A cross-over, double-blind comparison of the NAL-NL1 and the DSL v4.1 prescriptions for children with mild to moderately severe hearing loss

Impact of hearing aid technology level at first-fit on self-reported outcomes in patients with presbycusis: a randomized controlled trial

To provide clinical guidance in hearing aid prescription for older adults with presbycusis, we investigated differences in self-reported hearing abilities and hearing aid effectiveness for premium or basic hearing aid users. Secondly, as an explorative analysis, we investigated if differences in gain prescription verified with real-ear measurements explain differences in self-reported outcomes. The study was designed as a randomized controlled trial in which the patients were blinded towards the purpose of the study. In total, 190 first-time hearing aid users (>60 years of age) with symmetric bilateral presbycusis were fitted with either a premium or basic hearing aid. The randomization was stratified on age, sex, and word recognition score. Two outcome questionnaires were distributed: the International Outcome Inventory for Hearing Aids (IOI-HA) and the short form of the Speech, Spatial, and Qualities of Hearing Scale (SSQ-12). In addition, insertion gains were calculated from real-ear measurements at first-fit for all fitted hearing aids. Premium hearing aid users reported 0.7 (95%CI: 0.2; 1.1) scale points higher total SSQ-12 score per item and 0.8 (95%CI: 0.2; 1.4) scale points higher speech score per item, as well as 0.6 (95%CI: 0.2; 1.1) scale points higher qualities score compared to basic-feature hearing aid users. No significant differences in reported hearing aid effectiveness were found using the IOI-HA. Differences in the prescribed gain at 1 and 2 kHz were observed between premium and basic hearing aids within each company. Premium-feature devices yielded slightly better self-reported hearing abilities than basic-feature devices, but a statistically significant difference was only found in three out of seven outcome variables, and the effect was small. The generalizability of the study is limited to community-dwelling older adults with presbycusis. Thus, further research is needed for understanding the potential effects of hearing aid technology for other populations. Hearing care providers should continue to insist on research to support the choice of more costly premium technologies when prescribing hearing aids for older adults with presbycusis. Clinical Trial Registration: https://register.clinicaltrials.gov/, identifier NCT04539847.

Gain adjustment at tinnitus pitch to manage both tinnitus and speech perception in noise

To investigate how much gain variation is required from prescription to effect tinnitus percept, and if this revised prescription affects speech recognition. Twenty participants who experienced catastrophic tinnitus even after fitted with hearing aid were included. Participants were grouped based on their tinnitus pitch and the prescriptive formula used to fit hearing aid. They were evaluated for handicap from tinnitus using Tinnitus Handicap Inventory (THI). Hearing aid was programmed using either NAL- NL2 or DSL (I/o) v5 prescriptive formula and gain at tinnitus pitch was adjusted till the tinnitus get suppressed. SNR 50 was determined soon after fitted with hearing aid and 30 days of hearing aid use. Further, THI and international outcome inventory for hearing aid (IOI-HA) were determined after 30 days of hearing aid use. A significant higher gain adjustment was needed at tinnitus pitch to reduce tinnitus precept using NAL- NL2 than DSL (I/o) v5 prescriptive formula. Further, SNR 50 was not affected by either tinnitus pitch or revised prescription formulas. However, SNR 50 improved after 30 days of hearing aid use. A 76% of the participants’ experienced habituation to perception after 30 days of hearing aid use, 10% had slight, 10% had mild, and 4% had a moderate degree of tinnitus on THI. On IOA-HA, 96% (N=19) of participants have reported satisfactory, and 4% (N=1) reported moderate benefit from hearing aid. Irrespective of prescriptive formula adjusting gain at tinnitus pitch is an efficient method to reduce tinnitus symptoms and improve speech perception.

