Peripheral hearing loss at age 70 predicts brain atrophy and associated cognitive change.

BACKGROUND: Hearing loss has been proposed as a modifiable risk factor for dementia. However, the relationship between hearing, neurodegeneration, and cognitive change, and the extent to which pathological processes such as Alzheimer's disease and cerebrovascular disease influence these relationships, is unclear. METHODS: Data from 287 adults born in the same week of 1946 who underwent baseline pure tone audiometry (mean age=70.6 years) and two time point cognitive assessment/multimodal brain imaging (mean interval 2.4 years) were analysed. Hearing impairment at baseline was defined as a pure tone average of greater than 25 decibels in the best hearing ear. Rates of change for whole brain, hippocampal and ventricle volume were estimated from structural MRI using the Boundary Shift Integral. Cognition was assessed using the Pre-clinical Alzheimer's Cognitive Composite. Regression models were performed to evaluate how baseline hearing impairment associated with subsequent brain atrophy and cognitive decline after adjustment for a range of confounders including baseline ß-amyloid deposition and white matter hyperintensity volume. RESULTS: 111 out of 287 participants had hearing impairment. Compared with those with preserved hearing, hearing impaired individuals had faster rates of whole brain atrophy, and worse hearing (higher pure tone average) predicted faster rates of hippocampal atrophy. In participants with hearing impairment, faster rates of whole brain atrophy predicted greater cognitive change. All observed relationships were independent of ß-amyloid deposition and white matter hyperintensity volume. CONCLUSIONS: Hearing loss may influence dementia risk via pathways distinct from those typically implicated in Alzheimer's and cerebrovascular disease in cognitively unimpaired older adults.

Comprehension of acoustically degraded speech in Alzheimer's disease and primary progressive aphasia.

Successful communication in daily life depends on accurate decoding of speech signals that are acoustically degraded by challenging listening conditions. This process presents the brain with a demanding computational task that is vulnerable to neurodegenerative pathologies. However, despite recent intense interest in the link between hearing impairment and dementia, comprehension of acoustically degraded speech in these diseases has been little studied. Here we addressed this issue in a cohort of 19 patients with typical Alzheimer's disease and 30 patients representing the three canonical syndromes of primary progressive aphasia (non-fluent/agrammatic variant primary progressive aphasia; semantic variant primary progressive aphasia; logopenic variant primary progressive aphasia), compared to 25 healthy age-matched controls. As a paradigm for the acoustically degraded speech signals of daily life, we used noise-vocoding: synthetic division of the speech signal into frequency channels constituted from amplitude-modulated white noise, such that fewer channels convey less spectrotemporal detail thereby reducing intelligibility. We investigated the impact of noise-vocoding on recognition of spoken three-digit numbers and used psychometric modelling to ascertain the threshold number of noise-vocoding channels required for 50% intelligibility by each participant. Associations of noise-vocoded speech intelligibility threshold with general demographic, clinical and neuropsychological characteristics and regional grey matter volume (defined by voxel-based morphometry of patients' brain images) were also assessed. Mean noise-vocoded speech intelligibility threshold was significantly higher in all patient groups than healthy controls, and significantly higher in Alzheimer's disease and logopenic variant primary progressive aphasia than semantic variant primary progressive aphasia (all P < 0.05). In a receiver operating characteristic analysis, vocoded intelligibility threshold discriminated Alzheimer's disease, non-fluent variant and logopenic variant primary progressive aphasia patients very well from healthy controls. Further, this central hearing measure correlated with overall disease severity but not with peripheral hearing or clear speech perception. Neuroanatomically, after correcting for multiple voxel-wise comparisons in predefined regions of interest, impaired noise-vocoded speech comprehension across syndromes was significantly associated (P < 0.05) with atrophy of left planum temporale, angular gyrus and anterior cingulate gyrus: a cortical network that has previously been widely implicated in processing degraded speech signals. Our findings suggest that the comprehension of acoustically altered speech captures an auditory brain process relevant to daily hearing and communication in major dementia syndromes, with novel diagnostic and therapeutic implications.

