Current cochlear implant systems use fast pulsatile stimulation to deliver the temporal modulations of speech and to, potentially, improve the neural representation of such modulations by restoring the independence of neural firing. The realization of these benefits may vary with other pulse rate-dependent temporal interactions that occur at the neural membrane, e.g., per(i)stimulatory adaptation and its post-stimulatory or forward masking effects. This study attempted to characterize adaptation and recovery of the electrically evoked compound action potential (ECAP) using probe pulses delivered within and following brief (100 ms) high-rate masker (1800 pps) pulse trains at various current levels in adults and children. With this stimulus paradigm, the ECAP amplitude typically achieved a steady state during the course of pulse train stimulation. The ECAP amplitude at steady state was, on average, a similar proportion (50-70%) of the amplitude at onset for various stimulus levels and in both age groups. However, long-term adaptation effects, evidenced by the decrease in onset ECAP amplitude, were greater in adults particularly at lower levels in the ECAP dynamic range. Instances of alternation in ECAP amplitude were seen at stimulus levels that were higher in the ECAP dynamic range. The forward masking effects of pulse train stimulation were quantified by the ECAP amplitude in response to a subsequent probe pulse normalized by the response to the same pulse presented alone. Pulse train forward masking increased with the level of the masker pulse train and decreased with the level of the probe stimulus. The recovery of the ECAP for probes that were lower in level than the masker pulse train was incomplete at 600 ms after masker offset, consistent with long-term cumulative effects observed in the response to the probe alone. Masker pulse trains that are lower in level than the probe pulse produced proportionally small decrements in the ECAP amplitude with complete recovery within 250 ms of pulse train offset particularly in adults. ECAP recovery of a probe preceded by a masker pulse train of equal level followed a monotonic or non-monotonic pattern consistent with a hypothesis of both adaptation and facilitation occurring with pulse train stimulation. The various patterns of recovery may attest to the occurrence of more than a single process in the same subset of nerve fibers or in different fibers. We hypothesize that the variations in the recovery patterns may be attributable to individual differences in the status of the auditory nerve and possibly, the variations in temporal interactions across the spatial domain at different stimulus levels. Finally, the probe-evoked ECAP amplitude at steady state in children and briefly, e.g., 20 ms, after pulse train offset in both age groups could be predicted by the ECAP amplitude in response to the same probe pulse when preceded at a brief interval (1.2 or 2 ms) by a single masker pulse of the same level as the masker pulse train. Further investigation may reveal if the observed differences in neural responsiveness to pulsatile stimulation, among individuals account for differences in psychophysical measures, including speech perception and whether there may be an "optimal" neural output that could be evoked by an individually "optimized" signal.

<p>A cochlear implant (CI) is a hearing device that makes it possible for individuals who are deaf or has a severe hearing impairment to receive auditory information and develop spoken language. The pragmatic ability may be affected. In short, pragmatics may be described as the study of language use in social contexts. Pragmatic ability can be seen as the result of the individual‟s behavior as well as the underlying causes.</p><p>The aim of the present study was to describe the pragmatic ability in children with CI. An approach inspired by Conversation Analysis (CA) was used in order to highlight the various phenomena that occurred in the interaction.</p><p>Seven children with CI participated in the study, five girls and two boys. Each conversation consisted of either a child with CI interacting with a peer, or a child with CI interacting with a parent or a teacher. A total of 14 conversations were analyzed and phenomena relevant to the study were examined. To gather further information regarding the children‟s communicative behavior, Children’s Communication Checklist was filled in by parents and teachers.</p><p>The children who participated in the study constitute a heterogeneous group and there was no clear pattern when it comes to hearing-impairment and pragmatic ability. The result showed that children with CI used both specific and non-specific requests for clarification. It seems as if intelligibility on the sentence level may reflect how efficient the interaction turns out, as the children with high intelligibility were the ones who managed to solve misunderstandings the best in the conversations. Furthermore, the result demonstrated that the adult participants used a higher rate of specific requests for clarification in contrast to children with CI.