Adaptive Dynamic Range Optimization Research Articles

Personalization of Hearing Aid Fitting Based on Adaptive Dynamic Range Optimization.

Adaptive dynamic range optimization (ADRO) is a hearing aid fitting rationale which involves adjusting the gains in a number of frequency bands by using a series of rules. The rules reflect the comparison of the estimated percentile occurrences of the sound levels with the audibility and comfort hearing levels of a person suffering from hearing loss. In the study reported in this paper, a previously developed machine learning method was utilized to personalize the ADRO fitting in order to provide an improved hearing experience as compared to the standard ADRO hearing aid fitting. The personalization was carried out based on the user preference model within the framework of maximum likelihood inverse reinforcement learning. The testing of ten subjects with hearing loss was conducted, which indicated that the personalized ADRO was preferred over the standard ADRO on average by about 10 times. Furthermore, a word recognition experiment was conducted, which showed that the personalized ADRO had no adverse impact on speech understanding as compared to the standard ADRO.

The Role of Autosensitivity Control (ASC) in Cochlear Implant Recipients.

The purpose of the study was to examine the subjective and objective potential advantage for speech understanding in noise achieved by cochlear implant (CI) recipients when using the autosensitivity control (ASC) input signal processing in combination with the adaptive dynamic range optimization (ADRO). Eighteen subjects (8 females, 10 males, mean age 17.7 ± 6.7) were enrolled in a prospective open blinded comparative study between the ASC + ADRO condition vs. the ADRO alone; 16 were sequential binaural and 2 were monoaural CI recipients. All patients had been wearing their CI for at least 3 years, had no additional disabilities, had an age-appropriate receptive and expressive language. Word recognition performances in noise (at signal-to-noise ratio +5 dB HL) were significantly better in the ADRO-alone condition than in the ADRO + ASC condition. (p = 0.03) These objective outcomes were in agreement with the subjective reports. No significant difference was found in quiet. Our results, apparently in contrast with other reports in the literature, suggest that the decision of adding the slow-acting automatic reduction in microphone sensitivity provided by ASC should be limited to selected CI recipients.

Benefits of incorporating the adaptive dynamic range optimization amplification scheme into an assistive listening device for people with mild or moderate hearing loss

ABSTRACTThis study investigated whether a self-designed assistive listening device (ALD) that incorporates an adaptive dynamic range optimization (ADRO) amplification strategy can surpass a commercially available monaurally worn linear ALD, SM100. Both subjective and objective measurements were implemented. Mandarin Hearing-In-Noise Test (MHINT) scores were the objective measurement, whereas participant satisfaction was the subjective measurement. The comparison was performed in a mixed design (i.e., subjects’ hearing status being mild or moderate, quiet versus noisy, and linear versus ADRO scheme). The participants were two groups of hearing-impaired subjects, nine mild and eight moderate, respectively. The results of the ADRO system revealed a significant difference in the MHINT sentence reception threshold (SRT) in noisy environments between monaurally aided and unaided conditions, whereas the linear system did not. The benchmark results showed that the ADRO scheme is effectively beneficial to people who experience mild or moderate hearing loss in noisy environments. The satisfaction rating regarding overall speech quality indicated that the participants were satisfied with the speech quality of both ADRO and linear schemes in quiet environments, and they were more satisfied with ADRO than they with the linear scheme in noisy environments.

Effect of different signal-processing options on speech-in-noise recognition for cochlear implant recipients with the cochlear CP810 speech processor.

