Speech Recognition Threshold Research Articles

Comparison Between a New Implantable Transcutaneous Bone Conductor and Percutaneous Bone-Conduction Hearing Implant

Despite good results on osseointegration and limited skin reactions with percutaneous bone conductors, there remains room for improvement. Especially in children, adverse events with percutaneous bone conductors might occur more frequently. Transcutaneous bone conductors, if powerful enough, can provide a solution that minimizes adverse events and implant loss. This study compares a new transcutaneous bone conduction hearing aid, the Sophono Alpha 1 (Sophono), with the percutaneous BAHA system (BAHA). In our tertiary referral center, 12 patients (age 5-12 yr) with congenital unilateral conductive hearing loss were enrolled in the study as follows: 6 patients with the Sophono and 6 with the BAHA. Both clinical results and audiologic data were gathered. For an objective audiologic comparison between both systems, we used a skull simulator. The skin reactions were comparable between both groups, in 1 implant was lost 1 month after second phase surgery (BAHA). The users received audiologic benefits from both systems. The BAHA-based outcome was slightly better compared with Sophono-based results in sound field thresholds, speech recognition threshold, and speech comprehension at 65 dB. The skull simulator demonstrated that the BAHA device has an output that is 10 to 15 dB higher compared with the Sophono device. The Sophono offers appealing clinical benefits of transcutaneous bone conduction hearing; however, the audiologic challenges of transcutaneous application remain, as the Sophono does not exceed percutaneous application regarding audiologic output.

Unilateral and bilateral hearing aids, spatial release from masking and auditory acclimatization

Spatial release from masking (SRM) was tested within the first week of fitting and after 12 weeks hearing aid use for unilateral and bilateral adult hearing aid users. A control group of experienced hearing aid users completed testing over a similar time frame. The main research aims were (1) to examine auditory acclimatization effects on SRM performance for unilateral and bilateral hearing aid users, (2) to examine whether hearing aid use, level of hearing loss, age or cognitive ability mediate acclimatization, and (3) to compare and contrast the outcome of unilateral versus bilateral aiding on SRM. Hearing aid users were tested with and without hearing aids, with SRM calculated as the 50% speech recognition threshold advantage when maskers and target are spatially separated at ±90° azimuth to the listener compared to a co-located condition. The conclusions were (1) on average there was no improvement over time in familiar aided listening conditions, (2) there was large test-retest variability which may overshadow small average acclimatization effects; greater improvement was associated with better cognitive ability and younger age, but not associated with hearing aid use, and (3) overall, bilateral aids facilitated better SRM performance than unilateral aids.

Modified segmental signal-to-noise ratio reflecting spectral masking effect for evaluating the performance of hearing aid algorithms

Most traditional objective indices don’t distinguish between a real sound and a perceived sound, and therefore, these indices have limitations in regard to the evaluation of the real effect of an algorithm under investigation on the auditory perception of a hearing-impaired person. Though several objective indices, such as perceptual evaluation of speech quality (PESQ) and composite measurements, that reflect the psychoacoustic factors were already in use, it is helpful to develop more objective indices that take into account human psychoacoustic factors in order to accurately evaluate the performance of hearing aid algorithms. In this study, a new objective index that reflects the spectral masking effect into the calculation of the conventional segmental signal-to-noise ratio (segSNR) was proposed. The performance of this index was evaluated by analyzing the correlation of the result and (1) the mean opinion score and (2) the speech recognition threshold tests of 15 normal-hearing volunteers and 15 hearing-impaired patients. The correlation values of the proposed index were relatively high (0.83–0.97) across various ambient noise situations. Based on these experimental results, the proposed index has the potential to be widely used as a measuring index for the performance evaluation of various hearing aid algorithms prior to conducting clinical experiments.

Non-flat audiograms in sensorineural hearing loss and speech perception

OBJECTIVE:The audibility thresholds for the sound frequency of 137 upward- and downward-sloping audiograms showing sensorineural hearing loss were selected and analyzed in conjunction with speech recognition thresholds obtained from individuals seen at a public otolaryngology clinic to determine which frequencies in slope audiograms best represent speech recognition thresholds.METHOD:The linear regression model and mean square error were used to determine the associations between the threshold values.RESULT:The mean square error identified larger errors when using thresholds of 500, 1000, and 2000 Hz than when using audibility thresholds of 500, 1000, 2000, and 4000 Hz. The linear regression model showed a higher correlation (91%) between the audiogram thresholds for frequencies of 500, 1000, 2000, and 4000 Hz than for the frequencies of 500, 1000, and 2000 Hz (88%).CONCLUSION:Frequencies of 500, 1000, 2000, and 4000 Hz were the most significant in predicting the speech recognition threshold.

