As habilidades comunicativas de crianças portadoras de deficiência auditiva (DA) pré-lingual, submetidas à cirurgia do implante coclear (IC) desenvolvem-se ao longo dos anos de uso do dispositivo. O objetivo deste trabalho foi estudar o desempenho alcançado por adolescentes e jovens adultos com, no mínimo, dez anos de experiência com o IC, em relação à audição e à inteligibilidade de fala e, considerando o tipo de DA, o tempo de privação sensorial auditiva e o tipo de dispositivo. Participaram deste estudo, 61 adolescentes e jovens adultos portadores de DA pré-lingual, que receberam diferentes tipos de IC em média, aos 3 anos e 10 meses de idade. Reconhecimento da lista de palavras dissílabas, Teste Hint adaptativo e reconhecimento das sentenças Hint no silêncio e no ruído foram os procedimentos utilizados para avaliar o desempenho de audição. A inteligibilidade da fala dos participantes foi avaliada por dois julgadores sem experiência com deficientes auditivos, usando o método de transcrição e a escala de inteligibilidade de 5 pontos. Após 10 anos de experiência com o IC, 53 participantes (86,9%) alcançaram habilidade de reconhecimento auditivo em conjunto aberto. Os resultados médios obtidos na lista de palavras dissílabas foram de 49,4%; teste Hint adaptativo, a média dos resultados no silêncio foi igual a 54,7dB e, no ruído, 10,7 dB e; os valores médios de porcentagem nas sentenças Hint no silêncio 54% e no ruído, 33,3%. Quanto à inteligibilidade de fala dos participantes, a média de acertos no método de transcrição foi igual a 76,2%. Na escala de inteligibilidade, a pontuação média correspondeu a 3,3 pontos. Melhores desempenhos de audição no silêncio e no ruído foram correlacionados ao menor tempo de privação sensorial auditiva. Foi observada correlação entre o tipo de dispositivo utilizado e: o desempenho de audição no ruído e o desempenho de inteligibilidade da fala. Usuários do dispositivo Nucleus 24 e Med-El apresentaram melhor desempenho de audição e de inteligibilidade de fala do que os usuários Nucleus 22. Mais de 10 anos após a cirurgia de IC, 82% das crianças implantadas com as primeiras gerações do dispositivo eletrônico desenvolveram habilidade de reconhecimento auditivo no ruído e 90,1% alcançaram fala inteligível. O desempenho de audição e de inteligibilidade de fala dos participantes foi influenciado pelo tempo de privação sensorial auditiva e pelo tipo de dispositivo eletrônico. Considerando os critérios contemporâneos de indicação cirúrgica em associação as novas estratégias de codificação de fala disponíveis nos dispositivos eletrônicos da atualidade, resultados promissores são esperados para a nova geração de crianças submetidas ao IC / The communication skills of prelingually deafened children, underwent cochlear implant (CI) surgery, develop over the years of device use. The aim of this work was to study the performance achieved by teenagers and young adults with at least ten years of IC experience with regard to speech perception and speech intelligibility and, considering the type of hearing loss, duration of deafness, and type of device. Participated of this study, 61 teenagers and young adults prelingually deafened, who received different types of CI, on average at 3 years and 10 months of age. Recognition of two-syllable word list, test Hint and recognition of Hint sentence in quiet and noise were the procedures used to evaluate the hearing performance. The speech intelligibility of the participants was evaluated by two judges, using the writedown intelligibility method and a 5-points intelligibility rating-scale. After 10 years of experience with CI, 53 participants (86,9%) achieved open-set speech recognition. The average results obtained in the two-syllable word list were 49, 4%; in the test Hint in quiet, the average results were 54,7 dB in quiet and 10,7 dB in noise and; the mean percentage of Hint sentences in quiet was 54% and in noise, 33,3%. Regarding the speech intelligibility of the participants, the average write-down intelligibility score was 76,2% and the average rating-scale intelligibility score was 3,3 points. Better speech performances in quiet and in noise were correlated with shorter duration of deafness. Correlation was found between the type of device and: the speech perception in noise and the speech intelligibility. Nucleus 24 and Med-El device users performed better than Nucleus 22 users with regard to speech perception in noise and speech intelligibility. More than 10 years after the CI surgery, 82% of children implanted with the first generation of the electronic device developed speech recognition in noise and 90,1% achieved intelligible speech. Speech perception and speech intelligibility of the participants, both were influenced by duration of deafness and type of electronic device. Considering the contemporary criteria of surgical indication in association with the new speech coding strategies available, promising results were expected for the new generation of children underwent to CI

Speech intelligibility of voice alarm communication systems is extremely important for proper notification and direction of building occupants. Currently, there is no minimum standard to which all voice alarm communication systems must be held. Tests were conducted to determine how system and room characteristics, and the addition of occupants, affect the intelligibility of a voice signal. This research outlines a methodology for measuring the speech intelligibility of a room and describes the impact of numerous variables on these measurements. Eight variables were considered for this study: speaker quantity and location, speaker power tap, sound pressure level (SPL), number and location of occupants, presence of furniture, location of intelligibility measurements, data collection method, and floor covering. All room characteristics had some affect on the room intelligibility; the sound pressure level of the signal and the number and location of occupants had the greatest overall impact on the intelligibility of the room. It is recommended, based on the results of this study, that further investigation be conducted in the following areas: floor finishes, speaker directivity, various population densities, furniture packages and room sizes.

