1,721,486 research outputs found
Personalized fitting and evaluation of hearing aids using EEG: Evoked responses to speech
No full textMeasuring evoked responses to speech
No full textOur auditory brain is very good at detecting speech, which we are able to understand when listening in considerable background noise. However measuring the evoked response of the brain to speech using surface electrodes is challenging. A number of groups worldwide are carrying out research in this area, but the limitations and clinical applications of such methods are not yet fully understood.Artificial stimuli such as clicks and tone pips evoke robust responses such as the Auditory Brainstem Response that, whilst only fractions of a μV in amplitude, can be recorded reliably with appropriate averaging and filtering. Evoked responses to such stimuli are widely used in neonatal hearing assessment and have had great clinical impact as they allow hearing aids to be fitted to infants from a few weeks of age, minimising effects of auditory deprivation. When we fit hearing aids to infants the signal that we are generally most interested in making audible is speech. However measuring the response to clicks and tone pips does not allow us to directly demonstrate that the brain is responding to speech. Also the response of hearing aids to speech on a typical user setting may be different from that produced using artificial stimuli such as clicks or tone pips, so using artificial non-speech sounds may have limitations for evaluating hearing aid benefit.By measuring evoked responses to speech we may be able to demonstrate that hearing aids give access to speech and/or adjust hearing aids to maximise benefit for the user, but key questions for clinical use are the reliability and duration of measurements. Various approaches have been used in the literature to explore the measurement of evoked responses to speech, using stimuli ranging from simple repeating speech tokens such as ‘da’ through words and sentences to running speech. Also evoked responses to speech have been measured from the brainstem level through to the cortex. In this talk I will summarise key approaches that have been used to measuring evoked responses to speech and discuss their potential application to evaluate or adjust hearing aids. I will also give an update on findings from the EPSRC funded project EP/M026728/1 ‘Personalized fitting and evaluation of hearing aids with EEG responses’. In this project we are exploring the limits of measuring evoked responses to speech with a view to using the most promising methods to evaluate or adjust hearing aids for the end user.<br/
Can we measure evoked responses to speech?
No full textOur research group is exploring whether it may be possible to optimise hearing aids for individuals using brain responses to real world stimuli. Hearing for speech is the primary concern of most hearing aid users hence the initial phase of our project has been to explore the reliability of speech evoked responses.For short speech tokens such as ‘da’ brainstem and cortical responses can be reliably measured. However it is debatable how representative of real speech such short stimuli are, or whether responses to such stimuli represent detection or intelligibility. Another issue to consider is whether hearing aids will amplify short speech tokens in the same way that that they amplify running speech. Using more complex stimuli may alleviate this problem.At the brainstem level both onset and modulation following responses can be detected within a few minutes using short speech tokens, words or short sentences, but with significant intersubject variability. Although cortical responses to running speech have been reported, we find these challenging to measure in reasonable clinical time scales. A new correlation based approach developed at Imperial University can be used to measure brainstem responses to running speech and this appears sensitive to the speech intelligibility. The next phase of the study will be to explore the use of such measures to evaluate hearing aid fittings.This work is funded by Engineering and Physical Sciences Research Council grant EP/M026728/1 and is joint between the Universities of Southampton, Imperial College and Manchester and the Interacoustics Research Unit.<br/
Dataset related to An objective comparison of quality and reliability of auditory brainstem response features elicited by click and speech sounds
No full textThe data was recorded in the programme 'Signal' version 4 made by Cambridge Electronic Design: ced.co.uk.
There are 16 subjects. For subjects 1-9 and 15, the files are in CED format (.cfs), so these would need to be opened in 'Signal'. For subjects 10-14 and 16 the data have been exported as .txt files so that they can be loaded into Matlab directly.
The first row is time and the second row is voltage. Note that an amplified with gain 10,000 was used, so to convert to voltage at the scalp, divide all values by 10,000.
P is for participant, ck indicates click stimulation, Da indicated Da stimulation, 1 and 2 indicate repeats, N65 indicates a recording in background noise and NN indicates no stimulation level. e.g.for Participant 12 there are 7 files...
