Listening-Related Fatigue in New and Experienced Adult Cochlear Implant Users.

OBJECTIVES: Active listening in everyday settings is challenging and requires substantial mental effort, particularly in noisy settings. In some cases, effortful listening can lead to significant listening-related fatigue and negatively affect quality of life. However, our understanding of factors that affect the severity of fatigue is limited. Hearing aids and cochlear implants (CIs) can improve speech understanding and thus, potentially, reduce listening effort and fatigue. Some research supports this idea for adult hearing aid users with mild-to-moderate hearing loss, but similar work in CI users is very limited. This study examined (1) longitudinal changes in listening-related fatigue in new and established CI users, and (2) relationships between demographic and audiologic factors and preimplantation and postimplantation listening-related fatigue. DESIGN: Participants included an experimental group of 48 adult CI candidates receiving either a unilateral implant (n = 46) or simultaneous, bilateral implants (n = 2) and a control group of 96 experienced (>12 months experience) adult CI users (50 unilateral, 46 bilateral). Listening-related fatigue was evaluated using the 40-item version of the Vanderbilt Fatigue Scale for Adults. Experimental group ratings were obtained before implantation and again at 0.5-, 1-, 2-, 3-, 6-, and 12-month(s) postactivation. Control group participants completed the scale twice-upon study entry and approximately 3 months later. Additional measures, including a social isolation and disconnectedness questionnaire, hearing handicap inventory, and the Effort Assessment Scale, were also administered at multiple time points. The role of these measures and select demographic and audiologic factors on preimplant and postimplant fatigue ratings were examined. RESULTS: Adult CI candidates reported significantly more fatigue, greater self-perceived hearing handicap, greater listening effort, and more social isolation than experienced adult CI users. However, significant reductions in fatigue and effort were observed within 2 weeks postimplantation. By 3 months, there were no significant differences in fatigue, effort, hearing handicap, or social isolation between new CI recipients and experienced CI users. Secondary analyses revealed that age at onset of hearing loss (before or after 2 years of age) and subjective hearing handicap contributed significantly to the variance of preimplantation fatigue ratings (those with higher handicap reported higher fatigue). In contrast, variance in postimplantation fatigue ratings was not affected by age of hearing loss onset but was affected by gender (females reported more fatigue than males) and subjective ratings of effort, handicap, and isolation (those reporting more effort, handicap, and isolation reported more fatigue). CONCLUSIONS: Listening-related fatigue is a significant problem for many CI candidates, as well as for many experienced unilateral and bilateral CI users. Receipt of a CI significantly reduced listening-related fatigue (as well as listening effort, hearing handicap, and social isolation) as soon as 2 weeks post-CI activation. However, the magnitude of fatigue-related issues for both CI candidates and experienced CI users varies widely. Audiologic factors, such as hearing loss severity and aided speech recognition, were not predictive of individual differences in listening-related fatigue. In contrast, strong associations were observed between perceived hearing handicap and listening-related fatigue in all groups suggesting fatigue-related issues may be a component of perceived hearing handicap.

Benefits of Text Supplementation on Sentence Recognition and Subjective Ratings With and Without Facial Cues for Listeners With Normal Hearing.

OBJECTIVES: Recognizing speech through telecommunication can be challenging in unfavorable listening conditions. Text supplementation or provision of facial cues can facilitate speech recognition under some circumstances. However, our understanding of the combined benefit of text and facial cues in telecommunication is limited. The purpose of this study was to investigate the potential benefit of text supplementation for sentence recognition scores and subjective ratings of spoken speech with and without facial cues available. DESIGN: Twenty adult females (M = 24 years, range 21 to 29 years) with normal hearing performed a sentence recognition task and also completed a subjective rating questionnaire in 24 conditions. The conditions varied by integrity of the available facial cues (clear facial cues, slight distortion facial cues, great distortion facial cues, no facial cues), signal-to-noise ratio (quiet, +1 dB, -3 dB), and text availability (with text, without text). When present, the text was an 86 to 88% accurate transcription of the auditory signal presented at a 500 ms delay relative to the auditory signal. RESULTS: The benefits of text supplementation were largest when facial cues were not available and when the signal-to-noise ratio was unfavorable. Although no recognition score benefit was present in quiet, recognition benefit was significant in all levels of background noise for all levels of facial cue integrity. Moreover, participant subjective ratings of text benefit were robust and present even in the absence of recognition benefit. Consistent with previous literature, facial cues were beneficial for sentence recognition scores in the most unfavorable signal-to-noise ratio, even when greatly distorted. It is interesting that, although all levels of facial cues were beneficial for recognition scores, participants rated a significant benefit only with clear facial cues. CONCLUSIONS: The benefit of text for auditory-only and auditory-visual speech recognition is evident in recognition scores and subjective ratings; the benefit is larger and more robust for subjective ratings than for scores. Therefore, text supplementation might provide benefit that extends beyond speech recognition scores. Combined, these findings support the use of text supplementation in telecommunication, even when facial cues are concurrently present, such as during teleconferencing or watching television.

