synthesis using an F0 contour function obtained from a statistical jitter model. Six jitter values were used for each of two reference F0 values. Three groups of listeners were tested: expert speech therapists, speech therapy students, and naïve listeners. RESULTS: Perceptual functions appear to be similar and linear for both methods as the theory predicts. The answers of all groups of listeners tested with ME-CL present higher standard deviations than for IMP. When subjects were tested with IMP, intrareliability and interreliability measurements show a significant improvement for both expert and naïve listeners. CONCLUSIONS: Both intraindividual and interindividual differences for expert speech therapists could be better managed when tested with an IMP than when they use numerical estimations and internal standards to evaluate vowel perturbation produced by jitter. This procedure could be the basis for the development of a clinical evaluation tool.

Irregular Speech Rate Dissociates Auditory Cortical Entrainment, Evoked Responses, and Frontal Alpha.

The entrainment of slow rhythmic auditory cortical activity to the temporal regularities in speech is considered to be a central mechanism underlying auditory perception. Previous work has shown that entrainment is reduced when the quality of the acoustic input is degraded, but has also linked rhythmic activity at similar time scales to the encoding of temporal expectations. To understand these bottom-up and top-down contributions to rhythmic entrainment, we manipulated the temporal predictive structure of speech by parametrically altering the distribution of pauses between syllables or words, thereby rendering the local speech rate irregular while preserving intelligibility and the envelope fluctuations of the acoustic signal. Recording EEG activity in human participants, we found that this manipulation did not alter neural processes reflecting the encoding of individual sound transients, such as evoked potentials. However, the manipulation significantly reduced the fidelity of auditory delta (but not theta) band entrainment to the speech envelope. It also reduced left frontal alpha power and this alpha reduction was predictive of the reduced delta entrainment across participants. Our results show that rhythmic auditory entrainment in delta and theta bands reflect functionally distinct processes. Furthermore, they reveal that delta entrainment is under top-down control and likely reflects prefrontal processes that are sensitive to acoustical regularities rather than the bottom-up encoding of acoustic features. SIGNIFICANCE STATEMENT: The entrainment of rhythmic auditory cortical activity to the speech envelope is considered to be critical for hearing. Previous work has proposed divergent views in which entrainment reflects either early evoked responses related to sound encoding or high-level processes related to expectation or cognitive selection. Using a manipulation of speech rate, we dissociated auditory entrainment at different time scales. Specifically, our results suggest that delta entrainment is controlled by frontal alpha mechanisms and thus support the notion that rhythmic auditory cortical entrainment is shaped by top-down mechanisms.

Training production of lexical stress in typically developing children using orthographically biased stimuli and principles of motor learning.

PURPOSE: Impaired lexical stress production characterizes multiple pediatric speech disorders. Effective remediation strategies are not available, and little is known about the normal process of learning to assign and produce lexical stress. This study examined whether typically developing (TD) children can be trained to produce lexical stress on bisyllabic pseudowords that are orthographically biased to a strong-weak or weak-strong pattern (e.g., MAMbey or beDOON), in combination with the principles of motor learning (PML). METHOD: Fourteen TD children ages 5;0 (years;months) to 13;0 were randomly assigned to a training or control group using concealed allocation within blocks. A pre- to posttraining group design was used to examine the acquisition, retention, and generalization of lexical stress production. RESULTS: The training group learned to produce appropriate lexical stress for the pseudowords with strong maintenance and generalization to related untrained stimuli. Accuracy of stress production did not change in the control group. CONCLUSION: TD children can learn to produce lexical stress patterns for orthographically biased pseudowords via explicit training methods. Findings have relevance for the study of languages other than English and for a range of prosodic disorders.

Effect of priming on energetic and informational masking in a same-different task.

