Spatialized Noise-Sentences Test Research Articles

Beyond the cochlea: exploring the multifaceted nature of hearing loss in primary mitochondrial diseases

Abstract Primary mitochondrial diseases, with diverse systemic manifestations, often present with auditory impairments due to mitochondrial dysfunction. This study provides an in-depth exploration of auditory deficits in primary mitochondrial diseases, highlighting the impact of various pathogenic variants on both cochlea and neural/central auditory functions. An observational study involving 72 adults with primary mitochondrial diseases was conducted. Participants underwent extensive audiological evaluations including Pure-Tone Audiometry, Tympanometry, Acoustic Reflex Thresholds, Quick Speech-in-Noise Test, Listening in Spatialized Noise-Sentences test, Auditory-evoked Brainstem Responses, and Distortion Product Otoacoustic Emissions. Multivariate Analysis of Covariance and logistic regression analyses assessed the influence of various pathogenic DNA variants, accounting for age, cognitive status via the Montreal Cognitive Assessment, and disease severity through the Newcastle Mitochondrial Disease Adult Scale. Participants with the pathogenic m.3243A>G/T variants (m.3243A>G n=40; m.3243A>T n=1) exhibited significant elevations in Pure-Tone Audiometry thresholds, especially at high frequencies, suggesting cochlea involvement. Notably, the Listening in Spatialized Noise-Sentences test showed significant spatial processing deficits in the m.3243A>G/T group, possibly indicating a unique mutation-specific impact on central auditory processing. Auditory-evoked Brainstem Responses results highlighted a higher likelihood of auditory brainstem response abnormalities in this group, further substantiating neural/central auditory pathway involvement. This study emphasises the heterogeneous nature of hearing impairment in primary mitochondrial diseases, with a genotype-phenotype correlation, particularly in the m.3243A>G/T group. These insights advocate for personalised, genotype-specific auditory assessments and targeted management strategies. Conventional hearing aids and cochlear implants are ineffective for those with central auditory dysfunctions related to mitochondrial mutations. There is an urgent need for innovative rehabilitation strategies catering for both cochlear and neural/central auditory pathways.

Amplitude Modulation Perception and Cortical Evoked Potentials in Children With Listening Difficulties and Their Typically Developing Peers.

Amplitude modulations (AMs) are important for speech intelligibility, and deficits in speech intelligibility are a leading source of impairment in childhood listening difficulties (LiD). The present study aimed to explore the relationships between AM perception and speech-in-noise (SiN) comprehension in children and to determine whether deficits in AM processing contribute to childhood LiD. Evoked responses were used to parse the neural origins of AM processing. Forty-one children with LiD and 44 typically developing children, ages 8-16 years, participated in the study. Behavioral AM depth thresholds were measured at 4 and 40 Hz. SiN tasks included the Listening in Spatialized Noise-Sentences Test (LiSN-S) and a coordinate response measure (CRM)-based task. Evoked responses were obtained during an AM change detection task using alternations between 4 and 40 Hz, including the N1 of the acoustic change complex, auditory steady-state response (ASSR), P300, and a late positive response (late potential [LP]). Maturational effects were explored via age correlations. Age correlated with 4-Hz AM thresholds, CRM separated talker scores, and N1 amplitude. Age-normed LiSN-S scores obtained without spatial or talker cues correlated with age-corrected 4-Hz AM thresholds and area under the LP curve. CRM separated talker scores correlated with AM thresholds and area under the LP curve. Most behavioral measures of AM perception correlated with the signal-to-noise ratio and phase coherence of the 40-Hz ASSR. AM change response time also correlated with area under the LP curve. Children with LiD exhibited deficits with respect to 4-Hz thresholds, AM change accuracy, and area under the LP curve. The observed relationships between AM perception and SiN performance extend the evidence that modulation perception is important for understanding SiN in childhood. In line with this finding, children with LiD demonstrated poorer performance on some measures of AM perception, but their evoked responses implicated a primarily cognitive deficit. https://doi.org/10.23641/asha.25009103.

Associations Between Auditory Working Memory, Self-Perceived Listening Effort, and Hearing Difficulty in Adults With Mild Traumatic Brain Injury.

