Effects of age and gender on dichotic sentence identification

Subjective tinnitus patients with normal pure-tone hearing still suffer more informational masking in the noisy environment

Subjective tinnitus patients experience more hearing difficulties than normal peers in complex hearing environments, even though most of these patients have normal pure-tone hearing thresholds. Using speech recognition tasks under different masking conditions can provide insight into whether the effects of tinnitus are lateralized and the mechanisms behind the effects. By simulating sound field recordings, we obtain a target speech sentence that can be perceived as presented on one side and noise or speech masking with or without spatial separation from it. Our study used the virtual sound field technique to investigate the difference in speech recognition ability between chronic subjective tinnitus patients and a normal-hearing control group under the four masking conditions (speech-spectrum noise masking or two-talker speech masking, with or without perceived spatial separation). Experiment 1 showed no differences for target speech perceived location (left or right), which rules out a lateralization of the effect of tinnitus patients. Experiment 2 further found that although tinnitus patients had weaker performance than normal people in very complex auditory scenarios, when the spatial cue of the target speech exists, they can make good use of this cue to make up for the original processing disadvantage and achieve a similar performance as the normal-hearing group. In addition, the current study distinguished the effects of informational masking and energetic masking on speech recognition in patients with tinnitus and normal hearing. The results suggest that the impact of tinnitus on speech recognition in patients is more likely to occur in the auditory center rather than the periphery.

Insights from auditory cortex for GABA+ magnetic resonance spectroscopy studies of aging

Changes in levels of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) may underlie aging-related changes in brain function. GABA and co-edited macromolecules (GABA+) can be measured with MEGA-PRESS magnetic resonance spectroscopy (MRS). The current study investigated how changes in the aging brain impact the interpretation of GABA+ measures in bilateral auditory cortices of healthy young and older adults. Structural changes during aging appeared as decreasing proportion of grey matter in the MRS volume of interest and corresponding increase in cerebrospinal fluid. GABA+ referenced to H₂ O without tissue correction declined in aging. This decline persisted after correcting for tissue differences in MR-visible H₂ O and relaxation times but vanished after considering the different abundance of GABA+ in grey and white matter. However, GABA+ referenced to creatine and N-acetyl aspartate (NAA), which showed no dependence on tissue composition, decreased in aging. All GABA+ measures showed hemispheric asymmetry in young but not older adults. The study also considered aging-related effects on tissue segmentation and the impact of co-edited macromolecules. Tissue segmentation differed significantly between commonly used algorithms, but aging-related effects on tissue-corrected GABA+ were consistent across methods. Auditory cortex macromolecule concentration did not change with age, indicating that a decline in GABA caused the decrease in the compound GABA+ measure. Most likely, the macromolecule contribution to GABA+ leads to underestimating an aging-related decrease in GABA. Overall, considering multiple GABA+ measures using different reference signals strengthened the support for an aging-related decline in auditory cortex GABA levels.

Choir Singing Practice and Temporal Ordering in the Elderly

Introduction  The importance of temporal ordering and sequencing in the auditory system is discussed because these are considered basic functions for language. Objective  To verify the correlation between the practice of choir music and the temporal ordering in elderly with no prior formal musical experience. Method  The study design is cross-sectional. The sample consisted of 85 elderly individuals of both genders, ≥ 60 years old, and it was composed of 43 elderly individuals with no prior formal musical experience but choir participation (research group) and 42 elderly individuals who never sang in a choir and had no music training during their life (control group). The research group was divided based on three categories of choir time. The performances of the research and control groups were compared with pitch pattern sequence (PPS), verbal condition (PPSverb), humming condition (PPShum), and duration pattern sequence (DPS) tests. Results  The mean PPShum and PPSverb showed a statistically significant difference by choir time with a different mean of PPShum between the no singing experience group (59%) and the > 10 years of singing experience group (90%) ( p  = 0.02). Regarding the averages of PPSverb, there was a statistically significant difference between the no singing experience (23%) and > 10 years of choir time (54%) ( p  = 0.02) groups. Conclusion  The findings indicate a better performance in the temporal ordering of the elderly who are not formal musicians but who have choir experience in the research group in relation to those with no choir experience in the control group.

Speech Perception and Dichotic Listening Are Associated With Hearing Thresholds and Cognition, Respectively, in Unaided Presbycusis

Presbycusis or age-related hearing loss is a prevalent condition in the elderly population, which affects oral communication, especially in background noise, and has been associated with social isolation, depression, and cognitive decline. However, the mechanisms that relate hearing loss with cognition are complex and still elusive. Importantly, recent studies show that the use of hearing aids in presbycusis, which is its standard management, can induce neuroplasticity and modify performance in cognitive tests. As the majority of the previous studies on audition and cognition obtained their results from a mixed sample of subjects, including presbycusis individuals fitted and not fitted with hearing aids, here, we revisited the associations between hearing loss and cognition in a controlled sample of unaided presbycusis. We performed a cross-sectional study in 116 non-demented Chilean volunteers aged ≥65 years from the Auditory and Dementia study cohort. Specifically, we explored associations between bilateral sensorineural hearing loss, suprathreshold auditory brain stem responses, auditory processing (AP), and cognition with a comprehensive neuropsychological examination. The AP assessment included speech perception in noise (SIN), dichotic listening (dichotic digits and staggered spondaic words), and temporal processing [frequency pattern (FP) and gap-in-noise detection]. The neuropsychological evaluations included attention, memory, language, processing speed, executive function, and visuospatial abilities. We performed an exploratory factor analysis that yielded four composite factors, namely, hearing loss, auditory nerve, midbrain, and cognition. These four factors were used for generalized multiple linear regression models. We found significant models showing that hearing loss is associated with bilateral SIN performance, while dichotic listening was associated with cognition. We concluded that the comprehension of the auditory message in unaided presbycusis is a complex process that relies on audition and cognition. In unaided presbycusis with mild hearing loss (<40 dB HL), speech perception of monosyllabic words in background noise is associated with hearing levels, while cognition is associated with dichotic listening and FP.

Speech Perception in Older Adults: An Interplay of Hearing, Cognition, and Learning?

Older adults with age-related hearing loss exhibit substantial individual differences in speech perception in adverse listening conditions. We propose that the ability to rapidly adapt to changes in the auditory environment (i.e., perceptual learning) is among the processes contributing to these individual differences, in addition to the cognitive and sensory processes that were explored in the past. Seventy older adults with age-related hearing loss participated in this study. We assessed the relative contribution of hearing acuity, cognitive factors (working memory, vocabulary, and selective attention), rapid perceptual learning of time-compressed speech, and hearing aid use to the perception of speech presented at a natural fast rate (fast speech), speech embedded in babble noise (speech in noise), and competing speech (dichotic listening). Speech perception was modeled as a function of the other variables. For fast speech, age [odds ratio (OR) = 0.79], hearing acuity (OR = 0.62), pre-learning (baseline) perception of time-compressed speech (OR = 1.47), and rapid perceptual learning (OR = 1.36) were all significant predictors. For speech in noise, only hearing and pre-learning perception of time-compressed speech were significant predictors (OR = 0.51 and OR = 1.53, respectively). Consistent with previous findings, the severity of hearing loss and auditory processing (as captured by pre-learning perception of time-compressed speech) was strong contributors to individual differences in fast speech and speech in noise perception. Furthermore, older adults with good rapid perceptual learning can use this capacity to partially offset the effects of age and hearing loss on the perception of speech presented at fast conversational rates. Our results highlight the potential contribution of dynamic processes to speech perception.

