Deafness in early development can alter how the brain responds to sound, compromising the restoration of hearing with cochlear implants. We asked how the naïve brain responds to initial cochlear implant stimulation in children who are deaf. Results indicated large variability in initial responses. Deafness associated with GJB-2 mutations led to more uniformity in cortical responses than other etiologies. Responses associated with GJB-2 mutations were characterized by a response peak with large contributions from temporal and frontal regions of the brain. This response may reflect an early stage of auditory development. By contrast, another response type, typical of normal hearing children, received less contribution from frontal regions. Through consistent cochlear implant use, frontal regions of the brain may not be as strongly recruited. Effects of deafness in early development are heterogeneous, which may reflect differences in etiology of deafness and different stages of auditory development.

Users of cochlear implants typically have difficulty differentiating talkers, identifying vocal expressions of emotion, and recognizing familiar melodies because of the degraded spectral cues provided by conventional implants. This thesis examined these abilities in a small, relatively privileged sample of young bilateral implant users. In Study 1 child implant users and a control sample of hearing children were required to judge whether various utterances were produced by a man, woman, or girl (Experiment 1) and to identify the voices of cartoon characters from familiar television programs (Experiment 2). Child implant users’ performance on talker classification was comparable to that of hearing children. Their identification of cartoon characters’ voices was less accurate than that of hearing children but well above chance levels. These findings challenge conventional wisdom about the talker identification difficulties of implant users. In Study 2 the children were required to indicate whether semantically neutral utterances (Experiment 1) or classical piano excerpts (Experiment 2) sounded “happy” or “sad”. In both cases, implant users performed less accurately than hearing children but well above chance levels. Although the findings on emotion recognition in music are in line with those of previous research, the findings on emotion in speech are at odds with claims that young implant users are insensitive to vocal affect. In Study 3 the children were required to identify the theme songs from familiar television programs on the basis of combined timing and pitch cues as well as timing or pitch cues alone. Implant users’ performance was comparable to that of hearing children except when the cues were restricted to pitch relations, which resulted in performance at chance levels. The findings suggest that the musical representations of young implanted listeners include precise information about timing and coarser information about pitch. They also demonstrate, for the first time, that children, both implant users and those with normal hearing, can identify familiar music on the basis of timing cues alone. Overall, the findings highlight the importance of timing cues for implant users, the range of individual differences, and habilitation possibilities for the recognition of talkers, emotion, and music.

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 225-237.

Thesis (M. Communication Pathology)--University of Pretoria, 2005. / Summary in English and Afrikaans. Includes bibliographical references.

En 2010, plus de 200 000 personnes dans le monde en étaient équipées, dont plus de 10 000 en France (adultes et enfants). La technologie utilisée pour les premiers implants commercialisés au milieu des années 1980 a beaucoup évolué et l’implant cochléaire permet désormais à son utilisateur d’avoir accès à des caractéristiques acoustiques de plus en plus précises des sons de son environnement et notamment des sons de parole. Cependant, l’information auditive fournie par l’implant reste limitée, ce qui a pour conséquence des difficultés persistantes de production de certains sons de parole par l’utilisateur d’implant cochléaire, même après plusieurs années d’utilisation. Ces difficultés de production peuvent se traduire également par une intelligibilité moindre, et peuvent avoir des répercussions sur les relations familiales et sociales, en particulier chez l’enfant.Les études disponibles dans la littérature se concentrent sur les effets et les bénéfices à court-terme de l’implant cochléaire chez l’enfant, et il existe relativement peu d’études de production de parole chez l’enfant en âge scolaire, en particulier chez l’enfant francophone. L’objectif de ce travail est donc de proposer une évaluation des difficultés de production de plusieurs contrastes phonologiques chez l’enfant sourd, porteur d’implant cochléaire, plusieurs années après l’implantation cochléaire, et des facteurs qui influencent son intelligibilité.Dans le cadre de notre thèse, nous avons constitué un corpus de productions de parole de 13 enfants âgés de 6;6 à 10;7 ans, atteints de surdité pré- ou périlinguistique, ayant reçu un implant cochléaire entre 1;1 et 6;6 ans, et l’utilisant depuis plus d’un an et de 20 enfants normo-entendants appariés en âge chronologique (de 5;7 à 10;6 ans).Dans un premier