Auditory processing disorder: an online survey of hearing healthcare professionals' knowledge and practices.

OBJECTIVE: To investigate (1) the current level of awareness and knowledge on Auditory Processing Disorder (APD) among Audiologists and other hearing healthcare professionals; (2) current practices in screening, diagnosis, and management of APD in children and adults across the UK; (3) professional's acceptance of APD assessment and diagnosis. DESIGN: An online survey was disseminated through the British Academy of Audiology and ENT UK. STUDY SAMPLE: A total of 191 hearing healthcare professionals responded to the survey. RESULTS: Overall, while 63% of the respondents considered themselves to be adequately informed about APD, only 4% viewed themselves as very informed on the topic. Fewer than half of the respondents report screening (31%), diagnosing (14%), or managing (36%) cases of APD. For screening APD, professionals most commonly use auditory processing tests in adults and take case histories in children, whereas routine audiological procedures are the primary method for diagnosing APD in both adults and children. Although modifying the listening environment is a widely recommended management strategy for APD, half of the respondents indicated that a diagnosis of APD has no implications for patient management. CONCLUSIONS: There is a critical need to promote APD-related training to ensure they can provide appropriate referrals and management.

Hearing and dementia: from ears to brain.

The association between hearing impairment and dementia has emerged as a major public health challenge, with significant opportunities for earlier diagnosis, treatment and prevention. However, the nature of this association has not been defined. We hear with our brains, particularly within the complex soundscapes of everyday life: neurodegenerative pathologies target the auditory brain, and are therefore predicted to damage hearing function early and profoundly. Here we present evidence for this proposition, based on structural and functional features of auditory brain organization that confer vulnerability to neurodegeneration, the extensive, reciprocal interplay between 'peripheral' and 'central' hearing dysfunction, and recently characterized auditory signatures of canonical neurodegenerative dementias (Alzheimer's disease, Lewy body disease and frontotemporal dementia). Moving beyond any simple dichotomy of ear and brain, we argue for a reappraisal of the role of auditory cognitive dysfunction and the critical coupling of brain to peripheral organs of hearing in the dementias. We call for a clinical assessment of real-world hearing in these diseases that moves beyond pure tone perception to the development of novel auditory 'cognitive stress tests' and proximity markers for the early diagnosis of dementia and management strategies that harness retained auditory plasticity.

Classical infratentorial superficial siderosis of the central nervous system: pathophysiology, clinical features and management.

The term superficial siderosis (SS) is derived from the Greek word 'sideros', meaning iron. It includes two subtypes, distinguished by their anatomical distribution, causes and clinical features: 'classical' infratentorial SS (iSS, which sometimes also affects supratentorial regions) and cortical SS (cSS, which affects only supratentorial regions). This paper considers iSS, a potentially disabling disorder usually associated with very slow persistent or intermittent subarachnoid bleeding from a dural defect, and characterised by progressive hearing and vestibular impairment, ataxia, myelopathy and cognitive dysfunction. The causal dural defect-most often spinal but sometimes in the posterior fossa-typically follows trauma or neurosurgery occurring decades before diagnosis. Increasing recognition of iSS with paramagnetic-sensitive MRI is leading to an unmet clinical need. Given the diagnostic challenges and complex neurological impairments in iSS, we have developed a multidisciplinary approach involving key teams. We discuss pathophysiology, diagnosis and management of iSS, including a proposed clinical care pathway.

Auditory Phenotypic Variability in Friedreich's Ataxia Patients.

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

Adaption and preliminary validation of the Addenbrooke's Cognitive Examination-III as a screening test for mild cognitive impairment and dementia in hearing-impaired individuals.