Plasticity Changes in Central Auditory Systems of School-Age Children Following a Brief Training With a Remote Microphone System.

OBJECTIVES: The objective of this study was to investigate whether a brief speech-in-noise training with a remote microphone (RM) system (favorable listening condition) would contribute to enhanced post-training plasticity changes in the auditory system of school-age children. DESIGN: Before training, event-related potentials (ERPs) were recorded from 49 typically developing children, who actively identified two syllables in quiet and in noise (+5 dB signal-to-noise ratio [SNR]). During training, children completed the same syllable identification task as in the pre-training noise condition, but received feedback on their performance. Following random assignment, half of the sample used an RM system during training (experimental group), while the other half did not (control group). That is, during training' children in the experimental group listened to a more favorable speech signal (+15 dB SNR) than children from the control group (+5 dB SNR). ERPs were collected after training at +5 dB SNR to evaluate the effects of training with and without the RM system. Electrical neuroimaging analyses quantified the effects of training in each group on ERP global field power (GFP) and topography, indexing response strength and network changes, respectively. Behavioral speech-perception-in-noise skills of children were also evaluated and compared before and after training. We hypothesized that training with the RM system (experimental group) would lead to greater enhancement of GFP and greater topographical changes post-training than training without the RM system (control group). We also expected greater behavioral improvement on the speech-perception-in-noise task when training with than without the RM system. RESULTS: GFP was enhanced after training only in the experimental group. These effects were observed on early time-windows corresponding to traditional P1-N1 (100 to 200 msec) and P2-N2 (200 to 400 msec) ERP components. No training effects were observed on response topography. Finally, both groups increased their speech-perception-in-noise skills post-training. CONCLUSIONS: Enhanced GFP after training with the RM system indicates plasticity changes in the neural representation of sound resulting from listening to an enriched auditory signal. Further investigation of longer training or auditory experiences with favorable listening conditions is needed to determine if that results in long-term speech-perception-in-noise benefits.

Symmetrical and asymmetrical directional benefits are present for talkers at the front and side.

OBJECTIVE: The purpose of the study was to examine the effects of symmetrical and asymmetrical directional microphone settings on speech recognition, localisation and microphone preference in listening conditions with on- and off-axis talkers. DESIGN: A within-subjects repeated-measure evaluation of three hearing aid microphone settings (bilateral omnidirectional, bilateral directional, asymmetrical directional) was completed in a moderately reverberant laboratory. An exploratory analysis of the potential relationship between microphone preference and unaided measures was also completed. STUDY SAMPLE: Twenty adult listeners with mild to moderately severe bilateral hearing loss participated. RESULTS: The directional and asymmetric microphone settings resulted in equivalent benefits for sentence recognition in noise, word recall, and localisation speed regardless of the speech loudspeaker location (on- or off-axis). However, localisation accuracy was significantly worse with the asymmetric fitting than the directional setting when speech was presented from the rear hemisphere. Listeners who always preferred directional microphones had significantly poorer unaided speech recognition than those who preferred the omnidirectional setting for one or more listening condition. CONCLUSIONS: Benefits from directional and asymmetric processing were small in the current study, but generally similar to each other. Unaided speech recognition in noise performance may have utility as a clinical predictor of preference for directional processing.

The relationship between speech recognition, behavioural listening effort, and subjective ratings.

OBJECTIVE: The purpose of this study was to evaluate the reliability and validity of four subjective questions related to listening effort. A secondary purpose of this study was to evaluate the effects of hearing aid beamforming microphone arrays on word recognition and listening effort. DESIGN: Participants answered subjective questions immediately following testing in a dual-task paradigm with three microphone settings in a moderately reverberant laboratory environment in two noise configurations. Participants rated their: (1) mental work, (2) desire to improve the situation, (3) tiredness, and (4) desire to give up. Data were analysed using repeated measures and reliability analyses. STUDY SAMPLE: Eighteen adults with symmetrical sensorineural hearing loss participated. RESULTS: Beamforming differentially affected word recognition and listening effort. Analysis revealed the same pattern of results for behavioural listening effort and subjective ratings of desire to improve the situation. Conversely, ratings of work revealed the same pattern of results as word recognition performance. Ratings of tiredness and desire to give up were unaffected by hearing aid microphone or noise configuration. CONCLUSIONS: Participant ratings of their desire to control the listening situation appear to reliable subjective indicators of listening effort that align with results from a behavioural measure of listening effort.