temps, nous avons comparé les caractéristiques acoustiques des voyelles orales, des occlusives et des fricatives du français, ainsi que la réalisation de la coarticulation dans des séquences occlusive-voyelle par ces deux groupes d’enfants. Les résultats montrent une grande proximité entre les productions des enfants typiques et implantés, et certaines différences, par exemple sur les voyelles antérieures arrondies, les fricatives alvéolaires et les occlusives vélaires. Ces différences peuvent s’expliquer par les caractéristiques technologiques de l’implant et son usage par l’enfant, et révèlent également le poids des différents facteurs du développement phonologique : contraintes articulatoires, contraintes perceptives, caractéristiques de l’input langagier et de la langue maternelle.Dans un deuxième temps, nous avons élaboré une méthode d’évaluation perceptive de l’intelligibilité de la parole, que nous avons soumise à 9 auditeurs experts en parole pathologique et à 17 auditeurs naïfs, tous francophones. Notre étude perceptive d’intelligibilité met en évidence 1) une absence d’effet d’expertise sur le jugement d’intelligibilité puisque les notes données par les auditeurs experts et naïfs sont corrélées, 2) un effet de l’audition sur l’intelligibilité, puisque les enfants sourds porteurs d’implant cochléaire sont jugés moins intelligibles que les enfants normo-entendants, et 3) une meilleure intelligibilité chez les enfants implantés précocement (avant 20 mois) mais pas d’effet de la durée d’utilisation de l’implant cochléaire sur l’intelligibilité.Ce travail montre donc le bénéfice apporté par l’implant pour la communication orale, mais aussi l’existence de difficultés persistantes, qui doivent être prises en compte dans la rééducation et l’accompagnement familial, scolaire et social des enfants.Notre étude fournit en outre un ensemble de données de référence sur le développement phonologique tardif des enfants francophones, et un corpus de parole utilisable pour d’autres travaux de recherche sur le développement typique et pathologique. / As of 2010, cochlear implant has been used by over 200 000 persons (adults and children) worldwide and by 10 000 persons in France. Technology has largely improved since the first devices were put on the market in the 1980’s, and it now provides its user with more and more detailed acoustical information about the sounds of their environment in general, and about speech sounds in particular. However, perception with a cochlear implant remains limited, which leads to persisting difficulties in producing some speech sounds, even after several years of implant use. These difficulties in speech production can translate into a lower intelligibility, with effects on interactions with family and community members for its users, especially for children.A large body of studies in the literature focusses on short-term effects and gains of cochlear implant for young children and infants, but fewer studies in speech production in school-age children are available, especially in French-speaking children. The goal of this project is to assess the difficulties in the production of selected phonological contrasts in cochlear-implanted children, several years after cochlear implantation, and the factors influencing their intelligibility.For this thesis, we recorded thirteen 6;6-to-10;7 year old, pre- or perilinguistically deaf children wearing cochlear implants since they were 1;1 to 6;6 years old, with more than a year of use, and twenty normal-hearing age-matched children (chronological age ranging from 5;7 to 10;6 years).In a first experiment, we compared the acoustical characteristics of ten oral vowels, six stops and three fricatives of French. We also studied the realization of coarticulation in plosive-vowel sequences in these two groups of children.Our results show a high degree of similarity in typical and implant using children, and several differences, for example, for front rounded vowels, alveolar fricatives and velar stops. These differences can be explained by the implant’s technology and its use by the child. They also show the importance of several factors in phonological development: articulatory constraints, perceptual constraints, characteristics of language input and mother tongue.In a second experiment, we designed a method to perceptually assess the intelligibility of speech: 9 expert and 17 naïve French-speaking listeners participated in this experiment.Our perceptual assessment of intelligibility shows 1) no effect of expertise since grades given by expert and naïve listeners are correlated, 2) an effect of hearing level on intelligibility since cochlear-implanted children are less intelligible than their normal-hearing peers, and 3) a better intelligibility in early implanted children (before 20 months) but no effect of duration of implant use on intelligibility.This work emphasizes the benefits for oral communication provided by cochlear implants, but also the remaining difficulties, that need to be taken into acount for rehabilitation and support from the child’s family, school and society.Our study also provides both reference data on late stages of phonological development in French-speaking children, and a corpus of speech production which can be used for further research on typical and pathological speech development.