BACKGROUND: A large proportion of older adults assessed for cognitive impairment likely have hearing loss, potentially affecting accuracy of cognitive performance estimations. This study aimed to develop a hearing-impaired version of the Addenbrooke's Cognitive Examination-III (HI-ACE-III) and to assess whether the HI-ACE-III can accurately distinguish people with mild cognitive impairment (MCI) and dementia from cognitively intact controls. METHODS: The HI-ACE-III was developed by converting verbal instructions into a visual, timed PowerPoint presentation. Seventy-four participants over the age of 60 years were classified into three groups: 29 had MCI, 15 had mild to moderate dementia and 30 were cognitively intact controls. Receiver operating characteristic (ROC) curves were graphed to test screening accuracy. Concurrent validity was examined through correlations between HI-ACE-III domain scores and relevant, visually presented standardized neuropsychological measures. RESULTS: ROC analysis for dementia revealed an area under the curve (AUC) of 0.99, achieving excellent sensitivity (100%) and good specificity (93.3%) at an optimum cut-off of <87. The AUC for MCI was 0.86, achieving reasonable sensitivity (75.9%) and good specificity (86.7%) at an optimum cut-off of <92. HI-ACE-III subtests shared anticipated and statistically significant correlations with established measures of cognitive functioning. Internal consistency of the HI-ACE-III was excellent as verified with Cronbach's alpha (α = 0.904). CONCLUSIONS: Preliminarily, the HI-ACE-III showed good reliability, validity and screening utility for MCI and dementia in older adults in a hearing-impairment context. The adapted HI-ACE-III may offer accurate and reliable indication of cognitive performance, supporting timely diagnosis and research examining links between hearing loss and cognitive decline.

Pure tone audiometry and cerebral pathology in healthy older adults.

BACKGROUND: Hearing impairment may be a modifiable risk factor for dementia. However, it is unclear how hearing associates with pathologies relevant to dementia in preclinical populations. METHODS: Data from 368 cognitively healthy individuals born during 1 week in 1946 (age range 69.2-71.9 years), who underwent structural MRI, 18F-florbetapir positron emission tomography, pure tone audiometry and cognitive testing as part of a neuroscience substudy the MRC National Survey of Health and Development were analysed. The aim of the analysis was to investigate whether pure tone audiometry performance predicted a range of cognitive and imaging outcomes relevant to dementia in older adults. RESULTS: There was some evidence that poorer pure tone audiometry performance was associated with lower primary auditory cortex thickness, but no evidence that it predicted in vivo ß-amyloid deposition, white matter hyperintensity volume, hippocampal volume or Alzheimer's disease-pattern cortical thickness. A negative association between pure tone audiometry and mini-mental state examination score was observed, but this was no longer evident after excluding a test item assessing repetition of a single phrase. CONCLUSION: Pure tone audiometry performance did not predict concurrent ß-amyloid deposition, small vessel disease or Alzheimer's disease-pattern neurodegeneration, and had limited impact on cognitive function, in healthy adults aged approximately 70 years.

Hearing-impaired population performance and the effect of hearing interventions on Montreal Cognitive Assessment (MoCA): Systematic review and meta-analysis.

BACKGROUND: Older adults are at high risk of developing age-related hearing loss (HL) and/or cognitive impairment. However, cognitive screening tools rely on oral administration of instructions and stimuli that may be impacted by HL. This systematic review aims to investigate (a) whether people with HL perform worse than those without HL on the Montreal Cognitive Assessment (MoCA), a widely used screening tool for cognitive impairment, and what the effect size of that difference is (b) whether HL treatment mitigates the impact of HL. METHOD: We conducted a systematic review and meta-analysis including studies that reported mean MoCA scores and SDs for individuals with HL. RESULTS: People with HL performed significantly worse on the MoCA (4 studies, N = 533) with a pooled mean difference of -1.66 points (95% confidence interval CI -2.74 to -0.58). There was no significant difference in MoCA score between the pre- vs post-hearing intervention (3 studies, N = 75). However, sensitivity analysis in the cochlear implant studies (2 studies, N = 33) showed improvement of the MoCA score by 1.73 (95% CI 0.18 to 3.28). CONCLUSION: People with HL score significantly lower than individuals with normal hearing on the standard orally administered MoCA. Clinicians should consider listening conditions when administering the MoCA and report the hearing status of the tested individuals, if known, taking this into account in interpretation or make note of any hearing difficulty during consultations which may warrant onward referral. Cochlear implants may improve the MoCA score of individuals with HL, and more evidence is required on other treatments. J Am Geriatr Soc 68:-, 2020.