How directional microphones affect speech recognition, listening effort and localisation for listeners with moderate-to-severe hearing loss.

OBJECTIVE: The purpose of this study was to evaluate the effects of directional microphone use on laboratory measures of sentence recognition, listening effort and localisation. An additional purpose of this study was to evaluate the effects of asymmetric directional microphone use on the same laboratory measures. DESIGN: Three hearing aid conditions were evaluated: (1) bilateral omnidirectional microphones, (2) bilateral directional microphones and (3) asymmetric microphones (directional microphone for only one hearing aid). Sentence recognition performance was evaluated using a connected speech test. Listening effort was evaluated using a dual-task paradigm with a response time-based secondary task requiring word categorisation. Localisation was examined using a complex task requiring localisation and recall of speech originating from one of four loudspeakers in the horizontal plane (-60°, -45°, +45°, +60°). STUDY SAMPLE: Eighteen adults (M = 61.8 years) with symmetrical, moderate-to-severe hearing loss participated. RESULTS: Performance on each task was analysed separately using a repeated measures analysis of variance. Results revealed directional benefits for sentence recognition and listening effort, but microphone setting did not affect localisation. Performance was equivalent with symmetric and asymmetric directional configurations. CONCLUSIONS: Bilateral and asymmetric directional microphone configurations equally improved sentence recognition and listening effort; neither affected localisation or recall.

The Effects of Noise and Reverberation on Listening Effort in Adults With Normal Hearing.

OBJECTIVES: The purpose of this study was to investigate the effects of background noise and reverberation on listening effort. Four specific research questions were addressed related to listening effort: (A) With comparable word recognition performance across levels of reverberation, what are the effects of noise and reverberation on listening effort? (B) What is the effect of background noise when reverberation time is constant? (C) What is the effect of increasing reverberation from low to moderate when signal to noise ratio is constant? (D) What is the effect of increasing reverberation from moderate to high when signal to noise ratio is constant? DESIGN: Eighteen young adults (mean age 24.8 years) with normal hearing participated. A dual-task paradigm was used to simultaneously assess word recognition and listening effort. The primary task was monosyllable word recognition, and the secondary task was word categorization (press a button if the word heard was judged to be a noun). Participants were tested in quiet and in background noise in three levels of reverberation (T30 < 100 ms, T30 = 475 ms, and T30 = 834 ms). Signal to noise ratios used were chosen individually for each participant and varied by reverberation to address the specific research questions. RESULTS: As expected, word recognition performance was negatively affected by both background noise and by increases in reverberation. Furthermore, analysis of mean response times revealed that background noise increased listening effort, regardless of degree of reverberation. Conversely, reverberation did not affect listening effort, regardless of whether word recognition performance was comparable or signal to noise ratio was constant. CONCLUSIONS: The finding that reverberation did not affect listening effort, even when word recognition performance was degraded, is inconsistent with current models of listening effort. The reasons for this surprising finding are unclear and warrant further investigation. However, the results of this study are limited in generalizability to young listeners with normal hearing and to the signal to noise ratios, loudspeaker to listener distance, and reverberation times evaluated. Other populations, like children, older listeners, and listeners with hearing loss, have been previously shown to be more sensitive to reverberation. Therefore, the effects of reverberation for these vulnerable populations also warrant further investigation.

Evaluation of the effects of nonlinear frequency compression on speech recognition and sound quality for adults with mild to moderate hearing loss.

OBJECTIVE: While potentially improving audibility for listeners with considerable high frequency hearing loss, the effects of implementing nonlinear frequency compression (NFC) for listeners with moderate high frequency hearing loss are unclear. The purpose of this study was to investigate the effects of activating NFC for listeners who are not traditionally considered candidates for this technology. DESIGN: Participants wore study hearing aids with NFC activated for a 3-4 week trial period. After the trial period, they were tested with NFC and with conventional processing on measures of consonant discrimination threshold in quiet, consonant recognition in quiet, sentence recognition in noise, and acceptableness of sound quality of speech and music. STUDY SAMPLE: Seventeen adult listeners with symmetrical, mild to moderate sensorineural hearing loss participated. Better ear, high frequency pure-tone averages (4, 6, and 8 kHz) were 60 dB HL or better. RESULTS: Activating NFC resulted in lower (better) thresholds for discrimination of /s/, whose spectral center was 9 kHz. There were no other significant effects of NFC compared to conventional processing. CONCLUSION: These data suggest that the benefits, and detriments, of activating NFC may be limited for this population.