Development of Improved Software Intelligent System for Audiological Solutions

Of late, there has been an increase in hearing impairment cases and to provide the most advantageous solutions to them is an uphill task for audiologists. Significant difficulty faced by the audiologists is in effective programming of hearing aids to provide enhanced satisfaction to the users. The main aim of our study was to develop a software intelligent system (SIS): (i) to perform the required audiological investigations for finding the degree and type of hearing loss, and (ii) to suggest appropriate values of hearing aid parameters for enhancing the speech intelligibility and the satisfaction level among the hearing aid users. In this paper, we present a Neuro-Fuzzy based SIS to automatically predict and suggest the hearing-aid parameters such as gain values, compression ratio and threshold knee point, which are needed to be fixed for different octave frequencies of sound inputs during the hearing-aid trial. The test signals for audiological investigations are generated through the standard hardware present in a personal computer system and with the aid of a software algorithm. The proposed system was validated with 243 subjects' data collected at the Government General Hospital, Chennai, India. The calculated sensitivity, specificity and accuracy of the proposed audiometer incorporated in the SIS were 98.6%, 96.4 and 98.2%, respectively, by comparing its interpretations with those of the 'gold standard' audiometers. Furthermore, 91% (221 of 243) of the hearing impaired subjects attained satisfaction in the first hearing aid trials itself with the gain values as recommended by the improved SIS. The proposed system reduced around 75% of the 'trial and error' time spent by audiologists for enhancing satisfactory usage of the hearing aid. Hence, the proposed SIS could be used to find the degree and type of hearing loss and to recommend hearing aid parameters to provide optimal solutions to the hearing aid users.

Hearing aid fitting and developmental outcomes of children fit according to either the NAL or DSL prescription: fit-to-target, audibility, speech and language abilities

OBJECTIVE

This study examined the influence of prescription on hearing aid (HA) fitting characteristics and 5-year developmental outcomes of children.

DESIGN

A randomised controlled trial implemented as part of a population-based study on Longitudinal Outcomes of Children with Hearing Impairment (LOCHI).

STUDY SAMPLE

Two-hundred and thirty-two children that were fit according to either the National Acoustic Laboratories (NAL) or Desired Sensation Level (DSL) prescription.

RESULTS

Deviation from targets and root-mean-square error in HA fitting revealed no significant difference between fitting prescriptions. Aided audibility quantified by using the Speech Intelligibility Index (SII) model showed that DSL provided higher audibility than NAL at low and medium input levels but not at high input level. After allowing for hearing loss desensitisation, differences in audibility between prescription groups were significant only at low input level. The randomised trial of prescription that was implemented for 163 children revealed no significant between-group differences in speech production, perception, and language; but parent-rated functional performance was higher for the DSL than for the NAL group.

CONCLUSIONS

Proximity to prescriptive targets was similar between fitting prescriptions. The randomised trial revealed differences in aided audibility at low input level between prescription groups, but no significant differences in speech and language abilities.

Fit-to-Targets for the Desired Sensation Level Version 5.0a Hearing Aid Prescription Method for Children

PURPOSE

The purpose of this study was to measure the range of fit to Desired Sensation Level version 5.0 (DSL v5.0) targets in pediatric practice environments. Results will be used in the future to develop clinical-aided speech intelligibility index typical performance data.

METHOD

Clinical partners collected data from 161 final hearing aid settings for children aged ≤ 10 years. Measured data were obtained by performing 2-cm3 coupler-simulated real-ear measurements using the DSL v5.0 implementation on the Audioscan VF-1 (Etymonic Design Inc., Dorchester, ON, Canada) for soft, average, and loud speech inputs and maximum hearing aid output levels.

RESULTS

Fittings were within ± 5-dB root-mean-square (RMS) error of target for 77%, 80%, and 82% of fittings for the soft, medium, and loud speech test levels, respectively. Aided maximum power output measures were within ± 5-dB RMS error in 72% of cases. Degree of hearing loss, test frequency, and frequency by test level were significant factors in deviation from target. The range of aided speech intelligibility index values exhibited a strong correlation with the hearing levels of the children tested.

CONCLUSION

This study provides evidence that typical hearing aid fittings for children can be achieved within ± 5-dB RMS error of the DSL v5.0 target. Greater target deviations were observed at extreme frequencies and as the severity of hearing loss increased.

Software intelligent system for effective solutions for hearing impaired subjects

PURPOSE

The anatomy and physiology of the ear is complex in nature, which makes it a challenge for audiologists to prescribe solutions for varied hearing-impaired subjects. There is a need to increase the satisfaction level of hearing-aid users by adopting better strategies that involve modern technological advancements.