Application of Big Data to Support Evidence-Based Public Health Policy Decision-Making for Hearing.

Ideally, public health policies are formulated from scientific data; however, policy-specific data are often unavailable. Big data can generate ecologically-valid, high-quality scientific evidence, and therefore has the potential to change how public health policies are formulated. Here, we discuss the use of big data for developing evidence-based hearing health policies, using data collected and analyzed with a research prototype of a data repository known as EVOTION (EVidence-based management of hearing impairments: public health pOlicy-making based on fusing big data analytics and simulaTION), to illustrate our points. Data in the repository consist of audiometric clinical data, prospective real-world data collected from hearing aids and an app, and responses to questionnaires collected for research purposes. To date, we have used the platform and a synthetic dataset to model the estimated risk of noise-induced hearing loss and have shown novel evidence of ways in which external factors influence hearing aid usage patterns. We contend that this research prototype data repository illustrates the value of using big data for policy-making by providing high-quality evidence that could be used to formulate and evaluate the impact of hearing health care policies.

Public health policy-making for hearing loss: stakeholders' evaluation of a novel eHealth tool.

BACKGROUND: Hearing loss (HL) affects 466 million people of all ages worldwide, with a rapidly increasing prevalence, and therefore requires appropriate public health policies. Multi-disciplinary approaches that make use of eHealth services can build the evidence to influence public policy. The European Union-funded project EVOTION developed a platform that is fed with real-time data from hearing aids, a smartphone, and additional clinical data and makes public health policy recommendations based on hypothetical public health policy-making models, a big data engine and decision support system. The present study aimed to evaluate this platform as a new tool to support policy-making for HL. METHODS: A total of 23 key stakeholders in the United Kingdom, Croatia, Bulgaria and Poland evaluated the platform according to the Strengths, Weaknesses, Opportunities and Threats methodology. RESULTS: There was consensus that the platform, with its advanced technology as well as the amount and variety of data that it can collect, has huge potential to inform commissioning decisions, public health regulations and affect healthcare as a whole. To achieve this, several limitations and external risks need to be addressed and mitigated. Differences between countries highlighted that the EVOTION tool should be used and managed according to local constraints to maximise success. CONCLUSION: Overall, the EVOTION platform can equip HL policy-makers with a novel data-driven tool that can support public health policy-making for HL in the future.

Adult normative data for the speech in babble (SiB) test.

Objective: The Speech in Babble (SiB) test assesses the perception of speech in noise in UK adults. Here, we define the normal range of SiB scores to enable the use of the test in clinic.Design: In each test, 25 monosyllabic words were played in background multi-talker babble. Listeners had to repeat the word they heard. An adaptive procedure was used to determine the signal-to-noise ratio needed to reach 50% correct responses (i.e. the Speech Reception Threshold). Eight distinct equivalent lists were available.Study sample: Sixty-nine normal-hearing adults (aged 20-57 years) with no reported listening difficulties participated in the study and completed the SiB test twice in both ears.Results: Normative SiB scores varied from -0.8 dB to 3.7 dB suggesting that patients outside these limits should be considered as having abnormal scores. No statistically significant difference between ears and no effect of age or sex was found. There was "fair" test-retest reliability.Conclusion: The SiB test is a short, valid and reliable test that can be used in UK clinics, e.g. as part of a standard APD battery or evaluating the performance of hearing impaired patients.

Practical guidelines to minimise language and cognitive confounds in the diagnosis of CAPD: a brief tutorial.