The effect of changing the secondary task in dual-task paradigms for measuring listening effort.

OBJECTIVES: The purpose of this study was to evaluate the effect of changing the secondary task in dual-task paradigms that measure listening effort. Specifically, the effects of increasing the secondary task complexity or the depth of processing on a paradigm's sensitivity to changes in listening effort were quantified in a series of two experiments. Specific factors investigated within each experiment were background noise and visual cues. DESIGN: Participants in Experiment 1 were adults with normal hearing (mean age 23 years) and participants in Experiment 2 were adults with mild sloping to moderately severe sensorineural hearing loss (mean age 60.1 years). In both experiments, participants were tested using three dual-task paradigms. These paradigms had identical primary tasks, which were always monosyllable word recognition. The secondary tasks were all physical reaction time measures. The stimulus for the secondary task varied by paradigm and was a (1) simple visual probe, (2) a complex visual probe, or (3) the category of word presented. In this way, the secondary tasks mainly varied from the simple paradigm by either complexity or depth of speech processing. Using all three paradigms, participants were tested in four conditions, (1) auditory-only stimuli in quiet, (2) auditory-only stimuli in noise, (3) auditory-visual stimuli in quiet, and (4) auditory-visual stimuli in noise. During auditory-visual conditions, the talker's face was visible. Signal-to-noise ratios used during conditions with background noise were set individually so word recognition performance was matched in auditory-only and auditory-visual conditions. In noise, word recognition performance was approximately 80% and 65% for Experiments 1 and 2, respectively. RESULTS: For both experiments, word recognition performance was stable across the three paradigms, confirming that none of the secondary tasks interfered with the primary task. In Experiment 1 (listeners with normal hearing), analysis of median reaction times revealed a significant main effect of background noise on listening effort only with the paradigm that required deep processing. Visual cues did not change listening effort as measured with any of the three dual-task paradigms. In Experiment 2 (listeners with hearing loss), analysis of median reaction times revealed expected significant effects of background noise using all three paradigms, but no significant effects of visual cues. CONCLUSIONS: None of the dual-task paradigms were sensitive to the effects of visual cues. Furthermore, changing the complexity of the secondary task did not change dual-task paradigm sensitivity to the effects of background noise on listening effort for either group of listeners. However, the paradigm whose secondary task involved deeper processing was more sensitive to the effects of background noise for both groups of listeners. While this paradigm differed from the others in several respects, depth of processing may be partially responsible for the increased sensitivity. Therefore, this paradigm may be a valuable tool for evaluating other factors that affect listening effort.

Potential benefits and limitations of three types of directional processing in hearing aids.

OBJECTIVES: The purpose of this study was to evaluate hearing aid users' performance on four tasks across three types of directional processing implemented by the same pair of commercially available behind-the-ear hearing aids. The three types of directional processing were mild, moderate, and strong. The mild processing aimed at emulating the directionality of an unoccluded ear. The moderate processing was a traditional adaptive directional type. The strong directional processing was a cue-preserving bilateral beamformer. The four tasks included gross localization, sentence recognition, listening effort, and subjective preference. METHODS: Eighteen adults aged 48 to 83 years ((Equation is included in full-text article.)= 69.1, σ = 10.9) with sensorineural hearing loss participated in this study. Each participant was fitted bilaterally and the three types of directional processing were matched for frequency response but varied by directionality (mild, moderate, and strong). Performance was always evaluated in background noise, which surrounded the listener. Sentence recognition was evaluated in low and moderate reverberation, while gross localization, listening effort, and subjective ratings were evaluated only in moderate reverberation. Sentence recognition and gross localization were evaluated using auditory-only and auditory-visual stimuli (talker's face visible). The gross localization task included assessment of the ability to identify the origin of words, in addition to the ability to recall those words. Listening effort was evaluated using auditory-visual stimuli and a dual-task paradigm where the secondary task was a simple reaction time to a visual stimulus. RESULTS: The results revealed similar gross localization abilities across moderate and strong directional processing when visual stimuli were present. Conversely, localization accuracy was significantly poorer with the strong directional processing than with moderate directional processing in auditory-only conditions, but only for signals presented at the greatest eccentricities (±60 degrees). Regardless of signal to noise ratio or degree of reverberation, the moderate and strong directional processing resulted in significantly better sentence recognition in noise than the mild directional processing. In addition, sentence recognition in moderate reverberation was significantly better with strong directional processing than with moderate directional processing (~ 4 to 12 rationalized arcsine units across conditions), regardless of signal to noise ratio. Although not statistically significant, the same trend was present in low reverberation. There were no significant differences in listening effort or subjective preference across directional processing. CONCLUSIONS: The strong directional processing, which was a cue-preserving bilateral beamformer, provided additional sentence recognition benefit in realistic listening situations. Furthermore, despite reducing the interaural differences, the authors measured no significant negative consequences on listening effort or subjective preference, although it is unknown whether differences might be found using more sensitive measures. In addition, gross localization was disrupted at large eccentricities if visual cues were not present. While further study is needed, these results support consideration of this cue-preserving, bilateral beamformer technology for patients who experience difficulty with speech recognition in noise, which is not adequately addressed by conventional directional hearing aid processing.