Difficulty understanding speech in the presence of background noise is a common report among cochlear implant (CI) recipients. Several speech-processing options designed to improve speech recognition, especially in noise, are currently available in the Cochlear Nucleus CP810 speech processor. These include adaptive dynamic range optimization (ADRO), autosensitivity control (ASC), Beam, and Zoom. The purpose of this study was to evaluate CI recipients' speech-in-noise recognition to determine which currently available processing option or options resulted in best performance in a simulated restaurant environment. Experimental study with one study group. The independent variable was speech-processing option, and the dependent variable was the reception threshold for sentences score. Thirty-two adult CI recipients. Eight processing options were tested: Beam, Beam + ASC, Beam + ADRO, Beam + ASC + ADRO, Zoom, Zoom + ASC, Zoom + ADRO, and Zoom + ASC + ADRO. Participants repeated Hearing in Noise Test sentences presented at a 0° azimuth, with R-Space restaurant noise presented from a 360° eight-loudspeaker array at 70 dB sound pressure level. A one-way repeated-measures analysis of variance was used to analyze differences in Beam options, Zoom options, and Beam versus Zoom options. Among the Beam options, Beam + ADRO was significantly poorer than Beam only, Beam + ASC, and Beam + ASC + ADRO. A 1.6-dB difference was observed between the best (Beam only) and poorest (Beam + ADRO) options. Among the Zoom options, Zoom only and Zoom + ADRO were significantly poorer than Zoom + ASC. A 2.2-dB difference was observed between the best (Zoom + ASC) and poorest (Zoom only) options. The comparison between Beam and Zoom options showed one significant difference, with Zoom only significantly poorer than Beam only. No significant difference was found between the other Beam and Zoom options (Beam + ASC vs Zoom + ASC, Beam + ADRO vs Zoom + ADRO, and Beam + ASC + ADRO vs Zoom + ASC + ADRO). The best processing option varied across subjects, with an almost equal number of participants performing best with a Beam option (n = 15) compared with a Zoom option (n = 17). There were no significant demographic or audiological moderating variables for any option. The results showed no significant differences between adaptive directionality (Beam) and fixed directionality (Zoom) when ASC was active in the R-Space environment. This finding suggests that noise-reduction processing is extremely valuable in loud semidiffuse environments in which the effectiveness of directional filtering might be diminished. However, there was no significant difference between the Beam-only and Beam + ASC options, which is most likely related to the additional noise cancellation performed by the Beam option (i.e., two-stage directional filtering and noise cancellation). In addition, the processing options with ADRO resulted in the poorest performances. This could be related to how the CI recipients were programmed or the loud noise level used in this study. The best processing option varied across subjects, but the majority performed best with directional filtering (Beam or Zoom) in combination with ASC. Therefore in a loud semidiffuse environment, the use of either Beam + ASC or Zoom + ASC is recommended.

Converted and Upgraded Maps Programmed in the Newer Speech Processor for the First Generation of Multichannel Cochlear Implant

To identify the technological contributions of the newer version of speech processor to the first generation of multichannel cochlear implant and the satisfaction of users of the new technology. Among the new features available, we focused on the effect of the frequency allocation table, the T-SPL and C-SPL, and the preprocessing gain adjustments (adaptive dynamic range optimization). Prospective exploratory study. Cochlear implant center at hospital. Cochlear implant users of the Spectra processor with speech recognition in closed set. Seventeen patients were selected between the ages of 15 and 82 and deployed for more than 8 years. The technology update of the speech processor for the Nucleus 22. To determine Freedom's contribution, thresholds and speech perception tests were performed with the last map used with the Spectra and the maps created for Freedom. To identify the effect of the frequency allocation table, both upgraded and converted maps were programmed. One map was programmed with 25 dB T-SPL and 65 dB C-SPL and the other map with adaptive dynamic range optimization. To assess satisfaction, SADL and APHAB were used. All speech perception tests and all sound field thresholds were statistically better with the new speech processor; 64.7% of patients preferred maintaining the same frequency table that was suggested for the older processor. The sound field threshold was statistically significant at 500, 1,000, 1,500, and 2,000 Hz with 25 dB T-SPL/65 dB C-SPL. Regarding patient's satisfaction, there was a statistically significant improvement, only in the subscale of speech in noise abilities and phone use. The new technology improved the performance of patients with the first generation of multichannel cochlear implant.