Made available in DSpace on 2016-04-27T18:12:00Z (GMT). No. of bitstreams: 1 Renata de Souza Lima Figueiredo.pdf: 14578295 bytes, checksum: 0d904f592d32bb2f4dfd433cd697c85c (MD5) Previous issue date: 2013-03-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Objective: to establish the relationship between audibility for speech sounds, audiological characteristics and auditory behavioral responses in infants and children under three years of age with sensorineural hearing loss. Method: 41 children aged between 4 and 80 months participated in the study. Seventy-eight ears were analyzed. Auditory thresholds at 250, 500, 1000, 2000 and 4000Hz were considered and values of speech intelligibility index (SII) for the input signals 55, 65 and 75dB SPL were obtained in the Verifit®Audioscan hearing aid analyzer. Three hundred and twelve SII values were obtained. To study the relationship between audibility and auditory behavioral responses, 8 children aged between 11 and 28 months were selected. Auditory response for speech stimulus was observed (the Ling six and four onomatopoeias), before and after the stimuli familiarization activity, controlled by a decibel meter at different distances between evaluator and hearing aid microphone. Other variables were considered for auditory response quality analysis, besides SII values, when identified discrepancy between the expected and the observed behavior in each case. Results: the hearing thresholds have been classified into five groups as homogeneous audiological characteristics (degree and audiometric configuration) and heterogeneous among themselves. Three ranges of SII values were determined from within the groups. The range of 36 to 55% was the most affected by input signal intensity changes. Equations for classification of hearing loss as groups and equations for determination of adjusted SII values were established. In the 8-case study, two children with audibility expressed by SII 65 values lower than 20% did not provide answers for longer distances. In all cases, changes were observed in quality of post-familiarization-activity auditory behavior response. Complex factors such as otitis media, inconsistency of hearing aid use and hearing loss progression were present in some cases and seem to have influenced the quality of auditory behavior observed. Conclusions: SII is an objective measure that allows for amplification adequacy assessment of different hearing loss characteristics, as well as determination of hearing capacity. SII has a stronger correlation with the dynamic relationship between the degree and configuration of hearing loss, when compared to the relationship with the degree of hearing loss alone. Therefore a new classification of hearing loss by groups was established. Hearing losses Gr4 with SII values between 36 to 55% are most affected when the input signal intensity or the distance between speaker and the hearing aid microphone changes. The process of amplification validation in infants with systematic auditory behavior evaluation through familiarization stimuli tests showed that children of up to three years need to be familiar with the stimuli in order to trigger observable auditory responses, thus ensuring results compatible with auditory capacity. Cases classified with hearing loss group Gr4 showed changes in auditory response quality at greater distances. Complex factors affect the quality of auditory behavior responses observed / Estabelecer a relação entre audibilidade para sons de fala e características audiológicas e de respostas comportamentais em bebês e crianças com até três anos de idade usuárias de aparelhos de amplificação sonora. Métodos: Para estudar a relação audibilidade e características audiológicas, foram selecionadas 41 crianças com idades entre 4 e 80 meses, totalizando 78 orelhas para análise. Foram considerados os limiares auditivos nas frequências 250, 500, 1000, 2000 e 4000Hz e analisados valores do índice de inteligibilidade de fala (SII) para os sinais de entrada 55, 65 e 75dB NPS, obtidos na verificação dos AASI no equipamento Verifit®Audioscan, totalizando 312 valores de SII. Para estudar a relação audibilidade e respostas comportamentais, foram selecionados 8 crianças com idades entre 11 e 28 meses. O comportamento auditivo foi observado por meio do instrumento de avaliação sistemática do comportamento auditivo para sons de fala (Os seis sons de Ling e 4 onomatopeias) antes e depois de atividade de familiarização dos estímulos em 3 diferentes distâncias entre o avaliador e o microfone do AASI. A intensidade do dos estímulos foi controlada com decibelímetro. A qualidade das respostas foi analisada considerando variáveis de confusão quando identificada discrepância entre o comportamento esperado e observado em cada caso. Resultados: As perdas auditivas foram classificadas em cinco grupos homogêneos quanto as características audiológicas (grau e configuração audiométrica) e heterogêneos entre si. A partir dos grupos determinou-se 3 intervalos de valores de SII. O intervalo de valores SII entre 36 a 55% foi o mais afetado quando alterada a intensidade do sinal de entrada. Foram determinadas equações para classificação da perda auditiva