Assessing a Sensory-Motor-Cognition Triad in Amnestic Mild Cognitive Impairment With Dichotic Listening While Walking: A Dual-Task Paradigm

A contemporary topic in aging research relates to the significance of cognitive changes proper to mild cognitive impairment (MCI) to higher risk of falls and gait deteriorations. The present study addresses this question in the amnestic type of MCI (aMCI) by examining a triad of interrelated comorbidities occurring in the MCI condition: attentional impairments, hearing loss and gait disturbances. To this end, we applied a dichotic listening (DL) test during over-ground walking. DL assesses spontaneous and lateralized auditory attention in three conditions (i.e., free report or Non-forced (NF), Forced-Right (FR) ear and Forced-Left (FL) ear). Earlier reports suggest that this dual-task paradigm evoke asymmetric gait effects on healthy controls, which are moderated by degree of hearing loss. Therefore, the aim of the present study was to evaluate the effects of DL on bilateral (data from both limbs) and lateralized (each limb separately) gait outcomes in a group of forty-three aMCI participants (mean = 71.19) and fifty-two healthy older controls (mean = 70.90) by using hearing loss as a covariate in all analyses. Results showed the aMCI group presented overall compromised gait parameters, especially higher gait variability in all DL conditions during lateralized attentional control. These findings were observed bilaterally, and no lateralized effects on gait were observed. Only after controlling for hearing acuity, gait asymmetries on step length variability emerged almost exclusively in healthy controls. It was concluded that hearing loss in the aMCI group together with higher attentional impairments preclude aMCI individuals to properly execute DL and therefore, they do not display gait asymmetries. The present data demonstrate that varied demands on attentional control dependent on hearing acuity affects gait negatively in healthy older adults and aMCI individuals in very different ways. The appearance of asymmetric effects seems to be a perturbation related to normal aging, while the lack of asymmetries but exaggerated gait variability characterizes aMCI. The present findings show the intricate interplay of sensory, cognitive, and motor deteriorations in different group of older adults, which stresses the need of addressing co-occurring comorbidities behind gait perturbations in individuals prone to develop a dementia state.

Relation Between the Screening Checklist for Auditory Processing in Adults and Diagnostic Auditory Processing Test Performance

Purpose The aim of the study was to evaluate the relationship between the Screening Checklist for Auditory Processing in Adults and the performance of older adults on a battery of diagnostic tests for auditory processing. This was done for two versions of the checklist, one answered by older individuals at risk for auditory processing disorder (APD) and the other by the family of the older adults. Method Forty-nine older adults and 34 of their family members were initially tested with the screening checklist, each being tested with the version developed for them. Approximately half of the older adults had normal pure-tone thresholds, while the others had mild-moderate hearing loss above 2 kHz. The older adults were administered tests of auditory separation/closure, auditory integration, temporal resolution, temporal patterning, and auditory memory and sequencing. Results Most of the older adults and their family members reported of the presence of auditory processing difficulties on the screening checklist. On the diagnostic test battery, many of the older adults, irrespective of their high-frequency hearing sensitivity, failed the tests measuring temporal resolution and auditory integration. The sensitivity and specificity of the checklist answered by the older individuals were 69.05% and 71.43%, respectively. On the other hand, for the checklist answered by the family members, it was 77.78% and 33.33%, respectively. The test-retest reliability of the two versions of the checklist was found to be good. Conclusions As the specificity of the checklist answered by the family members was considerably lower than that answered by the older adults, the use of the version for the latter group is recommended. However, the checklist answered by the caregivers could be used to complement information obtained from the older adults at risk for APD when the older adults are unable to give valid responses.

Association Between the Right Ear Advantage in Dichotic Listening and Interaural Differences in Sensory Processing at Lower Levels of the Auditory System in Older Adults

OBJECTIVE

Current evidence suggests that an enhanced right ear advantage (REA) in dichotic listening (DL) among older adults may originate from age-related structural changes in the corpus callosum and age-related decline in cognitive processes. Less is known about the effect of information processing at lower portions of the auditory system on DL performance. The present study investigates whether interaural differences (ID) in sensory processing at lower levels of the auditory system are associated with the magnitude of the REA in DL among older adults.

DESIGN

Sixty-eight older adults participated in the study. Participants were assessed with a DL test using nonforced (NF) and forced attention paradigms. Hearing sensitivity, transient-evoked otoacoustic emission (TEOAE), contralateral suppression of TEOAE, a proxy measure of medial olivocochlear activation, and auditory brainstem response to speech stimuli (speech-ABR) were tested in both ears separately. The ID in sensory processing at lower levels of the auditory system was derived by calculating the difference between the RE and LE for each auditory measure. Bivariate and multivariate regression models were performed. One multivariate model for each DL paradigm (NF and forced attention) was independently constructed. Measures of cognitive speed of processing and cognitive flexibility were accounted for in the regression models.

RESULTS

For both multivariate regression models, ID in pure-tone thresholds and ID in MOC suppression of TEOAE were significantly associated with the magnitude of the REA for DL among older adults. Cognitive measures of speed of processing and cognitive flexibility also contributed to the magnitude of the REA.

CONCLUSION

These results suggest that ID in sensory processing at lower levels of the auditory system account, at least in part, for the increased magnitude of the REA in DL among older adults.

Dichotic sentence identification test in Portuguese: a study in young adults

Introduction

Among the currently-applied auditory processing tests, dichotic listening tests have been widely used, since they allow investigating the hemispheric and inter-hemispheric function and their respective skills to process the received auditory information.

Objective

To obtain normality reference measures with the new dichotic sentence identification test in right-handed adults with normal hearing.

Methods

Quantitative, observational, cross-sectional study. 72 subjects were assessed, aged 19–44 years, right-handed, with normal hearing, without hearing complaints. The dichotic sentence identification test consists of different lists of sentences, which were combined two by two and presented at the same time, using earphones in both ears, at 50 dB Sensation Level. The test was applied in four stages: training of the 3 stages, free attention, right and left directed attention, thus evaluating different auditory skills.

Results

In the free attention task, the average percentage of correct answers in the right ear was 93.59% and in the left ear 86.06%, with a statistically significant difference between the ears, with an advantage for the right ear. In the directed attention task, the average percentage of correct answers was 99.37% in the right ear and 98.8% in the left ear, with no statistical difference between the ears.

Conclusion

It is suggested, as a normality reference for the stage of free attention, 90%–100% for correct answers for the right ear and for the left ear, from 80% to 100%. When there is asymmetry between the ears, differences of up to 20% are expected, with an advantage for the right ear For the directed attention stage, the expected normality reference values ​​are 100% for the right ear and for the left ear, with no asymmetry between the ears; however, if it occurs, a difference of 10% is expected between the ears, with an advantage for the right ear.