Assessment of Directionality Performances: Comparison between Freedom and CP810 Sound Processors

To compare speech recognition in noise for the Nucleus Freedom and CP810 sound processors using different directional settings among those available in the SmartSound portfolio. Single-subject, repeated measures study. Tertiary care referral center. Thirty-one monoaurally and binaurally implanted subjects (24 children and 7 adults) were enrolled. They were all experienced Nucleus Freedom sound processor users and achieved a 100% open set word recognition score in quiet listening conditions. Each patient was fitted with the Freedom and the CP810 processor. The program setting incorporated Adaptive Dynamic Range Optimization (ADRO) and adopted the directional algorithm BEAM (both devices) and ZOOM (only on CP810). Speech reception threshold (SRT) was assessed in a free-field layout, with disyllabic word list and interfering multilevel babble noise in the 3 different pre-processing configurations. On average, CP810 improved significantly patients' SRTs as compared to Freedom SP after 1 hour of use. Instead, no significant difference was observed in patients' SRT between the BEAM and the ZOOM algorithm fitted in the CP810 processor. The results suggest that hardware developments achieved in the design of CP810 allow an immediate and relevant directional advantage as compared to the previous-generation Freedom device.

STRATEGIE WSTĘPNEGO PRZETWARZANIA I PERCEPCJA MOWY WŚRÓD UŻYTKOWNIKÓW IMPLANTÓW ŚLIMAKOWYCH

BackgroundThe aim of the study was to investigate whether noise reduction algorithms are beneficial for speech perception in the presence of noise in children using cochlear implants. Further, the study also aimed to determine whether any difference in speech perception existed between different pre-processing strategies such as Adaptive Dynamic Range Optimization (ADRO), Autosensitivity Control (ASC), and the two-stage adaptive beam-forming algorithm (Beam) in different signal-tonoise ratios (SNRs).Material and MethodSpeech identification scores of the participants were tested in quiet with the ‘Everyday’ default setting activated. They were also tested using speech in noise at +5 dB and +10 dB SNR with ADRO, ASC, and Beam activated. Exactly 17 children using Nucleus cochlear implants for at least 1 year were tested.ResultsA significant difference was found between performance in quiet (in the ‘Everyday’ default setting) and in the presence of noise (with ADRO, ASC, and Beam). No significant difference was found between the 3 pre-processing strategies at both SNRs and between the 2 SNRs for all 3 strategies.ConclusionsIn conditions where the signal and noise emerge from in front of the listener, no influence of the pre-processing strategies was seen.

A Comparison Between the First-Fit Settings of Two Multichannel Digital Signal-Processing Strategies: Music Quality Ratings and Speech-in-Noise Scores

The aim of this study was to determine which level-dependent hearing aid digital signal-processing strategy (DSP) participants preferred when listening to music and/or performing a speech-in-noise task. Two receiver-in-the-ear hearing aids were compared: one using 32-channel adaptive dynamic range optimization (ADRO) and the other wide dynamic range compression (WDRC) incorporating dual fast (4 channel) and slow (15 channel) processing. The manufacturers' first-fit settings based on participants' audiograms were used in both cases. Results were obtained from 18 participants on a quick speech-in-noise (QuickSIN; Killion, Niquette, Gudmundsen, Revit, & Banerjee, 2004) task and for 3 music listening conditions (classical, jazz, and rock). Participants preferred the quality of music and performed better at the QuickSIN task using the hearing aids with ADRO processing. A potential reason for the better performance of the ADRO hearing aids was less fluctuation in output with change in sound dynamics. ADRO processing has advantages for both music quality and speech recognition in noise over the multichannel WDRC processing that was used in the study. Further evaluations of which DSP aspects contribute to listener preference are required.

