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1
Zachrisson, Love. "Investigation of coherence between limbic structures in a rodent model of Parkinson's Disease." Thesis, Umeå universitet, Institutionen för psykologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-186674.
Abstract:
Parkinson’s Disease affects 10 million people worldwide, with 40% of patients developing an associated psychosis which has been identified by studies as the number one source of caretaker distress and is related to increased mortality. This is further complicated by the fact that typical antipsychotic drugs worsen many of the motor symptoms implicated in Parkinson’s Disease, with only one commercially available drug able to ameliorate both symptoms. This problem ushers the development of novel drugs to treat these symptoms, as first tested on research animals. Complicating matters, drug effectiveness on the degree of psychosis is hard to obtain in animals without a reliable biomarker. However, a hallmark of psychotic states is thought to be the reduced coordination between brain structures, through neuronal synchronization, as demonstrated by steady-state responses and is suggested to be a potential biomarker of psychosis. By building a MATLAB software we were able to analyze the degree of neural synchronization between structures, during an auditory steady-state response, in rats that had been unilaterally lesioned by the 6-Hydroxydopamine model of Parkinson’s Disease, before and after administration of the psychotomimetic drug MK801. These rats had been chronically implanted with 128-channel multi electrode array, enabling us to measure the strength of coherence between several limbic structures, associated with auditory processing, from the sampled local field potential, identifying the degree of synchronization in the animal brain. As our data demonstrate that coherence levels dropped in the psychotic drug state, for structures in both the healthy and the Parkinsonian hemisphere, we are able to further demonstrate the validity of coherence measures as a biomarker for psychosis. These results demonstrate that our software can be used as a tool to assess the therapeutic response of drugs developed, aimed at treating Parkinson’s associated psychosis.Parkinsons sjukdom drabbar 10 miljoner världen över, där 40% av patienterna utvecklar en associerad psykos vilket har visats vara en av de största stressfaktorerna för deras vårdgivare och är även förknippat med en högre dödlighetsgrad. Denna situation förvärras av det faktum att de vanliga antipsykotiska drogerna kan förvärra många av de motoriska symptom som utgörs av Parkinsons sjukdom och det finns i dagsläget enbart en enda kommersiell drog som kan dämpa bägge symptom samtidigt. Detta problem frammanar vidare utveckling av nya läkemedel som kan behandla dessa symptom, som innebär att de först måste testas på försöksdjur. En komplikation som uppstår i relation till detta är svårigheten att utvärdera om läkemedel har någon terapeutisk effekt på de psykotiska tillstånden, enbart genom att observera försöksdjurens beteenden, och en pålitlig biomarkör krävs istället. En lösning kan dock finnas i det faktum att psykotiska tillstånd karaktäriseras av en reducerad förmåga för olika hjärnområden att koordinera genom neural synkronisering vilket demonstreras av ‘steady- state’ responser. Detta föreslår att ett mått på graden av koordineringsförmåga kan agera som en möjlig biomarkör för psykotiska tillstånd. Genom att konstruera ett MATLAB-program kunde vi analysera graden av synkronicitet mellan hjärnstrukturer, under den auditiva steady- state responsen i råttor som hade blivit ensidigt lesionerade genom 6-Hydroxiddopamin modellen av Parkinsons sjukdom, före och efter administration av den psykotomimetiska drogen MK801. Dessa råttor hade blivit kroniskt implanterade med 128 elektroder vilket möjliggjorde att vi kunde mäta styrkan i koherens i den lokala fält potentialen mellan limbiska strukturer, som är associerade med auditiv processering, vilket möjliggjorde identifiering av3dessa strukturers synkronicitet. Vår data demonstrerar att koherensen minskade under det psykotiska drogtillståndet för limbiska strukturer både i den intakta och den lesionerade hjärnhalvan. Detta är en vidare demonstration av att koherensnivåer kan agera som en biomarkör för det psykotiska tillståndet, liksom att vår mjukvara kan nyttjas som ett verktyg för att utvärdera nya läkemedels behandlingsförmåga på Parkinsons psykos.
2
Small, Susan Anne. "Bone-conduction auditory steady-state responses." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31066.
Abstract:
The purpose of this dissertation was to determine whether multiple auditory-state
responses (ASSRs) to bone-conduction stimuli can be used to investigate bone-conduction
hearing, an essential part of any audiometric assessment. Infant bone-conduction testing methods,
maturation of bone-conduction hearing, and ipsilateral/contralateral asymmetries in ASSRs were
also assessed. The results show that bone-conduction ASSRs can be used to estimate thresholds
in infants and adults with normal hearing. It was also found that choice of electroencephalogram
(EEG) conditioning and processing can avoid spurious ASSRs due to aliasing. Non-auditory
ASSRs (probably vestibular and indistinguishable from an auditory response) were also
identified for high-intensity air-conduction stimuli (problematic when diagnosing residual
hearing). Investigation of infant testing methods on bone-conduction threshold shows that: (i)
bone-oscillator coupling method (elastic-band vs. hand-held) has no effect on threshold, (ii) use
of different oscillator locations on the temporal bone does not affect threshold but a forehead
placement results in elevated thresholds, and (iii) infants do not appear to have an occlusion
effect (thus one can can assess with or without earphones). Young infants have much better low-frequency
bone-conduction hearing compared to adults, which increases with maturation beyond
24 months of age. Infant bone-conduction hearing is slightly poorer in the high frequencies,
improving significantly with age only at 2000 Hz. Within all infant groups, low-frequency
thresholds are better than high-frequency thresholds; for adults, 500-Hz thresholds are poorer
than high frequencies and there is no difference among thresholds above 500 Hz. Bone-conducted
signals are much more effective for infants across frequency, especially at low
frequencies. Normal levels for bone-conduction hearing in young and older infants are proposed.
Ipsilateral/contralateral asymmetries in air- and bone-conduction ASSRs are clearly present more often and are larger in infants compared to adults, and suggest that most infants have 10-30 dB of
interaural attenuation. These asymmetries have potential as a clinical tool for isolating the
cochlea that is contributing to the response in infants. The results of these studies indicate that
infants can now be screened for normal bone-conduction hearing with ASSRs; however, infants
with hearing loss must be tested before elevated bone-conduction ASSRs thresholds can be
interpreted.Medicine, Faculty of
Audiology and Speech Sciences, School of
Graduate
3
Clinard, C., Owen D. Murnane, and J. Tampas. "Auditory Steady-State Response: Test-Retest Reliability." Digital Commons @ East Tennessee State University, 2006. https://dc.etsu.edu/etsu-works/1900.
4
Li, Yiwen. "Predicting hearing loss using auditory steady-state responses." Worcester, Mass. : Worcester Polytechnic Institute, 2009. http://www.wpi.edu/Pubs/ETD/Available/etd-011409-105327/.