Longitudinal Decline on the Dichotic Digits Test

Purpose The dichotic digits test (DDT) is commonly administered in clinical and research settings, but it is not well understood how performance changes in aging. The purpose of this study is to determine the 5-year change on the free recall task and right ear advantage (REA) in a population-based cohort and factors associated with change. Method Participants in the population-based Epidemiology of Hearing Loss Study, who completed the DDT during the fourth (2009-2010) and fifth (2013-2016) examination periods were included (n = 865, M _age = 72.8 years at baseline). Free recall DDT was administered using 25 sets of triple-digit pairs presented at 70 dB HL. The REA was calculated by subtracting the score in the left ear from the score in the right ear. Results In 5 years, most participants (62.4%) declined on free recall performance (mean decline = 3.0% [4.5 digits], p < .01). In age-sex-adjusted models, higher baseline scores, hearing impairment, and lower education were significantly associated with increased risk of decline. An REA at baseline (76.8%) and follow-up (77.9%) was common. Half of participants (50.6%) had a 5-year REA widening (M = 1.9% [1.4 digits], p = .01). Older age, but not hearing impairment, was associated with increased risk of REA widening. Conclusions The 5-year decline on free recall recognition performance was not associated with age but was associated with hearing impairment, whereas the 5-year widening of REA was associated with age but not hearing impairment. These results indicate that the REA may be a more sensitive measure of aging of the central auditory system than free recall performance.

Dichotic listening while walking: A dual-task paradigm examining gait asymmetries in healthy older and younger adults

Dual-task studies have employed various cognitive tasks to evaluate the relationship between gait and cognition. Most of these tests are not specific to a single cognitive ability or sensory modality and have limited ecological validity. In this study, we employed a dual-task paradigm using Dichotic Listening (DL) as concomitant cognitive task to walking. We argue that DL is a robust task to unravel the gait-cognition link in different healthy populations of different age groups. Thirty-six healthy older adults (Mean = 67.11) and forty younger adults (Mean = 22.75) participated in the study. DL consists of three conditions where spontaneous attention and attention directed to right or left-ear are tested while walking. We calculated dual-task costs (DTCs) and percent of baseline values for three spatio-temporal gait parameters as compared to single-walking during three DL conditions. Results showed that both groups had larger DTCs on gait during volitional control of attention, i.e., directing attention to one specific ear. Group differences were present across all DL conditions where older adults reported consistently less correct stimuli than younger participants. Similar findings were observed in the neuropsychological battery where older participants showed restricted abilities for executive functioning and processing speed. However, the main finding of this investigation was that younger adults exhibited unique adjustments in step length variability as shown by changes in DTCs and percent of baseline values. Particularly, an asymmetric effect was observed on the young group when attending right-ear stimuli. We interpreted this gait asymmetry as a compensatory outcome in the younger participants due to their optimal perceptual and motor abilities, which allow them to cope suitably with the dual-task situation. Many studies suggest that gait asymmetries are indicators of pathology, the present data demonstrate that gait asymmetries arise under specific constraints in healthy people as an adaptation to task requirements.

The Impact of Speech Recognition Testing on State Anxiety in Young, Middle-Age, and Older Adults

Purpose This study assessed state anxiety as a function of speech recognition testing using three clinical measures of speech in noise and one clinical measure of dichotic speech recognition. Method Thirty young adults, 30 middle-age adults, and 25 older adults participated. State anxiety was measured pre- and post-speech recognition testing using the State-Trait Anxiety Inventory. Speech recognition was measured with the Revised Speech Perception in Noise Test, the Quick Speech-in-Noise Test, the Words-in-Noise Test, and the Dichotic Digits Test (DDT). Results Speech recognition performance was as expected: Older adults performed significantly poorer on all measures as compared to the young adults and significantly poorer on the Revised Speech Perception in Noise Test, the Quick Speech-in-Noise Test, and the Words-in-Noise Test as compared to the middle-age adults. On average, State-Trait Anxiety Inventory scores increased posttesting, with the middle-age adults exhibiting significantly greater increases in state anxiety as compared to the young and older adults. Increases in state anxiety were significantly greater for the DDT relative to the speech-in-noise tests for the middle-age adults only. Poorer DDT recognition performance was associated with higher levels of state anxiety. Conclusions Increases in state anxiety were observed after speech-in-noise and dichotic listening testing for all groups, with significant increases seen for the young and middle-age adults. Although the exact mechanisms could not be determined, multiple factors likely influenced the observed increases in state anxiety, including task difficulty, individual proficiency, and age.

What Does Language Have to Do With It? The Impact of Age and Bilingual Experience on Inhibitory Control in an Auditory Dichotic Listening Task

Purpose The purpose of the current study was to examine inhibition of irrelevant information in younger and older English monolingual and Spanish-English bilingual adults. Method Sixty-one participants divided into four groups: 15 younger English monolinguals, 16 younger Spanish-English bilinguals, 15 older English monolinguals, and 15 older Spanish-English bilinguals participated in this study. Younger participants were 18-25 years of age, and older participants were 47-62 years of age. Bilingual participants had learned Spanish from birth and began learning English by the age of 3 years old (SD = 3.1). All participants had hearing thresholds of < 25 dB HL from 250 to 4000 Hz, bilaterally (American National Standards Institute [ANSI], 2004) and were right-handed. Inhibition was measured using a forced-attention dichotic consonant vowel listening task with a prime stimulus and the Simon task, a nonverbal visual test. Results Younger participants were better able to inhibit the irrelevant auditory and visual stimuli and modulate their attention according to the instructions that they were given compared to the older participants. However, no significant differences in inhibition performance or attention modulation were evidenced between the monolingual and bilingual groups in any of the dichotic listening conditions or on the Simon task. Conclusions No significant differences in performance on an auditory or a visual test of inhibition of irrelevant information was evidenced between the monolingual and bilingual participants in this study. These findings suggest that younger and older adult, early balanced Spanish-English bilinguals may not exhibit an advantage in the inhibition of irrelevant information compared to younger and older adult English monolinguals.

Functional Connectivity of Heschl's Gyrus Associated With Age-Related Hearing Loss: A Resting-State fMRI Study

A large proportion of older adults experience hearing loss. Yet, the impact of hearing loss on the aging brain, particularly on large-scale brain networks that support cognition and language, is relatively unknown. We used resting-state functional magnetic resonance imaging (fMRI) to identify hearing loss-related changes in the functional connectivity of primary auditory cortex to determine if these changes are distinct from age and cognitive measures known to decline with age (e.g., working memory and processing speed). We assessed the functional connectivity of Heschl's gyrus in 31 older adults (60-80 years) who expressed a range of hearing abilities from normal hearing to a moderate hearing loss. Our results revealed that both left and right Heschl's gyri were significantly connected to regions within auditory, sensorimotor, and visual cortices, as well as to regions within the cingulo-opercular network known to support attention. Participant age, working memory, and processing speed did not significantly correlate with any connectivity measures once variance due to hearing loss was removed. However, hearing loss was associated with increased connectivity between right Heschl's gyrus and the dorsal anterior cingulate in the cingulo-opercular network even once variance due to age, working memory, and processing speed was removed. This greater connectivity was not driven by high frequency hearing loss, but rather by hearing loss measured in the 0.5-2 kHz range, particularly in the left ear. We conclude that hearing loss-related differences in functional connectivity in older adults are distinct from other aging-related differences and provide insight into a possible neural mechanism of compensation for hearing loss in older adults.

Relative contributions of auditory and cognitive functions on speech recognition in quiet and in noise among older adults

Introduction

Hearing acuity, central auditory processing and cognition contribute to the speech recognition difficulty experienced by older adults. Therefore, quantifying the contribution of these factors on speech recognition problem is important in order to formulate a holistic and effective rehabilitation.

Objective

To examine the relative contributions of auditory functioning and cognition status to speech recognition in quiet and in noise.

Methods

We measured speech recognition in quiet and in composite noise using the Malay Hearing in noise test on 72 native Malay speakers (60–82 years) older adults with normal to mild hearing loss. Auditory function included pure tone audiogram, gaps-in-noise, and dichotic digit tests. Cognitive function was assessed using the Malay Montreal cognitive assessment.

