Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 116-117. / by Francine Robina Chen. / M.S.

The motivation of this study was to examine the effects of intensive speech treatment on the conversational intelligibility of Spanish speakers with Parkinson’s Disease (PD). It also aimed at investigating several acoustic variables in the speech of this population. Sixteen speakers with a medical diagnosis of PD participated in this study and their voice recordings were analyzed pre- and post-treatment. The intelligibility measures of transcription accuracy and median ease-of-understanding ratings increased significantly immediately post-treatment and gains were maintained at the one-month follow-up. The acoustic variables of vowel space and voice onset time did not change significantly pre-to-post treatment, whilst the prosodic targets of intensity and mean fundamental frequency increased significantly as a result of treatment. These findings support the implementation of intensive voice intervention to improve intelligibility in Spanish dysarthria. Clinical and theoretical considerations are discussed.

O aspecto temporal da fala é um dos fatores que interferem na inteligibilidade de fala, assim, o presente estudo teve como objetivo estudar a percepção das vogais do português brasileiro (PB) em diferentes taxas de elocução por meio de análise acústica e metodologia psicofísica. Na análise acústica foi averiguado a duração das frases contendo as vogais alvo e, posteriormente, apenas as vogais. No experimento I - a ANOVA mostrou que existe diferença significativa apenas entre a duração das frases nas duas taxas de elocução normal e rápida, enquanto na análise da duração das vogais há diferença estatística entre as taxas de elocução e também entre as vogais. No experimento II- o resultado da ANOVA mostrou que as frases são estatisticamente diferentes em relação a taxa de elocução, normal e mais rápida, mas não difere quanto as diferentes vogais alvo das frases, entretanto, o resultado das vogais na taxa de elocução mais rápida mostrou que há diferença entre as mesmas. A análise dos três conjuntos de vogais dos dois experimentos anteriores, mostrou que há diferença estatisticamente significativa nas taxas de elocução e também nas 7 vogais do PB. O julgamento psicofísico da fala comprimida foi realizado por meio de 28 frases aleatorizadas quanto as 7 vogais do PB, duas taxas de locução (normal e rápida) e duas apresentações para fidedignidade do teste. A amostra foi composta de 32 sujeitos, distribuídos em dois experimentos. No experimento I (n=16) os sujeitos não perceberam qualquer dificuldade na inteligibilidade de fala. No segundo experimento (n=16) a taxa de elocução das frases rápidas foi modificada em torno de 30% da taxa normal. O resultado mostrou que os sujeitos perceberam diminuição na inteligibilidade de fala devido a taxa de elocução, entretanto não encontraram qualquer dificuldades devido as vogais. Os resultados sugerem a taxa de elocução interfere na inteligibilidade de fala. / The temporal aspect of speech is one of the factors that affect the intelligibility of speech. Thus, the aim of the present study was to investigate the perception of Brazilian Portuguese (BP) vowels in different speech rates through acoustic analysis and psychophysical tests. In the acoustic analysis, we investigated the sentences duration containing target vowels and, subsequently, only the vowels. In Experiment I, there was a significant difference between the duration of sentences in both speech rates (normal and fast), and in the duration of the vowels there was a significant difference between the speech rates and between the vowels. In Experiments II, the results showed differences between the sentences concerning the speed rate, normal and 'faster', but not between the target vowels in the sentences. However, in the 'faster' speech rate showed difference between the vowels. The analyses of the 3 sets of vowels in both experiments revealed a significant difference in speed rates as well as in the 7 vowels of the BP. The psychophysical judgment of compressed speech was done using 28 randomized sentences with 7 BP vowels, 2 speed rates (normal and fast) and 2 repetitions (test and retest) to evaluate the test reliability. The sample was composed by 32 subjects distributed in 2 experiments. In Experiment 1 (n=16) the subjects did not have difficulty in the speech intelligibility In Experiment II (n=16) the speed rate of 'faster' sentences was increased in 30% in relation to the normal rate. The results showed that the subjects noticed that there was a decrease in the speech intelligibility due to the speed; however, they did not find difficulties due to the vowels. Taken together, our results suggest that the speech rate interferes in the speech intelligibility.