AIM

To design and develop a decision support Software Intelligent System (SIS) that performs audiological investigations to assess the degree of hearing loss and to suggest appropriate hearing-aid gain values.

METHODS

SIS is developed based on the study conducted in the Government General Hospital, Chennai, India, between 2013 and 2015. In the study period, audiological investigations were performed on 368 subjects, using the clinical audiometer (Inventis-Piano, Italy) and the SIS. Gain suggestions were recommended for hearing-aid users (Siemens Intuis life & Intuis-SP) using standard prescriptive procedures, alterations made by the audiologists, and by the SIS. It was developed with artificial neural network-based gain predictions.

RESULTS

Of the tested subjects, 256 were identified as hearing-impaired. The calculated sensitivity, specificity and accuracy of the computerised audiometer incorporated in the SIS are 93%, 85% and 90% respectively. Furthermore, 86% of the hearing-impaired subjects were satisfied during their first hearing-aid trial with the gain recommendations from SIS.

CONCLUSION

The findings suggest that the proposed SIS could be used to perform audiological screening tests and to recommend appropriate hearing-aid gain values to the hearing-impaired subjects. This could eventually be helpful for audiologists in the areas where routine mass audiological screening and fast hearing-aid solution is required.

Dynamic range for speech materials in korean, english, and mandarin: a cross-language comparison

PURPOSE

The purpose of this study was to identify whether differences in dynamic range (DR) are evident across the spoken languages of Korean, English, and Mandarin.

METHOD

Recorded sentence-level speech materials were used as stimuli. DR was quantified using different definitions of DR (defined as the range in decibels from the highest to the lowest signal intensities), for several integration times (from 1 to 512 ms) and in different frequency bands (center frequencies [CFs] ranging from 150 to 8600 Hz).

RESULTS

Across the 3 languages, DR was affected in similar ways with regard to changes in DR definition and integration time. In contrast, across-language differences in DR were evident when considering frequency-band effects. Specifically, the DR for Korean was smaller than the English DR and the Mandarin DR in low-frequency bands (less than the CF of 455 Hz). Compared with Korean and Mandarin, the DR for English was smallest in mid-frequency bands (between the CF of 455 Hz and 4050 Hz) and was greatest in high-frequency bands (above the CF of 4050 Hz).

CONCLUSION

The observed differences in DR across languages suggest that the best-fit DR for Korean and Mandarin may be different than the best fit for English.

Introduction to the longitudinal outcomes of children with hearing impairment (LOCHI) study: background, design, sample characteristics

OBJECTIVE

This article describes the background and the design of the longitudinal outcomes of children with hearing impairment (LOCHI) study, and the characteristics of the study cohort.

DESIGN

Children born between 2002 and 2007 who were identified with hearing loss and received audiological intervention by 3 years of age in Australia enrolled in the study. Their demographic characteristics are described.

STUDY SAMPLE

Four hundred and fifty-one children in New South Wales, Victoria, and Southern Queensland.

RESULTS

Data on age at first hearing-aid fitting for different degrees of hearing loss are reported together with demographic characteristics of the cohort.

CONCLUSION

A unique environment in Australia where all children with varied access to universal newborn hearing screening received the same consistent hearing services from a national hearing service provider makes it possible to investigate the effects of access to early auditory intervention on children's outcomes at a population level.

The Effects of Digital Signal Processing Features on Children's Speech Recognition and Loudness Perception

Purpose

The purpose of this study was to determine the effects of hearing instruments set to Desired Sensation Level version 5 (DSL v5) hearing instrument prescription algorithm targets and equipped with directional microphones and digital noise reduction (DNR) on children's sentence recognition in noise performance and loudness perception in a classroom environment.

Method

Ten children (ages 8–17 years) with stable, congenital sensorineural hearing losses participated in the study. Participants were fitted bilaterally with behind-the-ear hearing instruments set to DSL v5 prescriptive targets. Sentence recognition in noise was evaluated using the Bamford–Kowal–Bench Speech in Noise Test (Niquette et al., 2003). Loudness perception was evaluated using a modified version of the Contour Test of Loudness Perception (Cox, Alexander, Taylor, & Gray, 1997).