Results

Linear regression analyses using backward elimination technique revealed that had the better ear four frequency average (0.5–4 kHz) (4FA), high frequency average and Malay Montreal cognitive assessment attributed to speech perception in quiet (total r² = 0.499). On the other hand, high frequency average, Malay Montreal cognitive assessment and dichotic digit tests contributed significantly to speech recognition in noise (total r² = 0.307). Whereas the better ear high frequency average primarily measured the speech recognition in quiet, the speech recognition in noise was mainly measured by cognitive function.

Conclusions

These findings highlight the fact that besides hearing sensitivity, cognition plays an important role in speech recognition ability among older adults, especially in noisy environments. Therefore, in addition to hearing aids, rehabilitation, which trains cognition, may have a role in improving speech recognition in noise ability of older adults.

The Relationship of Cardiometabolic Risk and Auditory Processing among African Americans: The Jackson Heart Study

Objectives

There is limited research in population-based studies on auditory processing. The purpose of this work is to determine the prevalence of auditory processing impairment in the Jackson Heart Study cohort and to identify potential relationships with cardiometabolic risk factors.

Study Design

Cross-sectional study.

Setting

Jackson Heart Study in Jackson, Mississippi.

Subjects

Participants of an all–African American cardiovascular study cohort (n = 1314).

Methods

The Quick Speech-in-Noise and Dichotic Digits, Double Pairs tests were used to assess auditory processing. Logistic regression and multinomial logistic regression models were used to examine how participants’ cardiometabolic risk factors and audiologic characteristics were associated with speech perception in noise and binaural integration.

Results

Quick Speech-in-Noise and Dichotic Digits, Double Pairs testing showed a prevalence of auditory processing impairment in 69% and 71% of the cohort, respectively, which was significantly related to age, hearing thresholds, sex, and education level. With covariate adjustment in statistical models for age, sex, pure tone average, and education level, waist circumference, systolic blood pressure, and hypertension were statistically predictive of auditory processing impairment ( P < .05).

Conclusion

The results suggest a high prevalence of auditory processing deficits in the Jackson Heart Study cohort. In addition, cardiometabolic and audiologic factors show a statistically significant independent relationship with auditory impairment measures.

Deficit in Central Auditory Processing as a Biomarker of Pre-Clinical Alzheimer's Disease

Prevention of dementia due to Alzheimer's disease (d/AD) requires interventions that slow the disease process prior to symptom onset. To develop such interventions, one needs metrics that assess pre-symptomatic disease progression. Familiar measures of progression include cerebrospinal fluid (CSF) biochemical and imaging analyses, as well as cognitive testing. Changes in the latter can sometimes be difficult to distinguish from effects of "normal" aging. A different approach involves testing of "central auditory processing" (CAP), which enables comprehension of auditory stimuli amidst a distracting background (e.g., conversation in a noisy bar or restaurant). Such comprehension is often impaired in d/AD. Similarly, effortful or diminished auditory comprehension is sometimes reported by cognitively healthy elders, raising the possibility that CAP deficit may be a marker of pre-symptomatic AD. In 187 cognitively and physically healthy members of the aging, AD family history-positive PREVENT-AD cohort, we therefore evaluated whether CAP deficits were associated with known markers of AD neurodegeneration. Such markers included CSF tau concentrations and magnetic resonance imaging volumetric and cortical thickness measures in key AD-related regions. Adjusting for age, sex, education, pure-tone hearing, and APOEɛ4 status, we observed a persistent relationship between CAP scores and CSF tau levels, entorhinal and hippocampal cortex volumes, cortical thickness, and deficits in cognition (Repeatable Battery for Assessment of Neuropsychological Status total score, and several of its index scales). These cross-sectional observations suggest that CAP may serve as a novel metric for pre-symptomatic AD pathogenesis. They are therefore being followed up longitudinally with larger samples.

Right-Ear Advantage for Speech-in-Noise Recognition in Patients with Nonlateralized Tinnitus and Normal Hearing Sensitivity

Despite having normal hearing sensitivity, patients with chronic tinnitus may experience more difficulty recognizing speech in adverse listening conditions as compared to controls. However, the association between the characteristics of tinnitus (severity and loudness) and speech recognition remains unclear. In this study, the Quick Speech-in-Noise test (QuickSIN) was conducted monaurally on 14 patients with bilateral tinnitus and 14 age- and hearing-matched adults to determine the relation between tinnitus characteristics and speech understanding. Further, Tinnitus Handicap Inventory (THI), tinnitus loudness magnitude estimation, and loudness matching were obtained to better characterize the perceptual and psychological aspects of tinnitus. The patients reported low THI scores, with most participants in the slight handicap category. Significant between-group differences in speech-in-noise performance were only found at the 5-dB signal-to-noise ratio (SNR) condition. The tinnitus group performed significantly worse in the left ear than in the right ear, even though bilateral tinnitus percept and symmetrical thresholds were reported in all patients. This between-ear difference is likely influenced by a right-ear advantage for speech sounds, as factors related to testing order and fatigue were ruled out. Additionally, significant correlations found between SNR loss in the left ear and tinnitus loudness matching suggest that perceptual factors related to tinnitus had an effect on speech-in-noise performance, pointing to a possible interaction between peripheral and cognitive factors in chronic tinnitus. Further studies, that take into account both hearing and cognitive abilities of patients, are needed to better parse out the effect of tinnitus in the absence of hearing impairment.

Dichotic Digits Test Performance Across the Ages: Results From Two Large Epidemiologic Cohort Studies

OBJECTIVES

The Dichotic Digits test (DDT) has been widely used to assess central auditory processing but there is limited information on observed DDT performance in a general population. The purpose of the study was to determine factors related to DDT performance in a large cohort spanning the adult age range.

DESIGN

The study was cross-sectional and subjects were participants in the Epidemiology of Hearing Loss Study (EHLS), a population-based investigation of age-related hearing loss, or the Beaver Dam Offspring Study (BOSS), a study of aging in the adult offspring of the EHLS members. Subjects seen during the 4th EHLS (2008 to 2010) or the 2nd BOSS (2010 to 2013) examination were included (N = 3655 participants [1391 EHLS, 2264 BOSS]; mean age = 61.1 years, range = 21 to 100 years). The free and right ear-directed recall DDTs were administered using 25 sets of triple-digit pairs with a 70 dB HL presentation level. Pure-tone audiometric testing was conducted and the pure-tone threshold average (PTA) at 0.5, 1, 2, and 4 kHz was categorized using the worse ear: no loss = PTA ≤ 25 dB HL; mild loss = 25 < PTA ≤ 40 dB HL; moderate or marked loss = PTA > 40 dB HL. Cognitive impairment was defined as a Mini-Mental State Examination score < 24 (maximum = 30) or a self- or proxy-reported history of dementia or Alzheimer's disease. Demographic information was self-reported. General linear models were fit and multiple linear regression was performed.

RESULTS

The mean total free recall DDT score was 76.7% (range = 21.3 to 100%). Less than 10% of the participants had a total free recall score below 60% correct. The mean right ear-directed recall score was 98.4% with 69% of the participants scoring 100% and another 15.5% scoring 98.7% (1 incorrect digit). In multivariable modeling of the total free recall scores, the predicted mean free recall score was 1 percentage point lower for every 5-year increase in age, 2.3 percentage points lower in males than females, 8.7 percentage points lower in participants with less than a high school degree than in those with college degrees, 6.8 percentage points lower in participants with a moderate or marked hearing loss compared with no hearing loss, and 8.3 percentage points lower in participants with cognitive impairment compared with those without cognitive impairment. These 5 factors were independently and significantly related to performance and accounted for 22.7% of the total variability in free recall scores.