5
Leigh-Paffenroth, Elizabeth D., and Owen D. Murnane. "Auditory Steady State Responses Recorded in Multitalker Babble." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu-works/1787.
Abstract:
Objective: The primary purpose of this investigation was to determine the effect of multitalker babble on ASSRs in adult subjects with normal hearing (NH) and sensorineural hearing loss (HI). The secondary purpose was to investigate the relationships among ASSRs, word recognition in quiet, and word recognition in babble. Design: ASSRs were elicited by a complex mixed-modulation tonal stimulus (carrier frequencies of 500, 1500, 2500, and 4000 Hz; modulation rate of 40 or 90 Hz) presented in quiet and in babble. The level of each carrier frequency was adjusted to match the level of the multitalker babble spectrum, which was based on the long term speech spectrum average. Word recognition in noise (WIN) performance was measured and correlated to ASSR amplitude and ASSR detection rate. Study Sample: Nineteen normal-hearing adults and nineteen adults with sensorineural hearing loss were recruited. Results and Conclusions: The presence of babble significantly reduced the ASSR detection rate and ASSR amplitude for NH subjects, but had minimal effect on ASSRs for HI subjects. In addition, babble enhanced ASSR amplitude at high stimulus levels. ASSR detection rate and ASSR amplitude recorded in quiet and babble were significantly correlated with word recognition performance for NH and HI subjects.
Sumario
Objetivo: El objetivo fundamental de esta investigación fue determinar el efecto de balbuceo de hablantes múltiples en los ASSR de adultos jóvenes con audición normal (NH) y con pérdidas auditivas sensorineurales (HI). El objetivo secundario fue investigar las relaciones entre los ASSR, el reconocimiento de palabras en silencio y el reconocimiento de palabras con en medio de balbuceo. Diseño: Los ASSR fueron evocados por estímulo tonal de modulación mezclada compleja (frecuencias portadoras de 500, 1500, 2500 y 4000 Hz; tasa de modulación de 40 o 90 Hz) presentadas en silencio y con el balbuceo. Se ajustó el nivel de cada frecuencia portadora para emparejar el nivel del espectro del balbuceo de hablantes múltiples, el cual se basó en el promedio del espectro a largo plazo. Se midió el rendimiento para el reconocimiento de palabras en ruido (WIN) y se correlacionó con la amplitud de los ASSR y con la tasa de detección de los ASSR. Muestra Del Estudio: Se reclutaron diez y nueve adultos normoyentes y diez y nueve adultos con pérdida auditiva sensorineural. Resultados Y Conclusiones: La presencia del balbuceo reduce significativamente la tasa de detección de los ASSR y la amplitud de los ASSR en sujetos NH, pero tiene efectos mínimos en los ASSR de sujetos HI. Además, el balbuceo aumenta la amplitud de los ASSR con estímulos de niveles altos. La tasa de detección de los ASSR y la amplitud de los ASSR registrada en silencio y con balbuceo, fueron significativamente correlacionadas con el rendimiento para reconocer palabras en sujetos NH y HI.
6
li, yiwen. "Predicting Hearing Loss Using Auditory Steady-State Responses." Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/84.
Abstract:
Auditory Steady-State Response (ASSR) is a promising tool for detecting hearing loss. In this project, we analyzed hearing threshold data obtained from two ASSR methods and a gold standard, pure tone audiometry, applied to both normal and hearing-impaired subjects. We constructed a repeated measures linear model to identify factors that show significant differences in the mean response. The analysis shows that there are significant differences due to hearing status (normal or impaired) and ASSR method, and that there is a significant interaction between hearing status and test signal frequency. The second task of this project was to predict the PTA threshold (gold standard) from the ASSR-A and ASSR-B thresholds separately at each frequency, in order to measure how accurate the ASSR measurements are and to obtain a ¡°correction function¡± to correct the bias in the ASSR measurements. We used two approaches. In the first, we modeled the relation of the PTA responses to the ASSR values for the two hearing status groups as a mixture model and tried two prediction methods. The mixture modeling was successful, but the predictions gave disappointing results. A second approach, using logistic regression to predict group membership based on ASSR value and then using those predictions to obtain a predictor of the PTA value, gave successful results.
7
Bosnyak, Daniel J. Roberts L. E. "Mechanisms and dynamics of the human auditory steady-state response /." *McMaster only, 2003.
8
Potter, Christopher Robert. "Children's breath-by-breath ventilatory and gas exchange responses to exercise." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302571.
9
Mohammed, Ali Hjaji. "Steady State Response of Thin-walled Members Under Harmonic Forces." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24013.
Abstract:
The steady state response of thin-walled members subjected to harmonic forces is investigated in the present study. The governing differential equations of motion and associated boundary conditions are derived from the Hamilton variational principle. The harmonic form of the applied forces is exploited to eliminate the need to discretize the problem in the time domain, resulting in computational efficiency.
The formulation is based on a generalization of the Timoshenko-Vlasov beam theory and accounts for warping effects, shear deformation effects due to bending and non-uniform warping, translational and rotary inertial effects and captures flexural-torsional coupling arising in asymmetric cross-sections.
Six of the resulting seven field equations are observed to be fully coupled for asymmetric cross-sections while the equation of longitudinal motion is observed to be uncoupled. Separate closed form solutions are provided for the cases of (i) doubly symmetric cross sections, (ii) monosymmetric cross-sections, and (iii) asymmetric cross-sections. The closed-form solutions are provided for cantilever and simply-supported boundary conditions.
A family of shape functions is then developed based on the exact solution of the homogeneous field equations and then used to formulate a series of super-convergent finite beam elements. The resulting two-noded beam elements are shown to successfully capture the static and dynamic responses of thin-walled members. The finite elements developed involve no special discretization errors normally encountered in other finite element formulations and provide results in excellent agreement with those based on other established finite elements with a minimal number of degrees of freedom. The formulation is also capable to predict the natural frequencies and mode-shapes of the structural members.
Comparisons with non-shear deformable beam solutions demonstrate the importance of shear deformation effects within short-span members subjected to harmonic loads with higher exciting frequencies. Comparisons with shell element solution results demonstrate that distortional effects are more pronounced in cantilevers with short spans.
A generalized stress extraction scheme from the finite element formulation is then developed. Also, a generalization of the analysis procedure to accommodate multiple loads with distinct exciting frequencies is established. The study is concluded with design examples which illustrate the applicability of the formulation, in conjunction with established principles of fatigue design, in determining the fatigue life of steel members subjected to multiple harmonic forces.
10
Wood, Lori Laraine. "Multiple brainstem auditory steady-state response interactions for different stimuli." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/15532.