Binaural speech recognition in continuous and intermittent noises in people with hearing loss

Multiple tests have been developed to quantify speech recognition in noise, but the characteristics of the masking noise vary significantly across tests and can considerably impact performance and clinical interpretation. Using the HINT, speech perception in 24 young adults with normal hearing was assessed using both the standard masker (a continuous speech-spectrum noise) and an intermittent version of the masker at an ON-OFF rate of 16 Hz. Intermittency helps in extracting speech from the “quiet” segments of the noise. Speech recognition thresholds for frontal speech were better in the intermittent than the continuous noise by an amount of 13 and 10 dB for noise maskers located in front or side, respectively, The average difference in thresholds between the noise front and side conditions, called the binaural advantage, was 4.7 and 8.4 dB for the intermittent and continuous noises, respectively. Data collected with people presenting different hearing loss profiles also show binaural and intermittency advantages, but to a lesser degree. Considering that people encounter a wide a range of fluctuating noises in daily life, these results motivate adding an intermittent noise condition to the HINT protocol to better reflect the challenges faced by individuals with hearing loss.

Wirkung von Frequenzkompression in Hörgeräten auf das Sprachverstehen und das subjektive Klangempfinden der Nutzer

The acceptance of hearing aids by users with high frequency hearing loss still represents a problem. Processing algorithms that shift high frequency signal components into an audible frequency range are proposed as a solution. We looked into the issue of whether frequency compression becomes more beneficial with increasing high frequency hearing loss or/and for users with cochlear dead regions (DR). A total of 20 hearing aid candidates were assessed audiometrically and classified into two test groups in terms of their hearing loss and the presence of DR. The subjects then evaluated four hearing aid settings that differed solely in the degree of frequency compression. Speech recognition threshold measurements and subjective sound quality ratings were carried out for all four settings. Data showed that 15 of the 20 test subjects understood fricatives with a high frequency spectrum component better, since they were able to distinguish between the two logatomes "Afa" and "Asa". No correlation was found between the beneficial effect of frequency compression and the degree of high frequency hearing loss or the presence of DR. Subjective sound quality ratings indicated no clear preference, but excessive frequency compression was generally deemed counterproductive. Frequency compression may be appropriate for hearing aid users with high frequency hearing loss and can improve speech recognition. The degree of frequency compression required to achieve maximal benefit varies from case to case and has to be optimized on an individual basis.

Improving speech perception in noise with current focusing in cochlear implant users

Cochlear implant (CI) users typically have excellent speech recognition in quiet but struggle with understanding speech in noise. It is thought that broad current spread from stimulating electrodes causes adjacent electrodes to activate overlapping populations of neurons which results in interactions across adjacent channels. Current focusing has been studied as a way to reduce spread of excitation, and therefore, reduce channel interactions. In particular, partial tripolar stimulation has been shown to reduce spread of excitation relative to monopolar stimulation. However, the crucial question is whether this benefit translates to improvements in speech perception. In this study, we compared speech perception in noise with experimental monopolar and partial tripolar speech processing strategies. The two strategies were matched in terms of number of active electrodes, microphone, filterbanks, stimulation rate and loudness (although both strategies used a lower stimulation rate than typical clinical strategies). The results of this study showed a significant improvement in speech perception in noise with partial tripolar stimulation. All subjects benefited from the current focused speech processing strategy. There was a mean improvement in speech recognition threshold of 2.7 dB in a digits in noise task and a mean improvement of 3 dB in a sentences in noise task with partial tripolar stimulation relative to monopolar stimulation. Although the experimental monopolar strategy was worse than the clinical, presumably due to different microphones, frequency allocations and stimulation rates, the experimental partial-tripolar strategy, which had the same changes, showed no acute deficit relative to the clinical.