Submitted by MAÍSA KICH GRECCO null (maisakg@bol.com.br) on 2016-03-23T13:56:53Z No. of bitstreams: 1 Dissertação Maísa Kich Grecco.pdf: 2876385 bytes, checksum: 386e37f57cf8947da28a13b9dd7efb66 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-24T14:28:39Z (GMT) No. of bitstreams: 1 grecco_mk_me_bauru.pdf: 2876385 bytes, checksum: 386e37f57cf8947da28a13b9dd7efb66 (MD5) / Made available in DSpace on 2016-03-24T14:28:39Z (GMT). No. of bitstreams: 1 grecco_mk_me_bauru.pdf: 2876385 bytes, checksum: 386e37f57cf8947da28a13b9dd7efb66 (MD5) Previous issue date: 2016-02-16 / O ouvinte, se bem treinado, pode fornecer estímulos discriminativos e reforçadores para respostas do falante. No entanto, também pode emitir comportamentos supressores do comportamento verbal. Nos casos de deficiência auditiva, os pais podem ter dificuldade em estimular o comportamento verbal ainda que a privação sonora seja superada pelo implante coclear, pois ouvir e se comunicar oralmente requer aprendizagem. Considerando a importância do treino de pais enquanto audiência para estabelecimento do comportamento verbal de falante de crianças com deficiência auditiva, o presente estudo objetivou ampliar o repertório comportamental de ensino de operantes verbais de mães de crianças com deficiência auditiva e implante coclear por um programa instrucional desenvolvido para esse fim; e verificar se este programa aumentou a frequência de emissão de operantes verbais por seus filhos considerando a qualidade da produção oral. Participaram duas crianças de idades entre cinco e sete anos com deficiência auditiva neurossensorial pré-lingual e usuárias de implante coclear e suas mães. Foram avaliados comportamentos de ensino de comportamento verbal emitidos pelas mães e operantes verbais emitidos pelas crianças antes e após a intervenção, de acordo com um delineamento de linha de base múltipla entre participantes. Um questionário sondou comportamentos com função de antecedente e consequente emitidos pelas mães para os operantes verbais ecoico, tato, mando e intraverbal emitidos pelos filhos. As crianças foram avaliadas nos mesmos operantes verbais em tentativas discretas. O programa instruiu as mães a fornecer antecedentes e consequentes para operantes verbais emitidos pelos filhos. Os resultados compararam o número de operantes verbais identificados pelas mães e de comportamentos de ensino desses, antes e após a intervenção, e as produções orais das crianças. Foi observado um aumento no relato de comportamentos de ensino das duas mães após a intervenção para a maioria dos operantes verbais, fornecendo mais antecedentes e consequentes. Nas produções orais das crianças, observou-se uma fala mais precisa logo após as mães realizaram a intervenção. Pode-se sugerir que ampliar o repertório de ensino de operantes verbais das mães afeta positivamente a fala de seus filhos. Estudos futuros devem refinar esse programa enquanto tecnologia de ensino aplicável em escala maior. / The listener, if well trained, can provide discriminative and reinforcing stimuli to the speaker's answers. However, it can also issue suppressing behaviors of verbal behavior. In cases of hearing impairment, parents can find it difficult to stimulate verbal behavior although the sound deprivation is overcome by the cochlear implant because listen and communicate orally requires learning. Considering the importance of parent training as a hearing to establish the verbal behavior of children with hearing impairment speaker, this study aimed to extend the behavioral repertoire of verbal operant teaching of mothers of children with hearing loss and cochlear implants for an instructional program developed for this purpose; and verify that this program has increased the frequency of verbal operant by their children considering the quality of oral production. They included two children aged five and seven years with sensorineural hearing impairment before language and users of cochlear implants and their mothers. They were evaluated behaviors verbal behavior teaching issued by mothers and verbal operant issued by the children before and after the intervention, according to a line of delineation of multiple base among participants. A questionnaire probed behavior with a history of function and consequent issued by mothers to the echoic verbal operant, touch, command and intraverbal issued for the children. The children were evaluated in the same verbal operant in discrete trial. The program instructed mothers to provide antecedents and consequences for verbal operant issued for the children. The results compared the number of verbal operant identified by mothers and teaching these behaviors before and after the intervention, and the utterances of children. Reporting an increase in learning behavior of two mothers after surgery to most verbal operant was observed, providing more antecedents and consequences. The utterances of children, there was a more accurate speech soon after mothers underwent intervention. May be considered that expanding the verbal operant mothers teaching repertoire positively affects speech of their children. Future studies should refine the program as applicable learning technology on a larger scale.