Abstract:
Auditory steady-state responses (ASSRs) have been shown to be accurate in predicting thresholds of individuals with hearing loss. Although new stimuli are being proposed and clinically implemented, there are no data to indicate whether response interactions would be adversely affected by their use. This study investigated the effects of three different stimuli (AM, AM/FM and AM²) at two different intensities (60 dB HL and 80 dB HL) on response amplitudes and interactions in normal-hearing adults. Stimuli were generated by the Rotman MultiMASTER research system and presented via air conduction through EAR-3A insert earphones. Carrier frequencies of 0.5, 1, 2, and 4 kHz were 80-Hz modulated in three conditions: individually (monotic single; MS), simultaneously in one ear (monotic multiple; MM), and simultaneously in both ears (dichotic multiple; DM). It was predicted that stimuli with broader spectra would result in greater amplitudes. This was demonstrated in the MS condition by the AM/FM stimulus, which evoked responses significantly larger than those to both AM and AM² stimuli at all frequencies except 0.5 kHz at 60 and 80 dB HL. In the multiple (MM and DM) conditions, response amplitudes to AM² were significantly larger than AM and AM/FM response amplitudes at both intensities. It was also predicted that more interactions would be found when using stimuli with broader spectra, even at moderate intensities. This was illustrated by the drop in amplitude by the AM/FM stimulus in the multiple conditions versus in the single condition, even at 60 dB HL. Relative efficiency values in the multiple conditions were never less than that found in the single condition at 60 dB HL; at 80 dB HL, the majority (83%) of comparisons were more efficient in the multiple conditions than the single condition. Based on these results, the optimal stimulus to use appears to be dependent on the chosen condition. In the single condition, AM/FM stimuli result in the largest response amplitudes, however, in the multiple condition, AM² stimuli provide the best combination of amplitude values and testing efficiency.
11
Simpson, David Gordon Giles, and dsimpson@swin edu au. "Instrumentation for high spatial resolution of steady state visual evoked potentials." Swinburne University of Technology, 1998. http://adt.lib.swin.edu.au./public/adt-VSWT20060711.123100.
Abstract:
This thesis reports on several new and innovative instrumentation developments to
solve some of the problems of brain activity monitoring, particularly SSVEP (Steady
State Visual Evoked Potentials) studies. SSVEP systems generate suitable stimuli and
record the resulting brain biopotentials from scalp electrodes.
The instrumentation is configured as a 'Neuropsychiatric Workstation', supporting up to
136 scalp electrodes. Operating in the SSVEP mode, the Neuropsychiatric Workstation
reported here significantly improves upon the previously reported spatial resolution and
accuracy of maps related to the generated stimuli. These maps allows insights to be
gained into the cognitive workings of the brain.
A significant component of the work reported here covers the development of the multielectrode
EEG measurement modules and the associated techniques for minimising
interference and cross-talk. The techniques for synchronising recordings from all
electrodes with the stimulus, interfacing to a host computer and real-time storage of the
very large amounts of data generated to hard disk, are all reported.
The SSVEP paradigm uses a sinusoidal-modulated visual stimuli. A novel linearised
LED (light emitting diode) head-up display was developed, in addition to more
conventional stimuli, such as the alternating checker-board display, all with sinusoidal
modulation capability over a range of frequencies.
The Neuropsychiatric Workstation described in thesis has been replicated several times
and is in regular use at Brain Sciences Institute (BSI) at Swinburne University of
Technology, and other collaborative research institutes.
12
OTT, Gustavo. "Performance analysis of a framework for auditory steady-state response detection." Universidade Catolica de Pelotas, 2017. http://tede.ucpel.edu.br:8080/jspui/handle/tede/617.
Abstract:
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The Auditory Steady-State Response (ASSR) is a periodic electrical response from the brain which is generated by a healthy or impaired ear without conduction hearing loss subject. This response is evoked by presenting a subject to a periodically varying continuous acoustic signal, typically a sinusoidally modulated tone. The response consists of a waveform whose constituent discrete frequency components have the same periodicity as that of the acoustic signal and remain constant in amplitude and phase over an infinitely long time period. ASSR has been used to objectively assess hearing thresholds for hearing impairment diagnosis, in contrast to traditional subjective methods such as auditory brain-stem responses and audiometry. The objective of this study is to implement experimental setups that detect simulated ASSRs in single and multiple response recordings in order to asses detector performance in different approaches of signal recording parameters and signal processing techniques. The experimental setups were implemented using the MATLAB environment, in which three test scenarios were also developed: (i) a single channel ASSR detector in which the statistical detection tests F test, phase coherence (PC), magnitude-squared coherence (MSC) and Hotteling’s T 2 circular (T2) were used for comparative performance evaluation; (ii) a single channel ASSR detector in which the traditional sweep-by-sweep (SBS) averaging approach performance was compared to the proposed epoch-by-epoch (EBE) averaging aproach; and (iii) a multiple channel ASSR detector in which three Independent Component Analysis (ICA) algorithms – JADE, SOBI, and WASOBI – were applied for comparative performance evaluation from the reference method, in which ICA was not applied. The performance evaluation method was the Receiver Operating Characteristic (ROC) analysis, in which the Area Under the Curve (AUC) metric was used to estimate the detector’s accuracy levels for ASSR detection. From the results of the first test scenario it was concluded that the T2 and MSC tests presented the best overall performance, specially at lower SNR conditions. Results from scenario 2 indicated that the SBS approach resulted in higher accuracy levels after the transitory period of the AUC curve related to test time duration, while the EBE resulted in the steepest AUC curves for the first seconds of test time duration. From the results of scenario 3 it was not observed significant ASSR’s detection time reduction when ICA algorithms were applied in situations closely related to hearing threshold estimation.
A Resposta Auditiva de Estado Estável (RAEE) é uma resposta elétrica periódica gerada pelo cérebro em pacientes com ouvidos saudáveis. Esta resposta é evocada ao ser apresentado ao paciente um estímulo acústico contínuo que varia periodicamente, tipicamente um tom modulado por um sinal sinusoidal. A resposta é constituída por componentes em frequência que têm a mesma periodicidade do estímulo e permanecem constantes em termos de amplitude e fase por um período de tempo infinitamente longo. As RAEEs têm sido utilizadas para avaliar de forma objetiva os limiares de audição para diagnóstico de perda auditiva, em contraste aos métodos tradicionais subjetivos, como a audiometria. O objetivo deste trabalho é a implementação de estruturas experimentais que detectem RAEEs simuladas em abordagens de captação de canal único e de múltiplos canais a fim de avaliar o desempenho do detector em diferentes abordagens de processamento de sinal. As estruturas experimentais foram implementadas utilizando o ambiente MATLAB, no qual três cenários de teste foram desenvolvidos: (i) um detector de RAEE para canal simples com o qual os desempenhos dos testes estatísticos F, coerência de fase (PC), coerência da magnitude ao quadrado (MSC) e T 2 circular de Hotteling (T2) foram comparados; (ii) um detector de RAEE para canal simples com o qual o desempenho a abordagem de promediação tradicional sweep-a-sweep (SBS) foi comparado com o método proposto época-a-época (EBE); e (iii) um detector de RAEE para múltiplos canais com o qual o desempenho de três algoritmos de análise de componentes independentes (ICA) – JADE, SOBI e WASOBI – foram comparados com a detecção sem o uso de ICA. O método de avaliação do desempenho foi a análise Receiver Operating Characteristic (ROC), no qual a métrica de área sob a curva (AUC) for utilizada para estimar os níveis de acurácia da detecção das RAEEs. A partir dos resultados do cenário 1 concluiu-se que os testes T2 e MSC apresentaram os melhores desempenhos, especialmente para condições de baixa razão sinal-ruído. Resultados do cenário 2 indicaram que a abordagem SBS apresentou maiores níveis de acurácia após o período transitório da curva AUC, enquanto a abordagem EBE resultou em incrementos de acurácia mais abruptos para os primeiros segundos de duração do teste. A partir dos resultados do cenários 3 não foi observada uma redução significativa no tempo de detecção das RAEEs quando o ICA foi aplicado em situações próximas da estimação de limiar auditivo.