Evaluation of antioxidant treatment in presbyacusis: prospective, placebo-controlled, double-blind, randomised trial

There are many well-known aetiological mechanisms of presbyacusis, and free radicals have been shown to play an important role. This study aimed to evaluate the effect of antioxidant agents on the hearing threshold of patients with presbyacusis. One hundred and twenty individuals were divided into four groups and received one of the following treatment schemes: ginkgo biloba dry extract, α-lipoic acid plus vitamin C, papaverine chlorhydrate plus vitamin E, or placebo. All participants were evaluated at recruitment and after six months, using pure tone audiometry (at isolated and average frequencies), speech recognition threshold and percentage index of speech recognition. The various treatments had no effect on any of the evaluated measures of hearing, either between groups or over time. There was no statistically significant change in the hearing threshold after treatment with any of the tested drugs, during the study period.

Cochlear Dead Region and Word Recognition of Mandarin Chinese in Taiwan

In a tonal language, the identity of a word depends largely on the tonal identification of the contour of vocal fundamental frequency energy of which usually centers in a low frequency of less than 600 Hz. However, cochlear dead region (DR) is present mostly in the frequency range of 2000 Hz to 4000 Hz, and the effect of DR on a tonal language is worth investigating. Thirty-two native Mandarin speakers with moderate-to-severe degree of sensorineural hearing loss were included in this study. The pure-tone audiometry, speech recognition threshold (SRT) and word recognition score (WRS) were used to evaluate the degree of hearing loss and word recognition. The threshold equalizing noise (TEN) tests were used to identify the presence of DR. The results showed that most DRs were present in high frequencies. The hearing thresholds of the ears with a DR were not significantly different from those without DR. However, the WRS was significantly worse for the DR ears, especially for those whose DR included three or more audiometric frequencies. A DR caused a significantly worse word recognition for the tonal language speakers of Mandarin in Taiwan, although the DR frequency occurred in the high frequency of 2000 Hz to 4000 Hz.

Effects of Age on Pure Tone Hearing Thresholds and Speech Recognition Thresholds

Pure-tone sensitivity and speech recognition measurements in quiet are vital components in audiologic evaluation. Pure-tone hearing threshold level increases in proportion to ages and affects speech recognition threshold (SRT). The purpose of this study was to find out the relationship between changes in pure-tone threshold averages (PTAs) and SRTs as a function of ages. Sixty adults (120 ears) with normal hearing, aged 20 to 69 years, were participated. SRTs were performed by IEC 60645-2, and used with Korean Standard bisyllabic word list for adults (KS-BWL-A). As a results, there were significantly correlated PTAs and SRTs. SRT, 0.49 dB/year, increased more fast compare to PTA, 0.34 dB/year. These finding suggested to be used as reference data for determining reliability of pure-tone audiometry for the elderly.

Clinical evaluation of the performance of a blind source separation algorithm combining beamforming and independent component analysis in hearing aid use

There have been several reports on improved blind source separation algorithms that combine beamforming and independent component analysis. However, none of the prior reports verified the clinical efficacy of such combinational algorithms in real hearing aid situations. In the current study, we evaluated the clinical efficacy of such a combinational algorithm using the mean opinion score and speech recognition threshold tests in various types of real-world hearing aid situations involving environmental noise. Parameters of the testing algorithm were adjusted to match the geometric specifications of the real behind-the-ear type hearing aid housing. The study included 15 normal-hearing volunteers and 15 hearing-impaired patients. Experimental results demonstrated that the testing algorithm improved the speech intelligibility of all of the participants in noisy environments, and the clinical efficacy of the combinational algorithm was superior to either the beamforming or independent component analysis algorithms alone. Despite the computational complexity of the testing algorithm, our experimental results and the rapid enhancement of hardware technology indicate that the testing algorithm has the potential to be applied to real hearing aids in the near future, thereby improving the speech intelligibility of hearing-impaired patients in noisy environments.

The Relationship between High-Frequency Pure-Tone Hearing Loss, Hearing in Noise Test (HINT) Thresholds, and the Articulation Index

