Masking Level Difference Research Articles

Feasibility of Measuring the Behavioral and Electrophysiological Masking-Level Difference with Nonsense-Syllable Stimuli.

The masking-level difference (MLD) can be measured via voluntary behavioral responses (voluntary behavioral MLD [vMLD]) and/or via electrophysiological cortical auditory evoked potentials (CAEPs; electrophysiological MLD [eMLD]). It may be possible to enhance the ecologic validity of the MLD by using nonsense-syllable speech stimuli. The aim of this study is to determine the feasibility of measuring both the vMLD and eMLD with speech stimuli. The study also investigates whether certain nonsense-syllable stimuli (/α/, /dα/, /di/, /tα/, /wα/) may be more useful than others in measuring both the vMLD and eMLD. This is a descriptive feasibility pilot study. Seventeen young adults (age range 19-26 years; 15 women) with hearing thresholds of 0.25-8.0 kHz ≤ 25 dB HL, bilaterally, were recruited. Behavioral and electrophysiological MLDs were measured with similar methods. The MLD was defined as SoNo - SπNo thresholds. Stimuli were natural-sounding nonsense syllables (/α/, /dα/, /di/, /tα/, /wα/), which were presented in 65 dB HL continuous speech-weighted noise. The eMLD was measured with the CAEP P2. Group means, standard deviations, and distributions were presented. The feasibility of using nonsense syllables was evaluated by considering whether measurable vMLDs and eMLDs were produced. Useful nonsense syllables produced vMLDs and eMLDs with (1) comparatively large mean magnitudes, (2) few negligible MLDs, and (3) distributions with adequate spread and few extreme values. The stimuli /α/ (6.0 [1.9]) and /wα/ (7.5 [1.3]) produced vMLDs with the highest average magnitudes, with no vMLDs of 0 dB and with adequate spread. The stimulus /α/ produced eMLDs with the highest average magnitude (9.6 [2.8]), no eMLDs of 0 dB and adequate spread, whereas the stimulus /wα/ produced eMLDs with an adequate magnitude (6.9 [3.9]), no MLDs of 0 dB, but with a right-skewed distribution and an extreme value. The other stimuli produced vMLDs with low mean magnitudes and several vMLDs of 0 dB. These pilot data support the feasibility of using nonsense syllables to record vMLDs and eMLDs. The stimulus /α/ appeared most useful for both behavioral and electrophysiological modalities. Differences in MLDs across modalities may be attributed to low-level audibility of some high-frequency components of the stimuli.

Development of a Binaural Masking Level Differences Test Application Using Tonal and Speech Stimuli in Persian and Assessing its Test-Retest Reliability in Normal-Hearing Young People

Background and Aim: The masking level difference (MLD) test is a behavioral test that assesses binaural interactions and central auditory processing. This study aims to design a binaural MLD (BMLD) test application using tonal and Speech Stimuli in Persian.
 Methods: In the first stage, the BMLD test application was designed in MATLAB software. Then, the spondaic words were recorded and added to the sound processing panel of the application. In the next stage, the MLD of tonal and speech stimuli was measured on 20 subjects aged 18–25 years. To examine the test-retest reliability of the application, all steps were repeated after one week.
 Results: The MLD values for tonal and speech stimuli under the SoNo-SπNo condition were significantly different from those under the SoNo-SoNπ condition (p<0.05). These values for tonal and speech stimuli were 10.50 and 6.12 dB under the SoNo- SπNo condition, and 6.85 and 4.43 under the SoNo- SoNπ condition. There was no significant difference in the MLD values between males and females. The intraclass correlation coefficient value for different phase conditions was more than 0.8, indicating the high reliability of the BMLD test application for tonal and speech stimuli in Persian (p<0.05).
 Conclusion: The designed BMLD test application using tonal and speech stimuli in Persian has similar results compared to the conventional methods of MLD test for other languages, therefore, this application can be used in audiology clinics in Iran to perform the MLD test.
 Keywords: Release from masking; masking; binaural hearing; software

A Study on the Reference Values and Cutoff Criteria of Masking Level Difference for Children Aged 7-12 Years.