13
Jones, Keith Shawn. "AN EVALUATION OF A STEADY-STATE VISUAL EVOKED RESPONSE-BASED CONTROL." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin971880840.
14
Wilding, Timothy. "Using the auditory steady-state response to diagnose dead regions in the cochlea." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/using-the-auditory-steadystate-response-to-diagnose-dead-regions-in-the-cochlea(d25d8561-4ec4-4d37-9734-10ac9015d251).html.
Abstract:
The current behavioural dead region (DR) diagnosis methods such as psychophysical tuning curves and the threshold-equalising noise test require extensive subject co-operation. These present methods cannot be applied to infants. The work presented in the thesis aimed to develop a fast objective DR diagnosis method that could be applied to sleeping hearing-impaired infants. A novel fast objective electrophysiological method of recording response amplitude curves (RACs) which could enable objective DR diagnosis was developed.RACs were derived by recording auditory steady-state response amplitudes using modulated signals in the presence of narrow-band maskers. Two RAC methods were investigated. In the swept method, RACs were recorded in a single test run by recording the response amplitudes across the frequency range of a continuously swept-frequency narrow-band masker. In the fixed method, response amplitudes of eight separate test runs, each in the presence of differing fixed-frequency narrow-band maskers, were recorded.RACs were recorded in normally hearing adult subjects. The results showed that for normally hearing subjects in condition 1 (swept masker), the mean recorded RAC tip for a 2-kHz signal was 2250 Hz and the repeatability coefficient of two repeated recordings in each subject was 389 Hz; in condition 2 (fixed masker), the respective values were 2251 Hz and 342 Hz. These results indicated that the swept masking method is a viable and fast way to record RACs in normally hearing adults.RACs and psychophysical tuning curves (PTCs) were recorded in hearing-impaired adult subjects in order to asses the tip-frequency agreement between the tests. In some cases there were difficulties in using the required signal and masker levels due to maximum sound level limits. The RACs were poorly shaped and had poor repeatability. These findings indicate that the RAC method that was successfully applied to normally hearing subjects requires further development for use with the hearing impaired. The possible causes for the differences in the accuracy of the method between normally hearing and hearing-impaired subjects are discussed. The work presented in this thesis provides the basis upon which further research can be taken forward. It is envisaged that this work, together with further research, will lead to a clinically-effective objective DR diagnosis method.
15
Bosman, Riëtte. "Threshold estimation in normal and impaired ears using Auditory Steady State Responses." Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-10282004-080444.
16
John, Michael Sasha. "Investigations into the multiple auditory steady-state response (MASTER) technique in humans." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58624.pdf.
17
Alani, Alaa Fadhil. "A steady-state response test generation technique for mixed-signal integrated circuits." Thesis, Brunel University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316941.
18
Kelly, John Kip. "Estimation of Behavioral Thresholds in Normal Hearing Listeners Using Auditory Steady State Responses." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1237559225.
19
Hatton, Jennifer Lynn. "Efficiency of the single-versus multiple-stimulus auditory steady-state responses in infants." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5745.
Abstract:
Multiple Auditory Steady-State Responses (ASSRs) will likely be included in the
diagnostic test battery for estimating infant auditory thresholds in the near future;
however, the effects of single versus multiple stimulus presentation in infants has never
been investigated. There are known maturational differences between infants and
adults and these differences may lead to greater interactions between responses to
multiply-presented stimuli in infants. Thus, it is unknown whether or not interactions
between responses to multiple stimuli exist, and if they do, whether or not a single-stimulus
or multiple-stimulus presentation method is more efficient for testing infants. In
the present thesis, two studies were carried out to address this issue. All infants in
Study A participated in three stimulus conditions which differed in the number of stimuli
presented simultaneously. The monotic single (MS) condition consisted of 500, 1000,
2000, and 4000 Hz tones which were presented singly to one ear. The monotic multiple
(MM) condition was composed of four tones (500, 1000, 2000, and 4000 Hz) presented
to one ear simultaneously. The dichotic multiple (DM) condition consisted of eight
tones presented simultaneously to both ears (four tones to each ear). ASSR
amplitudes were obtained from 15 normal infants (mean age: 23.1 weeks) in response
to multiple (MM, DM) and single (MS) air-conduction AM tones [77-1 05 Hz modulation
rates; 60 dBSPL]. Mean single-stimulus amplitudes for 500, 1000, 2000, and 4000 Hz
were 30, 39, 45 and 43 nV, respectively. Presentation of multiple AM tones (i.e., 4
octave-spaced frequencies) to one ear resulted in ASSR amplitudes that were 97%,
87%, 82%, and 70% (for 500, 1000, 2000 and 4000 Hz, respectively) of the
single—stimulus ASSR amplitudes. Results for the dichotic presentation of eight AM
tones show ASSR amplitudes that were 70%, 77%, 67%, and 67% relative to the MS
condition. Although decreases in amplitude occurred using multiple stimuli in infants,
the multiple ASSR remained more efficient than the single-stimulus ASSR (i.e.,
multiple-stimulus amplitudes were greater than single-stimulus amplitudes divided by
M° 5,where M is the number of stimuli). The amplitude reductions seen in the multiple-stimulus
conditions in infants could have origins in the ear canal, middle ear, cochlea
and/or brainstem. Because greater interactions occur in the dichotic multiple-stimulus
condition compared to the monotic multiple-stimulus condition and baseline single-stimulus
condition, brainstem origins of these interactions are likely. In study B, ASSR
thresholds were determined for 500-Hz in the single- and dichotic multiple-stimulus
conditions (14 infants; mean age: 20.2 weeks). Results indicate that ASSR thresholds
for 500 Hz presented in the dichotic-multiple condition were elevated 3 dB compared to
that obtained in the 500-Hz single-stimulus condition. This statistically non-significant
difference is within the range of acceptable test-retest variability, and is thus not of
clinical significance. Results from both studies revealed that the multiple-stimulus
conditions resulted in shorter time-to-criteria, but this did not quite reach significance.