Speech recognition in noise testing has been conducted at least since the 1940s (Dickson et al, 1946). The ability to recognize speech in noise is a distinct function of the auditory system (Plomp, 1978). According to Kochkin (2002), difficulty recognizing speech in noise is the primary complaint of hearing aid users. However, speech recognition in noise testing has not found widespread use in the field of audiology (Mueller, 2003; Strom, 2003; Tannenbaum and Rosenfeld, 1996). The audiogram has been used as the "gold standard" for hearing ability. However, the audiogram is a poor indicator of speech recognition in noise ability. This study investigates the relationship between pure-tone thresholds, the articulation index, and the ability to recognize speech in quiet and in noise. Pure-tone thresholds were measured for audiometric frequencies 250-6000 Hz. Pure-tone threshold groups were created. These included a normal threshold group and slight, mild, severe, and profound high-frequency pure-tone threshold groups. Speech recognition thresholds in quiet and in noise were obtained using the Hearing in Noise Test (HINT) (Nilsson et al, 1994; Vermiglio, 2008). The articulation index was determined by using Pavlovic's method with pure-tone thresholds (Pavlovic, 1989, 1991). Two hundred seventy-eight participants were tested. All participants were native speakers of American English. Sixty-three of the original participants were removed in order to create groups of participants with normal low-frequency pure-tone thresholds and relatively symmetrical high-frequency pure-tone threshold groups. The final set of 215 participants had a mean age of 33 yr with a range of 17-59 yr. Pure-tone threshold data were collected using the Hughson-Weslake procedure. Speech recognition data were collected using a Windows-based HINT software system. Statistical analyses were conducted using descriptive, correlational, and multivariate analysis of covariance (MANCOVA) statistics. The MANCOVA analysis (where the effect of age was statistically removed) indicated that there were no significant differences in HINT performances between groups of participants with normal audiograms and those groups with slight, mild, moderate, or severe high-frequency hearing losses. With all of the data combined across groups, correlational analyses revealed significant correlations between pure-tone averages and speech recognition in quiet performance. Nonsignificant or significant but weak correlations were found between pure-tone averages and HINT thresholds. The ability to recognize speech in steady-state noise cannot be predicted from the audiogram. A new classification scheme of hearing impairment based on the audiogram and the speech reception in noise thresholds, as measured with the HINT, may be useful for the characterization of the hearing ability in the global sense. This classification scheme is consistent with Plomp's two aspects of hearing ability (Plomp, 1978).

Use of Audiometric Variables to Differentiate Groups of Adults Based on Hearing Aid Ownership and Use

Purpose: The purpose of this study was to determine the relationship between multiple audiometric variables and hearing aid ownership and use for first-time hearing aid candidates. In this study, use was defined as a participant report of hearing aid use 1 year following the initial evaluation. Method: Charts were reviewed and data were collected from the initial hearing evaluations of 144 adults with sensorineural hearing loss who presented for services and were candidates for amplification. The following audiomet- ric data were gathered from each participant: (a) pure-tone air conduction thresholds, (b) speech recognition thresholds (SRTs), (c) word recognition scores (WRSs), and (d) sig- nal-to-noise ratio (SNR) loss. In addition, each audiogram was classified as falling within or outside an area of the audiogram as described by Erber (2002, 2003). Participants were divided into 3 groups: (a) those who purchased hear- ing aids and reported wearing them 1 year following their initial evaluation (n = 51), (b) those who purchased hearing aids and rejected them during the first year following their initial evaluation (n = 48), and (c) those who received a recommendation for hearing aids but did not purchase any (n = 45). T

Ondansetron in patients with tinnitus: randomized double-blind placebo-controlled study

The aim of this study was to assess the effect of ondansetron on symptoms of patients with subjective tinnitus accompanied by sensorineural hearing loss or normal hearing. Sixty patients with a chief complaint of tinnitus (with duration of more than 3 months) were equally randomized to ondansetron or placebo for 4 weeks. The dose of ondansetron was gradually increased from 4 mg/day (one tablet) to 16 mg/day (4 tablets) during 12 days and then continued up to 4 weeks. The exact number of tablets was prescribed in the placebo group. Patients underwent audiologic examinations and filled questionnaires at baseline and after 4 weeks of treatment. Our primary outcomes were changes in Tinnitus Handicap Inventory questionnaire (THI), Tinnitus Severity Index (TSI) and visual analog scale (VAS) scores. Our secondary outcomes were the changes in depression and anxiety based on Hospital Anxiety and Depression (HADS) questionnaire, side effects, tinnitus loudness matching, tinnitus pitch matching, pure tone audiometry and speech recognition threshold (SRT). In the ondansetron and placebo groups, 27 and 26 patients completed the study, respectively. The changes in VAS (P = 0.934), THI (P = 0.776), anxiety (P = 0.313) and depression (P = 0.163) scores were not different between the groups. TSI score decreased significantly in the ondansetron compared with the placebo group (P = 0.004). Changes in tinnitus loudness matching (P = 0.75) and pitch matching (P = 0.56) did not differ between the two groups. Ondansetron, but not placebo, decreased the SRT threshold (right, P < 0.001; left, P = 0.043) and mean PTA (right, P = 0.006; left, P < 0.001). In conclusion, ondansetron reduces the severity of tinnitus hypothetically through cochlear amplification.