Mild traumatic brain injury (TBI) can have persistent effects in the auditory domain (e.g., difficulty listening in noise), despite individuals having normal pure-tone auditory sensitivity. Individuals with a history of mild TBI often perceive hearing difficulty and greater listening effort in complex listening situations. The purpose of the present study was to examine self-perceived hearing difficulty, listening effort, and performance on an auditory processing test battery in adults with a history of mild TBI compared with a control group. Twenty adults ages 20 to 53 years old participated divided into a mild TBI (n = 10) and control group (n = 10). Perceived hearing difficulties were measured using the Adult Auditory Processing Scale and the Hearing Handicap Inventory for Adults. Listening effort was measured using the National Aeronautics and Space Administration-Task Load Index. Listening effort ratings were obtained at baseline, after each auditory processing test, and at the completion of the test battery. The auditory processing test battery included (1) dichotic word recognition, (2) the 500-Hz masking level difference, (3) the Listening in Spatialized Noise-Sentences test, and (4) the Word Auditory Recognition and Recall Measure (WARRM). Results indicated that individuals with a history of mild TBI perceived significantly greater degrees of hearing difficulty and listening effort than the control group. There were no significant group differences on two of the auditory processing tasks (dichotic word recognition or Listening in Spatialized Noise-Sentences). The mild TBI group exhibited significantly poorer performance on the 500-Hz MLD and the WARRM, a measure of auditory working memory, than the control group. Greater degrees of self-perceived hearing difficulty were significantly associated with greater listening effort and poorer auditory working memory. Greater listening effort was also significantly associated with poorer auditory working memory. Results demonstrate that adults with a history of mild TBI may experience subjective hearing difficulty and listening effort when listening in challenging acoustic environments. Poorer auditory working memory on the WARRM task was observed for the adults with mild TBI and was associated with greater hearing difficulty and listening effort. Taken together, the present study suggests that conventional clinical audiometric battery alone may not provide enough information about auditory processing deficits in individuals with a history of mild TBI. The results support the use of a multifaceted battery of auditory processing tasks and subjective measures when evaluating individuals with a history of mild TBI.

The relationship between extended high-frequency hearing and the binaural spatial advantage in young to middle-aged firefightersa).

Relationships between extended high-frequency (EHF) thresholds and speech-in-spatialized noise were examined in firefighters with a history of occupational noise and airborne toxin exposure. Speech recognition thresholds were measured for co-located and spatially separated (±90° azimuth) sentences in a competing signal using the Listening in Spatialized Noise-Sentences test. EHF hearing was significantly correlated with the spatial advantage, indicating that firefighters with poorer EHF thresholds experienced less benefit from spatial separation. The correlation between EHF thresholds and spatial hearing remained significant after controlling for age. Deficits in EHF and spatial hearing suggest firefighters may experience compromised speech understanding in job-related complex acoustic environments.

The Impact of Traumatic Brain Injury on Binaural Processing in Young and Middle-Age Adults.

This study examined the impact of traumatic brain injury (TBI) on self-perceived hearing and suprathreshold binaural processing in young and middle-age adults. Ninety-three adults with normal hearing (thresholds ≤ 25 dB HL, 250-4000 Hz) participated in one of four groups: 38 young adults, 23 young adults with TBI, 16 middle-age adults, and 16 middle-age adults with TBI. Self-perceived hearing difficulty was measured via questionnaires. Binaural processing was measured using dichotic word recognition, the Listening in Spatialized Noise-Sentences Test (LiSN-S), and the 500-Hz masking level difference (MLD). For each participant, a composite binaural processing (CBP) score was calculated to obtain a global metric of binaural processing performance. The CBP was composed of six measures from the three behavioral tests, including the S0N0 and SπN0 thresholds from the 500-Hz MLD, the low- and high-cue speech recognition thresholds from the LiSN-S, and the free and directed recall ear advantages from the dichotic word test. The middle-age TBI group reported significantly greater degrees of self-perceived hearing difficulty than the other groups. On average, the middle-age TBI group performed poorer on the individual binaural processing tests; however, the differences were significant for the S0N0 and SπN0 MLD thresholds only. Results for the global metric of binaural processing revealed significantly poorer CBP scores for the middle-age TBI group compared to the other groups. Results demonstrate that both age and a positive history of TBI contributed to deficits in suprathreshold binaural processing. Middle-age adults with a history of TBI are at risk for experiencing presenescent deficits in suprathreshold binaural processing deficits, despite having clinically normal hearing.

