Hearing aid noise suppression and working memory function.

OBJECTIVE: Research findings concerning the relation between benefit from hearing aid (HA) noise suppression and working memory function are inconsistent. The current study thus investigated the effects of three noise suppression algorithms on auditory working memory and the relation with reading span. DESIGN: Using a computer simulation of bilaterally fitted HAs, four settings were tested: (1) unprocessed, (2) directional microphones, (3) single-channel noise reduction, and (4) binaural coherence-based noise reduction. Settings 2-4 were matched in terms of the speech-weighted signal-to-noise ratio (SNR) improvement. Auditory working memory was assessed at +6 dB SNR using listening span and N-back paradigms. STUDY SAMPLE: Twenty experienced HA users aged 55-80 years with large differences in reading span. RESULTS: For the listening span measurements, there was an influence of HA setting on sentence-final word recognition and recall, with the directional microphones leading to ∼6% better performance than the single-channel noise reduction. For the N-back measurements, there was substantial test-retest variability and no influence of HA setting. No interactions with reading span were found. CONCLUSION: HA noise suppression may affect the recognition and recall of speech at positive SNRs, irrespective of individual reading span. Future work should improve the reliability of the auditory working memory measurements.

Development and psychometric properties of the sound preference and hearing habits questionnaire (SP-HHQ).

OBJECTIVE: The aim of the study was, based on the individualisation of hearing aids (HA) and pre-sets for audio devices, to develop a questionnaire to determine the basis for profiling sound preferences and hearing habits to gather additional information usable for HA fitting and adjustment tools for audio-devices. METHODS: We developed a questionnaire consisting of 46 items. A postal survey was conducted with N = 622 users with a mean age of 66 years (47.9% aided with HA, 45.7% female). RESULTS: Seven factors were identified by means of Explanatory and Confirmatory Factor Analyses: F1: 'Annoyance/distraction by background noise', F2: 'Importance of sound quality', F3: 'Noise Sensitivity', F4: 'Avoidance of unpredictable sounds', F5: 'Openness towards loud/new sounds', F6: 'Preferences for warm sounds', and F7: 'Details of environmental sounds/music'. Only the first of these factors was related to the audiogram of the user. No difference with any of the factors could be observed with HA use/non-use. In contrast, gender effects were found with female respondents preferring warm sounds and being more sensitive to noise. CONCLUSIONS: The sound preference and hearing habits questionnaire (SP-HHQ) is a usable tool for profiling the users with respect to sound preferences relevant for HA fitting and pre-sets for audio devices.

Directional Processing and Noise Reduction in Hearing Aids: Individual and Situational Influences on Preferred Setting.

BACKGROUND: A better understanding of individual differences in hearing aid (HA) outcome is a prerequisite for more personalized HA fittings. Currently, knowledge of how different user factors relate to response to directional processing (DIR) and noise reduction (NR) is sparse. PURPOSE: To extend a recent study linking preference for DIR and NR to pure-tone average hearing thresholds (PTA) and cognitive factors by investigating if (1) equivalent links exist for different types of DIR and NR, (2) self-reported noise sensitivity and personality can account for additional variability in preferred DIR and NR settings, and (3) spatial target speech configuration interacts with individual DIR preference. RESEARCH DESIGN: Using a correlational study design, overall preference for different combinations of DIR and NR programmed into a commercial HA was assessed in a complex speech-in-noise situation and related to PTA, cognitive function, and different personality traits. STUDY SAMPLE: Sixty experienced HA users aged 60-82 yr with controlled variation in PTA and working memory capacity took part in this study. All of them had participated in the earlier study, as part of which they were tested on a measure of "executive control" tapping into cognitive functions such as working memory, mental flexibility, and selective attention. DATA COLLECTION AND ANALYSIS: Six HA settings based on unilateral (within-device) or bilateral (across-device) DIR combined with inactive, moderate, or strong single-microphone NR were programmed into a pair of behind-the-ear HAs together with individually prescribed amplification. Overall preference was assessed using a free-field simulation of a busy cafeteria situation with either a single frontal talker or two talkers at ±30° azimuth as the target speech. In addition, two questionnaires targeting noise sensitivity and the "Big Five" personality traits were administered. Data were analyzed using multiple regression analyses and repeated-measures analyses of variance with a focus on potential interactions between the HA settings and user factors. RESULTS: Consistent with the earlier study, preferred HA setting was related to PTA and executive control. However, effects were weaker this time. Noise sensitivity and personality did not interact with HA settings. As expected, spatial target speech configuration influenced preference, with bilateral and unilateral DIR "winning" in the single- and two-talker scenario, respectively. In general, participants with higher PTA tended to more strongly prefer bilateral DIR than participants with lower PTA. CONCLUSIONS: Although the current study lends some support to the view that PTA and cognitive factors affect preferred DIR and NR setting, it also indicates that these effects can vary across noise management technologies. To facilitate more personalized HA fittings, future research should investigate the source of this variability.