scholarly journals Electroacoustic Comparison of Hearing Aid Output of Phonemes in Running Speech versus Isolation: Implications for Aided Cortical Auditory Evoked Potentials Testing

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Vijayalakshmi Easwar ◽  
David W. Purcell ◽  
Susan D. Scollie
Keyword(s):  
Evoked Potentials ◽  
Hearing Aids ◽  
Auditory Evoked Potentials ◽  
Hearing Aid ◽  
Conversational Speech ◽  
Individual Basis ◽  
The Past ◽  
Cortical Auditory Evoked Potentials

Background. Functioning of nonlinear hearing aids varies with characteristics of input stimuli. In the past decade, aided speech evoked cortical auditory evoked potentials (CAEPs) have been proposed for validation of hearing aid fittings. However, unlike in running speech, phonemes presented as stimuli during CAEP testing are preceded by silent intervals of over one second. Hence, the present study aimed to compare if hearing aids process phonemes similarly in running speech and in CAEP testing contexts.Method. A sample of ten hearing aids was used. Overall phoneme level and phoneme onset level of eight phonemes in both contexts were compared at three input levels representing conversational speech levels.Results. Differences of over 3 dB between the two contexts were noted in one-fourth of the observations measuring overall phoneme levels and in one-third of the observations measuring phoneme onset level. In a majority of these differences, output levels of phonemes were higher in the running speech context. These differences varied across hearing aids.Conclusion. Lower output levels in the isolation context may have implications for calibration and estimation of audibility based on CAEPs. The variability across hearing aids observed could make it challenging to predict differences on an individual basis.

Cortical Auditory-Evoked Potentials (CAEPs) in Adults in Response to Filtered Speech Stimuli

2013 ◽  
Vol 24 (09) ◽  
pp. 807-822 ◽  
Author(s):  
Lyndal Carter ◽  
Harvey Dillon ◽  
John Seymour ◽  
Mark Seeto ◽  
Bram Van Dun
Keyword(s):  
Hearing Loss ◽  
Evoked Potentials ◽  
Hearing Aids ◽  
Auditory Evoked Potentials ◽  
Hearing Aid ◽  
Speech Sounds ◽  
Sensation Level ◽  
Behavioral Threshold ◽  
Speech Stimuli ◽  
Cortical Auditory Evoked Potentials

Background: Previous studies have demonstrated that cortical auditory-evoked potentials (CAEPs) can be reliably elicited in response to speech stimuli in listeners wearing hearing aids. It is unclear, however, how close to the aided behavioral threshold (i.e., at what behavioral sensation level) a sound must be before a cortical response can reliably be detected. Purpose: The purpose of this study was to systematically examine the relationship between CAEP detection and the audibility of speech sounds (as measured behaviorally), when the listener is wearing a hearing aid fitted to prescriptive targets. A secondary aim was to investigate whether CAEP detection is affected by varying the frequency emphasis of stimuli, so as to simulate variations to the prescribed gain-frequency response of a hearing aid. The results have direct implications for the evaluation of hearing aid fittings in nonresponsive adult clients, and indirect implications for the evaluation of hearing aid fittings in infants. Research Design: Participants wore hearing aids while listening to speech sounds presented in a sound field. Aided thresholds were measured, and cortical responses evoked, under a range of stimulus conditions. The presence or absence of CAEPs was determined by an automated statistic. Study Sample: Participants were adults (6 females and 4 males). Participants had sensorineural hearing loss ranging from mild to severe-profound in degree. Data Collection and Analysis: Participants' own hearing aids were replaced with a test hearing aid, with linear processing, during assessments. Pure-tone thresholds and hearing aid gain measurements were obtained, and a theoretical prediction of speech stimulus audibility for each participant (similar to those used for audibility predictions in infant hearing aid fittings) was calculated. Three speech stimuli, (/m/, /t/, and /g/) were presented aided (monaurally, nontest ear occluded), free field, under three conditions (+4 dB/octave, −4 dB/octave, and without filtering), at levels of 40, 50, and 60 dB SPL (measured for the unfiltered condition). Behavioral thresholds were obtained, and CAEP recordings were made using these stimuli. The interaction of hearing loss, presentation levels, and filtering conditions resulted in a range of CAEP test behavioral sensation levels (SLs), from −25 to +40 dB. Results: Statistically significant CAEPs (p < .05) were obtained for virtually every presentation where the behavioral sensation level was >10 dB, and for only 5% of occasions when the sensation level was negative. In these (“false-positive”) cases, the greatest (negative) sensation level at which a CAEP was judged to be present was −6 dB SL. Conclusions: CAEPs are a sensitive tool for directly evaluating the audibility of speech sounds, at least for adult listeners. CAEP evaluation was found to be more accurate than audibility predictions, based on threshold and hearing aid response measures.