Improving Speech Perception in Noise for Children with Cochlear Implants

Current cochlear implant recipients are achieving increasingly higher levels of speech recognition; however, the presence of background noise continues to significantly degrade speech understanding for even the best performers. Newer generation Nucleus cochlear implant sound processors can be programmed with SmartSound strategies that have been shown to improve speech understanding in noise for adult cochlear implant recipients. The applicability of these strategies for use in children, however, is not fully understood nor widely accepted. To assess speech perception for pediatric cochlear implant recipients in the presence of a realistic restaurant simulation generated by an eight-loudspeaker (R-SPACE™) array in order to determine whether Nucleus sound processor SmartSound strategies yield improved sentence recognition in noise for children who learn language through the implant. Single subject, repeated measures design. Twenty-two experimental subjects with cochlear implants (mean age 11.1 yr) and 25 control subjects with normal hearing (mean age 9.6 yr) participated in this prospective study. Speech reception thresholds (SRT) in semidiffuse restaurant noise originating from an eight-loudspeaker array were assessed with the experimental subjects' everyday program incorporating Adaptive Dynamic Range Optimization (ADRO) as well as with the addition of Autosensitivity control (ASC). Adaptive SRTs with the Hearing In Noise Test (HINT) sentences were obtained for all 22 experimental subjects, and performance-in percent correct-was assessed in a fixed +6 dB SNR (signal-to-noise ratio) for a six-subject subset. Statistical analysis using a repeated-measures analysis of variance (ANOVA) evaluated the effects of the SmartSound setting on the SRT in noise. The primary findings mirrored those reported previously with adult cochlear implant recipients in that the addition of ASC to ADRO significantly improved speech recognition in noise for pediatric cochlear implant recipients. The mean degree of improvement in the SRT with the addition of ASC to ADRO was 3.5 dB for a mean SRT of 10.9 dB SNR. Thus, despite the fact that these children have acquired auditory/oral speech and language through the use of their cochlear implant(s) equipped with ADRO, the addition of ASC significantly improved their ability to recognize speech in high levels of diffuse background noise. The mean SRT for the control subjects with normal hearing was 0.0 dB SNR. Given that the mean SRT for the experimental group was 10.9 dB SNR, despite the improvements in performance observed with the addition of ASC, cochlear implants still do not completely overcome the speech perception deficit encountered in noisy environments accompanying the diagnosis of severe-to-profound hearing loss. SmartSound strategies currently available in latest generation Nucleus cochlear implant sound processors are able to significantly improve speech understanding in a realistic, semidiffuse noise for pediatric cochlear implant recipients. Despite the reluctance of pediatric audiologists to utilize SmartSound settings for regular use, the results of the current study support the addition of ASC to ADRO for everyday listening environments to improve speech perception in a child's typical everyday program.

The Effect of Front-End Processing on Cochlear Implant Performance of Children

Previous research shows that children using cochlear implants experience significant difficulty with speech perception in noisy listening situations. There are several types of input signal processing available for the cochlear implant sound processor; however, there is a paucity of research to support this technology for children. The primary objective of this study was to examine the potential benefits of 2 types of input signal processing, adaptive dynamic range optimization (ADRO) as compared with autosensitivity (ASC) plus ADRO for children using Cochlear Corporation implants. Cross-sectional repeated-measures design. Outpatient nonprofit foundation providing audiology services and auditory-verbal therapy. Eleven children, aged 4 years 4 months to 12 years, with unilateral or bilateral Cochlear Limited implants. All children used their cochlear implant(s) for at least 1 year, had no additional disabilities, were enrolled in preschool or elementary school, and had age-appropriate receptive and expressive language. All children used Cochlear Limited cochlear implants with either the Nucleus Freedom or Nucleus 5 cochlear implant sound processor. Performance was assessed while these children used ADRO-only input processing and ASC+ADRO input processing. Speech perception of PBK-50 monosyllabic words in quiet and BKB-SIN sentences in noise was measured for each child. In the noise conditions, children were using the ADRO-only or ASC+ADRO input signal processing strategies. The data in quiet were analyzed with descriptive statistics, and the conditions in noise were compared using a 1-way repeated-measures analysis of variance. All children demonstrated word recognition in quiet at or above 90% correct. In noise, sentence-perception performance in the ASC+ADRO condition was significantly better than that in the ADRO-alone condition. The results of the study suggest substantial benefit from combining 2 types of input signal processing, ASC and ADRO, for children with unilateral and bilateral cochlear implants. Specifically, signal processing to adjust the sensitivity of the sound processor microphone automatically has substantial positive effects on speech-perception thresholds in noise.