OBJECTIVE: To provide audiologists with strategies to minimise confounding cognitive and language processing variables and accurately diagnose central auditory processing disorder (CAPD). DESIGN: Tutorial. STUDY SAMPLE: None. RESULTS: Strategies are reviewed to minimise confounding cognitive and language processing variables and accurately diagnose CAPD. CONCLUSIONS: Differential diagnosis is exceedingly important and can be quite challenging. Distinguishing between two or more conditions presenting with similar symptoms or attributes requires multidisciplinary, comprehensive assessment. To ensure appropriate interventions, the audiologist is a member of the multidisciplinary team responsible for determining whether there is an auditory component to other presenting deficits or whether one condition is responsible for the symptoms seen in another. Choice of tests should be guided both by the symptoms of the affected individual, as established in an in-depth interview and case history, the individual's age and primary language, and by the specific deficits reported to be associated with specific clinical presentations. Knowing which tests are available, their strengths and limitations, the processes assessed, task and response requirements, and the areas of the central auditory nervous system (CANS) to which each test is most sensitive provides the audiologist with critical information to assist in the differential diagnostic process.

Auditory Training Effects on the Listening Skills of Children With Auditory Processing Disorder.

OBJECTIVES: Children with auditory processing disorder (APD) typically present with "listening difficulties,"' including problems understanding speech in noisy environments. The authors examined, in a group of such children, whether a 12-week computer-based auditory training program with speech material improved the perception of speech-in-noise test performance, and functional listening skills as assessed by parental and teacher listening and communication questionnaires. The authors hypothesized that after the intervention, (1) trained children would show greater improvements in speech-in-noise perception than untrained controls; (2) this improvement would correlate with improvements in observer-rated behaviors; and (3) the improvement would be maintained for at least 3 months after the end of training. DESIGN: This was a prospective randomized controlled trial of 39 children with normal nonverbal intelligence, ages 7 to 11 years, all diagnosed with APD. This diagnosis required a normal pure-tone audiogram and deficits in at least two clinical auditory processing tests. The APD children were randomly assigned to (1) a control group that received only the current standard treatment for children diagnosed with APD, employing various listening/educational strategies at school (N = 19); or (2) an intervention group that undertook a 3-month 5-day/week computer-based auditory training program at home, consisting of a wide variety of speech-based listening tasks with competing sounds, in addition to the current standard treatment. All 39 children were assessed for language and cognitive skills at baseline and on three outcome measures at baseline and immediate postintervention. Outcome measures were repeated 3 months postintervention in the intervention group only, to assess the sustainability of treatment effects. The outcome measures were (1) the mean speech reception threshold obtained from the four subtests of the listening in specialized noise test that assesses sentence perception in various configurations of masking speech, and in which the target speakers and test materials were unrelated to the training materials; (2) the Children's Auditory Performance Scale that assesses listening skills, completed by the children's teachers; and (3) the Clinical Evaluation of Language Fundamental-4 pragmatic profile that assesses pragmatic language use, completed by parents. RESULTS: All outcome measures significantly improved at immediate postintervention in the intervention group only, with effect sizes ranging from 0.76 to 1.7. Improvements in speech-in-noise performance correlated with improved scores in the Children's Auditory Performance Scale questionnaire in the trained group only. Baseline language and cognitive assessments did not predict better training outcome. Improvements in speech-in-noise performance were sustained 3 months postintervention. CONCLUSIONS: Broad speech-based auditory training led to improved auditory processing skills as reflected in speech-in-noise test performance and in better functional listening in real life. The observed correlation between improved functional listening with improved speech-in-noise perception in the trained group suggests that improved listening was a direct generalization of the auditory training.

Mobile telephone use effects on perception of verticality.

Low-level radiofrequency (RF) signals may produce disorientation and nausea. In experiment I, we assessed mobile phone effects on graviception in nine symptomatic subjects after mobile telephone use and 21 controls. The mobile handset was strapped to each ear for 30 min in pulsed emission, continuous RF emission, or no emission test mode, respectively. The subjective visual vertical and horizontal (SVV/SVH) were tested from min 25 of exposure. There was no exposure effect; however, there was an ear effect, with the SVV/SVH being shifted to the opposite direction of the ear exposed. This could be due to thermal or RF effects or handset weight. In experiment II, we assessed the handset weight effect on 18 normal controls. After baseline SVV/SVH, the switched off handset was strapped to either ear; the SVV/SVH was repeated 25 min later. A significant ear effect was found. We compared the observed ear effect SVV/SVH change in the experiment II group to the continuous exposure ear effect change in the experiment I group, and the difference was not significant. The ear effect was attributed to a minor head tilt due to the handset weight, or proprioceptive stimulation of neck muscle affecting the perception of verticality.

