Binaural Summation Research Articles

Analysis of one-year outcomes after cochlear implantation in adults with single-sided deafness

Objectives: To investigate the outcomes of cochlear implantation in Mandarin-speaking cochlear implant (CI) users with single-sided deafness (SSD). Methods: This study was a single-center prospective cohort study. Eleven Mandarin-speaking adult SSD patients who underwent CI implantation at Capital Medical University Beijing Tongren Hospital from August 2020 to October 2021 were recruited, including 6 males and 5 females, with the age ranging from 24 to 50 years old. In a sound field with 7 loudspeakers distributed at 180°, we measured root-mean-square error(RMSE)in SSD patients at the preoperative, 1-month, 3-month, 6-month, and 12-month after switch-on to assess the improvement of sound source localization. The Mandarin Speech Perception (MSP) was used in the sound field to test the speech reception threshold (SRT) of SSD patients under different signal-to-noise locations in a steady-state noise under conditions of CI off and CI on, to reflect the head shadow effect(SSSDNNH), binaural summation effect(S0N0) and squelch effect(S0NSSD). The Tinnitus Handicap Inventory (THI) and the Visual Analogue Scale (VAS) were used to assess changes in tinnitus severity and tinnitus loudness in SSD patients at each time point. The Speech, Spatial and Qualities of Hearing Scale(SSQ) and the Nijmegen Cochlear Implantation Scale (NCIQ) were used to assess the subjective benefits of spatial speech perception and quality of life in SSD patients after cochlear implantation. SPSS 19.0 software was used for statistical analysis. Results: SSD patients showed a significant improvement in the poorer ear in hearing thresholds with CI-on compared with CI-off; The ability to localize the sound source was significantly improved, with statistically significant differences in RMSE at each follow-up time compared with the preoperative period (P<0.05). In the SSSDNNH condition, which reflects the head shadow effect, the SRT in binaural hearing was significantly improved by 6.5 dB compared with unaided condition, and the difference was statistically significant (t=6.25, P=0.001). However, there was no significant improvement in SRT between the binaural hearing condition and unaided conditions in the S0N0 and S0NSSD conditions (P>0.05). The total score of THI and three dimensions were significant decreased (P<0.05). Tinnitus VAS scores were significantly lower in binaural hearing compared to the unaided condition (P<0.001). The total score of SSQ, and the scores of speech and spatial dimensions were significant improved in binaural hearing compared to the unaided condition (P<0.001). There was no statistical difference in NCIQ questionnaire scores between preoperative and postoperative (P>0.05), and only the self-efficacy subscore showed a significant increase(Z=-2.497,P=0.013). Conclusion: CI could help Mandarin-speaking SSD patients restore binaural hearing to some extent, improve sound localization and speech recognition in noise. In addition, CI in SSD patients could suppress tinnitus, reduce the loudness of tinnitus, and improve subjective perceptions of spatial hearing and quality of life.

The right ear advantage – a perspective from speech perception in noise test

Objective So far, binaural summation for speech stimuli has been less evaluated in the literature, without the head shadow effect and spatial release from masking. Moreover, the right ear advantage has been shown mostly in the dichotic listening situation, but with conflicting results in the monaural/binaural listening condition. Therefore, the present study aimed to evaluate binaural hearing advantage utilizing only binaural summation without other factors and to evaluate the right ear advantage in the monaural listening situation. Methods Thirty-seven participants with normal hearing in the range of 0.125–20 kHz participated current study. Evaluation of speech perception in noise (SPIN) performances were conducted by Matrix test. Participants assessed in three different conditions including the right ear condition, the left ear condition and the binaural condition. Test order of the ears was counterbalanced and noises presented ipsilateral for monaural conditions. Results The lowest signal-to-noise ratio (SNR) values needed for understanding speech in noise were statistically significantly lower in binaural listening conditions compared to monaural listening conditions. In monaural listening conditions, the SNR value needed to understand speech in noise in the right ear was statistically significantly lower than in the left ear. Conclusion The results showed that the rehabilitation/habilitation of hearing-impairment patient should consider binaural amplification options to improve SPIN. In case of the symmetric hearing loss with the encountering compulsory situations which bring about the necessity to use only one ear, then right ear preference for amplification devices can provide better SPIN performance.

