Association of Performance on Dichotic Auditory Tests With Risk for Incident Dementia and Alzheimer Dementia.

Importance: Age-related hearing difficulties can include problems with signal audibility and central auditory processing. Studies have demonstrated associations between audibility and dementia risk. To our knowledge, limited data exist to determine whether audibility, central processing, or both drive these associations. Objective: To determine the associations between signal sensitivity, central auditory processing, and dementia and Alzheimer dementia (AD) risk. Design, Setting, and Participants: This follow-up observational study of a sample from the prospective Adult Changes in Thought study of dementia risk was conducted at Kaiser Permanente Washington, a western Washington health care delivery system, and included 280 volunteer participants without dementia who were evaluated from October 2003 to February 2006 with follow-up through September 2018. Analyses began in 2019 and continued through 2021. Exposures: Hearing tests included pure tone signal audibility, a monaural word recognition test, and 2 dichotic tests: the Dichotic Sentence Identification (DSI) test and the Dichotic Digits test (DDT). Main Outcomes and Measures: Cognition was assessed biennially with the Cognitive Abilities Screening Instrument (range, 1-100; higher scores are better), and scores of less than 86 prompted clinical and neuropsychological evaluations. All data were reviewed at multidisciplinary consensus conferences, and standardized criteria were used to define incident cases of dementia and probable or possible AD. Cox proportional hazard models were used to determine associations with hearing test performance. Results: A total of 280 participants (177 women [63%]; mean [SD] age, 79.5 [5.2] years). As of September 2018, there were 2196 person-years of follow-up (mean, 7.8 years) and 89 incident cases of dementia (66 not previously analyzed), of which 84 (94.4%) were AD (63 not previously analyzed). Compared with people with DSI scores of more than 80, the dementia adjusted hazard ratio (aHR) for DSI scores of less than 50 was 4.18 (95% CI, 2.37-7.38; P < .001); for a DSI score of 50 to 80, it was 1.82 (95% CI, 1.10-3.04; P = .02). Compared with people with DDT scores of more than 80, the dementia aHR for DDT scores of less than 50 was 2.66 (95% CI, 1.31-5.42; P = .01); for a DDT score of 50 to 80, it was 2.40 (95% CI, 1.45-3.98; P = .001). The AD results were similar. Pure tone averages were weakly and insignificantly associated with dementia and AD, and associations were null when controlling for DSI scores. Conclusions and Relevance: In this cohort study, abnormal central auditory processing as measured by dichotic tests was independently associated with dementia and AD risk.

At the interface of sensory and motor dysfunctions and Alzheimer's disease.

Recent evidence indicates that sensory and motor changes may precede the cognitive symptoms of Alzheimer's disease (AD) by several years and may signify increased risk of developing AD. Traditionally, sensory and motor dysfunctions in aging and AD have been studied separately. To ascertain the evidence supporting the relationship between age-related changes in sensory and motor systems and the development of AD and to facilitate communication between several disciplines, the National Institute on Aging held an exploratory workshop titled "Sensory and Motor Dysfunctions in Aging and AD." The scientific sessions of the workshop focused on age-related and neuropathologic changes in the olfactory, visual, auditory, and motor systems, followed by extensive discussion and hypothesis generation related to the possible links among sensory, cognitive, and motor domains in aging and AD. Based on the data presented and discussed at this workshop, it is clear that sensory and motor regions of the central nervous system are affected by AD pathology and that interventions targeting amelioration of sensory-motor deficits in AD may enhance patient function as AD progresses.

Comprehensive management of presbycusis: central and peripheral.

The prevailing otolaryngologic approach to treatment of age-related hearing loss (ARHL), presbycusis, emphasizes compensation of peripheral functional deficits (ie, hearing aids and cochlear implants). This approach does not address adequately the needs of the geriatric population, 1 in 5 of whom is expected to consist of the "old old" in the coming decades. Aging affects both the peripheral and central auditory systems, and disorders of executive function become more prevalent with advancing age. Growing evidence supports an association between age-related hearing loss and cognitive decline. Thus, to facilitate optimal functional capacity in our geriatric patients, a more comprehensive management strategy of ARHL is needed. Diagnostic evaluation should go beyond standard audiometric testing and include measures of central auditory function, including dichotic tasks and speech-in-noise testing. Treatment should include not only appropriate means of peripheral compensation but also auditory rehabilitative training and counseling.