Peripheral vestibular dysfunction is prevalent in older adults experiencing multiple non-syncopal falls versus age-matched non-fallers: a pilot study.

BACKGROUND: vestibular disorders are common in the general population, increasing with age. However, it is unknown whether older adults who fall have a higher proportion of vestibular impairment compared with age-matched older adult non-fallers. OBJECTIVE: to identify whether a greater proportion of older adult fallers have a peripheral vestibular impairment compared with age-matched healthy controls. DESIGN: case-controlled study. SETTING: tertiary falls and neuro-otology clinics and local community centres, London, UK. PARTICIPANTS AND METHODS: community-dwelling older adults experiencing: (i) ≥2 unexplained falls within the previous 12-months (Group F, n = 25), (ii) a confirmed peripheral vestibular disorder (Group PV, n = 15) and (iii) healthy non-fallers (Group H, n = 16). All the participants completed quantitative vestibular function tests, the functional gait assessment (FGA), physiological profile assessment (PPA) and subjective measures for common vestibular symptoms (i.e. giddiness), balance confidence during daily activities and psychological state. RESULTS: a clinically significant vestibular impairment was noted for 80% (20/25) of Group F compared with 18.75% (3/16) for Group H (P < 0.01). Group F performed less well in complex gait tasks (FGA), and reported a greater number of falls than both Groups H and PV (P < 0.05). Vestibular symptom scores showed no significant difference between Groups F and PV. CONCLUSION: vestibular dysfunction is significantly more prevalent in older adult fallers versus non-fallers. Individuals referred to a falls clinic are older, more impaired and report more falls than those referred to a neuro-otology department. A greater awareness of vestibular impairments may lead to more effective management and treatment for older adult fallers.

Feasibility and effect of supplementing a modified OTAGO intervention with multisensory balance exercises in older people who fall: a pilot randomized controlled trial.

OBJECTIVE: To investigate the feasibility and comparative effect of supplementing a modified OTAGO falls rehabilitation programme with multisensory balance exercises and informed sample size calculation for a definitive trial. DESIGN: Single-blinded randomized controlled trial with pre/postcomparisons using a per-protocol analysis. SETTING: Secondary care-based falls clinic, London, UK. SUBJECTS: Community-dwelling older people (n = 21) experiencing ≥2 non-syncopal falls during previous 12 months. INTERVENTION: Modified OTAGO exercise classes supplemented with supervised home-based rehabilitation consisting of multisensory balance or stretching exercises. Group classes and home sessions each occurred twice-weekly for eight weeks. MEASUREMENTS: A computerised randomization was used for group allocation. A rater, blinded to intervention, performed the assessment including the Functional Gait Assessment (primary outcome), Physiological Profile Assessment, and questionnaires relating to symptoms, balance confidence, and psychological state (secondary outcomes). RESULTS: Significant within-group improvements were noted for the Functional Gait (p < 0.01, r = -0.63) and Physiological Profile Assessments (p < 0.05, r = -0.63) in the OTAGO+multisensory rehabilitation group only and for balance confidence scores in the OTAGO+stretching group (p < 0.01, r = -0.63). Between-group differences were noted for the Functional Gait (p < 0.01, r = -0.71) and Physiological Profile (p < 0.05, r = -0.54) assessments with the OTAGO+multisensory group showing significantly greater improvement. The drop-out rate was similar for both groups (~30%). No serious adverse events were reported. CONCLUSIONS: Supplementing the OTAGO programme with multisensory balance exercises is feasible in older people who fall and may have a beneficial effect on falls risk as measured using the Functional Gait and Short-form Physiological Profile Assessments. An adequately powered randomized controlled trial would require 36 participants to detect an effect size of 1.35 on the Functional Gait Assessment.