OBJECTIVES: The primary goal of this study was to investigate how speech perception is altered by the provision of a preview or "prime" of a sample of speech just before it is presented in masking. A same-different test paradigm was developed which enabled the effect of priming to be measured with energetic maskers in addition to those that most likely produced both energetic and informational masking. Using this paradigm, the benefit of priming in overcoming energetic and informational masking was compared. DESIGN: Twenty-four normal-hearing subjects listened to nonsense sentences presented in a background of competing speech (two-talker babble) or one of two types of speech-shaped noise. Both target and masker were presented via loudspeaker directly in front of the listeners. In the baseline condition, the listeners were then shown a sentence on a computer screen that either matched the auditory target sentence exactly or contained a replacement for one of the three target key words. Their task was to judge whether the printed sentence matched the auditory target and respond via computer keyboard. In the first experimental condition, the printed sentence preceded rather than followed the auditory presentation (the priming condition). In the second experimental condition, the perception of spatial separation was created between target and masker by presenting the masker from two loudspeakers (front and 60° to the right) and imposing a 4-msec delay in the masker coming from the front loudspeaker. This resulted in the target being heard from the front while, because of the precedence effect, the masker was heard well to the right (the spatial condition). In a third experimental condition, spatial separation and priming were combined. A total of five signal-to-noise ratios were tested for each masker. RESULTS: The competing speech masker produced more masking than noise, consistent with previous findings. For the competing speech masker, the signal-to-noise ratio for 80% correct performance was approximately 6.7 dB lower when the listeners read the sentences first (the priming condition) than in the baseline condition. This priming effect was similar to the improvement obtained when the target and masker were separated spatially. Significant priming effects were also observed with speech-shaped noise maskers, and when there was perceived spatial separation between target and masker, conditions in which informational masking was believed to have been minimal. There seemed to be an additive effect of spatial separation and priming in the two-talker babble condition. CONCLUSIONS: (1) Priming was effective in improving speech perception in all conditions, including those consisting of primarily energetic masking. (2) It is not clear how much benefit from priming could be attributed to release from informational masking. (3) Performance on the same-different task was linearly related to performance on an open-set speech recognition task using the same target and masker.

Transtorno do processamento auditivo (central) em indivíduos com e sem dislexia / (Central) auditory processing disorders in individuals with and without dyslexia

TEMA: comparação do transtorno do processamento auditivo (central) em indivíduos com e sem dislexia. OBJETIVO: comparar o transtorno do processamento auditivo (central) em crianças brasileiras com e sem dislexia, por meio dos testes fala com ruído, dicótico de dígitos e padrão de freqüência. MÉTODO: foram avaliadas 40 crianças de 7:0 a 12:11 anos, sendo 20 pertencentes ao grupo com dislexia e 20 pertencentes ao grupo TPA(C). Os testes aplicados envolveram habilidades de fechamento auditivo, figura-fundo para sons lingüísticos e ordenação temporal. RESULTADOS: os indivíduos do grupo TPA (C) apresentaram maior probabilidade de alteração nos testes de fala com ruído e dicótico de dígitos do que os pertencentes ao grupo dislexia. CONCLUSÃO: os sujeitos do grupo dislexia apresentam padrões diferentes de transtorno de processamento auditivo (central), com alteração maior em testes que avaliam o processamento temporal do que em testes que avaliam outras habilidades auditivas.

BACKGROUND: comparison of (central) auditory processing disorders in children with and without dyslexia. AIM: to compare the (central) auditory processing disorders in Brazilian children with and without dyslexia using speech in noise, dichotic digits and pattern of frequency tests. METHOD: forty-five children with ages ranging between 7:0 and 12:11 years were assessed; twenty children composed the dyslexic group and twenty composed the (Central) auditory processing disorder group. The tests used involved closing aural, auditory figure-ground and temporal ordering abilities. RESULTS: individuals of the (Central) auditory processing disorder group presented a higher alteration probability in the speech in noise and dichotic digits tests than those from the dyslexic group. CONCLUSION: subjects from the dyslexic group presented different patterns of (central) auditory processing disorder, with greater alteration in the tests that evaluate the temporal processing when compared to the tests that evaluate other auditory abilities.

Intelligibility: effects of transcription analysis and speech stimulus.

BACKGROUND: intelligibility measures are limited to providing information on the severity level of clinical cases. A key limitation is that such measures are sensitive to changes in performance only in subjects with a determined severity level of speech disturbance. AIM: to investigate the influence of stimuli type and transcription analysis on intelligibility measures of speakers with no communication disorders. METHOD: an experimental study with no intervention procedures was developed. Two groups of subjects with no communication disorders took part in the research. The group of speakers was composed by 30 adults. Speech samples were recorded by repeating three lists of stimuli (sentences, words and non-words) equally distributed according to parameters of frequency of phonemes, syllabic structures and word length. The group of listeners was composed by 60 young adults who orthographically transcribed the speech samples. Two transcription intelligibility measures were obtained for each list of stimuli: percentage of correct answers per syllable unit and per item (for each sentence, word and non-word). RESULTS: intelligibility scores were statistically higher for syllable units than for the other items. Regarding intelligibility scores per syllables, a statistical difference was observed amongst scores for sentences, words and non-words. CONCLUSION: both transcription analysis and stimulus type influenced the intelligibility scores of the studied population, especially when non-words were used as speech material. The handling of these variables can help to improve intelligibility tests.

Does word length affect speech onset latencies when producing single words?

Most models of spoken production predict that shorter utterances should be initiated faster than longer ones. However, whether word-length effects in single word production exist is at present controversial. A series of experiments did not find evidence for such an effect. First, an experimental manipulation of word length in picture naming showed no latency differences. Second, Dutch and English speakers named 2 sets of either objects or words (monosyllabic names in Dutch and disyllabic names in English or vice versa). A length effect, which should manifest itself as an interaction between object set and response language, emerged in word naming but not in picture naming. Third, distractors consisting of the final syllable of disyllabic object names speeded up responses, but at the same time, no word-length effect was found. These results suggest that before the response is initiated, an entire word has been phonologically encoded, but only its initial syllable is placed in an articulatory buffer.