scholarly journals A Pilot Study on Cortical Auditory Evoked Potentials in Children: Aided CAEPs Reflect Improved High-Frequency Audibility with Frequency Compression Hearing Aid Technology

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Danielle Glista ◽  
Vijayalakshmi Easwar ◽  
David W. Purcell ◽  
Susan Scollie
Keyword(s):  
Evoked Potentials ◽  
Hearing Aids ◽  
Auditory Evoked Potentials ◽  
Time Window ◽  
Hearing Aid ◽  
Older Children ◽  
Frequency Compression ◽  
Cortical Responses ◽  
Cortical Auditory Evoked Potentials ◽  
Hearing Aid Benefit

Background. This study investigated whether cortical auditory evoked potentials (CAEPs) could reliably be recorded and interpreted using clinical testing equipment, to assess the effects of hearing aid technology on the CAEP.Methods. Fifteen normal hearing (NH) and five hearing impaired (HI) children were included in the study. NH children were tested unaided; HI children were tested while wearing hearing aids. CAEPs were evoked with tone bursts presented at a suprathreshold level. Presence/absence of CAEPs was established based on agreement between two independent raters.Results. Present waveforms were interpreted for most NH listeners and all HI listeners, when stimuli were measured to be at an audible level. The younger NH children were found to have significantly different waveform morphology, compared to the older children, with grand averaged waveforms differing in the later part of the time window (the N2 response). Results suggest that in some children, frequency compression hearing aid processing improved audibility of specific frequencies, leading to increased rates of detectable cortical responses in HI children.Conclusions. These findings provide support for the use of CAEPs in measuring hearing aid benefit. Further research is needed to validate aided results across a larger group of HI participants and with speech-based stimuli.

The Relationship between Obligatory Cortical Auditory Evoked Potentials (CAEPs) and Functional Measures in Young Infants

2007 ◽  
Vol 18 (02) ◽  
pp. 117-125 ◽  
Author(s):  
Maryanne Golding ◽  
Wendy Pearce ◽  
John Seymour ◽  
Alison Cooper ◽  
Teresa Ching ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Hearing Aids ◽  
Auditory Evoked Potentials ◽  
Hearing Aid ◽  
Detection Methods ◽  
Speech Detection ◽  
Screening Programs ◽  
Young Infants ◽  
Cortical Auditory Evoked Potentials ◽  
The Relationship

Finding ways to evaluate the success of hearing aid fittings in young infants has increased in importance with the implementation of hearing screening programs. Cortical auditory evoked potentials (CAEP) can be recorded in infants and provides evidence for speech detection at the cortical level. The validity of this technique as a tool of hearing aid evaluation needs, however, to be demonstrated. The present study examined the relationship between the presence/absence of CAEPs to speech stimuli and the outcomes of a parental questionnaire in young infants who were fitted with hearing aids. The presence/absence of responses was determined by an experienced examiner as well as by a statistical measure, Hotelling's T2. A statistically significant correlation between CAEPs and questionnaire scores was found using the examiner's grading (rs = 0.45) and using the statistical grading (rs = 0.41), and there was reasonably good agreement between traditional response detection methods and the statistical analysis. La búsqueda de formas de evaluar el éxito de una adaptación de auxiliares auditivos en niños pequeños ha aumentado en importancia con la implementación de los programas de tamizaje auditivo. Se pueden registrar potenciales evocados auditivos corticales (CAEP) en infantes y aportar evidencia sobre la detección del lenguaje a nivel cortical. La validez de esta técnica como una herramienta para la evaluación de las necesidades de adaptación de auxiliares auditivos necesita, sin embargo, ser demostrada. El presente estudio examinó la relación entre la presencia/ausencia de CAEP ante estímulos de lenguaje y el resultado de un cuestionario a los padres de infantes a los que se adaptaron auxiliares auditivos. La presencia/ausencia de respuestas fue determinada por un examinador con experiencia, así como por un procedimiento de medición estadística: la T2 de Hotelling. Se encontró una correlación estadísticamente significativa entre los CAEP y los puntajes del cuestionario, utilizando la gradación del examinador (rs = 0.45) y utilizando la gradación estadística (rs = 0.41), y existió un acuerdo razonablemente bueno entre los métodos tradicionales de detección de respuesta y el análisis estadístico.

