The importance of interaural time differences and level differences in spatial release from masking

Numerous studies have described improvements in speech understanding when interaural time differences (ITDs) and interaural level differences (ILDs) are present. The present study aimed to investigate whether either cue in isolation can elicit spatial release from masking (SRM) in a speech-on-speech masking paradigm with maskers positioned symmetrically around the listener. Twelve adults were tested using three presentations of the Listening in Spatialized Noise-Sentences Test, with each presentation modified to contain different interaural cues in the stimuli. Results suggest that ILDs provide a similar amount of SRM as ITDs and ILDs combined. ITDs alone provide significantly less benefit. (C) 2013 Acoustical Society of Americ

Critical appraisal of speech in noise tests: a systematic review and survey

Speech in noise tests that measure the perception of speech in presence of noise are now an important part of audiologic tests battery and hearing research as well. There are various tests available to estimate the perception of speech in presence of noise, for example, connected sentence test, hearing in noise test, words in noise, quick speech-in-noise test, bamford-kowal-bench speech-in-noise test, and listening in spatialized noise-sentences. All these tests are different in terms of target age, measure, procedure, speech material, noise, normative, etc. Because of the variety of tests available to estimate speech-in-noise abilities, audiologists often select tests based on their availability, ease to administer the test, time required in running the test, age of the patient, hearing status, type of hearing disorder and type of amplification device if using. A critical appraisal of these speech-in-noise tests is required for the evidence based selection and to be used in audiology clinics. In this article speech-in-noise tests were critically appraised for their conceptual model, measurement model, normatives, reliability, validity, responsiveness, item/instrument bias, respondent burden and administrative burden. Selection of a standard speech-in-noise test based on this critical appraisal will also allow an easy comparison of speech-in-noise ability of any hearing impaired individual or group across audiology clinics and research centers. This article also describes the survey which was done to grade the speech in noise tests on the various appraisal characteristics

Influence of Dialect and Stimulus Audibility on LiSN-S Performances

The main objectives were to investigate the effect of dialect on Listening in Spatialized Noise-Sentences (LISN-S) performances and to assess the relationship between bilateral pure-tone threshold averages (PTAs) and LISN-S performances. Participants were young adults with normal audiograms with self-identified American Southern or non-Southern dialects. No significant LiSN-S threshold differences were found between dialect groups. The strongest significant correlations were found between PTAs and the LiSN-S +/-90° conditions

Effect of audibility on spatial release from speech-on-speech masking

This study investigated to what extent spatial release from masking (SRM) deficits in hearing-impaired adults may be related to reduced audibility of the test stimuli. Sixteen adults with sensorineural hearing loss and 28 adults with normal hearing were assessed on the Listening in Spatialized Noise–Sentences test, which measures SRM using a symmetric speech-on-speech masking task. Stimuli for the hearing-impaired listeners were delivered using three amplification levels (National Acoustic Laboratories - Revised Profound prescription (NAL-RP) +25%, and NAL-RP +50%), while stimuli for the normal-hearing group were filtered to achieve matched audibility. SRM increased as audibility increased for all participants. Thus, it is concluded that reduced audibility of stimuli may be a significant factor in hearing-impaired adults' reduced SRM even when hearing loss is compensated for with linear gain. However, the SRM achieved by the normal hearers with simulated audibility loss was still significantly greater than that achieved by hearing-impaired listeners, suggesting other factors besides audibility may still play a role

Same or Different:The Overlap Between Children With Auditory Processing Disorders and Children With Other Developmental Disorders: A Systematic Review

Objectives: Children diagnosed with auditory processing disorders (APD) experience difficulties in auditory functioning and with memory, attention, language, and reading tasks. However, it is not clear whether the behavioral characteristics of these children are distinctive from the behavioral characteristics of children diagnosed with a different developmental disorder, such as specific language impairment (SLI), dyslexia, attention-deficit hyperactivity disorder (ADHD), learning disorder (LD), or autism spectrum disorder. This study describes the performance of children diagnosed with APD, SLI, dyslexia, ADHD, and LD to different outcome measurements. The aim of this study was to determine (1) which characteristics of APD overlap with the characteristics of children with SLI, dyslexia, ADHD, LD, or autism spectrum disorder; and (2) if there are characteristics that distinguish children diagnosed with APD from children diagnosed with other developmental disorders. Design: A systematic review. Six electronic databases (Pubmed, CINAHL, Eric, PsychINFO, Communication & Mass Media Complete, and EMBASE) were searched to find peer-reviewed studies from 1954 to May 2015. The authors included studies reporting behaviors and performance of children with (suspected) APD and children diagnosed with a different developmental disorder (SLI, Dyslexia, ADHD, and LD). Two researchers identified and screened the studies independently. Methodological quality of the included studies was assessed with the American Speech-Language-Hearing Association's levels-of-evidence scheme. Results: In total, 13 studies of which the methodological quality was moderate were included in this systematic review. In five studies, the performance of children diagnosed with APD was compared with the performance of children diagnosed with SLI: in two with children diagnosed with dyslexia, one with children diagnosed with ADHD, and in another one with children diagnosed with LD. Ten of the studies included children who met the criteria for more than one diagnosis. In four studies, there was a comparison made between the performances of children with comorbid disorders. There were no studies found in which the performance of children diagnosed with APD was compared with the performance of children diagnosed with autism spectrum disorder. Children diagnosed with APD broadly share the same characteristics as children diagnosed with other developmental disorders, with only minor differences between them. Differences were determined with the auditory and visual Duration Pattern Test, the Children's Auditory Processing Performance Scale questionnaire, and the subtests of the Listening in Spatialized Noise-Sentences test, in which noise is spatially separated from target sentences. However, these differences are not consistent between studies and are not found in comparison to all groups of children with other developmental disorders. Conclusions: Children diagnosed with APD perform equally to children diagnosed with SLI, dyslexia, ADHD, and LD on tests of intelligence, memory or attention, and language tests. Only small differences between groups were found for sensory and perceptual functioning tasks (auditory and visual). In addition, children diagnosed with dyslexia performed poorer in reading tasks compared with children diagnosed with APD. The result is possibly confounded by poor quality of the research studies and the low quality of the used outcome measures. More research with higher scientific rigor is required to better understand the differences and similarities in children with various neurodevelopmental disorders

Frequency modulation (FM) system in auditory processing disorder: an evidence-based practice?