Spatial cues on normal hearing and cochlear implant simulation with different coding strategies

Cochlear implant users are known to have limited access to spatial cues. This study investigated the perception of spatial cues in normal-hearing listeners and cochlear implant simulation users. Perception of spatial cues is assessed for performance in determining the direction of the sound and understanding the speech. The results show that cochlear implant simulation users still have access to spatial cues, just like normal- hearing listeners. Normal-hearing listeners and cochlear implant simulation users can perceive spatial cues in ILD and ITD. Both can accurately identify the direction of the sound (slope ≈ 1.00 and of set ≈ 0.00°). Cochlear implant simulation users can understand sentences as well as normal-hearing listeners (PCW = 113.64 rau) by using the coding strategy SPEAK in all channels or CIS with channel above 8. Perception of spatial cues in normal-hearing listeners and cochlear implant users can be improved by listening with two ears and spatially separating the target-masker position. The largest improvement in spatial cue perception was obtained from the head shadow effect (normal-hearing (NH) = 12.96, cochlear implant simulation users (CI) = 59.02), followed by binaural summation (NH = 5.72, CI = 19, 86) and binaural squelch (NH = 3.76, CI = 7.66).

Acceptable Noise Level in Children with Unilateral Cochlear Implant and Bimodal Hearing

Background and Aim: Difficulty in perception of speech in noise is one of the main complaints of hearing-impaired people. Due to profound hearing loss in cochlear implant (CI) users, they need higher signal-to-noise ratio for a better perception. Bimodal fitting is a preferred way for CI users because it prevents auditory nerve degeneration, is a complement of frequency range at the opposite ear, an is less invasive to provide binaural hearing. Acceptable noise level (ANL), as a reliable test to assess noise tolerance, has not yet been used in comparing children with bimodal hearing and CI. This study aimed to determine whether bimodal fitting can help CI children tolerate more noise.&#x0D; Methods: This descriptive-analytical study was conducted on 13 children with unilateral CI and bimodal hearing. Audiometry test was performed at aided and non-aided conditions. Then, their noise tolerance was assessed by the Persian version of ANL test.&#x0D; Results: Bimodal hearing resulted in statistically significant increase in ANL. The mean of ANL at unilateral CI and bimodal hearing conditions were 6.15±2.90 and 4.77±1.70, respectively.&#x0D; Conclusion: Bimodal fitting lead to more noise tolerance in unilateral CI children due to the combination of binaural summation and binaural release from masking.&#x0D; Keywords: Acceptable noise level; cochlear implant; hearing aid; bimodal hearing; profound hearing loss; binaural hearing

The Impact of Unilateral Sensorineural Hearing Loss on Quality of Life of Sub-Himalayan Population.

Introduction Unilateral Sensorineural Hearing Loss (USNHL) is an age-old known entity. Patients with USNHL lack the merits of binaural hearing, i.e., temporal summation, sound localization, and speech recognition in a noisy environment. The lack of binaural hearing affects such individuals' quality of life (QOL). The present study is the most extensive Indian series related to QOL in USNHL patients. Objectives This study aims to assess the impact of USNHL on the QOL of patients in the state of Uttarakhand. Methods A cross-sectional study was carried out at a tertiary care center in Uttarakhand over a period of 18 months, from January 2018 to July 2019. A total of 115 patients with pure USNHL were evaluated using a validated questionnaire—Hearing Handicap Inventory for Adults-Hindi (HHIA-H). Results In our study, patients with higher HHIA-H scores were male, young adults (age group 18–30 years), students, and laborers. Most of our patients (64%) had significant handicaps, followed by moderate handicaps in 25%. However, no significant correlation of degree of handicap was seen with age, duration, and degree of hearing loss. Conclusion USNHL can lead to a significant handicap that can severely affect the emotional and social aspects of life. Thus, early diagnosis and rehabilitation are essential to prevent handicap and uplift QOL in patients with USNHL. This trial is registered with Clinical Trials Registry of India (CTRI reg. no. CTRI/2018/06/014396).