Evaluation of noise reduction technologies in a contemporary cochlear implant system

Evaluation of noise reduction technologies in a contemporary cochlear implant system

Loudness and Satisfaction Ratings for Hearing Aid Users

Hearing aids amplify low-intensity sounds to make them audible while keeping high-intensity sounds at an acceptable loudness for listeners with impaired hearing. The purpose of this analysis was to assess loudness and satisfaction at the same time using a combined loudness and satisfaction questionnaire to rate 18 everyday environmental sounds. Ten sets of data from four studies, covering three conditions, were analyzed. The three conditions were unaided, wide dynamic range compression (WDRC), and adaptive dynamic range optimization (ADRO). In total, there were 61 subjects giving over 3,000 pairs of ratings for loudness and satisfaction. The analysis found a strong relationship between loudness and satisfaction ratings for this set of listeners and conditions. The maximum satisfaction ratings corresponded to sounds with "comfortable" loudness ratings. Satisfaction was lowest for sounds that were "uncomfortably loud." Sounds that were very soft or inaudible also received low satisfaction ratings unless the sounds were expected to be soft, such as the sound of one's own breathing. Hearing aid fittings that place most sounds at a comfortable level are likely to be more satisfactory than hearing aid fittings that produce more sounds close to hearing thresholds or discomfort levels. Aided conditions gave higher loudness and satisfaction ratings than the unaided condition, and the ADRO hearing aids gave significantly higher satisfaction ratings than the WDRC hearing aids.

Verbesserung der Sprachverständlichkeit durch neuen Cochlear-Implant-Sprachprozessor

The aim of this multicenter clinical field study was to assess the benefits of the new Freedom 24 sound processor for cochlear implant (CI) users implanted with the Nucleus 24 cochlear implant system. The study included 48 postlingually profoundly deaf experienced CI users who demonstrated speech comprehension performance with their current speech processor on the Oldenburg sentence test (OLSA) in quiet conditions of at least 80% correct scores and who were able to perform adaptive speech threshold testing using the OLSA in noisy conditions. Following baseline measures of speech comprehension performance with their current speech processor, subjects were upgraded to the Freedom 24 speech processor. After a take-home trial period of at least 2 weeks, subject performance was evaluated by measuring the speech reception threshold with the Freiburg multisyllabic word test and speech intelligibility with the Freiburg monosyllabic word test at 50 dB and 70 dB in the sound field. The results demonstrated highly significant benefits for speech comprehension with the new speech processor. Significant benefits for speech comprehension were also demonstrated with the new speech processor when tested in competing background noise.In contrast, use of the Abbreviated Profile of Hearing Aid Benefit (APHAB) did not prove to be a suitably sensitive assessment tool for comparative subjective self-assessment of hearing benefits with each processor. Use of the preprocessing algorithm known as adaptive dynamic range optimization (ADRO) in the Freedom 24 led to additional improvements over the standard upgrade map for speech comprehension in quiet and showed equivalent performance in noise. Through use of the preprocessing beam-forming algorithm BEAM, subjects demonstrated a highly significant improved signal-to-noise ratio for speech comprehension thresholds (i.e., signal-to-noise ratio for 50% speech comprehension scores) when tested with an adaptive procedure using the Oldenburg sentences in the clinical setting S(0)N(CI), with speech signal at 0 degrees and noise lateral to the CI at 90 degrees . With the convincing findings from our evaluations of this multicenter study cohort, a trial with the Freedom 24 sound processor for all suitable CI users is recommended. For evaluating the benefits of a new processor, the comparative assessment paradigm used in our study design would be considered ideal for use with individual patients.

Performance benefits for adults using a cochlear implant with adaptive dynamic range optimization (ADRO): a comparative study