In summary, as with adults, multiple-stimulus presentation in infants is more efficient (in
terms of amplitude and time-to-criteria) than single AM tones.
20
Emrick, Christopher. "Estimation of hearing sensitvity using the auditory brainstem and auditory steady state responses." Connect to resource, 2008. http://hdl.handle.net/1811/32141.
21
Aksu, Seref. "Steady state and transient responses of flexible ship structures travelling in irregular seaways." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334385.
22
Engelbrektsson, Jenny, and Anu Reilin. "Auditory Steady State Response: En jämförelse mellan två kliniska instrument : En experimentell studie." Thesis, Örebro University, School of Health and Medical Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-6902.
Abstract:
I denna studie har jämförelse gjorts mellan Interacoustics Eclipse och GSI Audera i samband med Auditory Steady-State Respons (ASSR) mätningar.
Syftet med studien var att undersöka ASSR som metod, att utvärdera dess tillförlitlighet i jämförelse med tonaudiometri för personer med normal hörsel och personer med hörselnedsättning. Avsikten var dessutom att undersöka om elektrodplacering på örsnibb eller på mastoid påverkade mätresultatet, försökspersonens upplevelse av instrumentens ljudstimuli, om de estimerade ASSR-värdena påverkades av att mättillfället påbörjades eller avslutades med Interacoustics Eclipse samt undersöka tiden för mätningarna.
En experimentell studie genomfördes. Mätningarna som utfördes var tonaudiometri och ASSR, den senare uppmättes med Interacoustics Eclipse och GSI Audera på (n=20) vuxna med normal hörsel och (n=4) vuxna med hörselnedsättning.
För personer med normal hörsel påvisades en god överensstämmelse mellan estimerade ASSR-värden och tonaudiometri för Interacoustics Eclipse, något sämre överensstämmelse för GSI Audera. Genomsnittlig mättid för båda instrumenten var ca 40 min. Resultaten visade att elektrodplaceringen inte har någon påverkan på ASSR-värden för Interacoustics Eclipse. Hälften av försökspersonerna upplevde att Interacoustics Eclipse hade ett behagligare ljudstimuli att slappna av till och den andra hälften upplevde GSI Audera som behagligast. De estimerade ASSR-värdena påverkades minimalt beroende på om mättillfället påbörjades eller avslutades med Interacoustics Eclipse.
23
Hansen, Erin Estelle. "Effective masking levels for bone-conduction auditory steady-state response thresholds in infants." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/25753.
Abstract:
To obtain ear-specific bone-conduction thresholds, masking of the non-test ear is often
required. Masking is not currently utilized in the pediatric diagnostic test battery, partly because
effective masking levels (EMLs) for bone-conducted stimuli in young infants are not known.
The purpose of this study is to determine EMLs for auditory steady-state responses (ASSRs)
elicited by bone-conducted stimuli in a group of normal-hearing infants under six-months of age
and adults. Using a two-channel ASSR recording, single 1000- and 4000-Hz bone-conducted
AM/FM stimuli were masked out with 1 and 4 kHz of narrowband noise presented binaurally.
Taking into consideration maturational differences in real-ear-to-coupler differences (RECDs)
and bone-conduction sensitivity (Small & Stapells, 2008a), it was predicted that infants would
require more and less masking at 1000 and 4000 Hz, respectively. As expected, infants have
higher and lower EMLs at 1000 and 4000 Hz, respectively, compared to adults. When RECDs
are accounted for, infants have even higher EMLs at 1000 Hz and similar EMLs at 4000 Hz
compared to adults. This is consistent with the frequency-dependent differences in boneconduction
sensitivity for infants. When differences in bone-conduction sensitivity are
accounted for, infants have lower EMLs at both frequencies. When RECDs and boneconduction
sensitivity are taken into account, infants have lower EMLs at 1000 Hz and similar
EMLs at 4000 Hz. Based on ipsilateral/contralateral asymmetries in masked amplitudes, adults
were estimated to have inter-aural attenuations of at least 0-5 and 0-10 dB at 1000 and 4000 Hz,
respectively. In contrast, infants were estimated to have inter-aural attenuations of at least 10 dB
at 1000 Hz and minimum inter-aural attenuations of greater than 35 dB at 4000 Hz. Similar to
behvaioural investigations, the amplitude findings of this study suggest processing efficiency
may be immature at 1000 Hz, but not at 4000 Hz. Based on the findings of this study, the following preliminary masking levels for bone-conduction stimuli are recommended: (i) 1000
Hz: 48 and 58 dB SPL at 15 and 25 dB HL, respectively, and (ii) 4000 Hz: 40 and 45 dB SPL at
25 and 35 dB HL, respectively.
24
Meehan, Anthony. "Steady state response of an axial compression system to a constant heat input." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/15975.
25
Zatschler, Harf. "Steady-state and response time analysis of modulated queues and networks with batches." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409310.
26
Biagio, Leigh. "Slow cortical auditory evoked potentials and auditory steady-state evoked responses in adults exposed to occupational noise." Diss., Pretoria : [s. n.], 2009. http://upetd.up.ac.za/thesis/available/etd-02222010-133535.
27
Schenk, Eric R. "Detection of specific steady-state visual evoked potentials when multiple frequencies are available for stimulation." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1176401258.
28
Briceno, Jose Alejandro. "Analysis of the Generation of Auditory Steady-State Cortical Evoked Responses in Guinea Pigs." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_theses/146.
Abstract:
Recent research shows that human auditory steady-state responses (ASSRs) develop a resonance at 40 Hz and the dramatic amplitude increase of the Pb component of the middle latency response (MLR) accounts for the high amplitude of the ASSR at 40 Hz. The first part of this study aimed to investigate the ASSR resonance characteristics as a function of rate in guinea pigs. A study of the grand average of the peak-to-peak and fundamental frequency amplitudes does indeed show a resonance around 40 Hz in guinea pigs. Unlike human ASSRs, this resonance is very broad (26-52 Hz) and flat. The centrally recorded ASSRs are smaller and tend to have resonances at higher rates compared to temporal signals. The second part of the analysis investigated whether the superposition of transient responses can predict the acquired ASSRs at each corresponding rate. This superposition theory is one of two competing theories on the origin of the ASSRs, with the other centering on the induced phase synchronization of brain waves. In order to test the first theory, transient responses were used to create synthetic ASSRs, which were then compared to the acquired ASSRs via correlation coefficient and phasor analysis. For the 40 Hz ASSR, both temporal and central electrode synthesized ASSRs show a correlation coefficient above 0.80. In the comparison at 20 Hz, the correlation coefficient is very high (about 0.9) in the temporal electrode, yet significantly lower (about 0.7) for the central electrode. Furthermore, at 80 Hz, the correlation coefficient is significantly lower in both temporal and central electrodes (about 0.7). At all rates, the correlation coefficients are highest with low jitter sequences. Finally, phasor analysis was also used to test the superposition theory of the generation of the acquired ASSRs at 20, 40, and 80 Hz. Overall, in the temporal recordings at 40 Hz, the superposition of the MLR responses accurately predicted the acquired 40 Hz ASSR as demonstrated by both magnitude and phase analysis. The recordings made in the central electrode only predicted the acquired ASSR in its phases, with significant differences found in magnitude at its main harmonics. Similarly, at 20 and 80 Hz in both temporal and central electrodes, the synthetic ASSRs did not appear to fully predict the acquired ASSRs. Although the phases were successfully predicted, large magnitude variations were observed. As shown by mean prediction error plots, the acquired ASSRs are best predicted by low jitter sequences, followed by low-medium and medium jitter sequences.