</p> / <p>Ett cochleaimplantat (CI) är ett hjälpmedel som gör att personer med grav hörselnedsättning eller personer som är döva får möjlighet att höra och utveckla talat språk. Den pragmatiska förmågan kan vara påverkad. Pragmatik kan i stort betecknas som studiet av språkanvändning i interaktion och pragmatisk förmåga kan beskrivas som ett resultat av individens beteende samt bakomliggande orsaker.</p><p>Syftet med föreliggande studie var att beskriva pragmatisk förmåga hos barn med CI. Ett arbetssätt inspirerat av Conversation Analysis (CA) har använts för att belysa fenomen som förekom i interaktionen.</p><p>I studien deltog sju barn med CI, varav fem flickor och två pojkar. Deltagarna videofilmades när de interagerade med en jämnårig kamrat, respektive en person ur förskolepersonalen eller en förälder. Totalt 14 samtal analyserades och för studien relevanta fenomen belystes. För att inhämta kompletterande information kring barnens samspelsförmåga fylldes Children’s Communication Checklist i av föräldrar och personal.</p><p>Barnen som deltog i studien är en heterogen grupp. Vidare ses inga entydiga mönster vad gäller hörselnedsättning och pragmatiska förmågor. I studien visades att barn med CI använder sig av både generella och specifika begäran om förtydligande. Förståelighet på meningsnivå tycks avspegla hur effektivt samspelet fortskrider då de barn som har hög förståelighet är de som har färre begäranden om förtydligande i samtal. Vidare visar resultaten att de vuxna samtalsdeltagarna använder fler andel specifika begäran om förtydligande i jämförelse med barn med CI.</p>

A cochlear implant (CI) is a hearing device that makes it possible for individuals who are deaf or has a severe hearing impairment to receive auditory information and develop spoken language. The pragmatic ability may be affected. In short, pragmatics may be described as the study of language use in social contexts. Pragmatic ability can be seen as the result of the individual‟s behavior as well as the underlying causes. The aim of the present study was to describe the pragmatic ability in children with CI. An approach inspired by Conversation Analysis (CA) was used in order to highlight the various phenomena that occurred in the interaction. Seven children with CI participated in the study, five girls and two boys. Each conversation consisted of either a child with CI interacting with a peer, or a child with CI interacting with a parent or a teacher. A total of 14 conversations were analyzed and phenomena relevant to the study were examined. To gather further information regarding the children‟s communicative behavior, Children’s Communication Checklist was filled in by parents and teachers. The children who participated in the study constitute a heterogeneous group and there was no clear pattern when it comes to hearing-impairment and pragmatic ability. The result showed that children with CI used both specific and non-specific requests for clarification. It seems as if intelligibility on the sentence level may reflect how efficient the interaction turns out, as the children with high intelligibility were the ones who managed to solve misunderstandings the best in the conversations. Furthermore, the result demonstrated that the adult participants used a higher rate of specific requests for clarification in contrast to children with CI. / Ett cochleaimplantat (CI) är ett hjälpmedel som gör att personer med grav hörselnedsättning eller personer som är döva får möjlighet att höra och utveckla talat språk. Den pragmatiska förmågan kan vara påverkad. Pragmatik kan i stort betecknas som studiet av språkanvändning i interaktion och pragmatisk förmåga kan beskrivas som ett resultat av individens beteende samt bakomliggande orsaker. Syftet med föreliggande studie var att beskriva pragmatisk förmåga hos barn med CI. Ett arbetssätt inspirerat av Conversation Analysis (CA) har använts för att belysa fenomen som förekom i interaktionen. I studien deltog sju barn med CI, varav fem flickor och två pojkar. Deltagarna videofilmades när de interagerade med en jämnårig kamrat, respektive en person ur förskolepersonalen eller en förälder. Totalt 14 samtal analyserades och för studien relevanta fenomen belystes. För att inhämta kompletterande information kring barnens samspelsförmåga fylldes Children’s Communication Checklist i av föräldrar och personal. Barnen som deltog i studien är en heterogen grupp. Vidare ses inga entydiga mönster vad gäller hörselnedsättning och pragmatiska förmågor. I studien visades att barn med CI använder sig av både generella och specifika begäran om förtydligande. Förståelighet på meningsnivå tycks avspegla hur effektivt samspelet fortskrider då de barn som har hög förståelighet är de som har färre begäranden om förtydligande i samtal. Vidare visar resultaten att de vuxna samtalsdeltagarna använder fler andel specifika begäran om förtydligande i jämförelse med barn med CI.