Bilateral Interactions in the Mouse Dorsal Inferior Colliculus Enhance the Ipsilateral Neuronal Responses and Binaural Hearing.

The inferior colliculus (IC) is a critical centre for the binaural processing of auditory information. However, previous studies have mainly focused on the central nucleus of the inferior colliculus (ICC), and less is known about the dorsal nucleus of the inferior colliculus (ICD). Here, we first examined the characteristics of the neuronal responses in the mouse ICD and compared them with those in the inferior colliculus under binaural and monaural conditions using in vivo loose-patch recordings. ICD neurons exhibited stronger responses to ipsilateral sound stimulation and better binaural summation than those of ICC neurons, which indicated a role for the ICD in binaural hearing integration. According to the abundant interactions between bilateral ICDs detected using retrograde virus tracing, we further studied the effect of unilateral ICD silencing on the contralateral ICD. After lidocaine was applied, the responses of some ICD neurons (13/26), especially those to ipsilateral auditory stimuli, decreased. Using whole-cell recording and optogenetic methods, we investigated the underlying neuronal circuits and synaptic mechanisms of binaural auditory information processing in the ICD. The unilateral ICD provides both excitatory and inhibitory projections to the opposite ICD, and the advantaged excitatory inputs may be responsible for the enhanced ipsilateral responses and binaural summation of ICD neurons. Based on these results, the contralateral ICD might modulate the ipsilateral responses of the neurons and binaural hearing.

Different binaural processing of the envelope component and the temporal fine structure component of a narrowband noise in rat inferior colliculus

Complex broadband sounds are decomposed by peripheral auditory filters into a series of relatively narrowband signals, each with a slowly varying envelope (ENV) and a rapidly fluctuating temporal fine structure (TFS). ENV and TFS information at the bilateral ears contribute differentially to auditory perception. However, whether the difference could attribute to mechanisms of binaural integration remains an open question. As a potential neural correlate, subsets of neurons in the central nucleus of the inferior colliculus (ICC) are known to integrate binaural information with binaural inhibition or binaural summation. Therefore, we recorded the frequency-following responses (FFRs) to the ENV and TFS components of narrowband noises in the ICC of anesthetized rats and examined changes in FFR amplitude and stimulus-response coherence under various sound-delivery settings. We showed that binaural FFRENV was predominantly elicited by contralateral inputs and inhibited by ipsilateral inputs, exhibiting a “binaural-inhibition” like property. On the other hand, binaural FFRTFS received a balanced contribution from both sides, echoing the “binaural-summation” mechanism. What is more, binaural FFRENV was significantly correlated with contralateral-evoked but not ipsilateral-evoked FFRENV, while binaural FFRTFS correlated with both contralateral- and ipsilateral-evoked FFRTFS. Overall, these results suggest distinct binaural processing of ENV and TFS information at the midbrain level.

Evaluation of adhesive bone conduction hearing aid in pediatric patients with unilateral congenital aural atresia

Objective: To evaluate the auditory efficacy and subjective satisfaction of adhesive bone conduction hearing aid in children with unilateral congenital aural atresia (UCAA). Methods: Ten subjects (5 males and 5 females) diagnosed with UCAA with an average age of 8.3 years old (ranged from 5 to 15) were included in Beijing Tongren Hospital, Capital Medical University from January to August 2019. The free sound field hearing threshold, word recognition score in quiet, speech reception threshold in noise and sound localization ability (results were measured by RMS error) tests were performed in unaided and aided situation, respectively. Subjective satisfaction questionnaires were also distributed to subjects. Paired t test and Wilcoxon signed rank test were used as statistical analysis methods. Results: The average hearing threshold in aided condition was improved by (21.9±4.4) dB (t=15.8，P<0.05). Speech recognition abilities were generally improved both under quiet and noise (P<0.05);however, when the binaural summation, squelch and head shadow effects were analyzed respectively, the binaural squelch effect was not statistically improved (P>0.05), while the other effects were improved in aided condition (P<0.05). In sound localization test, there was no significant difference of the RMS error value between the unaided and aided situation (P>0.05). The subjects got high satisfaction rates in three subjective questionnaires. Conclusion: The adhesive bone conduction hearing aid can provide significant audiological benefit for children with UCAA as well as raising the quality of their life.