The Masking Level Difference (MLD) test is one of the main instruments for investigating binaural interaction. Studies with children aged 7–12 years still disagree about the influence of age on test performance and present discordant reference values. This study aimed to verify the effect of age on the performance of children aged 7–12 years in the MLD test and to establish reference values and cutoff criteria for this age group. Fifty-nine children with normal hearing were organized in three groups according to their age: 7–8 (n = 20), 9–10 (n = 20), and 11–12 (n = 19) years. The participants completed the MLD test by Auditec®. The Kruskal–Wallis statistical test was used to compare groups. Reference values were obtained by calculating mean, standard deviation, median, mode, and percentiles, while the cutoff criterion was obtained by subtracting two standard deviations from the mean. No statistically significant differences were observed between the groups regarding the MLD test measures. The mean MLD was 10.51 ± 1.84 dB and the cutoff point was set at 7 dB. Thus, reference values for the MLD test were established for children aged 7–12 years, who presented no effect of age on test performance.

Relationship between Auditory Processing Abilities and Hearing Aid Benefit in Elderly Individuals with Hearing Impairment

Background and Aim: Cognitive and auditory processing deficits are seen in older individuals with normal hearing sensitivity. Studies on older individuals with hearing impairment have assessed the cognitive function and correlated with hearing devices benefit. Since auditory processing can also affect speech perception abilities, and there is a possible relationship between cognition and some of the auditory processing abilities, it is essential to assess the relationship between auditory processing abilities and hearing aid benefit in naïve and experienced hearing aid users in older adults. Methods: Fifty individuals in the age range of 51 to 70 years with mild to moderate hearing loss participated in the study. There were 30 participants without any hearing aid experience and 20 participants with hearing aid experience for at least six weeks. Their auditory processing abilities were tested using gap detection test, duration pattern test, speech perception in noise, dichotic consonant-vowel test, masking level difference, forward and backward span tests. The hearing aid benefit was assessed using aided speech perception in noise measures and International Outcome Inventory-Hearing Aids questionnaire in Kannada. Results: Spearman’s correlation showed only correlation between auditory closure ability and binaural integration abilities with hearing aid benefit in experienced users. There was no correlation between any other auditory processing abilities and hearing aid benefit. Conclusion: There is a correlation between a few auditory processes and hearing aid use in elderly individuals with mild to moderate hearing loss. Keywords: Auditory processing abilities; hearing aid benefit; hearing aid users; working memory

The electrophysiological masking level difference: effects of age and mediation of hearing and cognition

Objective Evaluate the conceptual framework that age effects on the electrophysiological binaural masking level difference (MLD) are partially mediated by age-related hearing loss and/or global cognitive function via mediation analysis. Design Participants underwent a series of audiometric tests. The MLD was measured via cortical auditory evoked potentials using a speech stimulus (/ɑ/) in speech-weighted background noise. We used mediation analyses to determine the total effect, natural direct effects, and natural indirect effects, which are displayed as regression coefficients ([95% CI]; p value). Study sample Twenty-eight individuals aged 19–87 years (mean [SD]: 53.3 [25.2]), recruited from the community. Results Older age had a significant total effect on the MLD (-0.69 [95% CI: −0.96, −0.45]; p < 0.01). Neither pure tone average (-0.11 [95% CI: −0.43, 0.24; p = 0.54] nor global cognitive function (-0.02 [95% CI: −0.13, 0.02]; p = 0.55) mediated the relationship of age and the MLD and effect sizes were small. Results were insensitive to use of alternative hearing measures or inclusion of interaction terms. Conclusions The electrophysiological MLD may be an age-sensitive measure of binaural temporal processing that is minimally affected by age-related hearing loss and global cognitive function.

Masking Level Difference: test-retest reliability assessment in normal hearing female university students.

To verify the test-retest reliability of the Masking Level Difference in normal hearing female university students. Prospective descriptive study with 78 young female adults without hearing complaints, submitted to the compact disc version of the Masking Level Difference by Auditec of Saint Louis. The threshold was determined by the difference between signal-to-noise ratios at hearing thresholds found in the antiphasic and homophasic conditions. The test was applied by the same examiner in two moments (test and retest) with an interval of seven to 14 days between them. Inferential statistical analysis included comparison of test and retest situations using Student's t test for paired samples, calculation of the intraclass correlation coefficient and calculation of 95% confidence intervals for signal-to-noise ratios at hearing thresholds found in the antiphasic and homophasic conditions and for masking level difference. The average signal-to-noise ratio at hearing threshold ​​in the homophasic condition was -12.59 dB and -12.46 dB in the Test and Retest situations, respectively, and -21.54 dB and -21.08 dB in the antiphasic condition. The average value ​​in the final Masking Level Difference result was 8.95 dB in the Test and 8.74 dB in the Retest. Intraclass correlation coefficient values ​​obtained were 0.436, 0.625 and 0.577 for homophasic, antiphasic and Masking Level Difference conditions, respectively. The Masking Level Difference showed moderate test-retest reliability in normal hearing adults female university students.