O objetivo principal deste estudo foi avaliar a influência da adaptação da prótese rebaixadora de palato na inteligibilidade e na ressonância de fala, e nas características acústicas espectrográficas dos três primeiros formantes das vogais orais do português brasileiro de pacientes submetidos à glossectomia. Participaram 36 pacientes, 33 do sexo masculino e 3 do sexo feminino, com idades entre 30 e 80 anos (Média=53,91±10,53 anos), sendo 14 submetidos à glossectomia total, 12 à glossectomia total e mandibulectomia parcial, 6 à hemiglossectomia e, 4 à glossectomia subtotal. Amostras de fala (conversa espontânea e repetição de 18 sílabas) de pacientes com e sem prótese foram randomizadas e a ressonância e inteligibilidade de fala foram julgadas por 2 fonoaudiólogos. Também foi realizada a análise espectrográfica dos formantes das 7 vogais do português brasileiro com e sem prótese, extraindo-se as médias dos três primeiros formantes. Houve melhora significante na inteligibilidade de fala e de sílabas após adaptação da prótese rebaixadora de palato (p < 0,001). Não houve diferença estatística nos julgamentos da ressonância com e sem prótese. Existiu diferença significante na situação com e sem prótese para o primeiro formante nas vogais /a/, /e/, /u/ (p < 0,001) e tendência estatística na vogal /o/ (p = 0,09); para segundo formante nas vogais /o/, / /, /u/ (p < 0,001), e tendência estatística nas vogais /e/ (p = 0,058) e /i/ (p = 0,080) e para o terceiro formante nas vogais /a/ e / / (p < 0,001). A prótese rebaixadora de palato melhorou a inteligibilidade da fala espontânea e das sílabas dos pacientes glossectomizados. Também aumentou os valores de F2 e F3 para todas as vogais e, de F1 para as vogais /o/, / /, /u/. Isto gerou uma aproximação dos valores dos formantes da maioria das vogais junto aos valores de normalidade. / The main objective of this study was to assess the influence of the palatal augmentation prostheses on speech intelligibility, ressonance and acoustic spectrographic characteristics of the first three formants of oral vowels in Brazilian Portuguese, in patients submitted to glossectomy. Thirty-six (33 men and 3 women), aged 30 to 80 years (mean = 53.9 ±10.5 years) underwent glossectomy (14 = total glossectomy; 12 = total glossectomy associated partial mandibulectomy; 6=hemiglossectomy, and 4 = subtotal glossectomy) constituted the study sample. Speech samples (spontaneous conversation and repetition of 18 syllables) from the patients with and without prosthesis were randomly distributed and the resonance and speech intelligibility were judged by 2 speech language pathologist. A spectrographic assessment of formants of the 7 vowels of Brazilian Portuguese, with and without prosthesis, was performed. The mean values of the first three formants were extracted. There was a statistically significant improvement of the spontaneous speech intelligibility and of the average number of correctly identified syllables with the use of the prosthesis (p<0.05). The speech resonance results have not demonstrated a significant reduction in hypernasality with the palatal augmentation prostheses in place. Statistically significant differences occurred in F1 values for the vowels /a/, /e/, /u/, for F2, there was a significant difference in the vowels /o/, / /, /u/; and for F3, there was a significant difference in the vowels /a/, / / (p < 0.001). Palatal augmentation prosthesis improved intelligibility of spontaneous speech and syllables in glossectomized patients. It also increased F2 and F3 values for all vowels and F1 values for the vowels /o/, / /, /u/. This effect has brought the values of many vowel formants closer to normality.