29
Gaetz, William C. "Dynamics of transient and steady-state responses evoked by mechanical stimulation of the digits /." *McMaster only, 2001.
30
Kelly, J. Kip. "Estimation of behavioral hearing thresholds in normal hearing listeners using auditory steady state responses." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1237559225.
31
Müller, Nadia. "Top-down modulation of the auditory Steady State Response in a task-switch paradigm." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-44582.
32
Raza, Muhammad Ummear, Rorie Dakota, Michael Makki, Sydney Faith Tabor, Caige Gaylon Plsek, and Digavalli V. Sivarao. "Effect of typical and atypical antipsychotics on the 40 Hz auditory steady-state response." Digital Commons @ East Tennessee State University, 2021. https://dc.etsu.edu/asrf/2021/presentations/17.
Abstract:
Oscillations in the brain’s electrical potential, recorded through the technique of electroencephalography (EEG), reflect the ensemble activity of a large population of neurons. Auditory steady-state response (ASSR) is the time-locked entrainment in EEG to an auditory stimulus such as a train of clicks. ASSR to a 40 Hz (gamma frequency) click train is especially reduced in schizophrenia patients, reflecting the sensory processing deficits that impact real-world functional outcomes. Since the 40 Hz ASSR is demonstrable across species and is responsive to pharmacological treatments, it can be a translational biomarker for drug development studies. Prototypical antipsychotic drugs (APDs) like haloperidol and clozapine are examples of typical and atypical classes used to treat schizophrenia patients. While both are D2 receptor blockers, they have additional pharmacological effects that may differentiate them. Here, we investigated the acute effect of clozapine (atypical) or haloperidol (typical) on the 40 Hz ASSR, in two independent studies. The doses for the two drugs were chosen to reflect comparable in vivo D2 receptor occupancy. We used female Sprague-Dawley rats implanted with epidural EEG recording electrodes. In the first experiment, vehicle or clozapine 2.5, 5, and 10 mg/kg were administered (sc) and the 40 Hz ASSR paradigm (65 dB, 40 clicks for 1 second, 2-sec inter-stimulus interval) was used to record responses at 30, 60, 90 and 120 minutes post-drug. Resting-state EEG was recorded at 60 minutes post-treatment. Treatment effects were evaluated on the evoked power and phase-locking factor (PLF), a measure of trial-to-trial consistency of the 40 Hz ASSR. Clozapine improved both measures in a dose and time-dependent manner. Clozapine also tended to reduce the resting-state gamma (30-100 Hz) power, a hallmark of cortical noise. However, the effect was not significant (P>0.05). Next, we tested the effect of haloperidol on the 40 Hz ASSR. Doses of 0.02 mg/kg -0.08 mg/kg (sc) were evaluated at 30, 60, 90 and 120-minutes post-injection. Haloperidol failed to improve the 40 Hz ASSR (evoked power and PLF). Moreover, it had no discernible effect on the resting-state gamma. These results show that despite the comparable blockade of D2 receptors, the putative target for these APDs, clozapine, and haloperidol have different effects on the 40 Hz ASSR. We conclude that the effects of clozapine on 40 Hz ASSR may be unrelated to its affinity to D2 receptors and may be mediated through other pharmacological mechanisms.
33
Nabavi, Seyed Ghavamoddin. "Statistical Analysis of Steady State Response in RF Circuits via Decoupled Generalized Polynomial Chaos." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35293.
Abstract:
One of the major factors in RF circuit design is the ability to predict the performance of these circuits in the presence of uncertainty in the key design parameters. This is referred to as uncertainty quantification in the mathematical literature. Uncertainty about the key design parameters arises mainly from the difficulty of controlling the physical or geometrical features of the underlying design, especially at the nanometer level. With the constant trend to scale down the process feature size, uncertainty quantification becomes crucial in shortening the design time.
This thesis presents a new approach to statistically characterize the
variability of the Harmonic Balance analysis and its application to Intermodulation distortion analysis in the presence of uncertainty in the design parameters. The new approach is based on the concept of Polynomial Chaos (PC) and Stochastic Galerkin (SG) methods. However, unlike the traditional PC, the proposed approach adopts a new mathematical formulation that decouples the Polynomial Chaos problem into several problems whose sizes are equal to the size of the original Harmonic Balance problem. The proposed algorithm produces significant CPU savings with equivalent accuracy to traditional Monte Carlo and standard PC approaches.
34
Plourde, Gilles. "Human auditory steady-state response, electroencephalogram, and late auditory evoked potentials during general anesthesia." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5787.
Abstract:
In order to identify neurophysiological correlates of the changes in the level of conciousness associated with general anesthesia, the 40 Hz auditory steady-state response (ASSR), the electroencephalogram (EEG) and the N1 and P3 components of the transient auditory evoked potential were recorded before anesthesia (pre-induction), at the onset of anesthesia (induction), during surgical anesthesia, at the time of emergence and during recovery from anesthesia. The amplitude of the ASSR, was reduced significantly during late induction and dropped below noise levels during surgical anesthesia. It increased during emergence and further increased during recovery although the amplitude during recovery was significantly less than pre-induction values. Total EEG power increased significantly after induction. The EEG median frequency and 95% quantile frequency decreased significantly during surgery and increased significantly during emergence. Muscle artifacts could account for many of the EEG changes. The results for the transient auditory evoked potential indicated that, except during emergence, detection was associated with clear N1 and P3 waves whereas undetection was not. The lack of either N1 and P3 for detection during emergence perhaps occurred because the patients were not yet fully conscious. (Abstract shortened by UMI.)
35
Presacco, Alessandro. "Evoked and Induced Activity in 40 Hz Auditory Responses." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_theses/164.