Relationship between masking release in fluctuating maskers and speech reception thresholds in stationary noise

In contrast to normal-hearing (NH) listeners, hearing-impaired (HI) listeners often show strongly reduced masking release (MR) in fluctuating interferers, which has commonly been associated with spectral and temporal processing deficits. However, it has recently been proposed that the reduced MR could result from an increased speech recognition threshold (SRT) in stationary noise [Bernstein and Grant, J. Acoust. Soc. Am. 125, 3358-3372 (2009)]. This was tested by presenting noise-band vocoded as well as low-pass and high-pass filtered stimuli to NH listeners, thereby increasing their stationary-noise SRTs to those of the HI listeners. If the primary determinant of MR is the SRT in stationary noise then the amount of the MR should be independent of the type of processing used to obtain the stationary-noise SRT. However, the relation between the amount of MR and the stationary-noise SRT depended on the type of processing. For a fluctuating interferer, none of the processing conditions reduced the MR of the NH listeners to that of the HI listeners. In contrast, for an interfering talker, the results for vocoded stimuli were similar to those of the HI listeners. Overall, these results suggest that the observed MR is only partially related to the stationary-noise SRT.

Speech recognition in noise using bilateral open-fit hearing aids: The limited benefit of directional microphones and noise reduction

Objective: To investigate speech recognition performance in noise with bilateral open-fit hearing aids and as reference also with closed earmolds, in omnidirectional mode, directional mode, and directional mode in conjunction with noise reduction. Design: A within-subject design with repeated measures across conditions was used. Speech recognition thresholds in noise were obtained for the different conditions. Study sample: Twenty adults without prior experience with hearing aids. All had symmetric sensorineural mild hearing loss in the lower frequencies and moderate to severe hearing loss in the higher frequencies. Results: Speech recognition performance in noise was not significantly better with an omnidirectional microphone compared to unaided, whereas performance was significantly better with a directional microphone (1.6 dB with open fitting and 4.4 dB with closed earmold) compared to unaided. With open fitting, no significant additional advantage was obtained by combining the directional microphone with a noise reduction algorithm, but with closed earmolds a significant additional advantage of 0.8 dB was obtained. Conclusions: The significant, though limited, advantage of directional microphones and the absence of additional significant improvement by a noise reduction algorithm should be considered when fitting open-fit hearing aids.

Neural Response Telemetry in Pediatric Cochlear Implantation

Objective: 1) Evaluate the neural response telemetry (NRT) of patients with inner ear anomalies, and determine correlations between NRT and postoperative speech recognition thresholds (SRT). 2) Determine if higher incidence of negative intraoperative NRT exists in pediatric patients with inner ear anomalies, namely enlarged vestibular aqueduct syndrome (EVAS). Method: Retrospective chart review of pediatric patients who underwent cochlear implantation at a tertiary care pediatric referral center from 2001 to present. Patients with inner ear anomalies were age matched to controls without anomalies. Associations between abnormal NRT and perilymphatic gusher and correlations between NRT and audiometry were assessed. Results: Twenty-seven subjects with radiographic evidence of EVAS were evaluated; 35 ears implanted. Median age of implantation was 77.5 months. NRT was normal in 69%, abnormal 11%, marginal 6%, missing 4%. Intraoperative data revealed a perilymphatic gusher in 8 patients (23%); of which 50% had abnormal NRT compared to 8% among patients without gusher ( P = .03). Postoperative audiometric data were available for 8 out of 35 ears. No significant correlations between intraoperative and postoperative NRT with postoperative SRT at 1 kHz, 2 kHz, 4 kHz ( P &gt; .2). There appeared to be a correlation between intraoperative NRT and postoperative SRT at 500 kHz (ρ = 0.68, P = .14); this was not statistically significant. Conclusion: The presence of perilymphatic gusher at the time of cochlear implantation in patients with enlarged vestibular aqueduct syndrome (EVAS) seems to be related to abnormal NRT. There is no significant correlation between intraoperative and postoperative NRT and speech recognition thresholds (SRT) at 1 kHZ, 2 kHz, and 4 kHz in patients with EVAS.