Toward an Individual Binaural Loudness Model for Hearing Aid Fitting and Development.

The individual loudness perception of a patient plays an important role in hearing aid satisfaction and use in daily life. Hearing aid fitting and development might benefit from individualized loudness models (ILMs), enabling better adaptation of the processing to individual needs. The central question is whether additional parameters are required for ILMs beyond non-linear cochlear gain loss and linear attenuation common to existing loudness models for the hearing impaired (HI). Here, loudness perception in eight normal hearing (NH) and eight HI listeners was measured in conditions ranging from monaural narrowband to binaural broadband, to systematically assess spectral and binaural loudness summation and their interdependence. A binaural summation stage was devised with empirical monaural loudness judgments serving as input. While NH showed binaural inhibition in line with the literature, binaural summation and its inter-subject variability were increased in HI, indicating the necessity for individualized binaural summation. Toward ILMs, a recent monaural loudness model was extended with the suggested binaural stage, and the number and type of additional parameters required to describe and to predict individual loudness were assessed. In addition to one parameter for the individual amount of binaural summation, a bandwidth-dependent monaural parameter was required to successfully account for individual spectral summation.

Binaural summation, binaural unmasking and fluctuating masker benefit in bimodal and bilateral adult cochlear implant users

Objectives The number of bilateral adult cochlear implant (CI) users and bimodal CI users is expanding worldwide. The addition of a hearing aid (HA) in the contralateral non-implanted ear (bimodal) or a second CI (bilateral) can provide CI users with some of the benefits associated with listening with two ears. Our was to examine whether bilateral and bimodal CI users demonstrate binaural summation, binaural unmasking and a fluctuating masker benefit. Methods Direct audio input was used to present stimuli to 10 bilateral and 10 bimodal CochlearTM CI users. Speech recognition in noise (speech reception threshold, SRT) was assessed monaurally, diotically (identical signals in both devices) and dichotically (antiphasic speech) with different masking noises (steady-state and interrupted), using the digits-in-noise test. Results Bilateral CI users demonstrated a trend towards better SRTs with both CIs than with one CI. Bimodal CI users showed no difference between the bimodal SRT and the SRT for CI alone. No significant differences in SRT were found between the diotic and dichotic conditions for either group. Analyses of electrodograms created from bilateral stimuli demonstrated that substantial parts of the interaural speech cues were preserved in the Advanced Combination Encoder, an n-of-m channel selection speech coding strategy, used by the CI users. Speech recognition in noise was significantly better with interrupted noise than with steady-state masking noise for both bilateral and bimodal CI users. Conclusion Bilateral CI users demonstrated a trend towards binaural summation, but bimodal CI users did not. No binaural unmasking was demonstrated for either group of CI users. A large fluctuating masker benefit was found in both bilateral and bimodal CI users.

Cochlear Implant and Hearing Aid: Objective Measures of Binaural Benefit.

