Predicting Matrix test effectiveness for evaluating auditory performance in noise using pure-tone audiometry and speech recognition in quiet in cochlear implant recipients.

INTRODUCTION: Auditory performance in noise of cochlear implant recipients can be assessed with the adaptive Matrix test (MT); however, when the speech-to-noise ratio (SNR) exceeds 15 dB, the background noise has any negative impact on the speech recognition. Here, we aim to evaluate the predictive power of aided pure-tone audiometry and speech recognition in quiet, and establish cut-off values for both tests that indicate whether auditory performance in noise can be assessed using the Matrix sentence test in a diffuse noise environment. METHODS: Here, we assessed the power of pure-tone audiometry and speech recognition in quiet to predict the response to the MT. Ninety-eight cochlear implant recipients were assessed using different sound processors from Advanced Bionics (n=56) and Cochlear (n=42). Auditory tests were performed at least 1-year after cochlear implantation or upgrading the sound processor to ensure the best benefit of the implant. Auditory assessment of the implanted ear in free-field conditions included: pure-tone average (PTA), speech discrimination score (SDS) in quiet at 65 dB, and speech recognition threshold (SRT) in noise that is the SNR at which the patient can correctly recognize 50% of the words using the MT in a diffuse sound field. RESULTS: The SRT in noise was determined in sixty patients (61%) and undetermined in 38 (39%) using the MT. When cut-off values for PTA <36 dB and SDS >41% were used separately, they were able to predict a positive response to the MT in 83% of recipients; using both cut-off values together, the predictive value reached 92%. DISCUSSION/CONCLUSION: As the pure-tone audiometry is standardized universally and the speech recognition in quiet could vary depending on the language used; we propose that the MT should be performed in recipients with PTA <36 dB, and in recipients with PTA >36 dB, a list of Matrix sentences at a fixed SNR should be presented to determine the percentage of words understood. This approach should enable clinicians to obtain information about auditory performance in noise whenever possible.

Reference data for a quick speech-in-noise hearing test in the French language.

INTRODUCTION: Difficulties in understanding speech in noise is the most common complaint of people with hearing impairment. Thus, there is a need for tests of speech-in-noise ability in clinical settings, which have to be evaluated for each language. Here, a reference dataset is presented for a quick speech-in-noise test in the French language (Vocale Rapide dans le Bruit, VRB; Leclercq, Renard & Vincent, 2018). METHODS: A large cohort (N=641) was tested in a nationwide multicentric study. The cohort comprised normal-hearing individuals and individuals with a broad range of symmetrical hearing losses. Short everyday sentences embedded in babble noise were presented over a spatial array of loudspeakers. Speech level was kept constant while noise level was progressively increased over a range of signal-to-noise ratios. The signal-to-noise ratio for which 50% of keywords could be correctly reported (Speech Reception Threshold, SRT) was derived from psychometric functions. Other audiometric measures were collected for the cohort, such as audiograms and speech-in-quiet performance. RESULTS: The VRB test was both sensitive and reliable, as shown by the steep slope of the psychometric functions and by the high test-retest consistency across sentence lists. Correlation analyses showed that pure tone averages derived from the audiograms explained 74% of the SRT variance over the whole cohort, but only 29% for individuals with clinically normal audiograms. SRTs were then compared to recent guidelines from the French Society of Audiology (Joly et al., 2021). Among individuals who would not have qualified for hearing aid prescription based on their audiogram or speech intelligibility in quiet, 18.4% were now eligible as they displayed SRTs in noise impaired by 3 dB or more. For individuals with borderline audiograms, between 20 dB HL and 30 dB HL, the prevalence of impaired SRTs increased to 71.4%. Finally, even though five lists are recommended for clinical use, a minute-long screening using only one VRB list detected 98.6% of impaired SRTs. CONCLUSION: The reference data suggest that VRB testing can be used to identify individuals with speech-in-noise impairment.

Speech understanding in diffuse steady noise in typically hearing and hard of hearing listeners.

Spatial cues can facilitate segregation of target speech from maskers. However, in clinical practice, masked speech understanding is most often evaluated using co-located speech and maskers (i.e., without spatial cues). Many hearing aid centers in France are equipped with five-loudspeaker arrays, allowing masked speech understanding to be measured with spatial cues. It is unclear how hearing status may affect utilization of spatial cues to segregate speech and noise. In this study, speech reception thresholds (SRTs) for target speech in "diffuse noise" (target speech from 1 speaker, noise from the remaining 4 speakers) in 297 adult listeners across 9 Audilab hearing centers. Participants were categorized according to pure-tone-average (PTA) thresholds: typically-hearing (TH; ≤ 20 dB HL), mild hearing loss (Mild; >20 ≤ 40 dB HL), moderate hearing loss 1 (Mod-1; >40 ≤ 55 dB HL), and moderate hearing loss 2 (Mod-2; >55 ≤ 65 dB HL). All participants were tested without aided hearing. SRTs in diffuse noise were significantly correlated with PTA thresholds, age at testing, as well as word and phoneme recognition scores in quiet. Stepwise linear regression analysis showed that SRTs in diffuse noise were significantly predicted by a combination of PTA threshold and word recognition scores in quiet. SRTs were also measured in co-located and diffuse noise in 65 additional participants. SRTs were significantly lower in diffuse noise than in co-located noise only for the TH and Mild groups; masking release with diffuse noise (relative to co-located noise) was significant only for the TH group. The results are consistent with previous studies that found that hard of hearing listeners have greater difficulty using spatial cues to segregate competing speech. The data suggest that speech understanding in diffuse noise provides additional insight into difficulties that hard of hearing individuals experience in complex listening environments.

Speech understanding in noise with the Roger Pen, Naida CI Q70 processor, and integrated Roger 17 receiver in a multi-talker network.

Roger is a digital adaptive multi-channel remote microphone technology that wirelessly transmits a speaker's voice directly to a hearing instrument or cochlear implant sound processor. Frequency hopping between channels, in combination with repeated broadcast, avoids interference issues that have limited earlier generation FM systems. This study evaluated the benefit of the Roger Pen transmitter microphone in a multiple talker network (MTN) for cochlear implant users in a simulated noisy conversation setting. Twelve post-lingually deafened adult Advanced Bionics CII/HiRes 90K recipients were recruited. Subjects used a Naida CI Q70 processor with integrated Roger 17 receiver. The test environment simulated four people having a meal in a noisy restaurant, one the CI user (listener), and three companions (talkers) talking non-simultaneously in a diffuse field of multi-talker babble. Speech reception thresholds (SRTs) were determined without the Roger Pen, with one Roger Pen, and with three Roger Pens in an MTN. Using three Roger Pens in an MTN improved the SRT by 14.8 dB over using no Roger Pen, and by 13.1 dB over using a single Roger Pen (p < 0.0001). The Roger Pen in an MTN provided statistically and clinically significant improvement in speech perception in noise for Advanced Bionics cochlear implant recipients. The integrated Roger 17 receiver made it easy for users of the Naida CI Q70 processor to take advantage of the Roger system. The listening advantage and ease of use should encourage more clinicians to recommend and fit Roger in adult cochlear implant patients.

Music to electric ears: pitch and timbre perception by cochlear implant patients.

The sounds of music play with many perceptual dimensions. We devised a set of psychophysical procedures to better understand how recipients of cochlear implants perceive basic sound attributes involved in music listening.