conforme grupos e, equações para determinação de valores de SII ajustado. No estudo dos 8 casos, observou-se que as duas crianças com audibilidade expressa por valores de SII 65 piores que 20% não apresentaram repostas para distâncias maiores. Para todos os casos observou-se mudança na qualidade da resposta auditiva após a familiarização dos estímulos. Fatores complexos como otite média de repetição, inconsistência no uso da amplificação e progressão da perda auditiva estavam presentes em alguns dos casos estudados e parecem ter influenciado na qualidade do comportamento auditivo observado. Conclusões: O SII é uma medida objetiva que permite avaliar a adequação da amplificação para diferentes características de perdas auditivas e, determinar a capacidade auditiva. O SII tem relação mais forte com a relação dinâmica entre o grau e configuração audiométrica, quando comparada com sua relação com o grau da perda auditiva isoladamente. Para tanto uma nova classificação da perda auditiva por grupos foi determinada. Perdas auditivas classificadas no Gr4, com valores de SII no intervalos de 36 a 55% são as mais afetadas quando alterada a intensidade do sinal de entrada ou a distância entre o falante e microfone do AASI. O processo de validação da amplificação em crianças com a avaliação sistemática do comportamento auditivo com a familiarização dos estímulos de teste, mostrou que as crianças até três anos de idade precisam conhecer os estímulos para que respostas auditivas sejam possíveis de ser observadas, garantindo assim a fidedignidade dos resultados. Casos classificados com perdas auditivas no Gr4 apresentaram mudanças na qualidade das respostas auditivas observadas para as distâncias maiores. Fatores complexos afetam a qualidade das respostas auditivas observadas

Esse estudo teve como objetivo propor e avaliar a eficácia de um Programa Fonoaudiológico para Formação de Locutores de Rádio (PFFLR), aplicado aos alunos de um Curso Profissionalizante de Radialista – Setor Locução. O Programa Fonoaudiológico para Formação de Locutores de Rádio foi estruturado em 7 módulos com duração de 7 aulas semanais. Esse Programa foi fundamentado na estimulação de 11 aspectos, os quais foram trabalhados seqüencialmente. Os participantes foram divididos em dois grupos, pareados quanto ao sexo e idade. O grupo de pesquisa foi constituído por 35 adultos, alunos do curso de locução e o grupo controle por 35 adultos, que espontaneamente se disponibilizaram a participar da pesquisa. Foram realizadas três análises, sendo: análise objetiva da voz, através da extração da freqüência fundamental, análise perceptivo-auditiva do uso vocal e análise objetiva da velocidade de fala na leitura. Os resultados indicaram que os grupos diferenciaram-se quanto ao uso vocal e à velocidade de fala na leitura. Em relação à análise do uso vocal, os grupos diferenciaram-se para os parâmetros de qualidade vocal, loudness, ressonância, coordenação pneumofonoarticulatória, articulação, modulação e ritmo de leitura. Quanto à análise da velocidade de fala, os grupos diferenciaram-se tanto para o número de palavras/minuto como de sílabas/minuto. Em relação à análise objetiva da voz, para o grupo de pesquisa houve diferenças entre o pré e pós-aplicação do PFFLR, com redução da freqüência fundamental. Os resultados indicam que o PFFLR foi eficaz na sua proposta, e os parâmetros onde houve melhoras são aqueles específicos para a boa locução. / The purpose of the present study was to propose and evaluate the effectiveness of the Speech Pathology Program for the preparation of radio speakers, with was used with students of the professional course for broadcaster-radio speakers. The speech pathology program for the preparation of radio speakers was structured 7 modules with the duration for 7 weekly lectures. The program was based on the simulation of 11 aspects, wich were presented in a sequential mode. The participants were divided in 2 groups and paired accvornding to age and gender. The research group consisted of 35 adults, stuidents of the radio sp[eakers course, and the control consisted of 35 adults who volunteerd to take part in the research. Three of analysis were mode: (1) na objective analysis of voice through the extraction of the fundamental frequency; (2) a perpective-auditory analyses of the vocal use; and (3) na objetive analysis of the speech rate during reading. The results indicated that the groups differed from each other in relation to the vocal use the speech rate during. Regarding the vocal use, the groups were differnt for tha parameters the vocal quality, loudness, resonance, coordination between breathing ans speaking, articulation, modulation and reading rhythm. Regarding the analysis of the speech rate, the groups were different for the number of words and syllabes per minute. As for the objetive analysis of voice, the research group presented in their pre and post program application perfomances, with the reduction of the fundamental frequency. The results indicate that the speech pathology program for the preparation of radio speakers was effective in the proposition. The parameters in wich improvements were observed are those specific for a good locution.