Abstract:
This study aims to investigate the evoked and the induced activity in 40 Hz auditory responses. The 40 Hz activity, also called Pb or P50 or P1 component, has a latency of 50ms and belongs to the category of MLRs (Middle latency responses), which occur right after Auditory Brainstem Responses (ABRs) between 15 and 80ms. Its importance is related to possible clinical applications such as anesthesia, schizophrenia and auditory development. In addition to this, evoked and induced activities at 40 Hz might play an important role in cognitive processing. Trains of right ear rarefaction clicks at the mean rate of 39.1 Hz, intensity of 50dB and duration of 100 were used to elicit the above mentioned activities. Three different sequences have been used: steady state, low jittered and medium jittered. Low jittered sequence has been the main sequence used to study the 40 Hz activity. The advantage of using this sequence is the fact that a deconvolution analysis can be performed and also the fact that it does not differ too much from the standard 40Hz steady-state sequence and this means that a resonance at 40 Hz can still be obtained. Ten healthy subjects (8 males and 2 females; ages ranging from 25 to 47), with no history of audiological or neurological hearing impairment were recorded. Informed consent was signed according to approved IRB protocols. All recordings were done in a sound-proof chamber (Acoustic Systems, Inc.) with subjects lying on a bed comfortably. The subjects were not asked to perform any tasks, but just to passively listen to the acoustical stimuli. Evoked and induced activities were recorded in response to the above mentioned acoustic stimuli. The deconvolution analysis showed that the peak of activity occurs around 152ms. Wavelets analysis has confirmed this observation and has also unveiled and induced activity in the low beta range. This induced activity seems to be strictly related to the evoked activity, as it seems to occur around 390ms, which corresponds to the situation where the 40 Hz evoked activity enters a steady state condition, which lasts until the last acoustic stimulus has been applied. The latter observation is again in accordance with the literature, where it is reported that the 40Hz evoked activity could reflect the initial coactivation of neural assemblies representing specific stimulus features. A change in such stimulus features could be reflected as induced oscillations occurring in the middle beta range (16-22 Hz).
36
Hansson, Tomas. "When the Siren Sounds : In Search of Acoustic Properties that make an Alarm Signal Effective at Capturing Attention." Thesis, Högskolan i Gävle, Miljöpsykologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-26905.
Abstract:
A functional and effective alarm signal is a critical component of alarm systems designed to alert workers of impending danger. In a previous study (Hansson, 2017) background alarm sirens composed of changing-state sounds with an embedded temporal deviant, produced greater disruption of serial short-term memory than a signal without a deviant. However, to give rise to disruption the siren needed to change from fast to slow, since a change from slow to fast was impotent in its effect on task performance. In the current study, whether acoustic change was a necessary prerequisite for obtaining the fast-to-slow deviant effect was explored. Thus, repeated tones—steady-state sequences—presented at slow or fast rates were used with or without a temporal deviant (change from slow-to-fast vs. change from fast-to-slow). In the context of the steady-state sequences, both slow-to-fast and fast-to-slow temporal deviants produced disruption relative to the fast and slow control sequences. This suggests that a changing-state sequence is required for the fast-to-slow temporal deviant effect to arise. However, an alternative explanation based upon inter-stimulus intervals is also entertained. Understanding the acoustic parameters of sound is necessary to develop alarms sirens that are better at capturing attention. The current study suggests that embedding temporal deviants within sirens can promote greater attentional capture, but that this may depend on the nature of the alarm signal (whether it is changing vs. steady-state) and the direction of the change of speed (slow-to-fast vs. fast-to-slow).
37
Hansson, Tomas. "Exploring the properties of alarm signals that makes them attention-capturing: The Role of interstimulus intervals." Thesis, Högskolan i Gävle, Miljöpsykologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-27817.
Abstract:
Alarm signals such as sirens are crucial in alerting users of impending dangers. Therefore, it is important that the siren is designed so it can capture user's attention. In a previous study (Hansson, 2017) background alarm sirens composed of changing-state sounds with an embedded temporal deviant, produced greater disruption of serial short-term memory than a signal without a temporal deviant. However, to give rise to disruption the siren needed to change from fast to slow, since a change from slow to fast was impotent in its effect on task performance. This was further addressed in Hansson (2018) where it was shown that acoustic change appeared to be a necessary prerequisite for obtaining the fast-to-slow temporal deviant effect: When steady-state sounds were used fast-to-slow and or slow-to-fast temporal deviants were equally disruptive of serial recall. However, in order to create a steady-state siren, inter-stimulus intervals were incorporated into the siren to prevent the continuous uninterrupted presentation of a single tone. Since inter-stimulus intervals were not used in Hansson (2017) it could be the presence of these that eliminated the potency of the fast-to-slow over the slow-to-fast temporal deviation effect in Hansson (2018). Therefore, the current study was undertaken to investigate whether the embedding inter-stimulus intervals within a changing-state siren would restore the potency of the fast-to-slow temporal deviation over the slow-to-fast temporal deviation in capturing attention. The additional disruption for fast-to-slow temporal deviants over slow-to-fast temporal deviants (that did not produce disruption relative to control) returned in the current study when inter-stimulus intervals were included within the siren. The results support the notion that the additional disruption produced by fast-to-slow, over slow-to-fast temporal deviants depend on the changing-state properties of the siren. Implications of this result for the design and operation of sirens within ecologically valid settings are discussed.
38
Orsi, Tony R. "Investigation into steady-state auditory brainstem response detection, weighted time averaging and autoregressive spectral estimation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/MQ40943.pdf.
39
Murnane, Owen D., C. Clinard, J. Tampas, Faith W. Akin, and R. H. Wilson. "Effects of Stimulus Type on Multiple Auditory Steady State Response Thresholds in Normal-Hearing Subjects." Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etsu-works/1901.
40
Ménard, Mikaël. "Exploration objective de l'audition à partir des auditory steady-state responses et adaptation à l'implant cochléaire." Phd thesis, Université Claude Bernard - Lyon I, 2008. http://tel.archives-ouvertes.fr/tel-00413409.
Abstract:
Parmi les différentes méthodes de mesure objective de l'audition, les Auditory steady-state responses (ASSR) sont en plein développement et présentent de multiples avantages. Associées à l'implant cochléaire, cette méthode permet d'envisager une évaluation des performances de l'implant et une aide précieuse à son réglage. Dans une première partie nous avons cherché à évaluer les performances et capacités de la mesure ASSR chez le sujet non implanté, au travers de 4 études. Nous avons confirmé que cette méthode permettait une évaluation précise des seuils auditifs. De plus, l'amplitude de cette réponse donne des informations sur la sonie du sujet (Hearing Research) et met en évidence le phénomène de recrutement. Pour finir, en faisant varier l'un des paramètres de la stimulation nous pouvons étudier l'impact de la stimulation binaurale. Ces études positionnent la mesure ASSR dans un cadre très large d'évaluation objective de l'audition. Dans une deuxième partie, nous avons étudié la possibilité de réaliser cette mesure ASSR chez le sujet implanté cochléaire en validant l'origine de la réponse mesurée et en mettant au point un système de mesure. Pour cela nous avons évalué la réponse mesurée chez un groupe de sujets implantés et déduit de la non linéarité de la réponse obtenue son origine non artéfactuelle (International Journal of Audiology). Cet artéfact rencontré lors de la mesure, nous a amenés à modéliser et analyser le signal émis par l'implant, afin d'en extraire les propriétés utiles à la mesure ASSR. Enfin à l'aide du système de mesure ASSR ainsi développé, nous avons mis en évidence la validité de la mesure ASSR chez l'implanté cochléaire.