CONCLUSIONS

Substantial variation in the total free recall DDT scores but very little variation in the right ear-directed recall DDT scores was observed. Age, sex, education, hearing loss severity, and cognitive impairment were found to be significantly related to DDT scores but explained less than 25% of the total variability in total free recall scores. The right ear-directed recall DDT by itself may not be of benefit in assessing central auditory processing in a general population because of its limited variability but further evaluation of factors potentially related to free recall DDT variability may prove useful.

An Epidemiologic Study of the Association between Free Recall Dichotic Digits Test Performance and Vascular Health

BACKGROUND

Associations between vascular health-related factors and hearing loss defined using audiometric pure-tone thresholds have been found. Studies have not focused on a potential relationship between vascular health-related factors and central auditory processing.

PURPOSE

The aim of this study was to evaluate, on a population level, the relationship of vascular health-related factors with central auditory function.

RESEARCH DESIGN

A cross-sectional, population study.

STUDY SAMPLE

Subjects were participants in the Epidemiology of Hearing Loss Study (EHLS) or the Beaver Dam Offspring Study (BOSS)-prospective studies of aging and sensory loss. BOSS participants were the adult offspring of participants in the EHLS. Participants who completed the Dichotic Digits Test (DDT) during the fourth examination period of the EHLS (2008-2010) or the second examination period of the BOSS (2010-2013) were included (n = 3,655, mean age = 61.1 years).

DATA COLLECTION AND ANALYSIS

The DDT-free recall test was conducted using 25 sets of triple-digit pairs at a 70 dB HL presentation level. The total number of correctly repeated digits from the right and left ears was converted to a percentage correct and used as an outcome. The percentage correct in the left ear was subtracted from the percentage correct in the right ear and used as an outcome. Vascular health-related measures obtained during the examination included blood pressure, mean carotid intima-media thickness, femoral pulse wave velocity (PWV), hemoglobin A1C, and non-high-density lipoprotein (HDL) cholesterol, and, in the EHLS participants, C-reactive protein and interleukin-6. Information on vascular health-related history and behaviors was self-reported. General linear modeling produced estimates of the age- and sex-adjusted least squares means for each vascular factor, and multiple linear regression was used for multivariable modeling of each outcome.

RESULTS

After multivariable adjustment, participants with diabetes had a significantly lower (worse) mean DDT-free recall total score (-2.08 percentage points, p < 0.001) than those without diabetes. Participants who exercised at least once per week had a significantly higher (better) mean DDT-free recall total score (+1.07 percentage points, p < 0.01) than those who did not exercise at least once per week. Alcohol consumption was associated with a higher DDT-free recall total score (+0.15 percentage points per +25 g ethanol, p < 0.01). In multivariable modeling of the right-left ear difference in DDT-free recall scores, participants with a history of cardiovascular disease (CVD) or higher PWV demonstrated significantly larger differences (CVD: +3.11 percentage points, p = 0.02; PWV: +0.36 percentage points per 1 m/sec, p < 0.01). Higher levels of non-HDL cholesterol were associated with smaller right-left ear differences (-0.22 percentage points per 10 mg/dL, p = 0.01). Adjustment for handedness did not affect the results.

CONCLUSIONS

Vascular health-related factors may play a role in central auditory function.

Effects of Age and Implanted Ear on Speech Recognition in Adults with Unilateral Cochlear Implants

The objective of this study was to examine how age and implanted ear contribute to functional outcomes with cochlear implantation (CI). A retrospective review was performed on 96 adults who underwent unilateral CI. Older adults with right-ear implants had higher Hearing in Noise Test (HINT) scores at 1 year by 10.3% (p = 0.06). When adjusted to rationalized arcsine units (rau), right-ear HINT scores in older adults were higher by 12.1 rau (p = 0.04). Older adults had an 8.9% advantage on the right side compared to the left in post- versus preimplant scores for consonant-vowel nucleus-consonant words (p = 0.05). No significant differences were observed for younger adults. In conclusion, although adults of all ages experience improvements in speech perception following CI, there might be a subtle but consistent right-ear advantage in older adults.

Aging Affects Neural Synchronization to Speech-Related Acoustic Modulations

As people age, speech perception problems become highly prevalent, especially in noisy situations. In addition to peripheral hearing and cognition, temporal processing plays a key role in speech perception. Temporal processing of speech features is mediated by synchronized activity of neural oscillations in the central auditory system. Previous studies indicate that both the degree and hemispheric lateralization of synchronized neural activity relate to speech perception performance. Based on these results, we hypothesize that impaired speech perception in older persons may, in part, originate from deviances in neural synchronization. In this study, auditory steady-state responses that reflect synchronized activity of theta, beta, low and high gamma oscillations (i.e., 4, 20, 40, and 80 Hz ASSR, respectively) were recorded in young, middle-aged, and older persons. As all participants had normal audiometric thresholds and were screened for (mild) cognitive impairment, differences in synchronized neural activity across the three age groups were likely to be attributed to age. Our data yield novel findings regarding theta and high gamma oscillations in the aging auditory system. At an older age, synchronized activity of theta oscillations is increased, whereas high gamma synchronization is decreased. In contrast to young persons who exhibit a right hemispheric dominance for processing of high gamma range modulations, older adults show a symmetrical processing pattern. These age-related changes in neural synchronization may very well underlie the speech perception problems in aging persons.

Hearing Aid-Induced Plasticity in the Auditory System of Older Adults: Evidence From Speech Perception

PURPOSE

We tested whether using hearing aids can improve unaided performance in speech perception tasks in older adults with hearing impairment.

METHOD

Unaided performance was evaluated in dichotic listening and speech-in-noise tests in 47 older adults with hearing impairment; 36 participants in 3 study groups were tested before hearing aid fitting and after 4, 8, and 14 weeks of hearing-aid use. The remaining 11 participants served as a control group and were similarly evaluated but were not fitted with hearing aids. Three protocols were compared in the study groups: amplification for the nondominant ear, amplification for the dominant ear, and bilateral amplification. Subsequently, after 4 weeks, all participants were afforded bilateral amplification.

RESULTS

In the study groups, unaided dichotic listening scores improved significantly in the nondominant ear by 8 weeks and onward. Significant improvements were also observed for unaided speech identification in noise, with some gains apparent after 4 weeks of hearing-aid use. No gains were observed in the control group.

CONCLUSIONS

Using hearing aids for a relatively short period can induce changes in the way older adults process auditory inputs in perceptual tasks such as speech identification in noise and dichotic listening. These changes suggest that the central auditory system of older adults retains the potential for behaviorally relevant plasticity.

Benchmarks for the Dichotic Sentence Identification test in Brazilian Portuguese for ear and age

Introduction

Dichotic listening tests should be used in local languages and adapted for the population.

Objective

Standardize the Brazilian Portuguese version of the Dichotic Sentence Identification test in normal listeners, comparing the performance for age and ear.

Methods

This prospective study included 200 normal listeners divided into four groups according to age: 13–19 years (GI), 20–29 years (GII), 30–39 years (GIII), and 40–49 years (GIV). The Dichotic Sentence Identification was applied in four stages: training, binaural integration and directed sound from right and left.