Background: An important goal of providing amplification to children with hearing loss is to ensure that hearing aids are adjusted to match targets of prescriptive procedures as closely as possible. The Desired Sensation Level (DSL) v5 and the National Acoustic Laboratories’ prescription for nonlinear hearing aids, version 1 (NAL-NL1) procedures are widely used in fitting hearing aids to children. Little is known about hearing aid fitting outcomes for children with severe or profound hearing loss. Purpose: The purpose of this study was to investigate the prescribed and measured gain of hearing aids fit according to the NAL-NL1 and the DSL v5 procedure for children with moderately severe to profound hearing loss; and to examine the impact of choice of prescription on predicted speech intelligibility and loudness. Research Design: Participants were fit with Phonak Naida V SP hearing aids according to the NAL-NL1 and DSL v5 procedures. The Speech Intelligibility Index (SII) and estimated loudness were calculated using published models. Study Sample: The sample consisted of 16 children (30 ears) aged between 7 and 17 yr old. Data Collection and Analysis: The measured hearing aid gains were compared with the prescribed gains at 50 (low), 65 (medium), and 80 dB SPL (high) input levels. The goodness of fit-to-targets was quantified by calculating the average root-mean-square (RMS) error of the measured gain compared with prescriptive gain targets for 0.5, 1, 2, and 4 kHz. The significance of difference between prescriptions for hearing aid gains, SII, and loudness was examined by performing analyses of variance. Correlation analyses were used to examine the relationship between measures. Results: The DSL v5 prescribed significantly higher overall gain than the NAL-NL1 procedure for the same audiograms. For low and medium input levels, the hearing aids of all children fit with NAL-NL1 were within 5 dB RMS of prescribed targets, but 33% (10 ears) deviated from the DSL v5 targets by more than 5 dB RMS on average. For high input level, the hearing aid fittings of 60% and 43% of ears deviated by more than 5 dB RMS from targets of NAL-NL1 and DSL v5, respectively. Greater deviations from targets were associated with more severe hearing loss. On average, the SII was higher for DSL v5 than for NAL-NL1 at low input level. No significant difference in SII was found between prescriptions at medium or high input level, despite greater loudness for DSL v5 than for NAL-NL1. Conclusions: Although targets between 0.25 and 2 kHz were well matched for both prescriptions in commercial hearing aids, gain targets at 4 kHz were matched for NAL-NL1 only. Although the two prescriptions differ markedly in estimated loudness, they resulted in comparable predicted speech intelligibility for medium and high input levels.

Objective: To examine the impact of prescription on predicted speech intelligibility and loudness for children. Design: A between-group comparison of speech intelligibility index (SII) and loudness, based on hearing aids fitted according to NAL-NL1, DSL v4.1, or DSL m[i/o] prescriptions. A within-group comparison of gains prescribed by DSL m[i/o] and NAL-NL2 for children in terms of SII and loudness. Study sample: Participants were 200 children, who were randomly assigned to first hearing-aid fitting with either NAL-NL1, DSL v4.1, or DSL m[i/o]. Audiometric data and hearing-aid data at 3 years of age were used. Results: On average, SII calculated on the basis of hearing-aid gains were higher for DSL than for NAL-NL1 at low input level, equivalent at medium input level, and higher for NAL-NL1 than DSL at high input level. Greater loudness was associated with DSL than with NAL-NL1, across a range of input levels. Comparing NAL-NL2 and DSL m[i/o] target gains revealed higher SII for the latter at low input level. SII was higher for NAL-NL2 than for DSL m[i/o] at medium- and high-input levels despite greater loudness for gains prescribed by DSL m[i/o] than by NAL-NL2. Conclusion: The choice of prescription has minimal effects on speech intelligibility predictions but marked effects on loudness predictions.