A Computerized Closed‐Response Speech Test in the ENT Clinic

Objective: 1) To assess the feasibility of a computer-based closed-response speech test (CRST) in the ENT clinic. 2) To compare a closed response speech test to standard speech audiometry. Method: Thirty patients underwent otoscopy, tympanometry, pure-tone audiometry, speech audiometry and a closed-response speech test (CRST). For the CRST, patients were asked to choose, on a tactile computer screen, the words that were presented to their ear, amongst a choice of 4 words. Fifteen sets of 4 words were used. Results: The CRST was well accepted by all patients, whatever their computer literacy, but took significantly longer (10 to 15 minutes per ear) than speech audiometry did. Pure transmission hearing losses showed a translation of the performance intensity function toward greater intensities, without change in slope, as in standard speech audiometry. Correlations between auditory thresholds and speech recognition thresholds were greater for the CRST ( r = 0.70, P &lt; .01) than for speech audiometry ( r = 0.46, P &lt; .05). Several cases of patients showing very similar speech audiometry performance intensity functions, but different CRST scores were identified. Conclusion: Although the closed-set computerized test took substantially longer than speech audiometry, it was well accepted by patients. It was more sensitive to minor alterations of hearing than speech audiometry and shows promise as a longitudinal assessment tool of speech perception.

Effects of sleep deprivation on central auditory processing

BackgroundSleep deprivation is extremely common in contemporary society, and is considered to be a frequent cause of behavioral disorders, mood, alertness, and cognitive performance. Although the impacts of sleep deprivation have been studied extensively in various experimental paradigms, very few studies have addressed the impact of sleep deprivation on central auditory processing (CAP). Therefore, we examined the impact of sleep deprivation on CAP, for which there is sparse information. In the present study, thirty healthy adult volunteers (17 females and 13 males, aged 30.75 ± 7.14 years) were subjected to a pure tone audiometry test, a speech recognition threshold test, a speech recognition task, the Staggered Spondaic Word Test (SSWT), and the Random Gap Detection Test (RGDT). Baseline (BSL) performance was compared to performance after 24 hours of being sleep deprived (24hSD) using the Student’s t test.ResultsMean RGDT score was elevated in the 24hSD condition (8.0 ± 2.9 ms) relative to the BSL condition for the whole cohort (6.4 ± 2.8 ms; p = 0.0005), for males (p = 0.0066), and for females (p = 0.0208). Sleep deprivation reduced SSWT scores for the whole cohort in both ears [(right: BSL, 98.4 % ± 1.8 % vs. SD, 94.2 % ± 6.3 %. p = 0.0005)(left: BSL, 96.7 % ± 3.1 % vs. SD, 92.1 % ± 6.1 %, p < 0.0001)]. These effects were evident within both gender subgroups [(right: males, p = 0.0080; females, p = 0.0143)(left: males, p = 0.0076; females: p = 0.0010).ConclusionSleep deprivation impairs RGDT and SSWT performance. These findings confirm that sleep deprivation has central effects that may impair performance in other areas of life.

Round window vibroplasty: Long-term results

Conclusions: The round window (RW) approach in the use of the Vibrant Soundbridge® (VSB) is a safe and effective treatment of conductive and mixed hearing losses for a period of more than 3 years of device use. Objective: To investigate the long-term safety and efficacy as well as user satisfaction of patients with conductive and mixed hearing losses implanted with the VSB using RW vibroplasty. Methods: Twelve patients with conductive and mixed hearing losses were evaluated after 40 months of daily VSB use. Safety was assessed by evaluating reports of postoperative medical and surgical complications as well as by changes in bone conduction hearing thresholds. Efficacy outcome measures included aided and unaided hearing thresholds, speech recognition in quiet and in noise and subjective benefit questionnaires. Results: The safety results revealed no significant medical complications. One subject experienced sudden hearing loss after 18–24 months of device use, but still continues to wear the device to her satisfaction. With regard to efficacy, there were no significant changes from short- to long-term results in aided word understanding, functional gain or speech recognition threshold, suggesting that the outcomes are stable over time. Subjective questionnaires revealed either the same or better results compared with the short-term data.