Syftet med föreliggande studie var att undersöka eventuella skillnader mellan barn med cochleaimplantat (CI) och/eller hörapparat (HA) och normalhörande barn i åldrarna fem till sju år avseende fonologiska och kognitiva förmågor. I studien jämfördes resultat från elva till 44 normalhörande barn med åtta till 25 barn med CI/HA från fyra olika studier. Undersökningsmaterialet utgjordes av kortversionen av Stora fonemtestet, fonologiska representationer, TOWRE samt fem deltest ur testbatteriet SIPS. Testresultaten analyserades kvantitativt och för kortversionen av Stora Fonemtestet även kvalitativt. Resultatet visade att barnen med CI/HA generellt presterade lägre än de normalhörande barnen på test av fonologisk förmåga och fonologiskt arbetsminne, men att de låg i nivå med de normalhörande barnen avseende generellt och visuospatialt arbetsminne. De slutsatser som kunde dras var att barnen med CI/HA presterade signifikant lägre avseende flertalet aspekter av fonologisk förmåga, på gruppnivå, dock var prestationen hos barnen med CI/HA vid uppdelning i åldersgrupper signifikant lägre på test av fonologisk produktion i femårsgruppen, men inte i sex- och sjuårsgrupperna. Beträffande kognitiv förmåga presterade barnen med CI/HA betydligt lägre på test av fonologiskt arbetsminne, men de presterade i nivå med de normalhörande barnen i samma åldrar avseende generellt och visuospatialt arbetsminne. / The aim of the current study was to examine potential differences in phonological and cognitive abilities between children with cochlear implants (CI) and/or hearing aids (HA) and hearing children in the ages five to seven years. The study compared results from eleven to 44 children with normal hearing with eight to 25 children with CI/HA from four different studies. The material consisted of a test of output phonology, a test of phonological representations, TOWRE and five subtests in SIPS. All of the results were analyzed quantitatively and the test of output phonology was also analyzed qualitatively. The results indicated that children with CI/HA in general performed poorer than the hearing children on tests of phonological ability and phonological working memory, but they performed on a par with hearing children on tests of complex and visuospatial working memory. The conclusions that may be drawn are that the children with CI/HA, as a group, exhibited poorer phonological ability on several of tests of phonological ability than the children with normal hearing. When analyzed according to age the children with CI/HA exhibited significantly lower phonological production skills in the group consisting of five year old children, but not in the groups consisting of six and seven year old children. Regarding cognitive ability the children with CI/HA exhibited poorer phonological working memory capacity compared to the children with normal hearing, but regarding complex and visuospatial working memory they exhibited abilities on a par with the children with normal hearing

Creating high resolution, or high-density, electrode arrays may be the key for improving cochlear implant users' speech perception in noise, comprehension of lexical languages, and music appreciation. Contemporary electrode arrays use multipolar stimulation techniques such as current steering (shifting the spread of neural excitation in between two physical electrodes) and current focusing (narrowing of the neural spread of excitation) to increase resolution and more specifically target the neural population. Another approach to increasing resolution incorporates microelectromechanical systems (MEMS) fabrication to create a thin film microelectrode (TFM) array with a series of high density electrodes. Validating the benefits of high density electrode arrays requires a systems-level approach. This hypothesis will be tested computationally via cochlea and auditory nerve simulations, and in vitro studies will provide structural proof-of-concept. By employing Rattay's activating function and entering it into Litvak's neural probability model, a first order estimation model was obtained of the auditory nerve's response to electrical stimulation. Two different stimulation scenarios were evaluated: current steering vs. a high density electrode and current focusing of contemporary electrodes vs. current focusing of high density electrodes. The results revealed that a high density electrode is more localized than current steering and requires less current. A second order estimation model was also created COMSOL, which provided the resulting potential and current flow when the electrodes were electrically stimulated. The structural tests were conducted to provide a proof of concept for the TFM arrays' ability to contour to the shape of the cochlea. The TFM arrays were integrated with a standard insertion platform (IP). In vitro tests were performed on human cadaver cochleae using the TFM/IP devices. Fluoroscopic images recorded the insertion, and post analysis 3D CT scans and histology were conducted on the specimens. Only three of the ten implanted TFM/IPs suffered severe delamination. This statistic for scala vestibuli excursion is not an outlier when compared to previous data recorded for contemporary cochlear electrode arrays.