P12ck1.txt - 1st click recording in quiet
P12ck2.txt - repeat click in quiet
P13ckN65.txt - click in 65 dB noise
P12Da1.txt - 1st Da in quiet
P12Da2.txt - 2nd Da in quiet
P12CkN65.txt - Da in 65 dB noise
P12NN.txt - no stimulation data
An example matlab analysis file 'Time_and_Freq_analysis_ABR_speech.m' is included. This shows how to load in data, how it was filtered, averaged, artefact rejected and then time and spectral bootstrapping is carried out.
The file 'Data_Description_Readme.txt' gives more detail of the recording of the data. It can also be found in the paper associated with this dataset (see dataset title). Participant 16 had particularly good data quality as an exemplar.
Approval for the study was given by The University of Southampton Ethics Committee (ERGO Ethics Number: 2411)</span
Objective comparison of the quality and reliability of auditory brainstem response elicited by click and speech sounds
No full textOBJECTIVES: Auditory brainstem responses (ABRs) are commonly generated using simple, transient stimuli (e.g., clicks or tone bursts). While resulting waveforms are undeniably valuable clinical tools, they are unlikely to be representative of responses to more complex, behaviorally relevant sounds such as speech. There has been interest in the use of more complex stimuli to elicit the ABR, with considerable work focusing on the use of synthetically generated consonant-vowel (CV) stimuli. Such responses may be sensitive to a range of clinical conditions and to the effects of auditory training. Several ABR features have been documented in response to CV stimuli; however, an important issue is how robust such features are. In the current research, we use time- and frequency-domain objective measures of quality to compare the reliability of Wave V of the click-evoked ABR to that of waves elicited by the CV stimulus /da/.DESIGN: Stimuli were presented to 16 subjects at 70 dB nHL in quiet for 6000 epochs. The presence and quality of response features across subjects were examined using Fsp and a Bootstrap analysis method, which was used to assign p values to ABR features for individual recordings in both time and frequency domains.RESULTS: All consistent peaks identified within the /da/-evoked response had significantly lower amplitude than Wave V of the ABR. The morphology of speech-evoked waveforms varied across subjects. Mean Fsp values for several waves of the speech-evoked ABR were below 3, suggesting low quality. The most robust response to the /da/ stimulus appeared to be an offset response. Only click-evoked Wave V showed 100% wave presence. Responses to the /da/ stimulus showed lower wave detectability. Frequency-domain analysis showed stronger and more consistent activity evoked by clicks than by /da/. Only the click ABR had consistent time-frequency domain features across all subjects.CONCLUSIONS: Based on the objective analysis used within this investigation, it appears that the quality of speech-evoked ABR is generally less than that of click-evoked responses, although the quality of responses may be improved by increasing the number of epochs or the stimulation level. This may have implications for the clinical use of speech-evoked ABR.<br/
Improving acquisition of auditory evoked potentials for clinical diagnosis and monitoring
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Comparing the sensitivity and specificity of cervical vestibular-evoked myogenic potentials and electrocochleography in the diagnosis of Ménière’s disease
No full textObjective: To compare the sensitivity and specificity of objective cervical vestibular evoked myogenic potential (cVEMP) tuning curves and Electrocochleography (ECochG) for the diagnosis of Ménière’s disease (MD).Design: Sensitivity and specificity were calculated from 95 % normative ranges of 500 Hz cVEMP threshold and ECochG SP/AP amplitude ratios.Measures: extra-tympanic ECochG testing to 90 dB nHL clicks and cVEMP threshold tuning curves (250 to 1000 Hz).Study sample: We tested 15 patients (30 ears) diagnosed with definite bilateral MD based on the clinical criteria proposed by the American Academy of Otolaryngology Head and Neck surgery, 1995 (assumed gold standard) and 20 controls. Results: 500 Hz cVEMP threshold was the most promising parameter to differentiate MD ears from controls. cVEMP and ECochG showed high specificity (83.3 % and 100 %, respectively) and low to moderate sensitivity (22.2 % and 71.4 %) for long term MD. ECochG sensitivity increased to 89 % during a symptomatic period, compared to 33 % for cVEMP. However, ECochG can be difficult to schedule during symptomatic periods. Sensitivity of cVEMP for the diagnosis of MD appears limited. Conclusions: ECochG has higher sensitivity than cVEMP in the diagnosis of Ménière’s patients, but the ECochG SP/AP amplitude ratio measure is not perfect for the diagnosis of MD. <br/
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