The aim of this study was to assess the qualitative and quantitative benefits for speech-recognition ability of a preprocessing strategy known as adaptive dynamic range optimization (ADRO), used in conjunction with the subject's standard MAP, in comparison with the subject's standard MAP alone, for a group of experienced Germanspeaking adults using the Nucleus® 24 Cochlear implant.In a prospective, single-subject, comparative study design, experienced adult CI-users were asked to trial and compare both their standard MAP and the newly fitted ADRO MAP (ADRO MAP fitting – week 0) following a take-home trial period of 5 weeks. Assessment of speech recognition ability performed in quiet (at 50, 60 and 70 dB SPL) and adaptively in noise was carried out repeatedly in two test sessions in weeks 5 and 7 (ADRO MAP postfitting) using both MAPs. The order of speech tests and MAPs tested was counterbalanced across the test sessions to control for potential learning effects during the study. Subjective assessments were performed at week 0 to assess details of current usage. Comparative subjective assessments were carried out at weeks 5 and 7 to obtain impressions of loudness of environmental sounds and speech understanding in a variety of conversational situations with both MAPs and finally MAP preference judgements.Fifteen adult, German-speaking, experienced implant users wearing their body-worn SPrint processor for a minimum of six hours and up to 16 hours per day were enrolled in the study across three university clinic hospitals in Germany.On average, speech-reception thresholds (SRT) were significantly improved with the ADRO MAP compared to using the standard MAP for all speech materials in quiet. The mean advantage for SRT values with the ADRO MAP was 2.9 dB, σ ± 2.8 dB (p = 0.002) for the Freiburger Numbers test and 3.3 dB, σ ± 3.2 dB (p = 0.008) for the Freiburger Monosyllabic Words test. In noise, the ADRO MAP led to a significant improvement for the group for the mean signal-to-noise ratio required for a 50% speech recognition score (SNR 50) for the Oldenburger sentences of 1.74 dB, σ ± 3.2 dB (p = 0.048). Comparison of subjective impressions of loudness of environmental sounds revealed no significant difference in the ratings observed with either MAP. For speech understanding in a variety of listening situations, 35% of subjects preferred the ADRO MAP, 29% preferred the standard MAP whereas 36% reported no difference. Statistically the MAP preferences for the groups were not significant, however a significant MAP preference was noted in four subjects for the ADRO MAP and in two subjects for the standard MAP.Our study results demonstrate significant benefits of ADRO for speech recognition ability in quiet and in noise for both soft and conversational levels of speech. For the majority of subjects, both the ADRO and standard MAPs were found to be useful on a daily basis. No reductions in performance were noted for speech recognition or loudness scaling judgements of environmental sounds when using the newly fitted ADRO MAP, suggesting a smooth transition to the use of the preprocessing algorithm. It is recommended that an ADRO MAP be provided for all CI users as an additional program option to offer potential added benefit in select environments. Copyright © 2008 John Wiley & Sons, Ltd.

Bimodal studies using adaptive dynamic range optimization (ADRO) technology

This study investigated the effects of adaptive dynamic range optimization (ADRO®) processing for six bimodal listeners who used a hearing aid in one ear and a cochlear implant in the other. ‘Bimodal’ refers to the use of acoustic and electrical stimulation together. Bimodal speech recognition thresholds with the Japanese hearing in noise test were significantly lower for two ADRO devices than two non-ADRO devices in quiet, in noise from the front, and in noise from the implanted side. When the noise was presented from the non-implanted side there was no significant difference between the ADRO and non-ADRO conditions. The hearing aid measure of contrast questionnaire indicated that participants preferred ADRO in 77.3% of situations. ADRO was especially preferred in more difficult situations. The ADRO processing was designed for use in bimodal prostheses, and this study confirmed that speech intelligibility and sound quality improvements are obtainable by using ADRO in a bimodal context.

Performance benefits for adults using a cochlear implant with adaptive dynamic range optimization (ADRO): a comparative study

Performance benefits for adults using a cochlear implant with adaptive dynamic range optimization (ADRO): a comparative study

Effect of Multichannel Digital Signal Processing on Loudness Comfort, Sentence Recognition, and Sound Quality

This study evaluated the effect of increasing the number of processing channels from 32- to 64-signal processing channels on subjects' loudness comfort and satisfaction, sentence recognition, and sound quality of his or her own voice. Ten experienced hearing aid users with mild-to-moderate sensorineural hearing loss wore behind-the-ear (BTE) hearing aids with Adaptive Dynamic Range Optimization (ADRO) signal processing for a period of six weeks in the 32-channel and 64-channel conditions. Results revealed no significant differences in loudness comfort or satisfaction for the majority of sound samples as measured by the Subjective Loudness Test and Environmental Sounds Questionnaire. No significant differences in sentence recognition between the two processing conditions were found as measured by the Hearing In Noise Test (HINT). Additionally, no subjective differences in sound quality of subjects' own voice were determined by the Listening Tasks Questionnaire.

