Biology subjects

Kidmose, P.

Publications and source records attributed to Kidmose, P..

4 recordsLinked to original sources

bioRxiv2025

Real-life ear-EEG Recordings of Auditory Responses to Ambient Sounds

Despite being one of the most researched neural responses, auditory potentials have primarily been measured in controlled laboratory environments. However, there is a big interest in measuring auditory potentials in more naturalistic environments, with stimuli resembling, to a higher degree, natural sounds. The objective of this study is to investigate auditory evoked potentials elicited by naturally occurring sounds in real-life environments. The paper presents an integration of a portable hearing aid research platform and a portable ear-EEG platform. This setup was validated through recordings of an Auditory Steady State Response (ASSR), elicited by real-time amplitude modulation of the ambient sound at 40Hz. Recordings were conducted in real-life under three conditions: walking and sitting with open and closed eyes. In addition to ear-EEG, scalp EEG was recorded as a reference. For analysis, EEG signals were categorized into three groups: scalp channels, cross-ear channels, and within-ear channels. For each condition and channel group, the signal-to-noise (SNR) of the ASSR was calculated. The ASSR was statistically significant across all channel groups and conditions. A post-hoc analysis assessed the recording duration required to obtain a significant ASSR, revealing that 10 minutes were enough for within ear ear-EEG for all but two cases, whereas less than 7 minutes were sufficient for all but one case when using scalp-EEG. Clinical relevanceThe Auditory Steady-State Response (ASSR) is a versatile tool for assessing various characteristics of the auditory pathway. The ability to measure ASSR in real-life conditions using ambient sound could facilitate the development of hearing aids capable of dynamically adapting to the users current hearing loss.

neuroscience↗

bioRxiv2025

A Pilot Study on Assessing Auditory Masking Using Auditory Steady-State Responses

Auditory masking is important in the characterization of human hearing and hearing impairment. Traditionally, masking is assessed through behavioral methods, witch requires active participant engagement. This study investigates the potential of using Auditory Steady-State Response (ASSR) to assess auditory masking, enabling masking assessment without requiring active participation. ASSRs were measured in response to a 40-Hz amplitude-modulated probe signal with and without the presence of a masker. The probe signals were 1/3-octave band-width Gaussian noise centered at 891 and 1414 Hz (center frequency, CF) and presented at 10, 20, 30, and 40 dB above individual behavioral masking thresholds (MT). The masker was lowpass Gaussian noise (cut-off 707 Hz) presented at 65 and 85 dB SPL (masker level, ML). The ASSR amplitude increased with presentation level (PL) and decreased in the presence of a masker, confirming a masking effect on ASSR. At 65 dB ML, ASSRs did not differ between center frequencies when probe signals were presented relative to MT, suggesting a simple relationship between MT and ASSR. At 85 dB ML, an effect of CF was observed, suggesting that the relationship between MT and ASSR is more complex than initially anticipated, and involving all the experimental parameters (CF, PL, and ML).

neuroscience↗

bioRxiv2024

The Speech Reception Threshold Can be Estimated Using EEG Electrodes In and Around the Ear

AbstractO_ST_ABSObjectiveC_ST_ABSPrevious studies have demonstrated that the speech reception threshold (SRT) can be estimated using scalp electroencephalography (EEG), referred to as SRTneuro. The present study assesses the feasibility of using ear-EEG, which allows for discreet measurement of neural activity from in and around the ear, to estimate the SRTneuro. Such an estimate can be highly useful e.g. for continuously adjusting noise-reduction algorithms in hearing aids or for logging the SRT in the users natural environment. ApproachTwenty young normal-hearing participants listened to audiobook excerpts at varying signal-to-noise ratios (SNRs) whilst wearing a 66-channel EEG cap and 12 ear-EEG electrodes. A linear decoder was trained on different electrode configurations to estimate the envelope of the audio excerpts from the EEG recordings. The reconstruction accuracy was determined by calculating the Pearsons correlation between the actual and the estimated envelope. A sigmoid function was then fitted to the reconstruction-accuracy-vs-SNR data points, with the midpoint of the sigmoid serving as the SRTneuro estimate for each participant. Main resultsUsing only in-ear electrodes, the estimated SRTneuro was within 3 dB of the behaviorally measured SRT (SRTbeh) for 6 out of 20 participants (30%). With electrodes placed both in and around the ear, the SRTneuro was within 3 dB of the SRTbeh for 19 out of 20 participants (95%) and thus on par with the reference estimate obtained from full-scalp EEG. Using only electrodes in and around the ear from the right side of the head, the SRTneuro remained within 3 dB of the SRTbeh for 19 out of 20 participants. SignificanceThese findings suggest that the SRTneuro can be reliably estimated using ear-EEG, especially when combining in-ear electrodes and around-the-ear electrodes.

bioengineering↗

bioRxiv2024

Speech-reception-threshold estimation via EEG-based continuous speech envelope reconstruction

This study investigates the potential of speech-reception-threshold (SRT) estimation through electroencephalography (EEG) based envelope reconstruction techniques with continuous speech. Additionally, we investigate the influence of the stimulis signal-to-noise ratio (SNR) on the temporal response function (TRF). Twenty young normal-hearing participants listened to audiobook excerpts with varying background noise levels while EEG was recorded. A linear decoder was trained to reconstruct the speech envelope from the EEG data. The reconstruction accuracy was calculated as the Pearsons correlation between the reconstructed and actual speech envelopes. An EEG SRT estimate (SRTneuro) was obtained as the midpoint of a sigmoid function fitted to the reconstruction accuracy versus SNR data points. Additionally, the TRF was estimated at each SNR level, followed by a statistical analysis to reveal significant effects of SNR levels on the latencies and amplitudes of the most prominent components. The SRTneuro was within 3 dB of the behavioral SRT for all participants. The TRF analysis showed a significant latency decrease for N1 and P2 and a significant amplitude magnitude increase for N1 and P2 with increasing SNR. The results suggest that both envelope reconstruction accuracy and the TRF components are influenced by changes in SNR, indicating they may be linked to the same underlying neural process.

bioengineering↗