Cochlear implants (CI) improve hearing for the severely hearing impaired. With an extension of implantation candidacy, today many CI listeners use a hearing aid on their contralateral ear, referred to as bimodal listening. It is uncertain, however, whether the brains of bimodal listeners can combine the electrical and acoustical sound information and how much CI experience is needed to achieve an improved performance with bimodal listening. Patients with bilateral sensorineural hearing loss undergoing implant surgery were tested in their ability to understand speech in quiet and in noise, before and again 3 and 6 months after provision of a CI. Results of these bimodal listeners were compared to age-matched, normal hearing controls (NH). The benefit of adding a contralateral hearing aid was calculated in terms of head shadow, binaural summation, binaural squelch, and spatial release from masking from the results of a sentence recognition test. Beyond that, bimodal benefit was estimated from the difference in amplitudes and latencies of the N1, P2, and N2 potentials of the brains’ auditory evoked response (AEP) toward speech. Data of fifteen participants contributed to the results. CI provision resulted in significant improvement of speech recognition with the CI ear, and in taking advantage of the head shadow effect for understanding speech in noise. Some amount of binaural processing was suggested by a positive binaural summation effect 6 month post-implantation that correlated significantly with symmetry of pure tone thresholds. Moreover, a significant negative correlation existed between binaural summation and latency of the P2 potential. With CI experience, morphology of the N1 and P2 potentials in the AEP response approximated that of NH, whereas, N2 remained different. Significant AEP differences between monaural and binaural processing were shown for NH and for bimodal listeners 6 month post-implantation. Although the grand-averaged difference in N1 amplitude between monaural and binaural listening was similar for NH and the bimodal group, source localization showed group-dependent differences in auditory and speech-relevant cortex, suggesting different processing in the bimodal listeners.

Current Perspectives in Management of Unilateral Sensorineural Hearing Loss and Single Sided Deafness

Unilateral Sensorineural Hearing Loss (USNHL) or even Single Sided Deafness (SSD) were mistakenly believed in the past that they could not induce a notable negative effect on the average individual adult. Respectively, a child with USNHL could eventually develop typically and adequately with no particular challenges. Today, it is well established that both children and adults with USNHL and SSD experience difficulties locating sound sources than their normal peers attributable to the concomitant deprivation of data utilized for localization; interaural time differences along with interaural intensity differences, especially for high frequency sounds. Moreover, USNHL and SSD patients suffer from the absence of the binaural benefits that permit people with bilateral Normal Hearing (NH) to perform relatively well in challenging listening environments. These benefits encompass binaural summation that causes improved speech perception, and binaural release from masking that facilitates word recognition in noise. Rising treatment strategies, involving various type of amplification, Assistive Listening Devices (ALSs) and Cochlear Implantation, can greatly widen our overall approach regarding USNHL and / or SSD. Nevertheless, most recent evidence points out that both prompt and adequate intervention is crucial to promote optimal outcomes.

Uni- and bilateral spectral loudness summation and binaural loudness summation with loudness matching and categorical loudness scaling

Objective Current hearing aid prescription rules assume that spectral loudness summation decreases with hearing impairment and that binaural loudness summation is independent of hearing loss and signal bandwidth. Previous studies have shown that these assumptions might be incorrect. Spectral loudness summation was measured and compared for loudness scaling and loudness matching. Design In this study, the effect of bandwidth on binaural summation was investigated by comparing loudness perception of low-pass filtered, high-pass filtered, and broadband pink noise at 35 Categorical Units for both unilateral and bilateral presentation. Study sample Sixteen hearing-impaired listeners. Results The results show that loudness differences between the three signals are different for bilateral presentation than for unilateral presentation. In specific, binaural loudness summation is larger for the low-pass filtered pink noise than for the high-pass filtered pink noise. Finally, individual variability in loudness perception near loudness discomfort level was found to be very large. Conclusions Loudness matching is offered as a fast and reliable method to measure individual loudness perception. As discomfort with loud sounds is one of the major problems encountered by hearing aid users, measurement of individual loudness perception could improve hearing aid fitting substantially.

Progress in the treatment of single-sided deafness with artificial hearing aids

Single-sided deafness（SSD） is a common disease. Compared with normal hearing people, unilateral deaf patients often suffer from the loss of sound source localization ability and speech recognition in complex environments due to the lack of binaural summation effect, squelch effect, spatial demasking effect, and the presence of head shadow effect. Patients' quality of life and professional activities are always poor. Therefore, this article will review the related definitions of SSD, epidemiology, hazards, and artificial hearing aids in the application of SSD patients.