Made available in DSpace on 2014-06-11T19:29:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-10Bitstream added on 2014-06-13T18:58:20Z : No. of bitstreams: 1 anastaciopessan_fl_me_bauru.pdf: 2388062 bytes, checksum: 55eeba49a5538b839c77b215b5de8645 (MD5) / Considerando a privação severa da audição e a reabilitação pelo implante coclear o presente estudo teve como objetivos verificar os efeitos de um programa sistemático de fortalecimento de repertório de linguagem receptiva sobre o repertório expressivo. Participaram desse estudo 06 crianças deficientes auditivas implantadas na faixa etária de 11 anos e 4 meses a 14 anos e 2 meses, todos com deficiência auditiva neurossensorial profunda bilateral, com categoria de linguagem 5 e de audição 6, regularmente matriculadas no Ensino Fundamental. Para coleta de dados foi utilizado um microcomputador e o software MST para a programação das rotinas de ensino e teste e registro das respostas do participante. As sessões foram filmadas para o registro e análise das vocalizações. O delineamento consistiu no ensino da tarefa pelo procedimento de emparelhamento com o modelo (pré-treino), em seguida uma avaliação do repertório do participante em modos ativos e receptivos de linguagem (pré-testes gerais). Foram selecionadas seis palavras cujas vocalizações apresentavam distorções para compor as rotinas de ensino e de teste e o fortalecimento ocorreu três a três. O ensino consistiu no fortalecimento do reconhecimento auditivo (relações condicionais auditivo-visuais AB); posteriormente foi realizado um pós-teste de nomeação de figuras (BD) e de leitura de palavras (CD), conduzidos com as seis palavras selecionadas dos pré-testes gerais. Na seqüência, o participante foi exposto ao fortalecimento de relações entre palavra ditada e palavra impressa (AC), seguido, novamente, pelos pós-testes de nomeação de figuras (BD) e leitura de palavras (CD). Após o segundo pós-teste de nomeação era verificada a formação de classes pelo teste das relações BC e CB, seguido pelos pós-testes de nomeação de figuras (BD) e de leitura de palavras (CD)... / Considering the severe deprivation of hearing and cochler implant rehabilitation for the present study was designed to evaluate the effects of a systematic program of building a repertoire of receptive language on the expressive repertoire. Study partiicipants 06 deaf children implanted at the age of 11 years and 4 months to 14 years and 2 months, all with profound bilateral sensorineural hearing loss, with language category 5 and hearing, regularly enrolled in elementary school. To collect data we used a microcomputer and software MST for pragramming the routines of teaching and recording of participant responses. The sessions were taped for the record and analysis of vacalizations. The experient consisted in teaching the task by the pairing procedure with the model (pretraining), then evaluate the repertoire of the participant active and receptive modes of language (pre-tests overall). Six words were selected which had distorted vocals to make up the routines of teaching and strengthening occurred three to three. The teaching consisted in strengthening the auditory recognition (auditory-visual conditional relations AB), later a post-test of picture naming (BD) and word reading (CD), conducted with the six selected words of the pre-tests General. Next, the participant was exposed to the strengthening of relations between word dictated and printed words (CA), followed again by post-tests of picture naming (BD) and word reading (CD). After the second post-test appointment was checked by testing training classes BC and CB relations, followed by post-tests of picture naming (BD) and word reading (CD). Finally, the teaching was done in the selection of syllables that made up the words of instruction (AC) followed by post-tests of vocalization. The relations, have learned auditory-visual relations and class formation attested; results showed variability in the repertoire... (Complete abstract click electronic access below)