The Relationship Between Self-Perceived Hearing Ability and Binaural Speech-in-Noise Performance in Adults With Normal Pure-Tone Hearing

PurposeThis study examined the relationship between self-perceived hearing abilities and binaural speech-in-noise performance in young to middle-age adults with normal pure-tone hearing.MethodSixty-six adults with normal hearing (thresholds ≤ 25 dB HL at 250–8000 Hz) participated. Self-perceived hearing abilities were assessed using the Adult Auditory Performance Scale (AAPS). The AAPS provides a single global score of self-perceived hearing abilities and individual subscale scores for six listening conditions, namely, Quiet, Ideal, Noise, Multiple Inputs, Auditory Memory, and Auditory Attention. Binaural speech-in-noise performance was measured with the Listening in Spatialized Noise–Sentences Test (LiSN-S).ResultsResults revealed significant correlations between the AAPS and the LiSN-S. Listeners who scored higher on the AAPS (greater self-perceived hearing difficulty) performed poorer on the LiSN-S. The strongest correlations were observed between the AAPS Noise subscale score and the LiSN-S low- and high-cue conditions. Age was significantly correlated with both pure-tone hearing and the LiSN-S spatial advantage, with older participants exhibiting poorer thresholds and smaller spatial advantages. Pure-tone hearing was also significantly correlated with binaural speech-in-noise performance. Listeners with poorer thresholds performed poorer across multiple LiSN-S conditions. Linear regression revealed that a significant amount of the variance in LiSN-S performance was accounted for by pure-tone hearing as well as the AAPS global score and Noise subscale score.ConclusionsResults demonstrate a clear relationship between an individual's self-perceived hearing ability and their binaural speech-in-noise performance. In addition, minimal threshold elevation within the normal range and age (i.e., middle adulthood) had a negative impact on binaural speech-in-noise performance. The results support the inclusion of speech-in-noise testing for all patients, even those whose pure-tone hearing falls within the traditional normal range.

Factor Analysis on Multiple Auditory Processing Assessment–2 and Listening in Spatialized Noise–Sentences Test in Children

Introduction There is need for greater understanding of tests used in assessing all aspects of auditory processing disorder (APD). This is important so that specific deficits can be identified and later remediated with the smallest possible test battery. The American Speech-Language-Hearing Association (ASHA) recommends five areas/domains for behavioral assessment: (a) temporal, (b) binaural (dichotic) separation/integration, (c) monaural low redundancy, (d) binaural interaction/localization/lateralization, and (e) auditory discrimination. Multiple-factor studies support the first three domains, which are most often used for APD assessment and which can be measured in a test battery normed within the United States (Multiple Auditory Processing Assessment-2 [MAPA-2]). This study was designed to determine if factored results from children would clarify whether a behavioral test (Listening in Spatialized Noise-Sentences Test [LiSN-S]) would factor within one of the first three domains or be separate, possibly within the fourth domain, binaural interaction. Method Fifty-one 8- and 9-year-olds with normal development and normal otoscopy and hearing responses bilaterally from 500 to 4000 Hz at 20 dB HL were recruited. Two sets of APD tests were administered: MAPA-2 and LiSN-S. Results Results verified the expected three-factor structure for MAPA-2. LiSN-S did not factor within one of those three, suggesting that some processes involved in the LiSN-S tasks require interactions between the two ears different from those involved in dichotic perception and thus better belong in the ASHA binaural interaction/lateralization domain. Conclusions Auditory processing abilities are sufficiently independent of each other that test batteries spanning the first three ASHA domains are not sensitive to at least some abilities in the fourth domain. This additional factor evidence is helpful. Future research should examine the utility of measuring additional factors within APD in order to achieve the most efficient and comprehensive test battery.

Auditory Phenotypic Variability in Friedreich\u2019s Ataxia Patients

Auditory neural impairment is a key clinical feature of Friedreich’s Ataxia (FRDA). We aimed to characterize the phenotypical spectrum of the auditory impairment in FRDA in order to facilitate early identification and timely management of auditory impairment in FRDA patients and to explore the relationship between the severity of auditory impairment with genetic variables (the expansion size of GAA trinucleotide repeats, GAA1 and GAA2), when controlled for variables such as disease duration, severity of the disease and cognitive status. Twenty-seven patients with genetically confirmed FRDA underwent baseline audiological assessment (pure-tone audiometry, otoacoustic emissions, auditory brainstem response). Twenty of these patients had additional psychophysical auditory processing evaluation including an auditory temporal processing test (gaps in noise test) and a binaural speech perception test that assesses spatial processing (Listening in Spatialized Noise-Sentences Test). Auditory spatial and auditory temporal processing ability were significantly associated with the repeat length of GAA1. Patients with GAA1 greater than 500 repeats had more severe auditory temporal and spatial processing deficits, leading to poorer speech perception. Furthermore, the spatial processing ability was strongly correlated with the Montreal Cognitive Assessment (MoCA) score. To our knowledge, this is the first study to demonstrate an association between genotype and auditory spatial processing phenotype in patients with FRDA. Auditory temporal processing, neural sound conduction, spatial processing and speech perception were more severely affected in patients with GAA1 greater than 500 repeats. The results of our study may indicate that auditory deprivation plays a role in the development of mild cognitive impairment in FRDA patients.