Binaural summation of amplitude modulation involves weak interaural suppression

The brain combines sounds from the two ears, but what is the algorithm used to achieve this summation of signals? Here we combine psychophysical amplitude modulation discrimination and steady-state electroencephalography (EEG) data to investigate the architecture of binaural combination for amplitude-modulated tones. Discrimination thresholds followed a ‘dipper’ shaped function of pedestal modulation depth, and were consistently lower for binaural than monaural presentation of modulated tones. The EEG responses were greater for binaural than monaural presentation of modulated tones, and when a masker was presented to one ear, it produced only weak suppression of the response to a signal presented to the other ear. Both data sets were well-fit by a computational model originally derived for visual signal combination, but with suppression between the two channels (ears) being much weaker than in binocular vision. We suggest that the distinct ecological constraints on vision and hearing can explain this difference, if it is assumed that the brain avoids over-representing sensory signals originating from a single object. These findings position our understanding of binaural summation in a broader context of work on sensory signal combination in the brain, and delineate the similarities and differences between vision and hearing.

Bimodal Hearing or Bilateral Cochlear Implants? Ask the Patient.

The objectives of this study were to assess the effectiveness of various measures of speech understanding in distinguishing performance differences between adult bimodal and bilateral cochlear implant (CI) recipients and to provide a preliminary evidence-based tool guiding clinical decisions regarding bilateral CI candidacy. This study used a multiple-baseline, cross-sectional design investigating speech recognition performance for 85 experienced adult CI recipients (49 bimodal, 36 bilateral). Speech recognition was assessed in a standard clinical test environment with a single loudspeaker using the minimum speech test battery for adult CI recipients as well as with an R-SPACE 8-loudspeaker, sound-simulation system. All participants were tested in three listening conditions for each measure including each ear alone as well as in the bilateral/bimodal condition. In addition, we asked each bimodal listener to provide a yes/no answer to the question, "Do you think you need a second CI?" This study yielded three primary findings: (1) there were no significant differences between bimodal and bilateral CI performance or binaural summation on clinical measures of speech recognition, (2) an adaptive speech recognition task in the R-SPACE system revealed significant differences in performance and binaural summation between bimodal and bilateral CI users, with bilateral CI users achieving significantly better performance and greater summation, and (3) the patient's answer to the question, "Do you think you need a second CI?" held high sensitivity (100% hit rate) for identifying likely bilateral CI candidates and moderately high specificity (77% correct rejection rate) for correctly identifying listeners best suited with a bimodal hearing configuration. Clinics cannot rely on current clinical measures of speech understanding, with a single loudspeaker, to determine bilateral CI candidacy for adult bimodal listeners nor to accurately document bilateral benefit relative to a previous bimodal hearing configuration. Speech recognition in a complex listening environment, such as R-SPACE, is a sensitive and appropriate measure for determining bilateral CI candidacy and also likely for documenting bilateral benefit relative to a previous bimodal configuration. In the absence of an available R-SPACE system, asking the patient whether or not s/he thinks s/he needs a second CI is a highly sensitive measure, which may prove clinically useful.

Binaural hearing advantages for children with bimodal fitting

ObjectivesBimodal fitting (BF) allows children with cochlear implant to benefit from binaural hearing advantages. Three major binaural hearing advantages, which enhance hearing function of people with normal hearing, are head shadow effect (HSE), binaural squelch effect (BSQ) and binaural summation effect (BSU). This study in pediatric patients attempting to measure the auditory benefits of bimodal stimulation in children with long-standing use of a cochlear implant (CI), and residual hearing on the contralateral side. MethodsThis cross-sectional study investigated binaural advantages in 24 children of 8–12 years who had undergone cochlear implantation in a cochlear implant center in Tehran and continuously used BF. Improved score of speech perception in noise (SPiN) under BF condition, as compared to the application of cochlear implant alone, was a binaural advantage found in this study. Each binaural advantage was measured by obtaining the SPiN score under different listening and noise conditions, using relevant formulas. The measured value of each advantage reflects the improved score of SPiN, caused by that certain advantage. ResultsIn this study, improved mean SPiN score caused by the HSE, BSQ and BSU was, respectively, 3.13, 1.42 and 2.04 dB, indicating greater binaural advantages and hence improved SPiN, under BF condition in comparison with cochlear implant alone. ConclusionChildren with unilateral cochlear implant and measurable residual hearing in non-implanted ear can benefit from binaural advantages and better SPiN when hearing aid is used in the unaided ear.