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.

Central presbycusis: an emerging view.

Age-related dysfunction of the central auditory system (central presbycusis) is common but rarely looked for by those who provide aural rehabilitation. Patients who complain of difficulty hearing in noise--the key symptom of central presbycusis--are generally disadvantaged with conventional rehabilitation. This symptom should be documented with commercially available speech-in-noise tests, which use materials that are uncomplicated to administer. Those patients who perform poorly on such tests should have a customized rehabilitation program aimed at optimizing their remaining communication abilities. Otolaryngologists who provide auditory rehabilitation may wish to consider expanding their practices to meet the communication needs of older patients with central presbycusis. Central presbycusis is an emerging area for basic and clinical research in auditory neurotology, particularly in the relation of cognitive dysfunction to impaired auditory processing.

Central auditory dysfunction as a harbinger of Alzheimer dementia.

OBJECTIVE: To confirm that central auditory dysfunction (CAD) may be a precursor to the onset of Alzheimer dementia (AD). DESIGN: Cohort study. SETTING: Research study center. PARTICIPANTS: Two hundred seventy-four volunteers from a dementia surveillance cohort were followed up for as long as 4 years after undergoing complete audiometric assessment. Twenty-one received a consensus diagnosis of AD after a hearing test. INTERVENTION: The following 3 central auditory tests were performed: the Dichotic Sentence Identification, the Dichotic Digits, and the Synthetic Sentence Identification With Ipsilateral Competing Message. MAIN OUTCOME MEASURES: A new diagnosis of AD using the National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer Disease and Related Disorders Association criteria at a consensus conference. RESULTS: The mean scores on each CAD test were significantly poorer in the incident dementia group. Cox proportional hazards models with age as the time scale were used to estimate the hazard ratio for incident dementia based on CAD test results. After adjusting for educational level, the hazard ratio for incident dementia in people with severe CAD based on a Dichotic Sentence Identification in free report mode of less than 50% was 9.9 (95% confidence interval, 3.6-26.7). CONCLUSIONS: Central auditory dysfunction is a precursor to AD. We recommend evaluation with CAD tests in older adults who report hearing difficulty. Those with severe CAD should receive a modified rehabilitation program and be considered for referral for neurologic evaluation.

Challenges and opportunities in presbycusis.

The population aged 65 years and older is increasing at a faster rate than the total population, with predictions that by 2030, 20% of the population will be 65 years or older. In 2006, between 35% and 50% of those aged 65 years or older reportedly had presbycusis, a sensory impairment that contributes to social isolation and loss of autonomy and is associated with anxiety, depression, and cognitive decline. To address these concerns, the Geriatric Committee of the American Academy of Otolaryngology, in conjunction with the Hearing Committee, focused on 3 challenges and opportunities in the management of presbycusis: (1) the financial burden of caring for patients with presbycusis in the face of increasing costs and declining reimbursements; (2) future treatment options arising from improved understanding of the molecular mechanisms underlying presbycusis, and (3) recognition of central presbycusis as a condition commonly superimposed on peripheral age-related hearing loss whose diagnosis and management can improve outcomes.

Executive dysfunction and presbycusis in older persons with and without memory loss and dementia.

OBJECTIVE: To determine the relation of age-related auditory processing dysfunction and executive functioning. BACKGROUND: Central auditory dysfunction is common in Alzheimer dementia, but the mechanism is not established. METHOD: A total of 313 volunteers from the Adult Changes in Thought surveillance cohort with adequate peripheral hearing were included in the study. Outcome measures such as (1) peripheral audition; (2) auditory-evoked potentials; (3) central auditory tests (Synthetic Sentence Identification with Ipsilateral Competing Message, Dichotic Sentence Identification, Dichotic Digits); (4) Executive Functioning: Trail Making; Clock Drawing, Stroop Color and Word, and subtests from the Cognitive Abilities Screening Instrument were used to measuring the mental concentration. A composite executive functioning score was created using item response theory. RESULTS: The composite executive functioning score was significantly associated with each central auditory measure, explaining 8% to 21% of the variance. Trails B test was most strongly associated with the auditory outcomes, explaining 8% to 14% of the variance. The relation between executive functioning and central auditory function was still significant when participants diagnosed with memory impairment or dementia were excluded. CONCLUSIONS: In elderly persons, reduced executive functioning is associated with central auditory processing, but not with primary auditory function. This suggests that central presbycusis and executive dysfunction may result from similar neurodegenerative processes.