41
Menard, Mikaël. "Exploration objective de l'audition à partir des auditory steady-state responses et adaptation à l'implant cochléaire." Lyon 1, 2008. http://tel.archives-ouvertes.fr/docs/00/41/34/09/PDF/MENARD_Mikael.pdf.
Abstract:
Parmi les différentes méthodes de mesure objective de l’audition, les Auditory steady-state responses (ASSR) sont en plein développement et présentent de multiples avantages. Associées à l’implant cochléaire, cette méthode permet d’envisager une évaluation des performances de l’implant et une aide précieuse à son réglage. Dans une première partie nous avons cherché à évaluer les performances et capacités de la mesure ASSR chez le sujet non implanté, au travers de 4 études. Nous avons confirmé que cette méthode permettait une évaluation précise des seuils auditifs. De plus, l’amplitude de cette réponse donne des informations sur la sonie du sujet (Hearing Research) et met en évidence le phénomène de recrutement. Pour finir, en faisant varier l’un des paramètres de la stimulation nous pouvons étudier l’impact de la stimulation binaurale. Ces études positionnent la mesure ASSR dans un cadre très large d’évaluation objective de l’audition. Dans une deuxième partie, nous avons étudié la possibilité de réaliser cette mesure ASSR chez le sujet implanté cochléaire en validant l’origine de la réponse mesurée et en mettant au point un système de mesure. Pour cela nous avons évalué la réponse mesurée chez un groupe de sujets implantés et déduit de la non linéarité de la réponse obtenue son origine non artéfactuelle (International Journal of Audiology). Cet artéfact rencontré lors de la mesure, nous a amenés à modéliser et analyser le signal émis par l’implant, afin d’en extraire les propriétés utiles à la mesure ASSR. Enfin à l’aide du système de mesure ASSR ainsi développé, nous avons mis en évidence la validité de la mesure ASSR chez l’implanté cochléaireAmong the different objective measurement methods, ASSR are in development and offer multiple advantages. Associated with cochlear implant, this objective method allows evaluation of implant performances and a useful tool for fitting. As a first step, we evaluated performances and capacities of the ASSR method on normal and hearing impaired subjects with four studies. The result confirms that this method allowed an accurate evaluation of auditory thresholds. Moreover, the ASSR amplitude correlates well with the loudness function (Hearing Research) and gives information about loudness recruitment. While, varying one of the stimulation parameters, we can study the impact of binaural stimulation. These results suggest that ASSR could be use as a large tool for the exploration of the auditory system. Then we evaluated this measure on cochlear implanted subjects. A first study validated the physiological origin of the ASSR measured (International Journal of Audiology). Models and measurement of the cochlear implant stimulation in the case of ASSR gave us precious information about the stimulation artefact. With a new ASSR tool, adapt to the specificities of the implant, we validated the measure of ASSR with cochlear implanted subjects
42
Kacin, Alan. "The role of absolute and relative work rate in the sweat response during steady-state exercise." Thesis, University of Portsmouth, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416224.
43
Deshpande, Shruti. "Characterization of Cochlear Implant related Artifact during Sound-Field Recording of the Auditory Steady State Response (ASSR): A Comparison between Normal Hearing Adults, Cochlear Implant Recipients and Implant-in-a-Box." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406820669.
44
Oh, Yunje. "Prediction of steady state response in dynamic mode atomic force microscopy and its applications in nano-metrology." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1135222817.
45
Oh, Yunje. "Prediction of steady state response in dynamic mode atomic force microscopy and its applications in nano-metrology." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1135222817.
46
Stingl, Astrid [Verfasser]. "Findung der optimalen Reizfolgerate einer auf Steady-state responses beruhenden BERA für ein generelles Neugeborenen-Hörscreening / Astrid Stingl." Aachen : Shaker, 2007. http://d-nb.info/1164340832/34.
47
Schlee, Winfried. "Single-trial neuromagnetic analysis of auditory steady state responses and its application for the studies of chronic tinnitus." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-44631.
48
Juckett, Sarah Eileen. "Steady State and Transient Dynamical Systems Analysis of Uncoupled Roll Response for a Traditional Versus Advanced Hull Form." ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/407.
Abstract:
The two ships represented in this thesis are dramatically different in design, but both exhibit similar properties such as length and breadth. The traditional hull form is represented by a typical flare-sided design with a forward reaching bow while the advanced hull form has a modified tumblehome and a truncated bow. The difference in shapes provides an interesting problem, comparing the roll responses for these two very different vessels while keeping certain shape parameters such as length, beam, and draft constant.
49
Adotey, Bless. "MATHEMATICAL MODELING OF CLOSTRIDIUM THERMOCELLUM’S METABOLIC RESPONSES TO ENVIRONMENTAL PERTURBATION." UKnowledge, 2011. http://uknowledge.uky.edu/bae_etds/1.
Abstract:
Clostridium thermocellum is a thermophilic anaerobe that is capable of producing ethanol directly from lignocellulosic compounds, however this organism suffers from low ethanol tolerance and low ethanol yields. In vivo mathematical modeling studies based on steady state traditional metabolic flux analysis, metabolic control analysis, transient and steady states’ flux spectrum analysis (FSA) were conducted on C. thermocellum’s central metabolism. The models were developed in Matrix Laboratory software ( MATLAB® (The Language of Technical Computing), R2008b, Version 7.7.0.471)) based on known stoichiometry from C. thermocellum pathway and known physical constraints. Growth on cellobiose from Metabolic flux analysis (MFA) and Metabolic control analysis (MCA) of wild type (WT) and ethanol adapted (EA) cells showed that, at lower than optimum exogenous ethanol levels, ethanol to acetate (E/A) ratios increased by approximately 29% in WT cells and 7% in EA cells. Sensitivity analyses of the MFA and MCA models indicated that the effects of variability in experimental data on model predictions were minimal (within ±5% differences in predictions if the experimental data varied up to ±20%). Steady state FSA model predictions showed that, an optimum hydrogen flux of ~5mM/hr in the presence of pressure equal to or above 7MPa inhibits ferrodoxin hydrogenase which causes NAD re-oxidation in the system to increase ethanol yields to about 3.5 mol ethanol/mol cellobiose.
50
Stroebel, Deidré. "The clinical value of the auditory steady state response for early diagnosis and amplification for infants (0 - 8 months) with hearing loss." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-03222007-190636.