Spatial Speech-in-Noise Performance in Bimodal and Single-Sided Deaf Cochlear Implant Users.

This study compared spatial speech-in-noise performance in two cochlear implant (CI) patient groups: bimodal listeners, who use a hearing aid contralaterally to support their impaired acoustic hearing, and listeners with contralateral normal hearing, i.e., who were single-sided deaf before implantation. Using a laboratory setting that controls for head movements and that simulates spatial acoustic scenes, speech reception thresholds were measured for frontal speech-in-stationary noise from the front, the left, or the right side. Spatial release from masking (SRM) was then extracted from speech reception thresholds for monaural and binaural listening. SRM was found to be significantly lower in bimodal CI than in CI single-sided deaf listeners. Within each listener group, the SRM extracted from monaural listening did not differ from the SRM extracted from binaural listening. In contrast, a normal-hearing control group showed a significant improvement in SRM when using two ears in comparison to one. Neither CI group showed a binaural summation effect; that is, their performance was not improved by using two devices instead of the best monaural device in each spatial scenario. The results confirm a “listening with the better ear” strategy in the two CI patient groups, where patients benefited from using two ears/devices instead of one by selectively attending to the better one. Which one is the better ear, however, depends on the spatial scenario and on the individual configuration of hearing loss.

APD in First Graders. Which tests discriminate between normal and impaired children?

In a controlled group comparison it was shown for 2nd, 3th and 4th graders that children with auditory processing disorders (APD) could be distinguished from those without (Non-APD) by three to four diagnostic tools. The hit rate was 93.6 % resp. 97.5 % 1, 2. The current study investigated whether such a separation is also possible in first graders. Performance of 77 first graders in two clinically and diagnostically confirmed groups (n = 40 with APD, mean age: 6.93, SD 0.53 yrs; n = 37 Non APD, mean age: 6.90, SD 0.52 yrs) in 8 auditory processing tests of an eclectic test battery were compared (Dichotic Words Test; Phoneme Discrimination and Phoneme Identification; Word-Understanding in Background Noise; Binaural Summation Word Test; Sound Blending; Auditory Sequential Memory of Digits; Nonword Repetition). A differentiation of each clinical group with a multivariate statistical tool (discriminant analysis) functioned successfully. Children with APD were significantly distinguished from unimpaired children with an accuracy of 94.8 % (cross-validated in 92.2 %) via four test variables: (1) Auditory Sequential Memory of digits; (2) Phoneme Discrimination; (3) Nonword Repetition; (4) Word Understanding in Background Noise. The quality of the diagnostic a-priori-grouping using a multivariate statistics (discriminant analysis) could be confirmed for first graders too.

Objective evaluation of binaural summation through acoustic reflex measures

Objective: A previous study [Rawool, V. W. (2016). Auditory processing deficits: Assessment and intervention. New York, NY: Thieme Medical Publishers, Inc., pp. 186–187] demonstrated objective assessment of binaural summation through right contralateral acoustic reflex thresholds (ARTs) in women. The current project examined if previous findings could be generalised to men and to the left ear. Design: Cross-sectional. Study sample: Sixty individuals participated in the study. Left and right contralateral ARTs were obtained in two conditions. In the alternated condition, the probe tone presentation was alternated with the presentation of the reflex activating clicks. In the simultaneous condition, the probe tone and the clicks were presented simultaneously. Binaural summation was calculated by subtracting the ARTs obtained in the simultaneous condition from the ARTs obtained in the alternated condition. Results: MANOVA on ARTs revealed no significant gender or ear effects. The ARTs were significantly lower/better in the simultaneous condition compared to the alternated condition. Conclusions: Binaural summation was 4 dB or higher in 88% of the ears and 6 dB or higher in 76% of ears. Stimulation of six out of the total 120 (0.5%) ears resulted in worse thresholds in the simultaneous condition compared with the alternating condition, suggesting binaural interference.