Increasing motivation changes subjective reports of listening effort and choice of coping strategy.

OBJECTIVE: The purpose of this project was to examine the effect of changing motivation on subjective ratings of listening effort and on the likelihood that a listener chooses either a controlling or an avoidance coping strategy. DESIGN: Two experiments were conducted, one with auditory-only (AO) and one with auditory-visual (AV) stimuli, both using the same speech recognition in noise materials. Four signal-to-noise ratios (SNRs) were used, two in each experiment. The two SNRs targeted 80% and 50% correct performance. Motivation was manipulated by either having participants listen carefully to the speech (low motivation), or listen carefully to the speech and then answer quiz questions about the speech (high motivation). STUDY SAMPLE: Sixteen participants with normal hearing participated in each experiment. Eight randomly selected participants participated in both. RESULTS: Using AO and AV stimuli, motivation generally increased subjective ratings of listening effort and tiredness. In addition, using auditory-visual stimuli, motivation generally increased listeners' willingness to do something to improve the situation, and decreased their willingness to avoid the situation. CONCLUSIONS: These results suggest a listener's mental state may influence listening effort and choice of coping strategy.

Speech recognition for bilaterally asymmetric and symmetric hearing aid microphone modes in simulated classroom environments.

OBJECTIVES: This study aimed to evaluate the potential utility of asymmetrical and symmetrical directional hearing aid fittings for school-age children in simulated classroom environments. This study also aimed to evaluate speech recognition performance of children with normal hearing in the same listening environments. DESIGN: Two groups of school-age children 11 to 17 years of age participated in this study. Twenty participants had normal hearing, and 29 participants had sensorineural hearing loss. Participants with hearing loss were fitted with behind-the-ear hearing aids with clinically appropriate venting and were tested in 3 hearing aid configurations: bilateral omnidirectional, bilateral directional, and asymmetrical directional microphones. Speech recognition testing was completed in each microphone configuration in 3 environments: Talker-Front, Talker-Back, and Question-Answer situations. During testing, the location of the speech signal changed, but participants were always seated in a noisy, moderately reverberant classroom-like room. RESULTS: For all conditions, results revealed expected effects of directional microphones on speech recognition performance. When the signal of interest was in front of the listener, bilateral directional microphone was best, and when the signal of interest was behind the listener, bilateral omnidirectional microphone was best. Performance with asymmetric directional microphones was between the 2 symmetrical conditions. The magnitudes of directional benefits and decrements were not significantly correlated. In comparison with their peers with normal hearing, children with hearing loss performed similarly to their peers with normal hearing when fitted with directional microphones and the speech was from the front. In contrast, children with normal hearing still outperformed children with hearing loss if the speech originated from behind, even when the children were fitted with the optimal hearing aid microphone mode for the situation. CONCLUSIONS: Bilateral directional microphones can be effective in improving speech recognition performance for children in the classroom, as long as child is facing the talker of interest. Bilateral directional microphones, however, can impair performance if the signal originates from behind a listener. However, these data suggest that the magnitude of decrement is not predictable from an individual's benefit. The results re-emphasize the importance of appropriate switching between microphone modes so children can take full advantage of directional benefits without being hurt by directional decrements. An asymmetric fitting limits decrements, but does not lead to maximum speech recognition scores when compared with the optimal symmetrical fitting. Therefore, the asymmetric mode may not be the best option as a default fitting for children in a classroom environment. While directional microphones improve performance for children with hearing loss, their performance in most conditions continues to be impaired relative to their normal-hearing peers, particularly when the signals of interest originate from behind or from an unpredictable location.

How hearing aids, background noise, and visual cues influence objective listening effort.