abstract: Two groups of cochlear implant (CI) listeners were tested for sound source localization and for speech recognition in complex listening environments. One group (n=11) wore bilateral CIs and, potentially, had access to interaural level difference (ILD) cues, but not interaural timing difference (ITD) cues. The second group (n=12) wore a single CI and had low-frequency, acoustic hearing in both the ear contralateral to the CI and in the implanted ear. These `hearing preservation' listeners, potentially, had access to ITD cues but not to ILD cues. At issue in this dissertation was the value of the two types of information about sound sources, ITDs and ILDs, for localization and for speech perception when speech and noise sources were separated in space. For Experiment 1, normal hearing (NH) listeners and the two groups of CI listeners were tested for sound source localization using a 13 loudspeaker array. For the NH listeners, the mean RMS error for localization was 7 degrees, for the bilateral CI listeners, 20 degrees, and for the hearing preservation listeners, 23 degrees. The scores for the two CI groups did not differ significantly. Thus, both CI groups showed equivalent, but poorer than normal, localization. This outcome using the filtered noise bands for the normal hearing listeners, suggests ILD and ITD cues can support equivalent levels of localization. For Experiment 2, the two groups of CI listeners were tested for speech recognition in noise when the noise sources and targets were spatially separated in a simulated `restaurant' environment and in two versions of a `cocktail party' environment. At issue was whether either CI group would show benefits from binaural hearing, i.e., better performance when the noise and targets were separated in space. Neither of the CI groups showed spatial release from masking. However, both groups showed a significant binaural advantage (a combination of squelch and summation), which also maintained separation of the target and noise, indicating the presence of some binaural processing or `unmasking' of speech in noise. Finally, localization ability in Experiment 1 was not correlated with binaural advantage in Experiment 2. / Dissertation/Thesis / Ph.D. Speech and Hearing Science 2013

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-03-22T17:52:21Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO APROVADA final 2.pdf: 1574842 bytes, checksum: 39509b4e3331d9ab65863461ea6b07b0 (MD5) / Made available in DSpace on 2017-03-22T17:52:21Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO APROVADA final 2.pdf: 1574842 bytes, checksum: 39509b4e3331d9ab65863461ea6b07b0 (MD5) Previous issue date: 2016-08-26 / A perda auditiva senil é denominada presbiacusia, processo degenerativo da orelha interna inerente ao envelhecimento que gera uma perda auditiva neurossensorial bilateral simétrica, cuja intensidade é variável. Estudos já demonstraram que a perda auditiva é um fator independentemente associado à aceleração do declínio cognitivo. Contudo, a capacidade de estratégias de reabilitação auditiva, como o implante coclear (IC), de desacelerar ou melhorar o desempenho cognitivo de idosos permanece desconhecida. Este estudo objetiva avaliar o desempenho cognitivo de idosos usuários de prótese auditiva convencional ou implantada. Trata-se de um estudo transversal, tipo série de casos, que selecionou dez idosos implantados nos serviços credenciados pelo Sistema Único de Saúde (SUS), para tal procedimento no estado de Pernambuco, e os avaliou através da aplicação do mini-exame do estado mental. Foi selecionado, ainda, um segundo grupo de dez idosos portadores de perda auditiva e usuários de próteses auditivas (AASI). Os valores absolutos do mini-exame do estado mental (MEEM) por indivíduo foram maiores no grupo usuário de IC, e quando considerados os pontos de corte por nível de escolaridade, esse grupo manteve melhor desempenho cognitivo do que o grupo usuário de AASI, independente do grau de intensidade da perda auditiva (p = 0,003). Desta forma, o atual estudo corrobora com as evidências que sugerem o possível impacto positivo do implante coclear no desempenho cognitivo de idosos. / Aging related hearing loss is known as presbycusis, an inner ear degenerative process which generates a symmetrical bilateral sensorineural hearing loss, whose intensity is variable. Studies have shown that hearing loss is independently associated with accelerated cognitive decline. However, the ability of hearing rehabilitation strategies, as the cochlear implant (CI), to improve cognitive performance of the elderly remains unknown. This study aims to evaluate the cognitive performance of elderly users of conventional hearing aids or cochlear implants. This is a cross-sectional study which selected ten elderly individuals submited to cochlear implantation in services accredited by the Health Unic System (SUS) for such procedure in the the state of Pernambuco, and evaluated them by applying the mini-mental state examination. It was still selected a second group of ten elderly individuals with hearing loss and users of hearing aids (HA). The absolute values of the mini-mental state examination (MMSE) by individual were higher in the cochlear implant group and when considering the cutoff points by level of education this group maintained better cognitive performance than the group of hearing aids users regardless of the degree of their hearing loss (p = 0,003). Thus, the current study corroborates the evidence that suggests the possible positive impact of cochlear implants on cognitive performance in the elderly.