Binaural processing and phonological awareness in Australian Indigenous children from the Northern Territory: A community based study

ObjectiveResearch has found that otitis media (OM) is highly prevalent in Australian Indigenous children, and repeated bouts of OM is often associated with minimal-to-moderate hearing loss. However, what is not yet clear is the extent to which OM with hearing loss impacts auditory signal processing specifically, but also binaural listening, listening in noise, and the potential impact on phonological awareness (PA) – an important, emergent literacy skill. The goal of this study was to determine whether auditory abilities, especially binaural processing, were associated with PA in children from populations with a high incidence of OM, living in a remote Australian Indigenous community in the Northern Territory (NT). MethodsForty-seven 5-12-year-olds from a bilingual school participated in the study. All were tested to determine hearing sensitivity (pure tone audiometry and tympanometry), with PA measured on a test specifically developed in the first language of the children. OM often results in a hearing loss that can affect binaural processing: the Dichotic Digit difference Test (DDdT) was used to evaluate the children's dichotic listening and the Listening in Spatialized Noise-sentences test (LiSN-S) was used to evaluate their abilities to listen to speech-in-noise. ResultsSeventeen (36%) and 16 (34%) had compromised middle ear compliance (combined Type-B and –C) in the right and left ear respectively. Six children demonstrated a bilateral mild hearing loss, and another five children demonstrated a unilateral mild hearing loss. Thirty-one children were able to complete the DDdT listening task, whereas only 24 completed the speech in noise task (LiSN-S). Forty-four children (94%) were able to complete the letter identification subtask, comprising part of the PA task. The findings revealed that age was significantly correlated with all tasks such that the older children performed better across the board. Once hearing thresholds were controlled for, PA also correlated significantly with both binaural processing tasks of dichotic listening (r = 0.59, p < 0.001) and listening to speech in noise (r = −0.56, p = 0.005); indicating a potential association between early, emergent literacy and listening skills. ConclusionsThe significant correlations between phonological awareness and dichotic listening as well as phonological awareness with listening to speech-in-noise skills suggests auditory processing, rather than hearing thresholds per se, are associated to phonological awareness abilities of this cohort of children. This suggests that the ability to process the auditory signal is critical.

Working Memory and Extended High-Frequency Hearing in Adults: Diagnostic Predictors of Speech-in-Noise Perception.

The purpose of this study was to identify the main factors that differentiate listeners with clinically normal or "near-normal" hearing with regard to their speech-in-noise perception and to develop a regression model to predict speech-in-noise difficulties in this population. We also aimed to assess the potential effectiveness of the formula produced by the regression model as a "diagnostic criterion" for clinical use. Data from a large-scale behavioral study investigating the relationship between noise exposure and auditory processing in 122 adults (30 to 57 years) was re-examined. For each participant, a composite speech-in-noise score (CSS) was calculated based on scores from three speech-in-noise measures, (a) the Speech, Spatial and Qualities of Hearing scale (average of speech items); (b) the Listening in Spatialized Noise Sentences test (high-cue condition); and (c) the National Acoustic Laboratories Dynamic Conversations Test. Two subgroups were created based on the CSS, each comprising 30 participants: those with the lowest scores and those with the highest scores. These two groups were compared for differences in hearing thresholds, temporal perception, noise exposure, attention, and working memory. They differed significantly on age, low-, high-, and extended high-frequency (EHF) hearing level, sensitivity to temporal fine structure and amplitude modulation, linguistic closure skills, attention, and working memory. A multiple linear regression model was fit with these nine variables as predictors to determine their relative effect on the CSS. The two significant predictors, EHF hearing and working memory, from this regression were then used to fit a second smaller regression model. The resulting regression formula was assessed for its usefulness as a "diagnostic criterion" for predicting speech-in-noise difficulties using Monte Carlo cross-validation (root mean square error and area under the receiver operating characteristics curve methods) in the complete data set. EHF hearing thresholds (p = 0.01) and working memory scores (p < 0.001) were significant predictors of the CSS and the regression model accounted for 41% of the total variance [R = 0.41, F(9,112) = 7.57, p < 0.001]. The overall accuracy of the diagnostic criterion for predicting the CSS and for identifying "low" CSS performance, using these two factors, was reasonable (area under the receiver operating characteristics curve = 0.76; root mean square error = 0.60). These findings suggest that both peripheral (auditory) and central (cognitive) factors contribute to the speech-in-noise difficulties reported by normal hearing adults in their mid-adult years. The demonstrated utility of the diagnostic criterion proposed here suggests that audiologists should include assessment of EHF hearing and working memory as part of routine clinical practice with this population. The "diagnostic criterion" we developed based on these two factors could form the basis of future clinical tests and rehabilitation tools and be used in evidence-based counseling for normal hearers who present with unexplained communication difficulties in noise.