OBJECTIVES: The purpose of this article was to evaluate factors that influence the listening effort experienced when processing speech for people with hearing loss. Specifically, the change in listening effort resulting from introducing hearing aids, visual cues, and background noise was evaluated. An additional exploratory aim was to investigate the possible relationships between the magnitude of listening effort change and individual listeners' working memory capacity, verbal processing speed, or lipreading skill. DESIGN: Twenty-seven participants with bilateral sensorineural hearing loss were fitted with linear behind-the-ear hearing aids and tested using a dual-task paradigm designed to evaluate listening effort. The primary task was monosyllable word recognition and the secondary task was a visual reaction time task. The test conditions varied by hearing aids (unaided, aided), visual cues (auditory-only, auditory-visual), and background noise (present, absent). For all participants, the signal to noise ratio was set individually so that speech recognition performance in noise was approximately 60% in both the auditory-only and auditory-visual conditions. In addition to measures of listening effort, working memory capacity, verbal processing speed, and lipreading ability were measured using the Automated Operational Span Task, a Lexical Decision Task, and the Revised Shortened Utley Lipreading Test, respectively. RESULTS: In general, the effects measured using the objective measure of listening effort were small (~10 msec). Results indicated that background noise increased listening effort, and hearing aids reduced listening effort, while visual cues did not influence listening effort. With regard to the individual variables, verbal processing speed was negatively correlated with hearing aid benefit for listening effort; faster processors were less likely to derive benefit. Working memory capacity, verbal processing speed, and lipreading ability were related to benefit from visual cues. No variables were related to changes in listening effort resulting from the addition of background noise. CONCLUSIONS: The results of this study suggest that, on the average, hearing aids can reduce objectively measured listening effort. Furthermore, people who are slow verbal processors are more likely to derive hearing aid benefit for listening effort, perhaps because hearing aids improve the auditory input. Although background noise increased objective listening effort, no listener characteristic predicted susceptibility to noise. With regard to visual cues, while there was no effect on average of providing visual cues, there were some listener characteristics that were related to changes in listening effort with vision. Although these relationships are exploratory, they do suggest that these inherent listener characteristics like working memory capacity, verbal processing speed, and lipreading ability may influence susceptibility to changes in listening effort and thus warrant further study.

Efficacy of hearing-aid based telephone strategies for listeners with moderate-to-severe hearing loss.

BACKGROUND: Understanding speech over the telephone when listening in noisy environments may present a significant challenge for listeners with moderate-to-severe hearing loss. PURPOSE: The purpose of this study was to compare speech recognition and subjective ratings across several hearing aid-based telephone listening strategies for individuals with moderate-to-severe sensorineural hearing loss. RESEARCH DESIGN: Speech recognition and subjective ratings were evaluated for a simulated telephone signal. The strategies evaluated included acoustic telephone, unilateral telecoil, unilateral wireless streaming, and bilateral wireless streaming. Participants were seated in a noisy room for all evaluations. STUDY SAMPLE: Eighteen adults, aged 49-88 yr, with moderate-to-severe sensorineural hearing loss participated. DATA COLLECTION AND ANALYSIS: Speech recognition scores on the Connected Speech Test were converted to rationalized arcsine units and analyzed using analysis of variance testing and Tukey post hoc analyses. Subjective ratings of ease and comfort were also analyzed in this manner. RESULTS: Speech recognition performance was poorest with acoustic coupling to the telephone and best with bilateral wireless routing. Telecoil coupling resulted in better speech recognition performance than acoustic coupling, but was significantly poorer than bilateral wireless routing. Furthermore, unilateral wireless routing and telecoil coupling generally led to similar speech recognition performance, except in lower-level background noise conditions, for which unilateral routing resulted in better performance than the telecoil. CONCLUSIONS: For people with moderate-to-severe sensorineural hearing loss, acoustic telephone listening with a hearing aid may not lead to acceptable performance in noise. Although unilateral routing options (telecoil and wireless streaming) improved performance, speech recognition performance and subjective ratings of ease and comfort were best when bilateral wireless routing was used. These results suggest that wireless routing is a potentially beneficial telephone listening strategy for listeners with moderate-to-severe hearing loss who are fitted with limited venting if the telephone signal is routed to both ears. Unilateral wireless routing may provide similar benefits to traditional unilateral telecoil. However, the newer wireless systems may have the advantage for some listeners in that they do not include some of the positioning constraints associated with telecoil use.

Evaluating Risk of Noise-Induced Hearing Loss in Otologic Surgery.