Differences in Auditory Perception Between Young and Older Adults When Controlling for Differences in Hearing Loss and Cognition.

This study was designed to examine age effects on various auditory perceptual skills using a large group of listeners (155 adults, 121 aged 60–88 years and 34 aged 18–30 years), while controlling for the factors of hearing loss and working memory (WM). All subjects completed 3 measures of WM, 7 psychoacoustic tasks (24 conditions) and a hearing assessment. Psychophysical measures were selected to tap phenomena thought to be mediated by higher-level auditory function and included modulation detection, modulation detection interference, informational masking (IM), masking level difference (MLD), anisochrony detection, harmonic mistuning, and stream segregation. Principal-components analysis (PCA) was applied to each psychoacoustic test. For 6 of the 7 tasks, a single component represented performance across the multiple stimulus conditions well, whereas the modulation-detection interference (MDI) task required two components to do so. The effect of age was analyzed using a general linear model applied to each psychoacoustic component. Once hearing loss and WM were accounted for as covariates in the analyses, estimated marginal mean thresholds were lower for older adults on tasks based on temporal processing. When evaluated separately, hearing loss led to poorer performance on roughly 1/2 the tasks and declines in WM accounted for poorer performance on 6 of the 8 psychoacoustic components. These results make clear the need to interpret age-group differences in performance on psychoacoustic tasks in light of cognitive declines commonly associated with aging, and point to hearing loss and cognitive declines as negatively influencing auditory perceptual skills.

Monaural and binaural phase sensitivity in school-age children with early-childhood otitis media

Objective Previous research has linked recurrent otitis media (OM) during early childhood to reduced binaural masking level differences (BMLDs) in school-age children. How this finding relates to monaural processing abilities and the individual otologic history has not been investigated systematically. The current study, therefore, addressed these issues. Design Sensitivity to monaural and binaural phase information was assessed using a common test paradigm. To evaluate the influence of the otologic history, overall OM duration, OM onset age, and the time since the last OM episode were considered in the analyses. Study sample Children aged 6–13 years with a history of recurrent OM (N = 42) or without any previous ear diseases (N = 20). Results Compared to the controls, the OM children showed smaller BMLDs (p < 0.05) whereas their monaural and binaural detection thresholds were comparable (p > 0.05). After controlling for age, the otologic history factors failed to predict the BMLDs of the OM children. Their monaural detection thresholds were correlated with the binaural detection thresholds (r = ∼0.5, p < 0.05) but not the BMLDs. Conclusions The current study suggests that early-childhood OM can impair binaural processing abilities in school-age children.

ZDOLNOŚCI SŁUCHOWE U OSÓB Z FORMALNYM WYKSZTAŁCENIEM MUZYCZNYM I BEZ TAKIEGO WYKSZTAŁCENIA

IntroductionAuditory perception can be enhanced by musical training and practice. Considering the multiple brain areas involved in musical learning, good auditory perceptual skills can contribute to phonological awareness, speech recognition in the presence of noise, reading, syllable recognition, and other language skills.Material and methodsThere were 30 adults between 18 and 27 years old who participated. They were divided into two groups: 15 individuals without formal musical training (Non-Musicians) and 15 individuals with 5 years or more of formal musical training (Musicians), paired by gender and age. Procedures used for assessing their hearing skills were the Duration Pattern test, Staggered Spondaic Word test, Masking Level Difference test, and Dichotic Consonant–Vowel test.ResultsIn all tests, the Musicians group showed a higher average score than the Non-Musicians. In the MLD test, the average level difference was 3 dB higher for the Musicians than for the Non-Musicians (p = 0.001). There were also statistically significant mean differences between the groups for the DP test, SSW test in the right ear, and DCV test (number of errors).ConclusionsIndividuals with formal musical training show better auditory attention abilities, which are important for developing good listening skills, resulting in good communication and linguistic performance compared to individuals without prior musical training.