The Effect of Increased Cognitive Demand on Auditory Processing Assessment.

Auditory processing (AP) is commonly regarded as the perceptual processing of auditory information in the central nervous system. However, the degree to which higher level cognitive processes are involved in AP or its disorders is contentious. Furthermore, there is little evidence regarding the effects of nonauditory cognitive processes on the various tests of AP in common clinical usage and thus on clinical diagnoses of auditory processing disorder. To determine the effects of increased cognitive demand, generated by using a dual-task paradigm, on performance on different AP tests and types of AP tests in common clinical usage. In addition, to investigate the relationship between executive function and changes in AP test performance associated with increased cognitive demand. Counterbalanced repeated measures design, with assessment of AP test performance both on its own and in a dual-task paradigm designed to increase cognitive demand. Twenty-nine young adults, with no reported hearing, learning, language or attention difficulties, English as first language, and hearing and middle-ear status within normal limits. Testing was completed within a single 90-min session. A selection of standard AP tests, representing both adaptive and nonadaptive tests, as well as tests employing difference scores, was administered. These were Competing Sentences Test, Dichotic Digits Test, Frequency Pattern Test (nonadaptive tests); and Listening in Spatialized Noise-Sentences test, conditions "same-voice, 0°", "different-voice, 0°", and "same-voice, 90°" (adaptive tests), from which the difference scores "talker advantage" and "spatial advantage" were also derived. Each AP test was completed on its own (alone condition), and simultaneously with a visually presented task (dual-task condition). Executive function was assessed using the phonemic subtest of the Verbal Fluency Test. Nonparametric statistical test procedures were used. All five AP measures obtained from the nonadaptive tests showed a significant performance decrement in the dual-task condition compared with the alone condition, with one exception because of a strong ceiling effect. By contrast, none of the three AP measures obtained from the adaptive tests showed a significant performance decrement in the dual-task condition. Furthermore, neither of the two AP measures based on difference scores showed a significant performance decrement, but this finding simply reflects the lack of significant decrements in the relevant raw scores. Consistent with past reports of associations between executive function and AP performance, a significant positive correlation was found between executive function scores and performance on the Dichotic Digits Test. However, there were no significant correlations between executive function scores and changes in AP test scores between alone and dual-task conditions. Performance on commonly used nonadaptive tests of AP was significantly compromised by the increased cognitive demand resulting from the dual-task paradigm. By contrast, performance on AP measures obtained by adaptive test procedures was not significantly affected. Further investigation of the resilience to increased cognitive demand of the adaptive tests used here, and other adaptive tests of AP, is warranted. Results from this study support the further development of computerized adaptive tests of AP for use in clinical test batteries.

Binaural processing in adults with a history of traumatic brain injury

An auditory processing deficit is a perceptual issue affecting how the central auditory nervous system understands and makes use of auditory information. Auditory processing deficits are typically associated with the pediatric population; however, anecdotal clinical evidence and the recent focus on central auditory effects of traumatic brain injury (TBI) suggests that auditory processing deficits may be prevalent among adults with a history of TBI. Individuals with symptoms of an auditory processing deficit often score within the normal range on standard clinical assessments. The objectiveof the current study, therefore, was to target measures of binaural processing to identify and characterize auditory processing deficits among adults with a history of TBI. Two groups were recruited: adults with a history of TBI and a control group. Binaural processing was measured with: 1) the Revised Speech Perception in Noise test measured in soundfield; 2) dichotic word recognition without and with low-pass filtering measured in the free recall and directed recall conditions; 3) the 500-Hz masking level difference; and 4) the Listening in Spatialized Noise Sentences Test. Results suggest that individuals with a history of TBI have lower than normal binaural performance.

Assessing Auditory Processing Abilities in Typically Developing School-Aged Children.