Results

Children's sentence recognition in noise performance was significantly better when using directional microphones alone or in combination with DNR than when using omnidirectional microphones alone or in combination with DNR. Children's loudness ratings for sounds above 72 dB SPL were lowest when fitted with the DSL v5 Noise prescription combined with directional microphones. DNR use showed no effect on loudness ratings.

Conclusion

Use of the DSL v5 Noise prescription with a directional microphone improved sentence recognition in noise performance and reduced loudness perception ratings for loud sounds relative to a typical clinical reference fitting with the DSL v5 Quiet prescription with no digital signal processing features enabled. Potential clinical strategies are discussed.

A comparison of NAL and DSL prescriptive methods for paediatric hearing-aid fitting: predicted speech intelligibility and loudness

OBJECTIVE

To examine the impact of prescription on predicted speech intelligibility and loudness for children.

DESIGN

A between-group comparison of speech intelligibility index (SII) and loudness, based on hearing aids fitted according to NAL-NL1, DSL v4.1, or DSL m[i/o] prescriptions. A within-group comparison of gains prescribed by DSL m[i/o] and NAL-NL2 for children in terms of SII and loudness.

STUDY SAMPLE

Participants were 200 children, who were randomly assigned to first hearing-aid fitting with either NAL-NL1, DSL v4.1, or DSL m[i/o]. Audiometric data and hearing-aid data at 3 years of age were used.

RESULTS

On average, SII calculated on the basis of hearing-aid gains were higher for DSL than for NAL-NL1 at low input level, equivalent at medium input level, and higher for NAL-NL1 than DSL at high input level. Greater loudness was associated with DSL than with NAL-NL1, across a range of input levels. Comparing NAL-NL2 and DSL m[i/o] target gains revealed higher SII for the latter at low input level. SII was higher for NAL-NL2 than for DSL m[i/o] at medium- and high-input levels despite greater loudness for gains prescribed by DSL m[i/o] than by NAL-NL2.

CONCLUSION

The choice of prescription has minimal effects on speech intelligibility predictions but marked effects on loudness predictions.

A randomized controlled comparison of NAL and DSL prescriptions for young children: hearing-aid characteristics and performance outcomes at three years of age

OBJECTIVE

To determine the influence of choice of prescription and other child-, family- and intervention-related factors on speech, language, and functional performance of hearing-impaired children by three years of age.

DESIGN AND STUDY SAMPLE

A randomized controlled design was implemented as part of a population-based, longitudinal study on outcomes of children with hearing impairment (LOCHI) in Australia. Two hundred and eighteen children were randomly assigned to either the NAL or the DSL prescription for first fitting of hearing aids. Their performance outcomes were evaluated.

RESULTS

Prescriptive targets were closely matched in children's hearing aids. There were no significant differences in children's language, speech production, or functional performance between prescriptions. Parents' ratings of children's device usage and loudness discomfort were not significantly different between prescription groups. Functional performance within the first year of fitting together with degree of hearing loss, presence of additional disabilities, and maternal education explained 44% of variation in language ability of children by three years of age.

CONCLUSIONS

There was no significant association between choice of hearing-aid prescription and variance in children's outcomes at three years of age. In contrast, additional disability, maternal educational level, and early functional performance were significant predictive factors of children's outcomes.

NAL-NL2 empirical adjustments

NAL-NL1, the first procedure from the National Acoustic Laboratories (NAL) for prescribing nonlinear gain, was a purely theoretically derived formula aimed at maximizing speech intelligibility for any input level of speech while keeping the overall loudness of speech at or below normal loudness. The formula was obtained through an optimization process in which speech intelligibility and loudness were predicted from selected models. Using updated models and applying some revisions to the derivation process, a theoretically derived NAL-NL2 formula was obtained in a similar way. Further adjustments, directed by empirical data collected in studies using NAL-NL1 as the baseline response, have been made to the theoretically derived formula. Specifically, empirical data have demonstrated that (a) female hearing aid users prefer lower overall gain than male users; (b) new hearing aid users with more than a mild hearing loss prefer increasingly less gain with increasing degree of hearing loss than experienced hearing aid users, and require up to 2 years to adapt to gain levels selected by experienced hearing aid users; (c) unilaterally and bilaterally fitted hearing aid users prefer overall gain levels that vary less than estimated by the bilateral correction factor; (d) adults prefer lower overall gain than children; and (e) people with severe/profound hearing loss prefer lower compression ratios than predicted when fitted with fast-acting compression. The literature and data leading to these conclusions are summarized and discussed in this article, and the procedure for implementing the adjustments to the theoretically derived NAL-NL2 formula is described.

