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

scholarly journals Effects of stimulation intensity, gender and handedness upon auditory evoked potentials

1992 ◽  
Vol 50 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Susana Camposano ◽  
Fernando Lolas
Keyword(s):  
Corpus Callosum ◽  
Evoked Potentials ◽  
Stimulus Intensity ◽  
Auditory Evoked Potentials ◽  
Right Hemisphere ◽  
Cognitive Components ◽  
Left Handed ◽  
And Gender ◽  
The Right ◽  
Cortical Auditory Evoked Potentials

Left handers and women show less anatomical brain asymmetry, larger corpus callosum and more bilateral representation of specific functions. Sensory and cognitive components of cortical auditory evoked potentials (AEF) have been shown to be asymmetric in right handed males and to be influenced by stimulus intensity. In this study the influence of sex, handedness and stimulus intensity upon AEP components is investigated under basal conditions of passive attention. 14 right handed males, 14 right handed females, 14 left handed males, and 14 left handed females were studied while lying awake and paying passive attention to auditory stimulation (series of 100 binaural clicks, duration 1 msec, rate 1/sec, at four intensities). Cz, C3 and C4 referenced to linked mastoids and right EOG were recorded. Analysis time was 400 msec, average evoked potentials were based on 100 clicks. Stimulus intensity and gender affect early sensory components (P1N1 and N1P2) at central leads, asymmetry is influenced only by handedness, right handers showing larger P1N1 amplitudes over the right hemisphere.

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.

scholarly journals Clinical Use of Aided Cortical Auditory Evoked Potentials as a Measure of Physiological Detection or Physiological Discrimination

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Curtis J. Billings ◽  
Melissa A. Papesh ◽  
Tina M. Penman ◽  
Lucas S. Baltzell ◽  
Frederick J. Gallun
Keyword(s):  
Evoked Potentials ◽  
Auditory Evoked Potentials ◽  
Clinical Decision Making ◽  
Hearing Aid ◽  
Clinical Decision ◽  
Clinical Use ◽  
Major Contributor ◽  
Wide Range ◽  
Pure Tones ◽  
Cortical Auditory Evoked Potentials

The clinical usefulness of aided cortical auditory evoked potentials (CAEPs) remains unclear despite several decades of research. One major contributor to this ambiguity is the wide range of variability across published studies and across individuals within a given study; some results demonstrate expected amplification effects, while others demonstrate limited or no amplification effects. Recent evidence indicates that some of the variability in amplification effects may be explained by distinguishing between experiments that focused on physiological detection of a stimulus versus those that differentiate responses to two audible signals, or physiological discrimination. Herein, we ask if either of these approaches is clinically feasible given the inherent challenges with aided CAEPs. N1 and P2 waves were elicited from 12 noise-masked normal-hearing individuals using hearing-aid-processed 1000-Hz pure tones. Stimulus levels were varied to study the effect of hearing-aid-signal/hearing-aid-noise audibility relative to the noise-masked thresholds. Results demonstrate that clinical use of aided CAEPs may be justified when determining whether audible stimuli are physiologically detectable relative to inaudible signals. However, differentiating aided CAEPs elicited from two suprathreshold stimuli (i.e., physiological discrimination) is problematic and should not be used for clinical decision making until a better understanding of the interaction between hearing-aid-processed stimuli and CAEPs can be established.

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.

scholarly journals Aided Electrophysiology Using Direct Audio Input: Effects of Amplification and Absolute Signal Level

2016 ◽  
Vol 25 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Ingyu Chun ◽  
Curtis J. Billings ◽  
Christi W. Miller ◽  
Kelly L. Tremblay
Keyword(s):  
Young Adults ◽  
Evoked Potentials ◽  
Pure Tone ◽  
Auditory Evoked Potentials ◽  
Hearing Aid ◽  
Normal Hearing ◽  
Signal To Noise ◽  
Noise Floor ◽  
Linear Analog ◽  
Cortical Auditory Evoked Potentials

Purpose This study investigated (a) the effect of amplification on cortical auditory evoked potentials (CAEPs) at different signal levels when signal-to-noise ratios (SNRs) were equated between unaided and aided conditions, and (b) the effect of absolute signal level on aided CAEPs when SNR was held constant. Method CAEPs were recorded from 13 young adults with normal hearing. A 1000-Hz pure tone was presented in unaided and aided conditions with a linear analog hearing aid. Direct audio input was used, allowing recorded hearing aid noise floor to be added to unaided conditions to equate SNRs between conditions. An additional stimulus was created through scaling the noise floor to study the effect of signal level. Results Amplification resulted in delayed N1 and P2 peak latencies relative to the unaided condition. An effect of absolute signal level (when SNR was constant) was present for aided CAEP area measures, such that larger area measures were found at higher levels. Conclusion Results of this study further demonstrate that factors in addition to SNR must also be considered before CAEPs can be used to clinically to measure aided thresholds.

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.

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