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.

Central auditory dysfunction in older persons with memory impairment or Alzheimer dementia.

OBJECTIVE: To assess the effect of memory impairment on central auditory function. DESIGN: Case-control study. SETTING: The Virginia Merrill Bloedel Hearing Research Center, Seattle, Washington. PARTICIPANTS: The study cohort of 313 volunteers from a dementia surveillance research program comprised 3 groups: (1) controls without memory loss (n = 232); (2) memory-impaired participants with mild memory impairment but without dementia (n = 64); and (3) memory-impaired participants with a dementia diagnosis (n = 17). MAIN OUTCOME MEASURES: Behavioral central auditory tests were the Synthetic Sentence Identification with Ipsilateral Competing Message test, the Dichotic Sentence Identification test, and the Dichotic Digits Test. Memory impairment was indicated by a total score on the Cognitive Ability Screening Instrument of 86 or less, or a total score of 90 or less with a memory subscale score of 10 or less. RESULTS: The mean score on each central auditory test worsened significantly across the 3 memory groups even after adjustment for age and peripheral hearing status (P<.05); it was poorest in the dementia group and moderately reduced in the memory-impaired group compared with the control group. Heterogeneity of results was noted in all 3 groups. CONCLUSIONS: Central auditory function was affected by even mild memory impairment. The Dichotic Sentence Identification test in the free report mode was the most sensitive test for the presence of memory impairment. We recommend that central auditory testing be considered in the evaluation of older persons with hearing complaints as part of a comprehensive, individualized program to assist their needs in both the aural rehabilitative and the cognitive domains.

Evaluation of cochlear hearing disorders: normative distortion product otoacoustic emission measurements.

OBJECTIVE: The overall objective was to begin the investigation, in humans, of distortion product otoacoustic emission measurements, which are intended to be part of a diagnostic protocol being developed. This protocol, designed to distinguish among different cochlear hearing disorders, has been tested to date only through lesion studies in the gerbil (Mills, Ear and Hearing, 27, 508-525, 2006). To be applied successfully to human subjects, it was required that parameters and procedures for emission measurements be found, which resulted in sufficiently small intersubject variability in normal subjects, among other requirements. To attain these objectives, measurements of particular otoacoustic emission responses were made in a reference group of young adults having excellent hearing. DESIGN: Twenty young adults (age 18 to 24 yr; 40 ears) comprised the subject group, with equal numbers of men and women. Inclusion criteria included hearing thresholds of 10 dB HL or better in both ears at all frequencies (0.5, 1, 2, 3, 4, 6, and 8 kHz), plus a tympanometric peak response located within +/-30 daPa of ambient pressure in both ears. The otoacoustic emission stimulus consisted of two tones (frequencies f1 and f2) varied in level using 5-dB steps with the lower-frequency stimulus level always 10 dB greater than that of the higher-frequency stimulus. The emission isoresponse threshold was defined to be the stimulus level required to obtain an emission amplitude of -10 dB SPL. Another potential measure was defined to be the emission amplitude at the highest stimulus levels routinely tested. Mean emission amplitudes and thresholds were determined for f2 frequencies equal to audiometric frequencies from 1 to 8 kHz, using two different stimulus frequency ratios, f2/f1=1.21 and 1.28. RESULTS: One result of the study was the derivation of reference standards for the emission threshold level, similar to the HL scale for pure-tone thresholds. For use in diagnosis, the optimal measure was found to be the otoacoustic emission threshold for the stimulus frequency ratio f2/f1=1.21 and for f2 frequencies from 1 to 6 kHz. The f2 frequency of 8 kHz seemed less useful because the emission had a relatively high mean threshold. For frequencies 1 to 6 kHz, the variances were adequately small: 95% of the emission thresholds fell within +/-13 dB of the mean at each frequency, a variability only slightly larger than that for the gerbil. Finally, even within the 10-dB HL limit, responses showed a slight trend for increased emission thresholds with increased auditory threshold. Only at 8 kHz was the amount of covariance important, however, with the relationship between emission and auditory thresholds strongest for men. CONCLUSIONS: Emission reference standards can be developed by testing a group of young adults with excellent hearing. The diagnostic procedure previously proposed on the basis of gerbil lesion studies may be adapted with relatively little modification for use in human subjects. However, validity of the test and specific numerical results for human subjects remain to be firmly established for the purpose of distinguishing among different cochlear disorders.