Background: Prescriptive methods have been at the core of modern hearing aid fittings for the past several decades. Every decade or so, there have been revisions to existing methods and/or the emergence of new methods that become widely used. In 2001 Byrne et al provided a comparison of insertion gain for generic prescriptive methods available at that time. Purpose: The purpose of this article was to compare National Acoustic Laboratories—Non-linear 1 (NAL-NL1), National Acoustic Laboratories—Non-linear 2 (NAL-NL2), Desired Sensation Level Multistage Input/Output (DSL m[i/o]), and Cambridge Method for Loudness Equalization 2—High-Frequency (CAMEQ2-HF) prescriptive methods for adults on the amplification characteristics of prescribed insertion gain and compression ratio. Following the differences observed in prescribed insertion gain among the four prescriptive methods, analyses of predicted specific loudness, overall loudness, and bandwidth of cochlear excitation and effective audibility as well as speech intelligibility of the international long-term average speech spectrum (ILTASS) at an average conversational input level were completed. These analyses allow for the discussion of similarities and differences among the present-day prescriptive methods. Research Design: The impact of insertion gain differences among the methods is examined for seven hypothetical hearing loss configurations using models of loudness perception and speech intelligibility. Study Sample: Hearing loss configurations for adults of various types and degrees were selected, five of which represent sensorineural impairment and were used by Byrne et al; the other two hearing losses provide an example of mixed and conductive impairment. Data Collection and Analysis: Prescribed insertion gain data were calculated in 1/3-octave frequency bands for each of the seven hearing losses from the software application of each prescriptive method over multiple input levels. The insertion gain data along with a diffuse field-to-eardrum transfer function were used to calculate output levels at the eardrums of the hypothetical listeners. Levels of hearing loss and output were then used in the Moore and Glasberg loudness model and the ANSI S3.5-1997 Speech Intelligibility Index model. Results: NAL-NL2 and DSL m[i/o] provided comparable overall loudness of approximately 8 sones for the five sensorineural hearing losses for a 65 dB SPL ILTASS input. This loudness was notably less than that perceived by a normal-hearing person for the same input signal, 18.6 sones. NAL-NL2 and DSL m[i/o] also provided comparable predicted speech intelligibility in quiet and noise. CAMEQ2-HF provided a greater average loudness, similar to NAL-NL1, with more high-frequency bandwidth but no significant improvement to predicted speech intelligibility. Conclusions: Definite variation in prescribed insertion gain was present among the prescriptive methods. These differences when averaged across the hearing losses were, by and large, negligible with regard to predicted speech intelligibility at normal conversational speech levels. With regard to loudness, DSL m[i/o] and NAL-NL2 provided the least overall loudness, followed by CAMEQ2-HF and NAL-NL1 providing the most loudness. CAMEQ2-HF provided the most audibility at high frequencies; even so, the audibility became less effective for improving speech intelligibility as hearing loss severity increased.

The hearing and understanding problems of the people with high frequency hearing loss are covered within the scope of this thesis. For overcoming these problems, two main studies, developing hearing loss simulation (HLS) and applying new frequency lowering methods (FLMs) were carried out. HLS was developed with the suprathreshold effects and new FLMs were applied with different combinations of the FLMs. For evaluating the studies, modified rhyme test (MRT) and speech intelligibility index (SII) were used as subjective and objective measures, respectively. Before both of the studies, offline studies were carried out for specifying the significant parameters and values for using in MRT. For the HLS study, twelve hearing impaired subjects listened to unprocessed sounds and thirty six normal hearing subjects listened to simulated sounds. In the evaluation of the HLS, both measures gave similar and consistent results for both unprocessed and simulated sounds. In FLMs study, hearing impaired subjects were simulated and normal hearing subjects listened to frequency lowered sounds with the specified methods, parameters and values. All FLMs were compared with the standard method of hearing aids (amplification) for five different noisy environments. FLMs satisfied 83% success of higher speech intelligibility improvement than amplification in all cases. As a conclusion, the necessity of using subject-specific FLMs was shown to achieve higher intelligibility than with amplification only. Accordingly, a methodology for selection of the values of parameters for different noisy environments and for different audiograms was developed.

