Impact of hearing aid noise reduction algorithms on the speech-evoked auditory brainstem response

Frequency-Following Responses in Sensorineural Hearing Loss: A Systematic Review

PURPOSE

This systematic review aims to assess the impact of sensorineural hearing loss (SNHL) on various frequency-following response (FFR) parameters.

METHODS

Following PRISMA guidelines, a systematic review was conducted using PubMed, Web of Science, and Scopus databases up to January 2023. Studies evaluating FFRs in patients with SNHL and normal hearing controls were included.

RESULTS

Sixteen case-control studies were included, revealing variability in acquisition parameters. In the time domain, patients with SNHL exhibited prolonged latencies. The specific waves that were prolonged differed across studies. There was no consensus regarding wave amplitude in the time domain. In the frequency domain, focusing on studies that elicited FFRs with stimuli of 170 ms or longer, participants with SNHL displayed a significantly smaller fundamental frequency (F0). Results regarding changes in the temporal fine structure (TFS) were inconsistent.

CONCLUSION

Patients with SNHL may require more time for processing (speech) stimuli, reflected in prolonged latencies. However, the exact timing of this delay remains unclear. Additionally, when presenting longer stimuli (≥ 170 ms), patients with SNHL show difficulties tracking the F0 of (speech) stimuli. No definite conclusions could be drawn on changes in wave amplitude in the time domain and the TFS in the frequency domain. Patient characteristics, acquisition parameters, and FFR outcome parameters differed greatly across studies. Future studies should be performed in larger and carefully matched subject groups, using longer stimuli presented at the same intensity in dB HL for both groups, or at a carefully determined maximum comfortable loudness level.

On prediction of aided behavioural measures using speech auditory brainstem responses and decision trees

Current clinical strategies to assess benefits from hearing aids (HAs) are based on self-reported questionnaires and speech-in-noise (SIN) tests; which require behavioural cooperation. Instead, objective measures based on Auditory Brainstem Responses (ABRs) to speech stimuli would not require the individuals’ cooperation. Here, we re-analysed an existing dataset to predict behavioural measures with speech-ABRs using regression trees. Ninety-two HA users completed a self-reported questionnaire (SSQ-Speech) and performed two aided SIN tests: sentences in noise (BKB-SIN) and vowel-consonant-vowels (VCV) in noise. Speech-ABRs were evoked by a 40 ms [da] and recorded in 2x2 conditions: aided vs. unaided and quiet vs. background noise. For each recording condition, two sets of features were extracted: 1) amplitudes and latencies of speech-ABR peaks, 2) amplitudes and latencies of speech-ABR F0 encoding. Two regression trees were fitted for each of the three behavioural measures with either feature set and age, digit-span forward and backward, and pure tone average (PTA) as possible predictors. The PTA was the only predictor in the SSQ-Speech trees. In the BKB-SIN trees, performance was predicted by the aided latency of peak F in quiet for participants with PTAs between 43 and 61 dB HL. In the VCV trees, performance was predicted by the aided F0 encoding latency and the aided amplitude of peak VA in quiet for participants with PTAs ≤ 47 dB HL. These findings indicate that PTA was more informative than any speech-ABR measure, as these were relevant only for a subset of the participants. Therefore, speech-ABRs evoked by a 40 ms [da] are not a clinical predictor of behavioural measures in HA users.

Effect of hearing aids on attention, memory, and auditory evoked potentials: A pragmatic, single-blinded, and randomised pilot clinical trial

PURPOSE

To compare the effects of hearing aids and their technology levels (premium and basic) on attention, memory, brain response, and self-perceived benefit amongst individuals who were naïve to sound amplification.

MATERIAL AND METHODS

A pragmatic, single-blinded, and randomised pilot clinical trial in three-parallel arms according to hearing aids technology: (a) premium; (b) basic; and (c) no amplification hearing devices. Participants were ≥60 years old with mild-to-moderate sensorineural symmetric hearing loss and naïve to sound amplification. We tested attention and memory skills, as well as brain response and self-perceived benefit before and after 12 weeks of using the hearing devices. The primary outcome was any improvement in the tests we performed.

RESULTS

The participants who missed the follow-up (n = 2) were excluded from our final analysis. We ended up with 22 patients (A = 8, B = 6, and C = 8) who were 80.4 (±6.1) years old, predominantly female (63.63%), and poorly educated (3.8 ± 1.6 years). After the intervention, we observed differences in attention and memory scores (reverse counting, P < .01, 95% CI 2.2; 11.63; digit sequence repetition, P = .03, 95% CI -1.9; -0.05; delayed recall, P = .03, 95% CI -1.2; -0.05; recognition, P < .01, 95% CI -2.6; -0.45; and visual memory, P < .01, 95% CI -0.9; -0.15), but only reverse counting (A vs C, P < .01,95% CI 5.9; 20.55) and recognition (B vs C, P < .01, 95% CI -6.1; -0.88) were observed in pairwise comparisons. The difference in N1 wave latency (/g/ sound, P = .01,95% CI 2.1; 18.59) could not be confirmed in pairwise comparison. The self-perceived benefit questionnaire revealed no difference between groups A and B; the groups A and C differed in benefit (P < .01, 95% CI -2.2; -0.76), satisfaction (P = .02,95% CI -2.0;-0.21), residual participation restrictions (P = .01, 95% CI -2.9; -0.38), and quality of life (P = .03, 95% CI -1.4; -0.08); the groups B and C differed in benefit (P < .001, 95% CI -2.3; -0.96), and satisfaction (P = .01,95% CI -2.1; -0.29).

CONCLUSION

In this study, premium and basic hearing aids impacted attention, memory, brain response, and self-perceived benefit similarly amongst individuals who were naïve to sound amplification after 12 weeks of using the hearing devices.