Quality of life instruments in Ménière's disease.

OBJECTIVE: Evaluate the sensitivity of quality of life (QoL) instruments over time in patients with Ménière's disease using general, symptom-specific, and disease-specific QoL instruments. STUDY DESIGN: Prospective study using QoL instruments administered serially over 4 months in patients undergoing treatment for Ménière's disease. METHODS: Sixty-one people aged 33 to 71 years with active, unilateral, cochleovestibular Ménière's disease refractory to medical management completed two general QoL instruments, Sense of Coherence (SOC) and World Health Organization Quality of Life-Abbreviated Version (WHOQOL-BREF), one symptom-specific QoL instrument, Vertigo Symptom Scale (VSS), and one disease-specific QoL instrument, Ménière's Disease Patient Oriented Severity Index (MDPOSI). All measures were administered at baseline and again 2 and 4 months later. RESULTS: Disease- and symptom-specific instruments including the MDPOSI and VSS were positively correlated with vertigo control category (Pearson's R=0.345, MDPOSI; 0.279, VSS), indicating sensitivity to the frequency of vertigo spells. These instruments were also sensitive to changes in vertigo over time. Standardized response means showed greatest responsiveness to change on the MDPOSI (0.80) and the VSS (0.79). Standardized response means for SOC and WHOQOL-BREF were 0.03, and 0.32, respectively, suggesting poor responsiveness to change of symptoms. The VSS and MDPOSI were highly correlated (Pearson's r coefficient 0.744; P<.001). CONCLUSIONS: A disease-specific QoL instrument such as the MDPOSI and a symptom-specific instrument such as the VSS more accurately reflect changes in control of vertigo in people with Ménière's disease over time than do general QoL instruments. These instruments can be used to determine the life impact of Ménière's disease and how aggressive therapy should be for the patient.

Meniett clinical trial: long-term follow-up.

OBJECTIVE: To delineate 2-year efficacy of Meniett device therapy in people with classic, unilateral, Ménière's disease unresponsive to traditional medical treatment. DESIGN: A 2-year long-term unblinded follow-up after a prior randomized, placebo-controlled, multicenter clinical trial of the Meniett device for Ménière's disease. SETTING: Follow-up was performed remotely by using diaries and questionnaires mailed to the data coordinating center by the participants. Those who failed to mail their diaries were interviewed by telephone. PARTICIPANTS: Sixty-one study participants agreed to use the Meniett device and report their symptoms for 2 years. All had active, unilateral cochleovestibular disease. Outcomes are available for 58 participants; 2 were unavailable for follow-up and 1 was excluded because of a concurrent condition that precluded Meniett device use. INTERVENTIONS: Participants were advised to adhere to a low-sodium diet, use the Meniett device 3 times daily, and maintain a patent tympanostomy tube in the affected ear. Diuretic and vestibular suppressant medications were used as needed. MAIN OUTCOME MEASURES: Outcomes were based on the participants' daily diary, questionnaires, and telephone interviews. Three different analyses were prepared: tracking of vertigo frequency throughout the study, comparison of vertigo frequency before and at the end of Meniett device use (American Academy of Otolaryngology-Head and Neck Surgery Foundation reporting guideline), and Kaplan-Meier estimates of vertigo remission and recurrence. RESULTS: Vertigo levels gradually improved for most but not all participants. American Academy of Otolaryngology-Head and Neck Surgery Foundation class A (remission) or class B (greatly improved) results occurred in 67% (39/58) of participants, and class F (dropped out to receive surgical therapy) results occurred in 24%. Of the 44 nondropout participants, 39 (89%) had American Academy of Otolaryngology-Head and Neck Surgery Foundation group A or B outcomes. People who went into remission were highly likely (80%) to remain in remission long term; participants who achieved remission (20/43; 47%) did so within the first year of follow-up. CONCLUSIONS: Use of the Meniett device was associated with a significant reduction in vertigo frequency in about two thirds of the participants, and this improvement was maintained long term. Therapy with the Meniett device is a safe and effective option for people with substantial vertigo uncontrolled by medical therapy.