The hospital sound environment is complex. Emergency Departments (EDs), in particular, have proven to be hectic work environments populated with diverse sound sources. Medical equipment, alarms, and communication events generate noise that can interfere with staff concentration and communication. In this study, sound measurements and analyses were conducted in six hospitals total: three civilian hospitals in Atlanta, Georgia and Dublin, Ohio, as well as three Washington, DC-area hospitals in the Military Health System (MHS). The equivalent, minimum, and maximum sound pressure levels were recorded over twenty-four hours in several locations in each ED, with shorter 15-30 minute measurements performed in other areas. Acoustic descriptors, such as spectral content, level distributions, and speech intelligibility were examined. The perception of these acoustic qualities by hospital staff was also evaluated through subjective surveys. It was found that noise levels in both work areas and patient rooms were excessive. Additionally, speech intelligibility measurements and survey results show that background noise presents a significant obstacle in effective communication between staff members and patients. Compared to previous studies, this study looks at a wider range of acoustic metrics and the corresponding perceptions of staff in order to form a more precise and accurate depiction of the ED sound environment.

This thesis investigates the use of an auxiliary sensor, the GEMS device, for improving the quality of noisy speech and designing noise preprocessors to MELP speech coders. Use of auxiliary sensors for noise-robust ASR applications is also investigated to develop speech enhancement algorithms that use acoustic-phonetic properties of the speech signal. A Bayesian risk minimization framework is developed that can incorporate the acoustic-phonetic properties of speech sounds and knowledge of human auditory perception into the speech enhancement framework. Two noise suppression systems are presented using the ideas developed in the mathematical framework. In the first system, an aharmonic comb filter is proposed for voiced speech where low-energy frequencies are severely suppressed while high-energy frequencies are suppressed mildly. The proposed system outperformed an MMSE estimator in subjective listening tests and DRT intelligibility test for MELP-coded noisy speech. The effect of aharmonic comb filtering on the linear predictive coding (LPC) parameters is analyzed using a missing data approach. Suppressing the low-energy frequencies without any modification of the high-energy frequencies is shown to improve the LPC spectrum using the Itakura-Saito distance measure. The second system combines the aharmonic comb filter with the acoustic-phonetic properties of speech to improve the intelligibility of the MELP-coded noisy speech. Noisy speech signal is segmented into broad level sound classes using a multi-sensor automatic segmentation/classification tool, and each sound class is enhanced differently based on its acoustic-phonetic properties. The proposed system is shown to outperform both the MELPe noise preprocessor and the aharmonic comb filter in intelligibility tests when used in concatenation with the MELP coder. Since the second noise suppression system uses an automatic segmentation/classification algorithm, exploiting the GEMS signal in an automatic segmentation/classification task is also addressed using an ASR approach. Current ASR engines can segment and classify speech utterances in a single pass; however, they are sensitive to ambient noise. Features that are extracted from the GEMS signal can be fused with the noisy MFCC features to improve the noise-robustness of the ASR system. In the first phase, a voicing feature is extracted from the clean speech signal and fused with the MFCC features. The actual GEMS signal could not be used in this phase because of insufficient sensor data to train the ASR system. Tests are done using the Aurora2 noisy digits database. The speech-based voicing feature is found to be effective at around 10 dB but, below 10 dB, the effectiveness rapidly drops with decreasing SNR because of the severe distortions in the speech-based features at these SNRs. Hence, a novel system is proposed that treats the MFCC features in a speech frame as missing data if the global SNR is below 10 dB and the speech frame is unvoiced. If the global SNR is above 10 dB of the speech frame is voiced, both MFCC features and voicing feature are used. The proposed system is shown to outperform some of the popular noise-robust techniques at all SNRs. In the second phase, a new isolated monosyllable database is prepared that contains both speech and GEMS data. ASR experiments conducted for clean speech showed that the GEMS-based feature, when fused with the MFCC features, decreases the performance. The reason for this unexpected result is found to be partly related to some of the GEMS data that is severely noisy. The non-acoustic sensor noise exists in all GEMS data but the severe noise happens rarely. A missing data technique is proposed to alleviate the effects of severely noisy sensor data. The GEMS-based feature is treated as missing data when it is detected to be severely noisy. The combined features are shown to outperform the MFCC features for clean speech when the missing data technique is applied.