OBJECTIVES: To evaluate risk for noise-induced hearing damage from otologic surgery-related noise exposure, given recent research indicating that noise levels previously believed to be safe and without long-term consequence may result in cochlear synaptopathy with subsequent degeneration of spiral ganglion neurons, degradation of neural transmission in response to suprathreshold acoustic stimuli, and difficulty understanding in background noise. METHODS: A prospective observational study of surgeon noise exposure during otologic and neurotologic procedures was performed in a tertiary care center. Surgeon noise exposure was recorded in A- and C-weighted decibel scales (dBA, dBC), including average equivalent (LAeq) and peak (LApeak, LCpeak) levels and noise dose. RESULTS: Sound measurements taken at the ear with continuous recording equipment during cadaveric otologic surgery demonstrated LAeq 80-83 dBA, LApeaks of 105 dBA, LCpeaks of 127 dBC, with noise doses of 0.9% to 6.7%. Sound level measurements during live surgery translabyrinthine approaches yielded lower LAeq of 72 to 74 dBA and lower noise doses compared with temporal bone lab measurements. Raw sound recordings during live surgery demonstrated narrow band, high frequency, high amplitude spikes between 4 and 12 kHz. CONCLUSION: Noise exposure to surgeons, staff, and patients in the operating room is acceptable per NIOSH recommendations. Temporal bone lab noise exposures are greater, possibly due to poorly maintained drill systems and lack of noise shielding from microscope bulk, yet are also within NIOSH recommended levels.

Horizontal plane localization in single-sided deaf adults fitted with a bone-anchored hearing aid (Baha).

OBJECTIVES: : One purpose of this investigation was to evaluate the effect of a unilateral bone-anchored hearing aid (Baha) on horizontal plane localization performance in single-sided deaf adults who had either a conductive or sensorineural hearing loss in their impaired ear. The use of a 33-loudspeaker array allowed for a finer response measure than has previously been used to investigate localization in this population. In addition, a detailed analysis of error patterns allowed an evaluation of the contribution of random error and bias error to the total rms error computed in the various conditions studied. A second purpose was to investigate the effect of stimulus duration and head-turning on localization performance. DESIGN: : Two groups of single-sided deaf adults were tested in a localization task in which they had to identify the direction of a spoken phrase on each trial. One group had a sensorineural hearing loss (SNHL group; N = 7), and the other group had a conductive hearing loss (CHL group; N = 5). In addition, a control group of four normal-hearing adults was tested. The spoken phrase was either 1250 msec in duration (a male saying "Where am I coming from now?") or 341 msec in duration (the same male saying "Where?"). For the longer-duration phrase, subjects were tested in conditions in which they either were or were not allowed to move their heads before the termination of the phrase. The source came from one of nine positions in the front horizontal plane (from -79° to +79°). The response range included 33 choices (from -90° to +90°, separated by 5.6°). Subjects were tested in all stimulus conditions, both with and without the Baha device. Overall rms error was computed for each condition. Contributions of random error and bias error to the overall error were also computed. RESULTS: : There was considerable intersubject variability in all conditions. However, for the CHL group, the average overall error was significantly smaller when the Baha was on than when it was off. Further analysis of error patterns indicated that this improvement was primarily based on reduced response bias when the device was on; that is, the average response azimuth was nearer to the source azimuth when the device was on than when it was off. The SNHL group, on the other hand, had significantly greater overall error when the Baha was on than when it was off. Collapsed across listening conditions and groups, localization performance was significantly better with the 1250 msec stimulus than with the 341 msec stimulus. However, for the longer-duration stimulus, there was no significant beneficial effect of head-turning. Error scores in all conditions for both groups were considerably larger than those in the normal-hearing control group. CONCLUSIONS: : On average, single-sided deaf adults with CHL showed improved localization ability when using the Baha, whereas single-sided deaf adults with SNHL showed a decrement in performance when using the device. These results may have implications for clinical counseling for patients with unilateral hearing impairment.

Applying the Hearing Aid Fitting Standard to Selection for Adults.

The recent hearing aid fitting standard for adults outlines the minimum practice for audiologists fitting adult patients with hearing loss. This article focuses on three items of the standard (5, 6, and 7), which focus on the selection of unilateral/bilateral hearing aids, hearing aid style, and coupling, in addition to feature selection. The standard emphasizes that decisions around these three aspects should be recommended for a patient in an individualized manner, based on their needs assessment. For these decisions, the needs assessment might include measures of speech-in-noise ability, social network size, patient preference, and a trial period. Additional elements could include assessments of manual dexterity, binaural interference, and attitude toward hearing aids. However, there are a multitude of ways to practice clinically and still meet the items outlined in the standard. As long as the selection decisions consider individualized patient factors and are capable of meeting validated prescriptive targets, a clinician would be meeting the adult hearing aid fitting minimum standard guidance. In addition, despite the large number of past studies supporting these standards, additional, high-quality research including randomized, controlled, clinical trials are still needed to further support appropriate minimum standard recommendations.