Large discrepancies exist in the literature regarding definition, diagnostic criteria, and appropriate assessment for auditory processing disorder (APD). Therefore, a battery of tests with normative data is needed. The purpose of this study is to collect normative data on a variety of tests for APD on children aged 7-12 yr, and to examine effects of outside factors on test performance. Children aged 7-12 yr with normal hearing, speech and language abilities, cognition, and attention were recruited for participation in this normative data collection. One hundred and forty-seven children were recruited using flyers and word of mouth. Of the participants recruited, 137 children qualified for the study. Participants attended schools located in areas that varied in terms of socioeconomic status, and resided in six different states. Audiological testing included a hearing screening (15 dB HL from 250 to 8000 Hz), word recognition testing, tympanometry, ipsilateral and contralateral reflexes, and transient-evoked otoacoustic emissions. The language, nonverbal IQ, phonological processing, and attention skills of each participant were screened using the Clinical Evaluation of Language Fundamentals-4 Screener, Test of Nonverbal Intelligence, Comprehensive Test of Phonological Processing, and Integrated Visual and Auditory-Continuous Performance Test, respectively. The behavioral APD battery included the following tests: Dichotic Digits Test, Frequency Pattern Test, Duration Pattern Test, Random Gap Detection Test, Compressed and Reverberated Words Test, Auditory Figure Ground (signal-to-noise ratio of +8 and +0), and Listening in Spatialized Noise-Sentences Test. Mean scores and standard deviations of each test were calculated, and analysis of variance tests were used to determine effects of factors such as gender, handedness, and birth history on each test. Normative data tables for the test battery were created for the following age groups: 7- and 8-yr-olds (n = 49), 9- and 10-yr-olds (n = 40), and 11- and 12-yr-olds (n = 48). No significant effects were seen for gender or handedness on any of the measures. The data collected in this study are appropriate for use in clinical diagnosis of APD. Use of a low-linguistically loaded core battery with the addition of more language-based tests, when language abilities are known, can provide a well-rounded picture of a child's auditory processing abilities. Screening for language, phonological processing, attention, and cognitive level can provide more information regarding a diagnosis of APD, determine appropriateness of the test battery for the individual child, and may assist with making recommendations or referrals. It is important to use a multidisciplinary approach in the diagnosis and treatment of APD due to the high likelihood of comorbidity with other language, learning, or attention deficits. Although children with other diagnoses may be tested for APD, it is important to establish previously made diagnoses before testing to aid in appropriate test selection and recommendations.

The Impact of Auditory Processing and Cognitive Abilities in Children.

To examine the links between auditory processing (AP) test results, functional deficits, and cognitive abilities. One hundred and fifty-five children, ages 7-12 years, comprising 50 control children and 105 children referred for AP assessment, all with normal peripheral hearing, completed an AP and cognitive (sustained attention, auditory working memory, and nonverbal intelligence) test battery. Functional outcome measures of listening ability (developed using questionnaires from parent, teacher, and child respondents) and reading fluency were also collected. AP scores for dichotic digits, frequency pattern, and listening in spatialized noise-sentences test baseline scores showed significant intertask correlations, and significant correlations with functional outcomes. The gaps in noise task showed correlation with reading fluency only. The AP tasks of masking level differences and spatial advantage showed no correlation with listening ability or reading fluency. Results showed significantly poorer cognitive abilities overall in the children referred for AP assessment compared with the control group. Within the referred group, children diagnosed with an auditory processing disorder had significantly poorer cognitive abilities than those passing the test battery. Correlation and regression studies showed significant associations between AP and cognitive scores. The results of multilinear regression analyses showed that the associations of AP scores with listening and academic results were no longer significant when cognitive scores were also included as predictors. A complex interaction of cognitive abilities and AP scores is evident. For many children with listening difficulties, who perform poorly on AP tasks, cognitive deficits are also in place. Although the direction of causality is unclear, it is likely that these cognitive deficits are causing the perceived difficulty and/or are having a significant effect on the test results. Interpretation of AP tests requires consideration of how cognitive abilities may have impacted on not only task results but also the functional difficulties experienced by the child.

Remediation of spatial processing deficits in hearing-impaired children and adults.

