Impact of aging on the auditory system and related cognitive functions: A narrative review

Age-related hearing loss (ARHL), presbycusis, is a chronic health condition that affects approximately one-third of the world’s population. The peripheral and central hearing alterations associated with age-related hearing loss have a profound impact on perception of verbal and non-verbal auditory stimuli. The high prevalence of hearing loss in the older adults corresponds to the increased frequency of dementia in this population. Therefore, researchers have focused their attention on age-related central effects that occur independent of the peripheral hearing loss as well as central effects of peripheral hearing loss and its association with cognitive decline and dementia. Here we review the current evidence for the age-related changes of the peripheral and central auditory system and the relationship between hearing loss and pathological cognitive decline and dementia. Furthermore, there is a paucity of evidence on the relationship between ARHL and established biomarkers of Alzheimer’s disease, as the most common cause of dementia. Such studies are critical to be able to consider any causal relationship between dementia and ARHL. While this narrative review will examine the pathophysiological alterations in both the peripheral and central auditory system and its clinical implications, the question remains unanswered whether hearing loss causes cognitive impairment or vice versa

Background report: Kurunegala, Sri Lanka

Development projects / Water resources / Social aspects / Population / Households / Income / Water supply / Sanitation / Wastewater / Water quality / Public health / Waterborne diseases / Land use / Land tenure / Legislation / Sri Lanka / Kurunegala / Wan Ela / Beu Ela

A study on behavioural effects of laboratory rats (albino wistar) after the sub-chronic noise stress

Background: Humans and animals can hear a wide range of sound frequencies. If the sense of hearing is impaired, both man and animal cannot fare well in their respective environments. Present study is aimed to investigate the behavioral effects following the sub-chronic noise stress of a rat species, Albino Wistar.Methods: The sound source consists of a set of speakers, GWINSTEK AFG-2000 series function generator and an amplifier. Sound levels and frequencies were monitored by B and K type 2250 sound level meter. Six adult Albino Wistars were exposed to sound frequencies of 1-20 kHz, at intervals of 1 kHz at LAeq of 70-80 dB for 5minute periods and their behavior was recorded. In the second test four adult rats were randomly divided into control and test groups. The test animals were exposed to noise of 7, 8, 9 and 10 kHz for 4hrs daily while keeping the control group in same room for same period of time without exposing to the sound. Locomotive activity, increase of defection and decrease of social activities, of rats was assessed by open field test (OFT). Anxiety and depressive behavior were monitored by elevated plus maze test (EPM) and tail suspension test (TST).Results: A different behavior in rats was observed in frequency range of 7-10 kHz. At the beginning of exposure, all rats were huddled in a group and then some were frozen into motionless stance. A less time spent and less number of entries in open arm was noticed in test sample compared to the controls in the EPM test. A tendency to move to open field compared to controls was identified in OFT. The TST revealed that a significant increase in immobility time, which indicates a depression like behavior of noise stressed rats compared to controls.Conclusions: According to the study the most effective noise frequency range for rats is 7-10 kHzl

Impact of the disaster-induced relocation process on the displaced communities in Kegalle district, Sri Lanka

Disaster induced displacement and relocation is a frequently occurring phenomenon in the Sri Lankan context. Resettlement has been recognized as a regular result of disasters such as landslides due to the large-scale property damage that occurs. This paper investigates the impact of the disasterinduced relocation process on displaced communities. The study revolves around the sub-objectives of investigating the various needs of victims in different stages of displacement and how relocation has altered the social, cultural, and livelihood dimensions of the victims. Victims of the Aranayake landslide who were residing in the Kegalle district and who were resettled mainly in a Donor Driven relocation site were selected for the study. A purposive sampling technique was implemented in two phases. In the first phase, in-depth interviews with officials and focus group interviews with community members were carried out. Next, a community needs analysis was conducted with the participation of the community and officials. The data suggests that there is a clear lacuna in strong, written policy frameworks and its practical implementation when satisfying the various needs of displaced communities. Being confined to only understanding the social and economic details of various displaced groups, policy planners have tended to neglect the necessity of conducting a needs analysis with the main reason being the lack of perception of relocation as a long-term process. Therefore, in conclusion, the study suggests a model that addresses the need for a holistic institutional arrangement with further disaster risk management strategies to address the adverse impact on the disaster-induced, displaced community

Auditory electrophysiological assessments of Alzheimer\u27s disease and preclinical stages: Protocol for a systematic review and meta-analysis

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. Introduction Investigating auditory functions in populations at risk of developing Alzheimer\u27s disease (AD) using auditory neurophysiological measurements can potentially identify a crucial and sensitive diagnostic window of opportunity in preclinical AD. Auditory electrophysiological assessments have gained interest as possible tools for early diagnosis of AD. This paper outlines the protocol that will be used to systematically review the published literature currently available on auditory electrophysiological assessments that have been used to assess the auditory functions of adults over the age of 60 years diagnosed with AD or its preclinical stages. Methods and analysis All full-length peer-reviewed publications of original data that use auditory electrophysiological assessments in AD and its preclinical stages (subjective cognitive decline (SCD) and mild cognitive impairment (MCI)) will be considered in this review. The search will be performed on major electronic databases (Ovid MEDLINE, Ovid Embase, PsycINFO, PubMed, Scopus and CINAHL Plus) using keywords alone or in combination with Medical Subject Headings divided into two domains; (i) auditory tests and (ii) AD. The database search will be conducted on the 7 th of May 2019. Data analysis will be completed and reported in the full review. A random effects meta-analysis will also be conducted using the Comprehensive Meta-Analysis software, V.3. This review will describe which auditory electrophysiological tests have been found to be useful in assessing the auditory function in cognitively impaired adults (MCI and AD) or adults with serious complaints about their cognition (SCD). This review will also identify and describe which auditory electrophysiological test demonstrates the most sensitivity in differentiating people at different stages of cognitive decline. Ethics and dissemination This systematic review focusses on analysing already available literature. Therefore, there will be no requirement for ethical approval. The systematic review findings will be disseminated through peer-reviewed publication as well as relevant media platforms, for example, conferences. Systematic review registration PROSPERO CRD42019133553