Results

Better results for the right ear were observed in the stages of binaural integration in all assessed groups. There was a negative correlation between age and percentage of correct responses in both ears for free report and training. The worst performance in all stages of the test was observed for the age group 40–49 years old.

Conclusions

Reference values for the Brazilian Portuguese version of the Dichotic Sentence Identification test in normal listeners aged 13–49 years were established according to age, ear, and test stage; they should be used as benchmarks when evaluating individuals with these characteristics.

Comparison of Performance of Older Adults on Two Tests of Temporal Resolution

PURPOSE

Gap-detection thresholds have been reported to vary depending on the type of stimuli used. The current study compared the performance of older adults on 2 tests of temporal resolution, one with random gaps and the other with gaps in the center of a noise signal. The study also determined which of the 2 tests was able to detect more temporal resolution deficits in older individuals.

METHOD

Two tests of temporal resolution, the Gap Detection Test (GDT; Shivaprakash, 2003) and the Gaps-In-Noise test (GIN; Musiek et al., 2005), were administered to 31 older adults with near normal hearing, aged 55 to 70 years. The order in which the tests were administered was randomized.

RESULTS

The gap-detection thresholds obtained using GIN were significantly higher than those obtained using GDT. The difference in thresholds was ascribed to the randomness with which gaps were interspersed within noise segments in the 2 tests. More individuals failed on GIN than GDT. The older adults with high-frequency hearing loss obtained poorer gap thresholds than those with normal hearing.

CONCLUSION

The results indicated that older individuals failed GIN more often compared to GDT. This was attributed to the differences in stimuli and procedure used in the 2 tests.

Individual Differences in Behavioral and Electrophysiological Measures of Binaural Processing Across the Adult Life Span

PURPOSE

The purpose of the present study was to examine individual differences in binaural processing across the adult life span.

METHOD

Sixty listeners (aged 23-80 years) with symmetrical hearing were tested. Binaural behavioral processing was measured by the Words-in-Noise Test, the 500-Hz masking level difference, and the Dichotic Digit Test. Electrophysiologic responses were assessed by the auditory middle latency response binaural interaction component.

RESULTS

No correlations among binaural measures were found. Age accounted for the greatest amount of variability in speech-in-noise performance. Age was significantly correlated with the Words-in-Noise Test binaural advantage and dichotic ear advantage. Partial correlations, however, revealed that this was an effect of hearing status rather than age per se. Inspection of individual results revealed that 20% of listeners demonstrated reduced binaural performance for at least 2 of the binaural measures.

CONCLUSIONS

The lack of significant correlations among variables suggests that each is an important measurement of binaural abilities. For some listeners, binaural processing was abnormal, reflecting a binaural processing deficit not identified by monaural audiologic tests. The inclusion of a binaural test battery in the audiologic evaluation is supported given that these listeners may benefit from alternative forms of audiologic rehabilitation.

Adults with sensorimotor disorders: enhanced physiological and psychological development following specific sensorimotor training

The aim of the study was to investigate, for the first time, if it is possible to integrate primary reflexes in adults with sensorimotor disorders through sensorimotor therapy (SMT). Participants consisted of 14 adults, one man and 13 women, with an average age of 35 years who completed a SMT program over 3 years. They were compared with a reference group of 100 youngsters spanning from 11 to 17 years. Procedures were the same for both youngsters and adults including regular visits to a therapist and training ~15 min each day at home throughout therapy. Assessments of sensorimotor abilities were made before and after the therapy. Results showed significant improvements on all measurements with regard to treatment for both age groups and the main picture indicated small differences between age groups. After therapy adults were better on balance and orientation tests while the youngsters performed better on sports related gross motor movements, processing of speech sounds and had acquired a better relation between visual skills and vestibular function. Conclusions were that motor problems do not disappear with age and that the same diagnostic instruments and treatment methods can be used for both children and adults with sensorimotor difficulties.

Effects of ageing and hearing thresholds on speech perception in quiet and in noise perceived in different locations

Background and Objectives

This study investigated the effect of ageing on speech perception in quiet and in noise, with noise directed from front, right and left.

Subjects and Methods

Sixty Malay native adults with normal or near normal hearing comprising of 20 young adults (21 to 39 years old), 20 middle aged (40 to 59 years old) and 20 older adults (60 to 74 years old) participated in this study. Their speech perception ability was measured using the Malay Hearing in Noise Test (HINT) in four test conditions; 1) in quiet (HINT Q), 2) with noise from front (HINT NF), 3) with noise from right (HINT NR), and 4) with noise from left (HINT NL). Reception thresholds for sentences (RTSs) were measured in each of the aforementioned conditions using an adaptive method.

Results

The results showed that, 1) genuine age-related decline was found in speech perception performance in HINT (NF), 2) hearing threshold was a major determinant differentiating speech perception performance for HINT (Q) and HINT (NL) conditions, and 3) speech perception performance for HINT (NR) was determined by both age and hearing threshold.

Conclusions

This study suggests that, in older adults, while hearing thresholds affect speech perception in quiet, other factors such as central auditory processing and cognitive functions might be more important determinant factors for speech perception performance in noise.

Semi-Structured Listening Experience (Listening Training) in Hearing Aid Fitting: Influence on Dichotic Listening

Purpose

In this study, the authors tested whether training with amplified, clear speech in regular room acoustics would result in larger perceptual gains of auditory processing in elderly hearing aid users.

Method

Elderly participants with hearing impairment ( N = 36, ages 64–88) were fitted with bilateral hearing aids and were randomly assigned to 2 unequal groups. Study group participants were provided with 7 sessions (1 month) of individual listening training during which a free conversation was conducted, with the aim of stimulating the amplified ears with verbal auditory input. The control group participants were fitted with hearing aids without training. Auditory processing changes were assessed through the use of dichotic listening tasks.

Results

During hearing aid use, dichotic listening scores—tested without the hearing aids—improved in both groups, mainly in the non-dominant ears. The overall dichotic performance was significantly higher in the study group, and the main effect of auditory training was manifested in the scores of the dominant ear.

Conclusions

Hearing aid use may improve auditory processing performance as tested in unaided conditions. Listening training has an additional beneficial effect on the dominant ear—that is, the ear with the lesser potential for improvement. Listening training in elderly adults presumably enhanced the acclimatization process by better recruiting the potential for auditory plasticity and improving attention recruitment.

An exploration of dichotic listening among adults who stutter

A pilot investigation of dichotic listening of CV stimuli was undertaken using seven adults who stutter (AWS) and a comparison group of seven adults who do not stutter (AWNS). The aim of this research was to investigate whether AWS show a difference in the strength of the right ear advantage (REA) in both undirected and directed attention tasks when compared to AWNS. The undirected attention task involved manipulating the interaural intensity difference (IID) of the CV stimuli presented to each ear. The CV stimuli were presented with equal intensity for the directed attention task. The undirected attention results indicated that both AWS and AWNS have a REA for processing speech information, with a primary difference observed between groups in regard to the IID point at which a REA shifts to a LEA. This crossing-over point occurred earlier for AWS, indicating a stronger right hemisphere involvement for the processing of speech compared to AWNS. No differences were found between groups in the directed attention task. The differences and similarities observed in dichotic listening between the two groups are discussed in regard to hemispheric specialization in the processing of speech.

Central presbycusis: a review and evaluation of the evidence

BACKGROUND

The authors reviewed the evidence regarding the existence of age-related declines in central auditory processes and the consequences of any such declines for everyday communication.

PURPOSE

This report summarizes the review process and presents its findings.