Effect of aging and signal frequencies on masking level differences

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; The typical masking level differences (MLD) paradigm involves homophasic and antiphasic masking conditions. Objectives of the study were to develop homophasic and antiphasic stimulus, to find out the effect of signal frequency, of age on MLD when all the antiphasic conditions are compared to the homophasic S&lt;sub&gt;0&lt;/sub&gt;N&lt;sub&gt;0&lt;/sub&gt; and S&lt;sub&gt;π&lt;/sub&gt;N&lt;sub&gt;π &lt;/sub&gt;condition and to find out effect of interaural time delay of stimulus on aging.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; 90 participants were divided into 3 groups of young adults, early presbycusic adults and geriatric presbycusic adults. Various stimuli were developed and presented. The MLD were using homophasic and antiphasic stimuli at 4 frequencies 250, 500, 1000 and 2000 Hz. Subsequently these were statistically analyzed using ANOVA and paired t test.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; All the conditions used in the study had some condition with and without significant differences. However, at 500 Hz in S&lt;sub&gt;0&lt;/sub&gt;N&lt;sub&gt;0 &lt;/sub&gt;homophasic condition all four antiphasic conditions among groups and MLD and Interaural time delay between groups showed significant differences were present.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; From these findings, the best frequency is 500 Hz as the homophasic S&lt;sub&gt;0&lt;/sub&gt;N&lt;sub&gt;0&lt;/sub&gt; baseline condition. A significant difference between the groups indicated presence of age-related effect on MLD and interaural time delay, suggesting that age related changes can be observed in the binaural hearing and temporal processing of the signals and can be measured using MLD.&lt;/p&gt;

Masking level difference among brazilian military personnel: a comparison between pilots and non-pilots

Objectives The aims of this study were to investigate auditory habits and binaural interaction among pilot and non-pilot military personnel from the Brazilian Air Force. Design A cross-sectional study using (1) an auditory habits questionnaire to outline the groups auditory profile and (2) the masking level difference test (MLD, Auditec, Saint Louis®) to evaluate and compare the groups. Study Sample Forty military male personnel aged between 30–40 years old, all with normal hearing, comprising 20 pilots in the study group (SG), and 20 non-pilots, not exposed to noise, in the control group (CG). Results There was no significant difference between groups regarding auditory habits. In the MLD test, a significantly better performance under the homophasic condition (S0N0) was found in the SG. Under the antiphasic condition (SπN0) there were no differences between groups. This combination resulted in a significantly lower MLD in the SG compared to the CG. Conclusions Repeated exposure to conditions where active pilots have to learn to recognise speech in noisy backgrounds may lead to a better performance in the MLD’s homophasic condition (S0N0).

Central Auditory Processing and Cognitive Functions in Children.

Introduction Nowadays, there is no consensus on whether central auditory processing disorder is a primary or a secondary deficit to other cognitive deficits. A better understanding of the association between cognitive functions and central auditory skills may help elucidate this dilemma. Objective To investigate possible associations between auditory abilities and cognitive functions in schoolchildren. Methods Fifty-eight schoolchildren, aged between 8 years and 0 months old and 11 years and 11 months old, who underwent the following tests: masking level difference, gaps in noise, pitch pattern sequence test, dichotic digits test, sustained auditory attention ability test, Wechsler intelligence scale for children – IV, junior Hayling test, five digits test, and behavior rating inventory of executive function. Results Significant correlations were found between the hearing ability of temporal resolution and executive functions, temporal ordering/sequencing, binaural integration and separation, and sustained auditory attention, operational memory, inhibitory control, and cognitive flexibility; binaural integration was also associated with intelligence. The statistically significant positive correlation found between the ability of binaural interaction and the components of emotional control and behavior regulation of the behavior rating inventory of executive function was unexpected. Conclusion The associations identified reinforce the complexity of the tasks involved in the evaluation of central auditory processing and the need for multidisciplinary evaluation for the differential diagnosis of auditory processing disorder. Confirmation of the presence or absence of comorbidities between different disorders allows directing the therapeutic behaviors and reducing the impact of possible auditory and/or cognitive deficits in the different daily life situations of children.