Understanding the relationship between age-related hearing loss and Alzheimer\u27s disease: A narrative review

Evidence suggests that hearing loss (HL), even at mild levels, increases the long-term risk of cognitive decline and incident dementia. Hearing loss is one of the modifiable risk factors for dementia, with approximately 4 million of the 50 million cases of dementia worldwide possibly attributed to untreated HL. This paper describes four possible mechanisms that have been suggested for the relationship between age-related hearing loss (ARHL) and Alzheimer\u27s disease (AD), which is the most common form of dementia. The first mechanism suggests mitochondrial dysfunction and altered signal pathways due to aging as a possible link between ARHL and AD. The second mechanism proposes that sensory degradation in hearing impaired people could explain the relationship between ARHL and AD. The occupation of cognitive resource (third) mechanism indicates that the association between ARHL and AD is a result of increased cognitive processing that is required to compensate for the degraded sensory input. The fourth mechanism is an expansion of the third mechanism, i.e., the function and structure interaction involves both cognitive resource occupation (neural activity) and AD pathology as the link between ARHL and AD. Exploring the specific mechanisms that provide the link between ARHL and AD has the potential to lead to innovative ideas for the diagnosis, prevention, and/or treatment of AD. This paper also provides insight into the current evidence for the use of hearing treatments as a possible treatment/prevention for AD, and if auditory assessments could provide an avenue for early detection of cognitive impairment associated with AD

Comparison of auditory steady-state responses with conventional audiometry in older adults

Behavioral measures, such as pure-tone audiometry (PTA), are commonly used to determine hearing thresholds, however, PTA does not always provide reliable hearing information in difficult to test individuals. Therefore, objective measures of hearing sensitivity that require little-to-no active participation from an individual are needed to facilitate the detection and treatment of hearing loss in difficult to test people. Investigation of the reliability of the auditory steady-state response (ASSR) for measuring hearing thresholds in older adults is limited. This study aimed to investigate if ASSR can be a reliable, objective measure of frequency specific hearing thresholds in older adults. Hearing thresholds were tested at 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz in 50 participants aged between 60 and 85 years old, using automated PTA and ASSR. Hearing thresholds obtained from PTA and ASSR were found to be significantly correlated (p \u3c .001) in a cohort consisting of participants with normal hearing or mild hearing loss. ASSR thresholds were significantly higher as compared to PTA thresholds, but for the majority of cases the difference remained within the clinically acceptable range (15 dB). This study provides some evidence to suggest that ASSR can be a valuable tool for estimating objective frequency-specific hearing thresholds in older adults and indicate that ASSR could be useful in creating hearing treatment plans for older adults who are unable to complete behavioral PTA. Further research on older adults is required to improve the methodological features of ASSR to increase consistency and reliability, as well as minimize some of the limitations associated with this technique

LAND USE PLANNING FOR AGRO - FORESTRY PROGRAMMES IN TEA ESTATES

Land use planning in tea estates is of prime importance in order to identify profitable andenvironmentally friendly land use options for lands unsuitable for tea. Agro-forestry isone of the land use options adopted in tea estates in order to meet the high fuel woodrequirements of tea factories and estate labour communities. A study was undertaken toselect lands for Agro-Forestry Programmes in five estates in the Nuwara Eliya district.Geographic Information System was used as a tool for land suitability classification.Uneconomical lands were classified based on factors such as existing tea type and presentyield, geographical distribution within the estates, and slope and elevation. A range oflands were identified for immediate and future agro-forestry programmes. Potentialimprovement in profitability was estimated for individual estate and as a group of estates.

Impact of vision impairment and self-reported barriers to vision care: The views of elders in Nuwara Eliya district, Sri Lanka

The growing burden of vision impairment (VI) among older people is a development challenge in Asian countries. This study aimed to understand older people’s views and experiences about the impact of VI and barriers to eye care to inform policies to address this challenge. We conducted 12 focus group discussions in 2013 with retired Tamil and Sinhala elders in Nuwara Eliya district, Sri Lanka (n = 107). Data were analysed thematically. Older people described the broad impacts VI has on their lives. They worry about becoming dependent. VI restricts their ability to contribute to their families and communities, access information, socialise, maintain their health, and earn. Barriers to eye care services include transport difficulties, costs of treatment, fear, lack of knowledge, waiting times, and health staff attitudes. Older people experience and fear the impacts of VI on their health and well-being. Eye health promotion and care services need strengthening and integration with the primary health care system to address the backlog and growing need among older people in an equitable way. Older people should be consulted about how to overcome the economic, social, and cultural barriers to access to eye care and to minimise the impact of VI