DATA COLLECTION AND ANALYSIS

The authors reviewed 165 articles germane to central presbycusis. Of the 165 articles, 132 articles with a focus on human behavioral measures for either speech or nonspeech stimuli were selected for further analysis.

RESULTS

For 76 smaller-scale studies of speech understanding in older adults reviewed, the following findings emerged: (1) the three most commonly studied behavioral measures were speech in competition, temporally distorted speech, and binaural speech perception (especially dichotic listening); (2) for speech in competition and temporally degraded speech, hearing loss proved to have a significant negative effect on performance in most of the laboratory studies; (3) significant negative effects of age, unconfounded by hearing loss, were observed in most of the studies of speech in competing speech, time-compressed speech, and binaural speech perception; and (4) the influence of cognitive processing on speech understanding has been examined much less frequently, but when included, significant positive associations with speech understanding were observed. For 36 smaller-scale studies of the perception of nonspeech stimuli by older adults reviewed, the following findings emerged: (1) the three most frequently studied behavioral measures were gap detection, temporal discrimination, and temporal-order discrimination or identification; (2) hearing loss was seldom a significant factor; and (3) negative effects of age were almost always observed. For 18 studies reviewed that made use of test batteries and medium-to-large sample sizes, the following findings emerged: (1) all studies included speech-based measures of auditory processing; (2) 4 of the 18 studies included nonspeech stimuli; (3) for the speech-based measures, monaural speech in a competing-speech background, dichotic speech, and monaural time-compressed speech were investigated most frequently; (4) the most frequently used tests were the Synthetic Sentence Identification (SSI) test with Ipsilateral Competing Message (ICM), the Dichotic Sentence Identification (DSI) test, and time-compressed speech; (5) many of these studies using speech-based measures reported significant effects of age, but most of these studies were confounded by declines in hearing, cognition, or both; (6) for nonspeech auditory-processing measures, the focus was on measures of temporal processing in all four studies; (7) effects of cognition on nonspeech measures of auditory processing have been studied less frequently, with mixed results, whereas the effects of hearing loss on performance were minimal due to judicious selection of stimuli; and (8) there is a paucity of observational studies using test batteries and longitudinal designs.

CONCLUSIONS

Based on this review of the scientific literature, there is insufficient evidence to confirm the existence of central presbycusis as an isolated entity. On the other hand, recent evidence has been accumulating in support of the existence of central presbycusis as a multifactorial condition that involves age- and/or disease-related changes in the auditory system and in the brain. Moreover, there is a clear need for additional research in this area.

Sex differences in language asymmetry are age-dependent and small: a large-scale, consonant-vowel dichotic listening study with behavioral and fMRI data

Men are often believed to have a functionally more asymmetrical brain organization than women, but the empirical evidence for sex differences in lateralization is unclear to date. Over the years we have collected data from a vast number of participants using the same consonant-vowel dichotic listening task, a reliable marker for language lateralization. One dataset comprised behavioral data from 1782 participants (885 females, 125 non-right-handers), who were divided in four age groups (children <10 yrs, adolescents = 10-15 yrs, younger adults = 16-49 yrs, and older adults >50 yrs). In addition, we had behavioral and functional imaging (fMRI) data from another 104 younger adults (49 females, aged 18-45 yrs), who completed the same dichotic listening task in a 3T scanner. This database allowed us to comprehensively test whether there is a sex difference in functional language lateralization. Across all participants and in both datasets a right ear advantage (REA) emerged, reflecting left-hemispheric language lateralization. Accordingly, the fMRI data revealed a leftward asymmetry in superior temporal lobe language processing areas. In the N = 1782 dataset no main effect of sex but a significant sex by age interaction emerged: the REA increased with age in both sexes but as a result of an earlier onset in females the REA was stronger in female than male adolescents. In turn, male younger adults showed greater asymmetry than female younger adults (accounting for <1% of variance). There were no sex differences in children and older adults. The males in the fMRI dataset (N = 104) also had a greater REA than females (accounting for 4% of variance), but no sex difference emerged in the neuroimaging data. Handedness did not affect these findings. Taken together, our findings suggest that sex differences in language lateralization as assessed with dichotic listening exist, but they are (a) not necessarily reflected in fMRI data, (b) age-dependent and (c) relatively small.

Speech Perception in Noise in Normally Hearing Children: Does Binaural Frequency Modulated Fitting Provide More Benefit than Monaural Frequency Modulated Fitting?

The aim of the present study was to compare the benefit of monaural versus binaural ear-level frequency modulated (FM) fitting on speech perception in noise in children with normal hearing. Reception threshold for sentences (RTS) was measured in no-FM, monaural FM, and binaural FM conditions in 22 normally developing children with bilateral normal hearing, aged 8 to 9 years old. Data were gathered using the Pediatric Malay Hearing in Noise Test (P-MyHINT) with speech presented from front and multi-talker babble presented from 90°, 180°, 270° azimuths in a sound treated booth. The results revealed that the use of either monaural or binaural ear level FM receivers provided significantly better mean RTSs than the no-FM condition (P<0.001). However, binaural FM did not produce a significantly greater benefit in mean RTS than monaural fitting. The benefit of binaural over monaural FM varies across individuals; while binaural fitting provided better RTSs in about 50% of study subjects, there were those in whom binaural fitting resulted in either deterioration or no additional improvement compared to monaural FM fitting.

The present study suggests that the use of monaural ear-level FM receivers in children with normal hearing might provide similar benefit as binaural use. Individual subjects’ variations of binaural FM benefit over monaural FM suggests that the decision to employ monaural or binaural fitting should be individualized. It should be noted however, that the current study recruits typically developing normal hearing children. Future studies involving normal hearing children with high risk of having difficulty listening in noise is indicated to see if similar findings are obtained.

Auditory-cognitive interactions underlying interaural asymmetry in an adult listener: a case study

OBJECTIVE

Abnormal interaural asymmetry on tests of dichotic listening is commonly observed in individuals suspected of auditory processing disorder (APD). Although a structural basis for the abnormality has been widely accepted, the influence of cognitive variables on the degree of observed asymmetry has gained increasing attention. To study this issue, we manipulated cognitive influences on interaural asymmetry in an adult with the auditory complaints typically associated with APD.

STUDY SAMPLE

A 55 year-old woman with complaints of difficulty understanding speech in noisy environments despite normal audiometric levels.

DESIGN

Several experimental dichotic procedures were administered. Each procedure was characterized by the manipulation of cognitive task demands.

RESULTS

Interaural asymmetry was greatest when the demands on attention and/or memory were maximal. Electrophysiological data revealed interaural asymmetry on later stages of information processing.

CONCLUSIONS

Results are discussed in relation to auditory-specific outcomes on clinical tests for APD.

Central auditory function in early Alzheimer's disease and in mild cognitive impairment

OBJECTIVE

to investigate auditory function in subjects with early Alzheimer's disease, mild cognitive impairment and with subjective memory complaints, in search of signs of central auditory processing dysfunction even in early stages of cognitive impairment.

DESIGN AND SUBJECTS

a consecutive group of men and women, referred to the Memory Clinic at the Karolinska University Hospital, was approached for inclusion in this prospective study. One hundred and thirty-six subjects, mean age 64 years (range 50-78 years), diagnosed with Alzheimer's disease (n = 43), mild cognitive impairment (n = 59) or with subjective memory complaints (n = 34), were included.

METHODS

auditory function was assessed with pure tone audiometry, speech perception in quiet and in background noise and dichotic digits tests with two or three digits.