O implante coclear tem sido considerado uma opção de reabilitação em pacientes com a Desordem do Espectro da Neuropatia Auditiva. Contudo, a sua indicação é relativamente recente, e, com isso, poucos estudos investigaram o desenvolvimento cortical nestes pacientes. Até o momento, não há estudos longitudinais que caracterizem o desenvolvimento do sistema auditivo central após a ativação do implante coclear. O objetivo deste trabalho foi caracterizar o componente P1 do potencial evocado auditivo cortical nos primeiros meses de uso do implante coclear em crianças com a Desordem do Espectro da Neuropatia Auditiva. Participaram deste estudo oito crianças diagnosticadas com Desordem do Espectro da Neuropatia Auditiva, com perda auditiva pré-lingual de grau severo ou profundo e usuárias de implante coclear. A pesquisa do potencial evocado auditivo cortical foi realizada com o estímulo de fala /da/, apresentado em campo livre, em três sessões de avaliação: na ativação dos eletrodos, com três e com seis meses após a ativação do implante coclear. Os registros obtidos foram analisados pela pesquisadora e por um juiz experiente em eletrofisiologia a fim de verificar a concordância das análises. Houve concordância de 100% (Kappa=1) entre os juízes quanto à ocorrência do componente P1, com coeficiente de correlação interclasse excelente para os valores de latência e amplitude. Quanto à morfologia, o componente P1 caracterizou-se como um pico positivo robusto na primeira sessão de avaliação. O componente P1 foi registrado em 71,43% da casuística na primeira sessão, em 87,50 % na segunda e em 85,71% na terceira sessão de avaliação. Nos pacientes em que foi possível observar o componente P1 em todas as sessões de avaliação, observou-se uma redução da latência considerando o primeiro e último momento de avaliação, contudo, os resultados mostraram-se heterogêneos entre as crianças avaliadas. Assim, na pesquisa do componente P1 do potencial evocado auditivo cortical, não foi possível determinar um padrão de comportamento deste componente em crianças com a Desordem do Espectro da Neuropatia Auditiva nos seis primeiros meses de uso do implante coclear. / Cochlear implants have been considered a rehabilitation option in patients with auditory neuropathy spectrum disorder. However, their indication is relatively recent, thus, few studies have investigated cortical development in these patients. So far, no longitudinal study has characterized the development of the central auditory system, following cochlear implant activation. This study aimed at characterizing P1 cortical auditory evoked potential in the first months of cochlear implant use, in children presented with auditory neuropathy spectrum disorder. Eight children diagnosed with auditory neuropathy spectrum disorder, with severe or profound pre-lingual hearing loss, users of cochlear implant, participated in this study. The cortical auditory evoked potential research was performed with the /da/ speech stimulus presented in free field, in three assessment sessions: at electrodes activation, at three and at six months, following cochlear implant activation. The recordings obtained were analyzed by the researcher and by an experienced electrophysiologist, so as to verify the agreement of the analyses. There was 100% agreement (Kappa=1) between the referees, as to the occurrence of component P1, with an excellent interclass correlation coefficient for latency and amplitude values. Regarding morphology, P1 was characterized as a robust positive peak in the first assessment session, being recorded in 71.43% of the sample, in the first session, in 87.50%, in the second, and in 85.71%, in the third. In patients in whom it was possible to observe P1 in all assessment sessions, a latency reduction was observed, considering the first and last time of evaluation, nevertheless, the results were shown to be heterogeneous among the children assessed. Thus, in the P1 cortical auditory evoked potential research, it was not possible to determine a behavior pattern of this component in children presented with auditory neuropathy spectrum disorder, in the first six months of cochlear implant use.