INTRODUÇÃO: A introdução dos princípios da soft surgery desencadeou busca constante pela preservação auditiva, principalmente após a expansão dos critérios de inclusão para a cirurgia do implante coclear. Esses princípios cirúrgicos, associados a novos modelos de eletrodos e ao uso de fármacos no intraoperatório, têm sido utilizados a partir do melhor conhecimento da anatomia da orelha interna e da repercussão dos mecanismos inflamatórios desencadeados pelo trauma de inserção dos eletrodos. O objetivo deste estudo é avaliar o efeito de dexametasona tópica isolada e associada ao ácido hialurônico no intraoperatório de pacientes com audição residual submetidos ao implante coclear na preservação dos limiares tonais dos mesmos. MÉTODO: Foram avaliados 18 pacientes adultos com surdez severaprofunda submetidos à cirurgia de implante coclear divididos em 3 grupos: Implante coclear como grupo-controle, grupo 1; implante coclear com uso de dexametasona tópica no intraoperatório, grupo 2; e implante coclear com uso de dexametasona tópica associada ao ácido hialurônico no intraoperatório, grupo 3. Foram comparadas as médias dos limiares tonais nas frequências de 125, 250 e 500 Hz e nas frequências de 1000, 2000 e 4000 Hz no pré-operatório e no pós-operatório. RESULTADOS: A diferença entre as médias dos limiares tonais nas frequências baixas obtidas no 6º mês de pós-operatório e no pré-operatório foi de 28,03 dB + 6,77 dB no grupo 1, 30 dB + 14,53 dB no grupo 2 e 7,23 dB + 6,12 dB no grupo 3. Houve diferença estatisticamente significante dos valores do grupo 3 em relação ao grupo 1 e 2 (p = 0,002). A diferença entre as médias dos limiares tonais nas frequências altas obtidas no 6º mês de pós-operatório e no pré-operatório foi de 11,12 dB (DP + 9,71 dB) no grupo 1, 22,77 dB (DP + 12,79 dB) e 3,89 dB (DP + 3,1 dB). Houve diferença estatística entre os grupos 2 e 3 (p = 0,01). CONCLUSÕES: A associação do uso tópico de dexametasona e ácido hialurônico no intraoperatório de pacientes submetidos à cirurgia do implante coclear foi significantemente superior ao grupo controle e ao grupo no qual foi utilizado apenas a dexametasona tópica na preservação dos limiares auditivos. Por outro lado, o uso isolado de dexametasona tópica não demonstrou resultados superiores na preservação dos limiares acústicos quando comparado ao grupo controle / INTRODUCTION: The expansion of candidacy criteria for cochlear implantation led to a constant care for hearing preservation. The in-depth knowledge of the anatomy and function of the inner ear as well as the inflammatory repercussion caused by the insertion trauma led to the development of soft surgery principles, new electrode designs and pharmacotherapy. The purpose of this study was to compare the effects of topical dexamethasone isolated and associated with hyaluronic acid in hearing preservation in cochlear implantation. METHOD: Eighteen severely to profoundly hearing impaired adult patients were evaluated and divided into 3 groups: Cochlear implantation as a control group in group 1, cochlear implantation using topical dexamethasone intraoperatively in group 2 and cochlear implantation using topical dexamethasone associated with hyaluronic acid intraoperatively in group 3. Preimplant and postimplant low frequency and high frequency pure-tone average (PTA) from 125, 250, 500 Hz and 1000, 2000, 4000 Hz were calculated and compared from unaided audiograms. RESULTS: The mean changes in the low frequency PTA of preoperative and postoperative thresholds were 28.03 dB + 6.77 dB in group 1, 30 dB + 14.53 dB in group 2 and 7.23 dB + 6.12 dB in group 3. There was statistical difference comparing group 3 with group 1 and 2 (p = 0.002). The mean changes in the high frequency PTA of preoperative and postoperative thresholds were 11.12 dB + 9.71 dB in group 1, 22.77 dB + 12.79 dB e 3.89 dB + 3.1 dB. There was statistical difference between group 2 and 3 (p = 0.01). CONCLUSIONS: The use of topical dexamethasone associated with hyaluronic acid intraoperatively in cochlear implant surgery demonstrated a statistically significant difference in the preservation of low frequency thresholds when compared with the use of isolated topical dexamethasone and a control group. The use of isolated topical dexamethasone was not superior in hearing preservation when compared to a control group

Recipients of present-day cochlear implants (CIs) display remarkable success with speech recognition in quiet, but not with speech recognition in noise. Normal-hearing (NH) listeners, in contrast, perform relatively well with speech recognition in noise. Understanding which speech features support successful perception in noise in NH listeners could provide insight into the difficulty that CI listeners experience in background noise. One set of speech features that has not been thoroughly investigated with regard to its noise immunity is prosody. Existing reports show that CI users have difficulty with prosody perception. The present study endeavoured to determine if prosody is particularly noise-immune in NH listeners and whether the difficulty that CI users experience in noise can be partly explained by poor prosody perception. This