Masking Level Difference: Performance of School Children Aged 7–12 Years

Background and ObjectivesIn masking level difference (MLD), the masked detection threshold for a signal is determined as a function of the relative interaural differences between the signal and the masker. Study 1 analyzed the results of school-aged children with good school performance in the MLD test, and study 2 compared their results with those of a group of children with poor academic performance.Subjects and MethodsStudy 1 was conducted with 47 school-aged children with good academic performance (GI) and study 2 was carried out with 32 school-aged children with poor academic performance (GII). The inclusion criteria adopted for both studies were hearing thresholds within normal limits in basic audiological evaluation. Study 1 also considered normal performance in the central auditory processing test battery and absence of auditory complaints and/or of attention, language or speech issues. The MLD test was administered with a pure pulsatile tone of 500 Hz, in a binaural mode and intensity of 50 dBSL, using a CD player and audiometer.ResultsIn study 1, no significant correlation was observed, considering the influence of the variables age and sex in relation to the results obtained in homophase (SoNo), antiphase (SπNo) and MLD threshold conditions. The final mean MLD threshold was 13.66 dB. In study 2, the variables did not influence the test performance either. There was a significant difference between test results in SπNo conditions of the two groups, while no differences were found both in SoNo conditions and the final result of MLD.ConclusionsIn study 1, the cut-off criterion of school-aged children in the MLD test was 9.3 dB. The variables (sex and age) did not interfere with the MLD results. In study 2, school performance did not differ in the MLD results. GII group showed inferior results than GI group, only in SπNo condition.

Binaural Etkileşimin Değerlendirilmesi: Normal İşiten Bireylerde Yaşa Bağlı Değişen Maskeleme Düzeyi Farkı

Amaç: Çalışmamızın amacı, normal işitmeye sahip erişkin bireylerde maskeleme düzeyi farkı değerlerini karşılaştırmak ve yaş değişkeni ile saf ses ortalaması, konuşma testleri ve maskeleme düzeyi farkı test sonuçları aralarındaki ilişkiyi incelemektir. Gereç ve Yöntemler: Çalışmaya normal işitmeye sahip 18-30 yaş arası 45 birey, 45- 75 yaş arası 42 birey olmak üzere 87 birey dâhil edilmiş olup toplam 174 kulak değerlendirilmiştir. Bireylere sırasıyla otoskopik muayene, akustik immitansmetri, saf ses odyometrisi, konuşma odyometrisi ve binaural etkileşimi değerlendirmek için maskeleme düzeyi farkı testleri yapılmıştır. Maskeleme düzeyi farkı testi 500 Hz saf ton ve dar bant gürültü kullanılarak S0N0 homofazik ve SπN0 antifazik olmak üzere 2 koşulda ayrı ayrı değerlendirilmiştir. Bulgular: İki grup arasında konuşmayı alma eşiği (sağ kulak ve sol kulak p<0,001), konuşmayı ayırt etme skoru (sağ kulak ve sol kulak p<0,001) ve maskeleme düzeyi farkı (p=0,003) test sonuçları arasında istatistiksel olarak anlamlı bir farklılık vardır. Yaş ile yapılan tüm testler arasında istatistiksel olarak anlamlı ilişkiye rastlanmıştır. Yaş ile saf ses ortalaması (r=0,724, p<0,001; r=0,688, p<0,001) ve konuşmayı alma eşiği (r=0,599, p<0,001; r=0,651, p<0,001) arasında istatistiksel açıdan pozitif yönde, konuşmayı ayırt etme skoru (r=-0,567, p<0,001; r=-0,553, p<0,001) ve maskeleme düzeyi farkı (r=-0,260, p=0,015) arasında istatistiksel açıdan negatif yönde anlamlı ilişkiye rastlanmıştır. Sonuç: Normal işitme eşiklerine rağmen yaşın artması ile işitsel ve binaural etkileşim fonksiyonlarında azalma olduğu gözlenmiştir.

A notched-noise precursor affects both diotic and dichotic notched-noise masking

The present study investigates how diotic and dichotic masked thresholds, in a notched-noise masking paradigm, are affected by activation of the Medial OlivoCochlear (MOC) reflex. Thresholds were obtained for a 500-Hz pure tone diotic or a dichotic signal, S (S0 or Sπ respectively), in the presence of a simultaneous or forward diotic masker (bandpass noise with no notch or a 400-Hz notch). A diotic precursor sound (bandpass noise with a 400- or 800-Hz notch) was presented prior to the signal and masker to activate the MOC reflex. For simultaneous- and forward-masking conditions, the decrease in masked thresholds as a notch was introduced in the masker was larger for the diotic than for the dichotic condition. This resulted in a reduced binaural masking level difference (BMLD) for the masker with a notch. The precursor augmented these two effects. The results indicate that the effect of the precursor, eliciting the MOC reflex, is less pronounced when binaural cues are processed.