TEMA: uso do sistema de frequência modulada (FM) no transtorno do processamento auditivo. OBJETIVO: verificar a existência de evidência científica que comprove a efetividade do sistema FM para tratamento do transtorno do processamento auditivo (TPA) por meio de revisão sistemática da literatura pertinente encontrada em bases de dados eletrônicas (Medline, Lilacs e registro de ensaios clínicos da biblioteca Cochrane) e buscadores da internet, sendo os artigos recuperados analisados com base na declaração CONSORT e classificados quanto ao nível de evidência. CONCLUSÃO: a busca resultou em 1589 referências, das quais somente 19 enquadraram-se nos critérios de inclusão. Todos os artigos analisados foram classificados com baixo nível de evidência (opinão de especialista ou estudo de casos). Não foi encontrada forte evidência científica que comprove a efetividade do uso do sistema FM na intervenção de indivíduos com TPA. Uma vez que este equipamento é freqüentemente recomendado para a intervenção nos casos do TPA, se torna imprescindível a realização de estudos com alta evidência científica que possam guiar seguramente as tomadas de decisões clínicas a este respeito.BACKGROUND: use of frequency modulation (FM) system in auditory processing disorder. AIM: to verify the existence of scientific evidence confirming the effectiveness of personal FM systems in the treatment of central auditory processing disorders (APD). For this purpose a systematic review of the literature was made, using data found in electronic databases (Medline, Lilacs and Cochrane library) as well as on the internet. The articles retrieved were analyzed according to the CONSORT statement and then classified by their evidence level. CONCLUSION: the search resulted in 1,589 references out of which only 19 met the inclusion criteria. All of the analyzed articles were classified as having low level of evidence (expert opinion or case studies). Strong scientific evidence supporting the use of personal FM systems for APD intervention was not found. Since such device is frequently recommended for the treatment of APD, it becomes essential to carry out studies with high scientific evidence that could safely guide clinical decision making on this subject

Temporal resolution efficiency and auditory stream segmentation development

Background: The ability to hear changes in a sound envelope is called temporal resolution and is assumed to have a key role in binaural speech segmentation. The development of temporal resolu-tion is not fully explored, but studies indicate that it develops into adult-like efficiency at approxi-mately 8-13 years of age, while binaural speech segmentation has an extended development up until approximately 13-16 years of age. Method: A group of children (9-12 years of age) were compared to a group of 16 young adults. Temporal resolution was tested with a monaural non-speech amplitude modulation (AM) test at six modulation rates (10, 50, 75, 125, 150 and 250 Hz). Auditory stream segmentation was investigated with the binaural Listening in Spatialized Noise Sentence Test (LiSN–S). The purpose was to in-vestigate in what age-span these abilities become adult-like, if there were development differences depending on modulation rate and if there was a correlation between the tests. Results: A repeated measures ANOVA showed a significant difference between the two groups both on the AM-test (p=0.001) and LiSN-S test (p=0.002). A trend could also be seen that the 11-12 year old children (n=11) scored higher on the higher modulation rates compared to the lower ones. A positive significant correlation between LiSN-S spatial advantage score and the AM test at the modulation rates 50, 150 and 250 Hz was also found. Conclusions: The results indicate that temporal resolution efficiency is still developing at 9-12 years of age, but that children can reach adult-like temporal resolution efficiency at about 11-12 years of age, especially at higher modulation rates (between 150-250 Hz). The last steps of the anatomical maturation is continuing until approximately the age of 11-12, which corresponds well to these findings. The correlation between the tests might indicate that an efficient temporal resolu-tion is an advantage when use spatial cues

Effects of an auditory lateralization training in children suspected to central auditory processing disorder

Background and Objectives: Central auditory processing disorder (C)APD refers to a deficit in auditory stimuli processing in nervous system that is not due to higher-order language or cognitive factors. One of the problems in children with (C)APD is spatial difficulties which have been overlooked despite their significance. Localization is an auditory ability to detect sound sources in space and can help to differentiate between the desired speech from other simultaneous sound sources. Aim of this research was investigating effects of an auditory lateralization training on speech perception in presence of noise/competing signals in children suspected to (C)APD. Subjects and Methods: In this analytical interventional study, 60 children suspected to (C)APD were selected based on multiple auditory processing assessment subtests. They were randomly divided into two groups: control (mean age 9.07) and training groups (mean age 9.00). Training program consisted of detection and pointing to sound sources delivered with interaural time differences under headphones for 12 formal sessions (6 weeks). Spatial word recognition score (WRS) and monaural selective auditory attention test (mSAAT) were used to follow the auditory lateralization training effects. Results: This study showed that in the training group, mSAAT score and spatial WRS in noise (p value�0.001) improved significantly after the auditory lateralization training. Conclusions: We used auditory lateralization training for 6 weeks and showed that auditory lateralization can improve speech understanding in noise significantly. The generalization of this results needs further researches. © 2016 The Korean Audiological Society