was done through the use of three listening experiments. The first listening experiment examined the noise immunity of prosody in NH listeners by comparing perception of a prosodic pattern to word recognition in speech-weighted noise (SWN). Prosody perception was tested in a two-alternatives forced-choice (2AFC) test paradigm using sentences conveying either conditional or unconditional permission, agreement or approval. Word recognition was measured in an open set test paradigm using meaningful sentences. Results indicated that the deterioration slope of prosody recognition (corrected for guessing) was significantly shallower than that of word recognition. At the lowest signal-to-noise ratio (SNR) tested, prosody recognition was significantly better than word recognition. The second experiment compared recognition of prosody and phonemes in SWN by testing perception of both in a 2AFC test paradigm. NH and CI listeners were tested using single words as stimuli. Two prosody recognition tasks were used; the first task required discrimination between questions and statements, while the second task required discrimination between a certain and a hesitant attitude. Phoneme recognition was measured with three vowel pairs selected according to specific acoustic cues. Contrary to the first experiment, the results of this experiment indicated that vowel recognition was significantly better than prosody recognition in noise in both listener groups. The difference between the results of the first and second experiments was thought to have been due to either the test paradigm difference in the first experiment (closed set versus open set), or a difference in stimuli between the experiments (single words versus sentences). The third experiment tested emotional prosody and phoneme perception of NH and CI listeners in SWN using sentence stimuli and a 4AFC test paradigm for both tasks. In NH listeners, deterioration slopes of prosody and phonemes (vowels and consonants) did not differ significantly, and at the lowest SNR tested there was no significant difference in recognition of the different types of speech material. In the CI group, prosody and vowel perception deteriorated with a similar slope, while consonant recognition showed a steeper slope than prosody recognition. It is concluded that while prosody might support speech recognition in noise in NH listeners, explicit recognition of prosodic patterns is not particularly noise-immune and does not account for the difficulty that CI users experience in noise. ## Ontvangers van hedendaagse kogleêre inplantings (KI’s) behaal merkwaardige sukses met spraakherkenning in stilte, maar nie met spraakherkenning in geraas nie. Normaalhorende (NH) luisteraars, aan die ander kant, vaar relatief goed met spraakherkenning in geraas. Begrip van die spraakeienskappe wat suksesvolle persepsie in geraas ondersteun in NH luisteraars, kan lei tot insig in die probleme wat KI-gebruikers in agtergrondgeraas ervaar. Een stel spraakeienskappe wat nog nie deeglik ondersoek is met betrekking tot ruisimmuniteit nie, is prosodie. Bestaande navorsing wys dat KI-gebruikers sukkel met persepsie van prosodie. Die huidige studie is onderneem om te bepaal of prosodie besonder ruisimmuun is in NH luisteraars en of die probleme wat KI-gebruikers in geraas ondervind, deels verklaar kan word deur swak prosodie-persepsie. Dit is gedoen deur middel van drie luistereksperimente. Die eerste luistereksperiment het die ruisimmuniteit van prosodie in NH luisteraars ondersoek deur die persepsie van ’n prosodiese patroon te vergelyk met woordherkenning in spraakgeweegde ruis (SGR). Prosodie-persepsie is getoets in ’n twee-alternatiewe-gedwonge-keuse- (2AGK) toetsparadigma met sinne wat voorwaardelike of onvoorwaardelike toestemming, instemming of goedkeuring oordra. Woordherkenning is gemeet in ’n oopstel-toetsparadigma met betekenisvolle sinne. Resultate het aangedui dat die helling van agteruitgang van prosodieherkenning (gekorrigeer vir raai) betekenisvol platter was as dié van woordherkenning, en dat by die laagste sein-tot-ruiswaarde (STR) wat getoets is, prosodieherkenning betekenisvol beter was as woordherkenning. Die tweede eksperiment het prosodie- en foneemherkenning in SGR vergelyk deur die persepsie van beide te toets in ’n 2AGK-toetsparadigma. NH en KI-luisteraars is getoets met enkelwoorde as stimuli. Twee prosodieherkenningstake is gebruik; die eerste taak het diskriminasie tussen vrae en stellings vereis, terwyl die tweede taak diskriminasie tussen ’n seker en onseker houding vereis het. Foneemherkenning is gemeet met drie vokaalpare wat