O redirecionamento das estruturas auditivas centrais em pacientes que foram submetidos à cirurgia de implante coclear bilateral sequencial é pouco conhecido. Contudo, a pesquisa dos potenciais evocados auditivos corticais pode auxiliar na compreensão de como ocorrem o desenvolvimento, a plasticidade e a função cortical destes pacientes. Os objetivos deste trabalho foram caracterizar longitudinalmente o complexo P1-N1-P2 dos potenciais evocados auditivos corticais em usuários de implante coclear bilateral sequencial que realizaram a ativação do primeiro implante coclear na infância e a ativação do segundo dispositivo na adolescência; e analisar sua correlação com a percepção auditiva da fala. A casuística foi composta por indivíduos atendidos no Centro de Pesquisas Audiológicas, Seção de Implante Coclear, do Hospital de Reabilitação de Anomalias Craniofaciais da Universidade de São Paulo, com perda auditiva pré-lingual e usuários de implante coclear bilateral. A pesquisa dos potenciais evocados auditivos corticais foi realizada com o estímulo de fala /da/, apresentado em campo livre em cinco momentos distintos: antes da cirurgia do segundo implante coclear, na ativação do segundo dispositivo e com três, seis e 12 meses após a ativação do segundo implante coclear. Os registros obtidos foram analisados pela pesquisadora e por um juiz experiente em eletrofisiologia a fim de verificar a concordância das análises. Houve concordância de 100% (Kappa=1) entre os juízes quanto à ocorrência dos componentes P1, N1 e P2, com coeficiente de correlação interclasse excelente para os valores de latência e amplitude. A resposta cortical obtida com o uso dos dois implantes cocleares ligados, aparentemente, reflete a melhor resposta cortical obtida, quanto à ocorrência e latência dos componentes, independente se registrada com o primeiro implante coclear ou com o segundo implante coclear ligado. Os componentes P1, N1 e P2 dos potenciais evocados auditivos corticais não são preditores dos resultados de percepção auditiva da fala tanto no silêncio quanto no ruído. / The redirection of central auditory structures in patients who underwent sequential bilateral cochlear implant surgery is little known. However, cortical auditory evoked potentials testing can aid in understanding how the development, the plasticity and cortical function of these patients, occur. This study aimed at characterizing, longitudinally, the P1-N1-P2 complex of cortical auditory evoked potentials in sequential bilateral cochlear implant users who had the first cochlear implant fitted in their childhood and the second device activated in their adolescence, and analyze its correlation with speech auditory perception. The sample consisted of individuals seen at the Audiological Research Center of the Craniofacial Anomalies Rehabilitation Hospital of the University of São Paulo, with pre-lingual hearing loss, users of bilateral cochlear implant. The cortical auditory evoked potentials research was performed with the /da/ speech stimulus, presented in free field, in five different times: before the second cochlear implant surgery, upon the fitting of the second device and three, six and 12 months following the activation of the second cochlear implant. The records obtained were analyzed by the researcher and by a judge experienced in electrophysiology, so as to verify the agreement of the analyses. A 100% agreement (kappa = 1) was seen between judges as to the occurrence of P1, N1 and P2, with an excellent inter-class correlation coefficient for the latency and amplitude values. The cortical response obtained with the use of the two cochlear implants, turned on, apparently reflects the best cortical response accomplished, as to the occurrence and latency of the components, regardless of being recorded with the first cochlear implant, or with the second one, turned on. The P1, N1 and P2 components of cortical auditory evoked potentials are not predictors of the results of auditory speech perception, both in silence and in noise.