Effects of Critical Distance and Reverberation on Listening Effort in Adults.

PURPOSE: Mixed historical data on how listening effort is affected by reverberation and listener-to-speaker distance challenge existing models of listening effort. This study investigated the effects of reverberation and listener-to-speaker distance on behavioral and subjective measures of listening effort: (a) when listening at a fixed signal-to-noise ratio (SNR) and (b) at SNRs that were manipulated so that word recognition would be comparable across different reverberation times and listening distances. It was expected that increased reverberation would increase listening effort but only when listening outside critical distance. METHOD: Nineteen adults (21-40 years) with no hearing loss completed a dual-task paradigm. The primary task was word recognition and the secondary task was timed word categorization; response times indexed behavioral listening effort. Additionally, participants provided subjective ratings in each condition. Testing was completed at two reverberation levels (moderate and high, RT30 = 469 and 1,223 ms, respectively) and at two listener-to-speaker distances (inside and outside critical distance for the test room, 1.25 and 4 m, respectively). RESULTS: Increased reverberation and listening distances worsened word recognition performance and both behavioral and subjective listening effort. The effect of reverberation was exacerbated when listeners were outside critical distance. Subjective experience of listening effort persisted even when word recognition was comparable across conditions. CONCLUSIONS: Longer reverberation times or listening outside the room's critical distance negatively affected behavioral and subjective listening effort. This study extends understanding of listening effort in reverberant rooms by highlighting the effect of listener's position relative to the room's critical distance.

Comparison of wireless and acoustic hearing aid-based telephone listening strategies.

OBJECTIVE: The purpose of this study was to examine speech recognition through hearing aids for seven telephone listening conditions. DESIGN: Speech recognition scores were measured for 20 participants in six wireless routing transmission conditions and one acoustic telephone condition. In the wireless conditions, the speech signal was delivered to both ears simultaneously (bilateral speech) or to one ear (unilateral speech). The effect of changing the noise level in the nontest ear during unilateral conditions was also examined. Participants were fitted with hearing aids using both nonoccluding and occluding dome ear tips. Participants were seated in a room with background noise present and speech was transmitted to the participants without additional noise. RESULTS: There was no effect of changing the noise level in the nontest ear and no difference between unilateral wireless routing and acoustic telephone listening. For wireless transmission, bilateral presentation resulted in significantly better speech recognition than unilateral presentation. Bilateral wireless conditions allowed for significantly better recognition than the acoustic telephone condition for participants fitted with occluding ear tips only. CONCLUSION: Routing the signal to both hearing aids resulted in significantly better speech recognition than unilateral signal routing. Wireless signal routing was shown to be beneficial compared with acoustic telephone listening and in some conditions resulted in the best performance of all of the listening conditions evaluated. However, this advantage was only evident when the signal was routed to both ears and when hearing aid wearers were fitted with occluding domes. Therefore, it is expected that the benefits of this new wireless streaming technology over existing telephone coupling methods will be most evident clinically in hearing aid wearers who require more limited venting than is typically used in open canal fittings.

Individual Differences Offer Insight Into Clinical Recommendations for Directional and Remote Microphone Technology Use in Children.

Purpose This study sought to evaluate the effects of common hearing aid microphone technologies on speech recognition and listening effort, and to evaluate potential predictive factors related to microphone benefits for school-age children with hearing loss in a realistic listening situation. Method Children (n = 17, ages 10-17 years) with bilateral, sensorineural hearing loss were fitted with hearing aids set to include three programs: omnidirectional, adaptive directional, and omnidirectional + remote microphone. Children completed a dual-task paradigm in a moderately reverberant room. The primary task included monosyllabic word recognition, with target speech presented at 60 dB A from 0° (front) or 180° (back) azimuth. The secondary task was a "go/no-go," visual shape-recognition task. Multitalker babble noise created a +5 dB SNR. Children were evaluated in two speaker conditions (front, back) using all three hearing aid programs. The remote microphone transmitter remained at the front speaker throughout testing. Speech recognition performance was calculated from the primary task while listening effort was measured as response time during the secondary task. Results Speech presented from the back significantly increased listening effort and caused a reduction in speech perception when directional and remote microphones were used. Considerable variability was found in pattern of benefit across microphones and source location. Clinical measures did not predict benefit patterns with directional or remote microphones; however, child age and performance with omnidirectional microphones did. Conclusions When compared to a traditional omnidirectional setting, the directional and remote microphone configurations evaluated in this study have the potential to provide benefit for some children and increase difficulty for others when used in dynamic environments. A child's performance with omnidirectional hearing aids could be used to better inform clinical recommendations for these technologies.