Accounting as a tool for communicating relevant information to multiple users must overcome issues and barriers of presenting such information. One of the issues is its understandability, once lack of understanding can impact decisions. However, understandability is not easily measured. Previous studies use readability metrics as proxies for understandability. They understand that these concepts are related to some extent, but while readability focuses on the text, understandability includes the reader characteristics. Thus, the main purpose of this research was to verify how readability impacts the understandability of the information from the notes to the financial statements. I also verified whether the distance between them was due to reporting language. The specific goals were: (i) to verify whether different readability levels have impact on the notes to the financial statements\' understandability; (ii) to verify whether the understandability levels are due to accounting specific terms; (iii) to verify if those notes\' understandability and readability are different for different languages; and (iv) to verify if the levels of readability and understandability changed after OCPC 07. I performed two different types of research methods, archival and experimental research. The archival research applied mean tests to 44 firms that presented their notes both in Portuguese and in English from 2012 to 2015. I studied the notes of Financial Instruments and Provisions. I used indexes of intelligibility as proxies to understandability, calculated by a linguistic software. I found that, for most indexes where firms had worse levels of readability, they showed better levels of intelligibility, which goes against the expected. My results also show that with few exceptions, the readability and intelligibility indexes are different for Portuguese and English. Moreover, I found that there was no change after the adoption of OCPC 07 on both readability and intelligibility indexes. In the experimental research, I applied a self-created instrument based on the MIT test to 112 students in Brazil of graduate and undergraduate courses related to business, to verify how readability impacts on understandability, by manipulating readability components of the Flesch index (number of words per sentence and number of syllables per word). I controlled for some characteristics of each participant and the technicality of accounting language. I used an ANCOVA to test the difference between treatments and a Mediation Analysis to verify the impact of the glossary. I found no difference in understanding through different levels of readability, while some participant\'s characteristics - such as previous understanding skills, level of education, courses and the type of school - showed relevance in explaining understandability. The evidence also suggests that using a glossary to assist the reader affected understandability, but mostly for those who have less prior knowledge regarding notes to the financial statements. These results allow me to conclude readability metrics are not good proxies to measure understandability in Accounting, glossary assists on reader\'s understandability, language has an impact over readability and understandability, and readability and understandability did not change with the OCPC 07. / A Contabilidade como ferramenta para comunicar informação relevante a múltiplos usuários, deve superar problemas e barreiras na apresentação dessa informação. Um dos problemas é sua compreensibilidade, dado que a falta de compreensão pode impactar as decisões. Contudo, compreensibilidade não é mensurada facilmente. Estudos anteriores usam métricas de legibilidade como proxies de compreensibilidade. Eles entendem que esses conceitos estão relacionados em certa medida, mas enquanto legibilidade foca no texto, compreensibilidade inclui características do leitor. Assim, o objetivo principal dessa pesquisa foi verificar como a legibilidade impacta na compreensibilidade das informações das Notas Explicativas. Foi verificado também se a distância entre elas se deve à língua do relatório. Os objetivos específicos eram: (i) verificar se diferentes níveis de legibilidade impactam a compreensibilidade das notas explicativas; (ii) verificar se os níveis de compreensibilidade dependem de termos específicos contábeis; (iii) verificar se a compreensibilidade e a legibilidade das notas são diferente em diferentes línguas; e (iv) verificar se a compreensibilidade e a legibilidade das notas mudaram depois da OCPC 07. Realizaram-se dois métodos de pesquisas diferentes, um de arquivo e outro experimental. A pesquisa de arquivo aplicou testes de média em 44 empresas abertas que apresentaram suas notas em português e em inglês de 2012 a 2015. Foram estudadas notas de Instrumentos Financeiros e Provisões. Utilizaram-se índices de inteligibilidade como proxies para compreensibilidade, calculados por um software linguístico. Os resultados mostram que a maior parte das empresas que possuíam os piores níveis de legibilidade, apresentaram os melhores níveis de inteligibilidade, o que é contrário ao esperado. Os resultados também mostram que, com algumas exceções, os índices de legibilidade e compreensibilidade são diferentes em português e inglês. Ademais, descobriu-se que não houve mudança após a adoção da OCPC 07 em ambos os índices de legibilidade e compreensibilidade. No experimento, foi aplicado um instrumento criado pela autora, baseado no teste MIT, a 112 estudantes no Brasil de cursos relacionados a negócios de graduação e pós-graduação, para verificar como a legibilidade impacta na compreensibilidade, manipulando os componentes de legibilidade do índice Flesch (número de palavras por frase e número de sílabas por palavra). Controlou-se algumas características de cada participante e pela tecnicidade da linguagem contábil. Usou-se a ANCOVA para testar a diferença entre tratamentos e a Análise de Mediação para verificar o impacto de um glossário. Não foram encontradas diferenças de compreensão entre os diferentes níveis de legibilidade, enquanto que algumas características dos participantes - como habilidades de compreensão prévias, nível educacional, curso e tipo de universidade - se mostraram relevantes para explicar compreensibilidade. Os resultados também sugerem que o uso de um glossário para ajudar o leitor afetou compreensibilidade, mas mais para aqueles que possuíam menor conhecimento prévio sobre Notas Explicativas. Os resultados permitem concluir que as métricas de legibilidade não são boas proxies para mensurar compreensibilidade em Contabilidade, o glossário auxilia na compreensibilidade do leitor, a língua impacta legibilidade e compreensibilidade e legibilidade e compreensibilidade não mudaram com a OCPC 07.