RESULTS

pure tone audiometry and speech perception scores in quiet and in background noise were normal for age and without between-group differences. Dichotic digits tests showed strongly significant differences between the three groups, where the Alzheimer's disease group performed significantly poorer than the other two groups, with the mild cognitive impairment group in an intermediate position.

CONCLUSIONS

our results demonstrate that central auditory processing dysfunction is highly evident in subjects with Alzheimer's disease, and to a considerable extent even in subjects with mild cognitive impairment.

Dichotic word recognition in noise and the right-ear advantage

PURPOSE

This study sought to compare dichotic right-ear advantages (REAs) of young adults to older adult data (C. M. Roup, T. L. Wiley, & R. H. Wilson, 2006) after matching for overall levels of recognition performance. Specifically, speech-spectrum noise was introduced in order to reduce dichotic recognition performance of young adults to a level consistent with that of older adults with hearing loss.

METHOD

Dichotic word-recognition performance was evaluated in the free-recall response paradigm across 2 conditions: (a) quiet and (b) noise (+11 dB signal-to-noise ratio). Participants included a group of right-handed young adults (n = 32) with normal hearing.

RESULTS

The introduction of noise resulted in significantly poorer dichotic word-recognition performance than in the quiet condition for the young adults. REAs, however, did not differ between the 2 conditions. Relative to the Roup et al. (2006) older adult data, performance of the young adults in the noise condition resulted in (a) similar levels of overall recognition performance and (b) significantly smaller REAs.

CONCLUSIONS

Results suggest that the magnitude of the REA is not dependent upon the difficulty of the dichotic task. Rather, the large REAs exhibited by older adults are more likely related to age-related deficits in auditory processing.

Aging effect on dichotic listening of Cantonese

Cantonese dichotic digits recognition was evaluated in free-recall, directed-attention right, and directed-attention left response conditions. All participants were right-handed and included a group of young adults with normal hearing and a group of older adults with minimal sensorineural hearing loss. In all conditions, performance by the young adults was better than performance by the older adults. A right-ear advantage was observed for both groups. Due to a greater deficit in dichotic digits recognition performance in the left ear of older subjects their right-ear advantages were larger than those for the young adults. The results support an age-related disadvantage in recognition performance for dichotic stimuli presented to the left ear of older subjects that is not entirely accounted for by differences in hearing sensitivity between subject groups but may be related to a primary cognitive deficit.

Auditory processing assessment in older people with no report of hearing disability

In the elderly, the results of central auditory pathways behavioral assessments are considered to be difficult to read because of the possible interference of peripheral auditory pathway involvement. Aim: Assess the efficacy of the central auditory function in elderly patients who do not complain of hearing. Materials and Methods: Case study involving 40 individuals within the age range of 60 to 75 years. The patients underwent auditory processing evaluation based on anamnesis, otorhinolaryngological exam, threshold tonal audiometry, speech recognition threshold, speech recognition index, immittance measures, stapes reflex study, synthetic phrases identification test with ipsilateral competitive message, frequency pattern test and alternate twin-syllable test through dichotic task; age range and hearing loss influenced results from the phrases identification with ipsilateral competitive message. Percentages of right answers below normal standards were seen in the three tests that assessed the central auditory functions. Conclusion: Elderly individuals who did not complain of hearing presented relevant prevalence of signs of central auditory function inefficiencies.

Cross-sectional age-changes of hearing in the elderly

OBJECTIVE

Compare the rates of change with age in tests of hearing function that measure the peripheral and central segments of the auditory system.

DESIGN

Cross-sectional cohort study.

PARTICIPANTS

Two hundred forty-one volunteer members of a dementia surveillance cohort aged 71 to 96 yrs selected by having sufficient and symmetric auditory function to perform central auditory tests.

RESULTS

Measures of central auditory function declined with age at a faster rate than did measures of peripheral auditory function. The mean distortion product otoacoustic emission thresholds at 1, 2, and 3 kHz (Distortion Product Otoacoustic Emissions1,2,3) increased 0.34 dB/yr (95% C.I. 0.07, 0.60) or 0.45 standard deviations (S.D.)/decade, whereas the pure-tone threshold average of 1, 2, and 3 kHz (PTA1,2,3) increased by 0.5 dB/yr (95% C.I. 0.32, 0.81) or 0.59 S.D./decade. The auditory-evoked potential latencies for wave V of the Auditory Brain Stem Response, Pa of the middle latency response, and P2 of the late latency response did not vary by age. The mean Synthetic Sentence Identification test with ipsilateral competing message scores dropped 1.7 percentage points (95% C.I. -2.2, -1.2) per year or 0.78 S.D./decade, which was significantly greater than the drop with age in either the Distortion Product Otoacoustic Emissions1,2,3 or the PTA1,2,3. After adjustment for drop in hearing threshold level with age, the decline in Synthetic Sentence Identification test with ipsilateral competing message was still significant and averaged 1.1 percentage points per year (95% C.I. 1.8, -0.88).

CONCLUSION

Central auditory function is a prominent component of presbycusis and should be assessed routinely. Rehabilitative measures for presbycusis should take central auditory function into account.

Avaliação do processamento auditivo em idosos que relatam ouvir bem

Em idosos, os resultados da avaliação comportamental das vias auditivas centrais são considerados de difícil interpretação devido à possível interferência do comprometimento das vias auditivas periféricas. OBJETIVO: Avaliar a eficiência das funções auditivas centrais de idosos que relatam ouvir bem. MATERIAL E MÉTODO: Estudo de casos que incluiu 40 indivíduos na faixa etária de 60 a 75 anos. Os pacientes foram submetidos à avaliação do processamento auditivo que constou de anamnese, exame otorrinolaringológico, audiometria tonal liminar, limiar de reconhecimento de fala, índice de reconhecimento de fala, imitanciometria, pesquisa de reflexos estapedianos, teste de identificação de sentenças sintéticas com mensagem competitiva ipsilateral, teste de padrões de freqüência e teste de dissílabos alternados por meio de tarefa dicótica. RESULTADOS: Gênero, faixa etária e perda auditiva não influenciaram os resultados dos testes de padrões de freqüência e dissílabos alternados por meio de tarefa dicótica; faixa etária e perda auditiva influenciaram os resultados do teste de identificação de sentenças com mensagem competitiva ipsilateral. Porcentagens de acertos abaixo dos padrões da normalidade de adultos foram observadas nos três testes que acessam as funções auditivas centrais. CONCLUSÃO: Indivíduos idosos que relatam ouvir bem apresentam prevalência relevante de sinais de ineficiência das funções auditivas centrais.

Cognitive Predictors of Improvements in Adults’ Spoken Word Recognition Six Months after Cochlear Implant Activation

This study investigated whether cognitive measures obtained prior to cochlear implant surgery activation could predict improvements in spoken word recognition in adult cochlear implant recipients 6 months after activation. In addition to noncognitive factors identified by previous studies (i.e. younger age, shorter duration of hearing loss), the present results indicated that improvement in spoken word recognition was associated with higher verbal learning scores and better verbal working memory. Contrary to expectation, neither general cognitive ability nor processing speed was significantly correlated with outcome at 6 months. Multiple regression analyses revealed that a combination of verbal learning scores and lip-reading skill accounted for nearly 72% of the individual differences in improvement in spoken word recognition (i.e. the variance in spoken word recognition scores at 6 months that remained unexplained after controlling for baseline spoken word recognition scores). These findings have relevance for research on auditory processing with cochlear implants as well as implications for clinical interventions.