The ability to use interaural cues to segregate target speech from competing signals allows people with normal hearing to understand speech at significantly poorer signal-to-noise ratios. This ability, referred to as spatial processing ability or spatial release from masking, has been shown to be deficient in people with a sensorineural hearing loss even after amplification is applied. Spatial processing deficits in a population of children with auditory processing deficits have been found to be remediable through the use of a deficit-specific auditory training program called the LiSN & Learn. The aim of the present study was to determine whether LiSN & Learn auditory training could improve the spatial processing ability of hearing-impaired adults and children. In addition, the research investigated whether the age of the participant would affect the efficacy of the training program. In a repeated-measures design, participants' spatial processing ability was assessed pretraining and posttraining using the Listening in Spatialized Noise-Sentences Test (LiSN-S). Questionnaire responses were also collected from participants pretraining and posttraining to provide a subjective measure of real-life listening difficulty. Between the two assessment periods, participants were asked to train with the LiSN & Learn for 15 min per day, 5 days per week for 60 training sessions. Participants were five children (aged 6-11 yr) and five adults (aged 60-74 yr) with up to a moderate sensorineural hearing loss. The LiSN & Learn auditory training software incorporates five computer games in which target sentences, processed with head-related transfer functions, are perceived as coming from 0° azimuth, and simultaneous distracting speech streams are perceived as coming from ±90° azimuth. Participants are tasked with identifying a word from the target sentence and selecting the corresponding picture from a selection of four images displayed on the screen. The signal-to-noise ratio is adapted based on whether the response given is correct or incorrect. Despite an average improvement of 10 dB on the LiSN & Learn training program, no significant improvements were seen posttraining in either of the spatially separated conditions of the LiSN-S (p ranging 0.47-0.75). A 1.2 dB improvement was found in the baseline condition of the LiSN-S, which incorporates no spatial separation between distracter and target stimuli (p < 0.01). Age did not significantly affect training outcomes (p = 0.21). No significant improvements were found posttraining on the self-report questionnaires (p = 0.84 and p = 0.20). This study has demonstrated that LiSN & Learn training does not significantly improve spatial processing deficits in adults or children with a sensorineural hearing loss. As auditory training did not prove to be effective, further research should be directed toward the development of hearing aid processing schemes that will compensate for the degraded interaural time difference and interaural level difference cues which underpin spatial processing.

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.

Release from masking through spatial separation in distance in hearing impaired listeners

It is widely accepted that speech intelligibility improves as a speech signal and interfering masker are separated spatially in azimuth. In a previous study [Westermann et al. IHCON (2012)] a similarly strong improvement was found for normal hearing (NH) listeners when target and masker are separated in distance. In this study speech reception thresholds (SRTs) were measured for 16 hearing impaired (HI) listeners using the Listening in Spatialized Noise-Sentences Test (LiSN-S) and the Coordinate Response Measure (CRM). Acoustic scenarios were auralized via headphones using binaural room impulse responses recorded in an auditorium. In the first scenario, the target was presented at a distance of 0.5 m from the center of the listener’s head and the interferer at a distance of 0.5 m or 10 m. In a second setup, the interferer’s location was fixed and the target’s location was varied. HI listeners showed a substantial release from masking as target and interferer were separated in distance. This effect was consistent for both LiSN-S and CRM, but less pronounced than for NH listeners. This study suggests that distance related cues play a significant role when listening in complex environments and are also to some extent available to HI listeners.

The Effects of Hearing Impairment and Aging on Spatial Processing

Difficulty in understanding speech in background noise is frequently reported by hearing-impaired people despite well-fitted amplification. Understanding speech in the presence of background noise involves segregating the various auditory stimuli into distinct streams using cues such as pitch characteristics, spatial location of speakers, and contextual information. One possible cause of listening difficulties in noise is reduced spatial-processing ability. Previous attempts to investigate spatial processing in hearing-impaired people have often been confounded by inadequate stimulus audibility. The present research aimed to investigate the effects of hearing impairment and aging on spatial-processing ability. The effect of cognitive ability on spatial processing was also explored. In addition, the relationship between spatial-processing ability and self-report measures of listening difficulty was examined to investigate how much effect spatial-processing ability has in real-world situations. Eighty participants aged between 7 and 89 years took part in the study. Participants' hearing thresholds ranged from within normal limits to a moderately severe sensorineural hearing loss. All participants had English as their first language and no reported learning disabilities. The study sample included both hearing aid users and non-hearing aid users. Spatial-processing ability was assessed with a modified version of the Listening in Spatialized Noise-Sentences test (LiSN-S). The LiSN-S was modified to incorporate a prescribed gain amplifier that amplified the target and distracting stimulus according to the National Acoustic Laboratories-Revised Profound (NAL-RP) prescription. In addition, participants aged 18 years and above completed the Neurobehavioral Cognitive Status examination and the Speech, Spatial and Qualities questionnaire. Participants aged under 18 years completed the Listening Inventory for Education questionnaire. Spatial-processing ability, as measured by the spatial advantage measure of the LiSN-S, was negatively affected by hearing impairment. Aging was not significantly correlated with spatial-processing ability. No significant relationship was found between cognitive ability and spatial processing. Self-reported listening difficulty in children, as measured with the Listening Inventory for Education, and spatial-processing ability were not correlated. Self-reported listening difficulty in adults, as measured by the Speech, Spatial and Qualities questionnaire, was significantly correlated with spatial-processing ability. All hearing-impaired people will have a spatial processing deficit of some degree. This should be given due consideration when counseling patients in regard to realistic expectations of how they will perform in background noise. Further research is required into potential remediation for spatial-processing deficits and the cause of these deficits.