Inteligibilidade: efeitos da análise de transcrição e do estímulo de fala / Intelligibility: effects of transcription analysis and speech stimulus

BACKGROUND: intelligibility measures are limited to providing information on the severity level of clinical cases. A key limitation is that such measures are sensitive to changes in performance only in subjects with a determined severity level of speech disturbance. AIM: to investigate the influence of stimuli type and transcription analysis on intelligibility measures of speakers with no communication disorders. METHOD: an experimental study with no intervention procedures was developed. Two groups of subjects with no communication disorders took part in the research. The group of speakers was composed by 30 adults. Speech samples were recorded by repeating three lists of stimuli (sentences, words and non-words) equally distributed according to parameters of frequency of phonemes, syllabic structures and word length. The group of listeners was composed by 60 young adults who orthographically transcribed the speech samples. Two transcription intelligibility measures were obtained for each list of stimuli: percentage of correct answers per syllable unit and per item (for each sentence, word and non-word). RESULTS: intelligibility scores were statistically higher for syllable units than for the other items. Regarding intelligibility scores per syllables, a statistical difference was observed amongst scores for sentences, words and non-words. CONCLUSION: both transcription analysis and stimulus type influenced the intelligibility scores of the studied population, especially when non-words were used as speech material. The handling of these variables can help to improve intelligibility tests.

TEMA: apesar de seu amplo emprego com fins clínicos e de pesquisa, as medidas de inteligibilidade da fala por transcrição são criticadas por fornecer apenas informações sobre o grau de severidade dos quadros, bem como por ter sensibilidade restrita, dependendo do grau de alteração do paciente. OBJETIVO: investigar a influência da análise de transcrição e do tipo de estímulo sobre as medidas de inteligibilidade de sujeitos sem distúrbios da comunicação. MÉTODO: um estudo experimental sem intervenção foi realizado. Dois grupos de sujeitos sem distúrbios da comunicação participaram desta pesquisa. O grupo de falantes foi composto por 30 adultos. Amostras de fala foram gravadas em áudio a partir da repetição de três listas de estímulos (frases, palavras e pseudopalavras) igualmente distribuídas de acordo com os parâmetros: frequência dos fonemas, estruturas silábicas e extensão das palavras. O grupo ouvinte foi formado por 60 adultos jovens que transcreveram ortograficamente as amostras. Duas medidas de inteligibilidade foram obtidas para cada lista de estímulos: percentagem de respostas corretas por unidade silábica e por item (cada frase, palavra ou pseudopalavra). RESULTADOS: os escores de inteligibilidade por unidade silábica foram estatisticamente superiores aos escores de inteligibilidade por item. Diferenças também foram observadas entre os escores de inteligibilidade por sílabas para frases, palavras e pseudopalavras. CONCLUSÃO: tanto a análise de transcrição quanto o tipo de estímulo influenciaram os escores da população estudada, especialmente quando as pseudopalavras foram utilizadas como material de fala. A manipulação destas variáveis pode seu útil ao aprimoramento dos testes de inteligibilidade da fala.

Activation and application of an obligatory phonotactic constraint in German during automatic speech processing is revealed by human event-related potentials.

In auditory speech processing, implicit linguistic knowledge is activated and applied on phonetic and segment-related phonological processing level even if the perceived sound sequence is outside the focus of attention. In this study, the effects of language-specific phonotactic restrictions on pre-attentive auditory speech processing were investigated, using the Mismatch Negativity component of the human event-related brain potential. In German grammar, the distribution of the velar and the palatal dorsal fricative is limited by an obligatory phonotactic constraint, Dorsal Fricative Assimilation, which demands that a vowel and a following dorsal fricative must have the same specifications for articulatory backness. For passive oddball stimulation, we used three phonotactically correct VC syllables and one incorrect VC syllable, composed of the vowels [epsilon] and [open o] and the fricatives [ç] and []. Stimuli were contrasted pairwise in experimental oddball blocks in a way that they differed in regard to their respective vowel but shared the fricative. Additionally to the usual Mismatch Negativity which is attributable to the change of the initial vowel and which was elicited by all deviants, we observed a second negative deflection in the deviant ERP elicited by the phonotactically ill-formed syllable only. This negativity cannot be attributed to any acoustical or phonemic difference between standard and deviant, it rather reflects the effect of a phonotactic evaluation process after both sounds of the syllable were identified. Our finding suggests that implicit phonotactic knowledge is activated and applied even outside the focus of the participants' attention.