geselekteer is na aanleiding van spesifieke akoestiese eienskappe. In teenstelling met die eerste eksperiment, het resultate van hierdie eksperiment aangedui dat vokaalherkenning betekenisvol beter was as prosodieherkenning in geraas in beide luisteraarsgroepe. Die verskil tussen die resultate van die eerste en tweede eksperimente kon moontlik die gevolg wees van óf die verskil in toetsparadigma in die eerste eksperiment (geslote- teenoor oop-stel), óf ’n verskil in stimuli tussen die eksperimente (enkelwoorde teenoor sinne). Die derde eksperiment het emosionele-prosodie- en foneempersepsie van NH en KI-luisteraars getoets in SGR met sinstimuli en ’n 4AGK-toetsparadigma vir beide take. In NH luisteraars het die helling van agteruitgang van die persepsie van prosodie en foneme (vokale en konsonante) nie betekenisvol verskil nie, en by die laagste STR wat getoets is, was daar nie ’n betekenisvolle verskil in die herkenning van die twee tipes spraakmateriaal nie. In die KI-groep het prosodie- en vokaalpersepsie met soortgelyke hellings agteruitgegaan, terwyl konsonantherkenning ’n steiler helling as prosodieherkenning vertoon het. Die gevolgtrekking was dat alhoewel prosodie spraakherkenning in geraas in NH luisteraars mag ondersteun, die eksplisiete herkenning van prosodiese patrone nie besonder ruisimmuun is nie en dus nie ’n verklaring bied vir die probleme wat KI-gebruikers in geraas ervaar nie. / Thesis (PhD)--University of Pretoria, 2014. / lk2014 / Electrical, Electronic and Computer Engineering / PhD / unrestricted

L'implant cochléaire représente le dispositif de référence pour réhabiliter l'audition des patients atteints de surdités sévère à profonde. Les indications se sont récemment étendues vers les patients avec une audition résiduelle avec de bons résultats. Il persiste cependant une grande hétérogénéité des résultats auditifs. Plusieurs facteurs ont été identifiés comme influençant les performances auditives: durée de la surdité, intelligibilité préopératoire et stratégie de codage. Dans cette thèse, l'anatomie de la cochlée et la position postopératoire du porte-électrodes ont été étudiés afin d'identifier les facteurs de variabilité de la discrimination vocale inter- et intra-individuelle. Les résultats de cette thèse ont montré un lien entre la position de l'électrode et les performances auditives à court terme, alors que la plasticité neuronale pourrait jouer un rôle important dans l'adaptation de l'implant cochléaire aux structures neurales à long terme. De plus, la préservation des structures cochléaires est maintenant recommandée pour tous les candidats à l'implantation, quelle que soit leur audition préopératoire. Une étude radio-histologique sur rochers avec une insertion motorisée du porte-électrodes a été réalisée afin d'identifier les paramètres des forces d'insertion qui pourraient prédire le traumatisme de l'oreille interne lié à l'insertion. Une corrélation entre les valeurs de forces d'insertion et le traumatisme cochléaire a été trouvée dans les os temporaux. Ces valeurs, serviront au développement d'outils d'insertion " intelligents " pour réduire les lésions liées à l'insertion et ainsi conduire à des conditions de rééducation auditive optimale. / The cochlear implantation represents the standard technique to restore the hearing in totallydeafened persons, and the indications during the last years are widening also to patients withresidual hearing or presenting single sided deafness. Despite the overall good to very goodresults after cochlear implantation reported in literature a wide heterogeneity of the hearingoutcomes emerges in the single studies and poor results both in unilateral and bilateralcochlear implantation are still reported. Several patients’ specific factors have been identifiedas affecting postimplant speech perception score, including duration of deafness, residualpreoperative speech recognition, and different speech coding strategy. In this thesis theanatomy of the cochlea and the position of the electrode array in implanted patients have beenstudied with the attempt to identify the affecting factors that contribute to the variability of theinter- and intra-individual speech discrimination scores both in bilaterally and unilaterallyimplanted patients. Moreover, following the expanding indication for cochlear implantation,the preservation of inner ear structures is becoming recommended for all cochlear implantcandidates, regardless of their preoperative hearing. A radio-histological temporal bone studywith a motorized insertion of the array was performed in order to identify the insertion forcesparameters