An Opinion on the Assessment of People Who May Have an Auditory Processing Disorder

We need to rethink how we assess auditory processing disorder (APD). The current use of test batteries, while necessary and well accepted, is at risk of failing as the size of these batteries increases. To counter the statistical, fatigue, and clinical efficiency problems of large test batteries, we propose a hierarchical approach to APD assessment. This begins with an overall test of listening difficulty in which performance is measurably affected for anyone with an impaired ability to understand speech in difficult listening conditions. It proceeds with a master test battery containing a small number of single tests, each of which assesses a different group of skills necessary for understanding speech in difficult listening conditions. It ends with a detailed test battery, where the individual tests administered from this battery are only those that differentiate the skills assessed by the failed test(s) from the master test battery, so that the specific form of APD can be diagnosed. An example of how hierarchical interpretation of test results could be performed is illustrated using the Listening in Spatialized Noise-Sentences test (LiSN-S). Although consideration of what abilities fall within the realm of auditory processing should remain an important issue for research, we argue that patients will be best served by focusing on whether they have difficulty understanding speech, identifying the specific characteristics of this difficulty, and specifically remediating and/or managing those characteristics.

Listening in Spatialized Noise—Sentences Test (LiSN-S): Normative and Retest Reliability Data for Adolescents and Adults up to 60 Years of Age

The Australian version of the Listening in Spatialized Noise-Sentences Test (LiSN-S) was originally developed to assess auditory stream segregation skills in children aged 6 to 11 yr with suspected central auditory processing disorder. The LiSN-S creates a three-dimensional auditory environment under headphones. A simple repetition-response protocol is used to assess a listener's speech reception threshold (SRT) for target sentences presented in competing speech maskers. Performance is measured as the improvement in SRT in decibels gained when either pitch, spatial, or both pitch and spatial cues are incorporated in the maskers. To collect additional normative data on the Australian LiSN-S for adolescents and adults up to 60 yr of age, to analyze the effects of age on LiSN-S performance, to examine retest reliability in the older population, and to extrapolate findings from the Australian data so that the North American version of the test can also be used clinically with older adults. In a descriptive design, normative and test-retest reliability data were collected from adolescents and adults and combined with previously published data from Australian children aged 6 to 11 yr. One hundred thirty-two participants with normal hearing aged 12 yr, 0 mo, to 60 yr, 7 mo, took part in the normative data study. Fifty-five participants returned between 2 and 4 mo after the initial assessment for retesting. Analysis of variance revealed a significant effect of age on LiSN-S performance (p < .01 for all LiSN-S measures, ηp2 ranging from 0.16 to 0.54). On the low and high cue SRT measures, planned contrasts revealed significant differences between adults and children aged 13 yr and younger, as well as between 50- to 60-yr-olds and younger adults aged 18-29 yr. Whereas there were significant differences between adults and children on the talker, spatial, and total advantage measures, there were no significant differences in performance in adults aged 18-60 yr. There was a small but significant improvement on retest ranging from 0.5 to 1.2 dB across the four LiSN-S test conditions (p ranging from .01 to <.001). However, there was no significant difference between test and retest on the advantage measures (p ranging from .143 to .768). Test-retest differences across all LiSN-S measures were significantly correlated (r ranging from 0.2 to 0.7, p ranging from .023 to <.00000001) and did not differ as a function of age (p ranging from .178 to .980). As there was no significant difference among adults aged 18-60 yr on the LiSN-S talker, spatial, and total advantage measures, it appears that the decline in ability to understand speech in noise experienced by 50- to 60-yr-olds is not related to their ability to use either spatial or pitch cues. This result suggests that some other factor/s contributes to the decline in speech perception in noise experienced by older adults that is reported in the literature and was demonstrated in this study on the LiSN-S low and high cue SRT measures.