Age-related altering temporal processing and binaural interaction functions in normal hearing individuals: Observational and cross-sectional study

ObjectiveThis study aimed to investigate the temporal processing and binaural interaction functions of central auditory processing tests according to the anatomical localizations of young and elderly individuals. It also sought to evaluate the relationships between the same individuals’ central auditory processing tests. MethodsThis observational and cross-sectional study included individuals with normal hearing between 18 and 30 and 60–75 years of age, who were referred to as the young group and the elderly group, respectively. The evaluation of the central auditory processing tests was completed using the frequency pattern test, duration pattern test, masking level difference test, and random gap detection test. Furthermore, speech discrimination and speech in noise scores were analyzed for both groups. ResultsStatistically significant differences were identified between the groups’ scores for the speech in noise test, masking level difference test, random gap detection test, frequency pattern test, and duration pattern test (p < 0.05). A statistically significant relationship was observed between the age and the results of the central auditory processing tests (p < 0.05). ConclusionWhen compared to younger individuals, elderly individuals presented with declined temporal sequences, temporal resolutions, and binaural interaction skills.

Deep learning of the binaural masking level difference

The binaural masking level difference (BMLD) is the improvement in the detection of a signal in noise observed for different interaural configurations. Durlach [J. Acoust. Sci. Am. 1206–1218 (1963)] derived equations that accurately predict much of the human BMLD psychophysical data. We trained a deep neural network to predict BMLDs, as calculated with Durlach's equations, based on waveforms of a 500 Hz signal in a white noise each presented from different locations. Crucially, the network was constrained via nodes configured to embody informative representations (Iten etal., 2018; arXiv:1807.10300). The deep neural network accurately predicted BMLDs for stimuli within a simulated azimuth and for stimuli with interaural time differences (ITDs) outside the range of a human head. Further, even though the model was not designed to imitate neural biophysics, we discovered that the dynamics of latent nodes bore similarities with published data on neural ITD tuning and rate-level responses to BMLD stimuli. The work demonstrates how advances in deep learning can be used to consolidate theoretical and experimental approaches to binaural detection.

Prematurity and the Auditory System: Considerations for Audiologists

Prematurity and the Auditory System: Considerations for Audiologists

Masking Level Difference and Electrophysiological Evaluation in Adults with Normal Hearing.

Introduction The auditory structures of the brainstem are involved in binaural interaction, which contributes to sound location and auditory figure-background perception. Objective To investigate the performance of young adults in the masking level difference (MLD) test, brainstem auditory-evoked potentials (BAEPs) with click stimulus, and frequency-following response (FFR), as well as to verify the correlation between the findings, considering the topographic origin of the components of these procedures. Methods A total of 20 female subjects between 18 and 30 years of age, with normal hearing and no complaints concerning central auditory processing underwent a basic audiological evaluation, as well as the MLD test, BAEP and FFR. Results The mean result on the MLD test was of 10.70 dB. There was a statistically significant difference in the absolute latencies of waves I, III and V in the BAEPs of the ears. A change in the FFR characterized by the absence of the C, E and F waves was noticed. There was a statistically significant difference in the positive correlation of wave V in the BAEPs with the MLD. There was a statistically significant difference in the positive correlation of the mean MLD and the V, A and F components of the FFR. Conclusion The mean MLD was adequate. In the BAEPs, we observed that the click stimulus transmission occurred faster in the right ear. The FFR showed absence of some components. The mean MLD correlated positively with the BAEPs and FFR.

Behavioral tests in adults: reference values and comparison between groups presenting or not central auditory processing disorder

ABSTRACT Purpose: to generate reference values for different behavioral central auditory processing (CAP) tests in normally hearing adults, with age stratification, as well as to compare the results, according to the presence or absence of CAP disorder (CAPD). Methods: the study sample consisted of 94 adults with normal auditory thresholds, with at least 11 years of schooling, who were divided into two groups, according to the performance in the Dichotic Sentences Identification Test (DSI), Masking Level Difference (MLD), Random Gap Detection Test (RGDT), Adapted Time-Compressed Speech (ATCS) and Duration and Frequency Pattern Tests (DPT/FPT).The 64 subjects who presented normality in all the tests formed the G1 group and the 30 subjects who presented alteration in at least one of them, originated the G2 group. To accomplish the analysis it was used the Mann-Whitney U Test. In all analyzes, the significance level was 5% (p≤0.05). Results: the sum of the two standard deviations for the mean performance of G1 yielded reference values for the different tests addressed. When G1 and G2 groups were compared, G1 presented better results, this being significant in the DSI (left ear), MLD, RGDT, DPT and FPT tests, for the group aged between 18 and 29 years and, DSI (right ear), RGDT and ATCS (right ear), for the group from 30 to 58 years. Conclusion: it was possible to generate reference values for different behavioral tests of CAP in normally hearing adults, as well as to verify a better performance for the group with no CAPD.