Ménière's disease review 2005.

Ménière's disease (MD) is a complex, multifactorial disorder of the inner ear that is the most common cause of the syndrome of episodic vertigo combined with fluctuating hearing loss. In spite of a century of investigation, the etiology and pathophysiology of MD remain controversial and incompletely understood. Among the factors that have contributed to these controversies are the absence of (1) a validated clinical test, (2) an appropriate animal model, and (3) a specific treatment. Nonetheless, physicians are able to assist MD patients with a variety of tailored, symptom-specific medications and therapies. Given that the vertigo induced by MD, in general, is self-limited, the long-term outlook for balance function is good. The same cannot be said for the hearing dysfunction of MD.

Treatment of Meniere's disease with the low-pressure pulse generator (Meniett device).

Until recently, surgery was the only treatment option for people with disabling Meniere's disease that did not respond to adequate medical therapy. A new intermediate level treatment modality, the Meniett device, which applies low-pressure micropulses to the inner ear, has now been shown to be safe and effective. The device is portable and self-administered, requiring a 5-min three-times daily application for an indefinite period. Placement of a tympanostomy tube in the ear drum of the affected ear is necessary. Patient acceptance has been high. Long-term success in control of vertigo is over 80%. Although hearing loss is not improved, Meniett device usage does not adversely affect balance, as do most forms of surgical therapy. Use of the device does not preclude later surgical therapy.

Validation of the Ménière's Disease Patient-Oriented Symptom-Severity Index.

OBJECTIVE: To validate a disease-specific, health-related quality-of-life instrument for people with active, unilateral, cochleovestibular Ménière's disease (MD). DESIGN: Prospective, blinded, randomized cohort study using a 16-item instrument, the Ménière's Disease Patient-Oriented Symptom-Severity Index (MDPOSI), version 2. SETTING: Four clinical sites, including 3 university hospitals and 1 private practice. PARTICIPANTS: Sixty-one adult participants in a clinical trial of a new treatment modality (the Meniett device) at 4 medical centers. INTERVENTION: The MDPOSI was administered at baseline and at 2 and 4 months after the use of the Meniett device or the placebo. MAIN OUTCOME MEASURES: Each item, domain, and overall MDPOSI score was compared with self-reported cumulative frequency of definitive attacks of vertigo at baseline and 2 and 4 months later. RESULTS: The MDPOSI global score, domain scores, and 13 of 16 items were significantly associated with the frequency of vertigo (gold standard) as noted on the daily symptom report card. CONCLUSIONS: The MDPOSI is a valid and reliable instrument to evaluate the impact of MD on patients' disease-related quality of life, and it is responsive to change in the status of the disorder. The MDPOSI is suitable for use in clinical practice and clinical research in people with MD.

Presbycusis.

The inevitable deterioration in hearing ability that occurs with age--presbycusis--is a multifactorial process that can vary in severity from mild to substantial. Left untreated, presbycusis of a moderate or greater degree affects communication and can contribute to isolation, depression, and, possibly, dementia. These psychological effects are largely reversible with rehabilitative treatment. Comprehensive rehabilitation is widely available but underused because, in part, of social attitudes that undervalue hearing, in addition to the cost and stigma of hearing aids. Remediation of presbycusis is an important contributor to quality of life in geriatric medicine and can include education about communication effectiveness, hearing aids, assistive listening devices, and cochlear implants for severe hearing loss. Primary care physicians should screen and refer their elderly patients for assessment and remediation. Where hearing aids no longer provide benefit, cochlear implantation is the treatment of choice with excellent results even in octogenarians.