New possibility for measuring the cortical auditory evoked potentials: the HEARLab

2014 ◽  
Vol 155 (38) ◽  
pp. 1524-1529
Author(s):  
Ádám Bach ◽  
Ferenc Tóth ◽  
Vera Matievics ◽  
József Géza Kiss ◽  
József Jóri ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Evoked Potentials ◽  
Auditory System ◽  
Hearing Aids ◽  
Pure Tone ◽  
Auditory Evoked Potentials ◽  
Normal Hearing ◽  
Speech Stimuli ◽  
Novel Method ◽  
Cortical Auditory Evoked Potentials

Introduction: Cortical auditory evoked potentials can provide objective information about the highest level of the auditory system. Aim: The purpose of the authors was to introduce a new tool, the “HEARLab” which can be routinely used in clinical practice for the measurement of the cortical auditory evoked potentials. In addition, they wanted to establish standards of the analyzed parameters in subjects with normal hearing. Method: 25 adults with normal hearing were tested with speech stimuli, and frequency specific examinations were performed utilizing pure tone stimuli. Results: The findings regarding the latency and amplitude analyses of the evoked potentials confirm previously published results of this novel method. Conclusions: The HEARLAb can be a great help when performance of the conventional audiological examinations is complicated. The examination can be performed in uncooperative subjects even in the presence of hearing aids. The test is frequency specific and does not require anesthesia. Orv. Hetil., 2014, 155(38), 1524–1529.

Effects of Hearing Aid Amplification and Stimulus Intensity on Cortical Auditory Evoked Potentials

2007 ◽  
Vol 12 (4) ◽  
pp. 234-246 ◽  
Author(s):  
Curtis J. Billings ◽  
Kelly L. Tremblay ◽  
Pamela E. Souza ◽  
Malcolm A. Binns
Keyword(s):  
Evoked Potentials ◽  
Stimulus Intensity ◽  
Auditory Evoked Potentials ◽  
Hearing Aid ◽  
Cortical Auditory Evoked Potentials

The Use of Cortical Auditory Evoked Potentials to Evaluate Neural Encoding of Speech Sounds in Adults

2006 ◽  
Vol 17 (08) ◽  
pp. 559-572 ◽  
Author(s):  
Katrina Agung ◽  
Suzanne C. Purdy ◽  
Catherine M. McMahon ◽  
Philip Newall
Keyword(s):  
Evoked Potentials ◽  
Hearing Aids ◽  
Auditory Evoked Potentials ◽  
Speech Sounds ◽  
Speech Discrimination ◽  
Neural Encoding ◽  
Speech Stimuli ◽  
Speech Encoding ◽  
Cortical Level ◽  
Cortical Auditory Evoked Potentials

There has been considerable recent interest in the use of cortical auditory evoked potentials (CAEPs) as an electrophysiological measure of human speech encoding in individuals with normal as well as impaired auditory systems. The development of such electrophysiological measures such as CAEPs is important because they can be used to evaluate the benefits of hearing aids and cochlear implants in infants, young children, and adults that cannot cooperate for behavioral speech discrimination testing. The current study determined whether CAEPs produced by seven different speech sounds, which together cover a broad range of frequencies across the speech spectrum, could be differentiated from each other based on response latency and amplitude measures. CAEPs were recorded from ten adults with normal hearing in response to speech stimuli presented at a conversational level (65 dB SPL) via a loudspeaker. Cortical responses were reliably elicited by each of the speech sounds in all participants. CAEPs produced by speech sounds dominated by high-frequency energy were significantly different in amplitude from CAEPs produced by sounds dominated by lower-frequency energy. Significant effects of stimulus duration were also observed, with shorter duration stimuli producing larger amplitudes and earlier latencies than longer duration stimuli. This research demonstrates that CAEPs can be reliably evoked by sounds that encompass the entire speech frequency range. Further, CAEP latencies and amplitudes may provide an objective indication that spectrally different speech sounds are encoded differently at the cortical level.

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