that could predict the possible traumatism involving the inner ear. The results ofthis thesis showed a relationship between the intracochlear electrode position and hearingperformance in the short term follow up, whereas the neural plasticity would play animportant role in the adaptation of the cochlear implant to the neural structures in the longterm. A correlation between insertion forces and inner ear traumatism was found in temporalbones. Two different force profiles for traumatic and atraumatic insertion were obtained; thesevalues, if confirmed by further studies, could be useful for the development of future forcefeedback automated cochlear implant insertion tool in order to reduce the risk of insertionrelated damage and provide the best chance for an optimal hearing rehabilitation in cochlearimplanted candidates.

Some children with severe to profound hearing loss are implanted with a cochlear implant on the hypothesis that short-term outcomes in auditory receptive skills can be utilized into greater social independence and quality of life. In order to measure the outcomes and progress achieved from cochlear implants, effective assessment protocols are vital. The purpose of assessment after cochlear implantation, is to monitor an individual child’s rate of progress in speech and language acquisition, with reference to other cochlear implant users; to collect data on the range of linguistic benefits observed against cochlear implant users over time and to investigate and amend unforeseen difficulties. Furthermore, the outcome measures provide concrete information to the multidisciplinary team, and parents, and for collection of prevalence data for further research, which is crucial for funding purposes. The dynamic and natural approach to assessment has been recommended as the most effective, to ensure a holistic assessment in young children with cochlear implants. The aim of the current study was to determine the relevance of an assessment protocol proposed by the Pretoria Cochlear Implant Programme. The protocol was administered on eight children in the transitional stage of spoken language development, within an inclusive educational setting. A descriptive research design was selected in order to describe the qualitative results obtained during the study. The following assessments were included in the protocol: A questionnaire on background information, an aided audiogram (with cochlear implants and hearing aids), speech discrimination, Speech in Noise Test; Developmental Assessment Schema (Auditory Communication), Developmental Assessment Schema (General Development), Rossetti Infant-Toddler Language Scale, Reynell Developmental Language Scales III (Verbal Comprehension), Speech Intelligibility Rating, Voice Skills Assessment, Preschool Literacy Assessment, Mother Infant Communication Scale, Caregiver-Child Interaction, Meaningful Auditory Integration Scale, Meaningful Use of Speech Scale and Profile of Actual Linguistic Skills. The results indicated that all the vital areas of assessment are included in the protocol, and under-evaluation is not a concern. Some of the areas of assessment overlap in the protocol, ensuring that the cross-check principle is being applied. The information gained from the assessment protocol can be used effectively for future intervention planning and adaptations can be made where necessary. Moreover, it was concluded that the administration and interpretation of the assessment protocol is time efficient and can be used effectively within a clinical setting. Cultural barriers did not have an effect on the administration and interpretation of the assessment protocol, however, linguistic barriers can influence the outcome of the results obtained. In summary, the assessment protocol has been found to be innovative, time effective, user-friendly, informative and relevant for the assessment of young cochlear implant users in the transitional stage of verbal linguistic development. Recommended changes for the assessment protocol were suggested, as well as recommendations for the educational setting. It was suggested that the questionnaires be available in all South African languages and that some of the protocols only be used if age-appropriate. Another recommendation was that the Listening Progress (LiP) and a pragmatic profile should be included in the protocol. Furthermore, it was suggested that an assistant audiologist could be involved to ensure more accurate and quicker hearing assessments. / Thesis (M Communication Pathology)--University of Pretoria, 2007. / Speech-Language Pathology and Audiology / unrestricted