abstract: Speech intelligibility measures how much a speaker can be understood by a listener. Traditional measures of intelligibility, such as word accuracy, are not sufficient to reveal the reasons of intelligibility degradation. This dissertation investigates the underlying sources of intelligibility degradations from both perspectives of the speaker and the listener. Segmental phoneme errors and suprasegmental lexical boundary errors are developed to reveal the perceptual strategies of the listener. A comprehensive set of automated acoustic measures are developed to quantify variations in the acoustic signal from three perceptual aspects, including articulation, prosody, and vocal quality. The developed measures have been validated on a dysarthric speech dataset with various severity degrees. Multiple regression analysis is employed to show the developed measures could predict perceptual ratings reliably. The relationship between the acoustic measures and the listening errors is investigated to show the interaction between speech production and perception. The hypothesize is that the segmental phoneme errors are mainly caused by the imprecise articulation, while the sprasegmental lexical boundary errors are due to the unreliable phonemic information as well as the abnormal rhythm and prosody patterns. To test the hypothesis, within-speaker variations are simulated in different speaking modes. Significant changes have been detected in both the acoustic signals and the listening errors. Results of the regression analysis support the hypothesis by showing that changes in the articulation-related acoustic features are important in predicting changes in listening phoneme errors, while changes in both of the articulation- and prosody-related features are important in predicting changes in lexical boundary errors. Moreover, significant correlation has been achieved in the cross-validation experiment, which indicates that it is possible to predict intelligibility variations from acoustic signal. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2019

Background: Limited access of oral language caused by hearing loss poses a risk for the development of reading problems. A functional overlap in outcomes between children fit with hearing aids (HAs) and children provided with cochlear implants (CIs) results in a gray area in pediatric CI candidacy criteria. This gray area makes it more difficult to determine which device will provide the best developmental outcomes for children with borderline CI eligibility. Objective: In an effort to gain outcome data that could inform decision-making regarding CI versus HA candidacy, the question posed in this study concerned the speech intelligibility index (SII) levels of children with HAs that were comparable to children with CIs based upon reading outcomes of both groups. Methods: The study sample comprised of 77 children between the ages of 6;10 and 9;6 with hearing loss: 58 children with HAs and 19 children with CIs. Reading performance data was obtained using the Word Attack and Passage Comprehension subtests of the Woodcock Reading Mastery Tests. SII information was obtained for the HA group. To allow a comparison of reading performance relative to SII between children with CIs and children with HAs, multiple imputation was used to estimate a functional SII for the CI group based off the available reading information. Results: Children in the HA and CI groups demonstrated overall similar reading performance. The relationship between aided SII and reading in the HA group was found to be three times as large as that found for unaided PTA and reading. Children in the CI group were found to have reading abilities similar to children in the HA group with known SIIs of 0.73. Functional SII was imputed for the CI group with strong relative efficiency, but because confidence intervals were rather large, more data is needed in order to make statements with greater levels of confidence regarding implications for CI candidacy criteria.

Hearing aid manufacturers commonly engineer automatic gain control (AGC) circuits which are aimed at reducing'sound tolerance problems and improving speech intelligibility among wearers. The most common type of AGC engineered is one utilizing a fast attack time. The present study was designed to evaluate the effects of both fast and slow attack times on the intelligibility of speech. Twenty-four normal hearing subjects listened to sixty pre-recorded sentences through two types of hearing aid circuits. Thirty sentences were modified by a fast attack AGC circuit, and thirty sentences were modified by a slow attack AGC. The subjects marked one of four multiple~choice answers for each sentence. The mean number of sentences answered incorrectly when heard through fast attack AGC was 8.25. When heard through slow attack AGC, the mean was 6.67. The performance differences which exist between these two modes of signal modification suggest that the fast attack does not improve intelligibility as significantly as slow attack time among normal listeners. Further investigation into the effects of slow attack AGC circuits on the user's ability to understand speech are recommended.

The purpose of this study was to investigate the effects of a 500 Hz and 3,150 Hz one-third octave band augmentation on the speech discrimination ability of listeners with cochlear hearing impairments. The results were analyzed both within the experimental group of subjects included in the present study and in comparison with data collected on a control group of normal hearing subjects reported earlier.

Highly unintelligible children may mistakenly be assumed to have difficulty only with the misarticulation of consonants. Expressive language concerns may be ignored while the primary focus of intervention becomes the correction of misarticulated speech. Questions have arisen regarding the possibility of both speech and expressive language difficulties contributing to unintelligibility. Shriberg and Kwiatkowski (1982) developed an ordinal means of rating severity of involvement. One of the constructs of the severity scale was intelligibility. The metric percentage consonants correct (PCC) was developed to identify severity of involvement of disorders of phonology.