Adaptive Dynamic Range Optimization (ADRO): A Digital Amplification Strategy for Hearing Aids and Cochlear Implants

Adaptive dynamic range optimization (ADRO) is an amplification strategy that uses digital signal processing techniques to improve the audibility, comfort, and intelligibility of sounds for people who use cochlear implants and/or hearing aids. The strategy uses statistical analysis to select the most information-rich section of the input dynamic range in multiple-frequency channels. Fuzzy logic rules control the gain in each frequency channel so that the selected section of the dynamic range is presented at an audible and comfortable level. The ADRO processing thus adaptively optimizes the dynamic range of the signal in multiple-frequency channels. Clinical studies show that ADRO can be fitted easily to all degrees of hearing loss for hearing aids and cochlear implants in a direct and intuitive manner, taking the preferences of the listener into account. The result is high acceptance by new and experienced hearing aid users and strong preferences for ADRO compared with alternative amplification strategies. The ADRO processing is particularly well suited to bimodal and hybrid stimulation which combine electric and acoustic stimulation in opposite ears or in the same ear, respectively.

Optimizing dynamic range in children using the nucleus cochlear implant.

The aim of this study was to investigate the benefits of the preprocessing scheme "Adaptive Dynamic Range Optimization" (ADRO) in children using Nucleus cochlear implants. Previous research with adults indicates improved speech perception in quiet and improved sound quality in everyday listening environments with the ADRO scheme. Children were given 4 wk of take-home experience with ADRO, with a minimum of 2 wk in which ADRO was "locked-in." After 1 wk of ADRO use and again after 4 wk of ADRO use, Bench-Kowal-Bamford (BKB) sentence perception in quiet at a low input level of 50 dB SPL (unweighted root mean square) and sentence perception in noise were compared with the child's everyday (Standard) program and the ADRO program. Children also rated the loudness of a variety of environmental sounds and indicated which program provided the best hearing in a variety of everyday listening situations. On average, BKB sentence perception in quiet at 50 dB SPL was significantly better with the ADRO program compared with the Standard program. The group mean improvement was 8.60%. Similarly, group mean scores for BKB sentences presented at 65 dB SPL in multitalker babble were significantly higher with the ADRO program (an improvement of 6.87%). The ADRO program was the preferred program in 46% of the listening situations, whereas the Standard program was preferred in 26% of situations. Everyday sounds were not unacceptably loud with ADRO. There was an ADRO benefit for this group of children in quiet and in noise. These findings suggest that young children would benefit from the ADRO programming option being locked in along with other processor settings in the SPrint processor once their MAP levels have stabilized. Some older children and teenagers may choose to use ADRO selectively for specific listening situations.

Adaptive dynamic range optimization for cochlear implants: a preliminary study.

The present study investigated the acceptability and the effect of Adaptive dynamic range optimization (ADRO) on speech perception for cochlear implant subjects. ADRO is a preprocessing scheme that continuously adjusts the gain in each frequency band to optimize the signal in the output dynamic range. Speech processor programs were created with and without ADRO processing. Nine subjects were tested in the laboratory and encouraged to use both programs in everyday listening situations. Take-home experience was assessed with preference questionnaires. Speech perception performance was compared for the standard and ADRO programs using City University of New York (CUNY) sentences, consonant-nucleus-consonant (CNC) words, and closed set spondees presented in quiet. A range of presentation levels were used; from 70 to 40 dB sound pressure level (unweighted RMS). CUNY sentences were also presented in multi-talker babble with +15 dB and +10 dB signal to noise ratios. There was a significant improvement in speech perception scores with the ADRO programs compared with the standard. At 50 dB, the mean open set sentence scores in quiet improved by 16% (p < 0.001). There was an improvement in mean word score for CNC words presented at 60 dB of 9.5% (p < 0.001) and a 20% improvement in mean score for spondees presented at 40 dB. There was no significant difference in sentence scores between the ADRO and the standard program for sentences presented in either noise condition. ADRO was the preferred program in 59% of listening situations, with five out of nine subjects indicating a strong overall preference and three subjects indicating a slight preference for ADRO. Continual adjustment of channel gains using ADRO provided improved sound quality and improved speech perception performance. Therefore, ADRO is a viable alternative to fixed channel gain and offers a means for cochlear implantees to gain more benefit from their devices.