Children’s Speech Recognition and Loudness Perception With the Desired Sensation Level v5 Quiet and Noise Prescriptions

Purpose

To determine whether Desired Sensation Level (DSL) v5 Noise is a viable hearing instrument prescriptive algorithm for children, in comparison with DSL v5 Quiet. In particular, the authors compared children’s performance on measures of consonant recognition in quiet, sentence recognition in noise, and loudness perception when fitted with DSL v5 Quiet and Noise.

Method

Eleven children (ages 8 to 17 years) with stable, congenital sensorineural hearing losses participated in the study. Participants were fitted bilaterally to DSL v5 prescriptions with behind-the-ear hearing instruments. The order of prescription was counterbalanced across participants. Repeated measures analysis of variance was used to compare performance between prescriptions.

Results

Use of the Noise prescription resulted in a significant decrease in consonant perception in Quiet with low-level input, but no difference with average-level input. There was no significant difference in sentence-in-noise recognition between the two prescriptions. Loudness ratings for input levels above 72 dB SPL were significantly lower with the noise prescription.

Conclusions

Average-level consonant recognition in quiet was preserved and aversive loudness was alleviated by the Noise prescription relative to the quiet prescription, which suggests that the DSL v5 Noise prescription may be an effective approach to managing the nonquiet listening needs of children with hearing loss.

Speech perception and localisation with SCORE bimodal: a loudness normalisation strategy for combined cochlear implant and hearing aid stimulation

A significant fraction of newly implanted cochlear implant recipients use a hearing aid in their non-implanted ear. SCORE bimodal is a sound processing strategy developed for this configuration, aimed at normalising loudness perception and improving binaural loudness balance. Speech perception performance in quiet and noise and sound localisation ability of six bimodal listeners were measured with and without application of SCORE. Speech perception in quiet was measured either with only acoustic, only electric, or bimodal stimulation, at soft and normal conversational levels. For speech in quiet there was a significant improvement with application of SCORE. Speech perception in noise was measured for either steady-state noise, fluctuating noise, or a competing talker, at conversational levels with bimodal stimulation. For speech in noise there was no significant effect of application of SCORE. Modelling of interaural loudness differences in a long-term-average-speech-spectrum-weighted click train indicated that left-right discrimination of sound sources can improve with application of SCORE. As SCORE was found to leave speech perception unaffected or to improve it, it seems suitable for implementation in clinical devices.

The accuracy of matching target insertion gains with open-fit hearing aids

PURPOSE

To assess the accuracy with which target insertion gains were matched for a single type of open-fit hearing aid, both on initial fitting and after adjustment.

METHOD

The hearing aids were fitted using the first-fit setting in the programming software and the target formula was selected as NAL-NL1. The difference between the real ear insertion gain (REIG) and the NAL-NL1 target REIG was recorded. The initial fitting was considered acceptable if the difference was less than 10 dB at all frequencies. If an initial fitting was not acceptable, the frequency-gain response was modified. The difference between the final REIG and the NAL-NL1 target REIG was recorded as final target mismatch.

RESULTS

Of the 51 initial fittings, 36 (71%) failed to achieve a match within ±10 dB of the NAL-NL1 insertion gain target at 1 or more frequencies between 0.25 and 4 kHz. After the authors adjusted the frequency-gain response of the hearing aids, only 9 fittings (18%) failed to achieve a match.

CONCLUSION

These outcomes suggest that target insertion gains for the open-fit hearing aids used here are rarely achieved with a first fitting but can usually be achieved through adjustments based on REIG measurements.