4. Presbycusis.pptx

Presbycusis age related hearing loss

1. PRESBYCUSIS

2. INTRODUCTION Presbycusis , or age-related hearing loss (ARHL) , is the loss of hearing that gradually occurs in most people as they grow older. According to theWorld Health Organization, approximately one third of people over 65 years of age are affected by disabling hearing loss. In 2025, there will be 1.2 billion people over 60 years of age worldwide, with more than 500 million individuals who will suffer significant impairment from presbycusis

3. Age-related hearing loss according to the International Organization for Standardization

4. ARHL is a progressive, irreversible, and symmetrical bilateral neuro -sensory hearing loss resulting either from degeneration of the cochlea , or loss of auditory nerve fibers during cochlear aging associated with difficulty in speech discrimination, as well as in sound detection and localization, particularly in noise. Males are generally more severely affected than females Untreated presbycusis can contribute to social isolation, depression, and dementia

5. Epidemiology Increases with age. 25 – 30% of people aged 65 – 75 are estimated to have impaired hearing. For people aged 75 or older incidence is thought to be 40 – 50%

6. Proposed Etiologies Presbycusis is a multifactorial condition that represents the lifetime accumulation of both intrinsic and extrinsic insults on the inner ear, including the inner and outer hair cells, stria vascularis , and afferent spiral ganglion neurons

7. Risk Factors Four primary categories of risk factors for presbycusis : Cochlear aging, Noise exposure, Genetic predisposition, and Health comorbidities

8. Increasing Age strong, consistent association Increased mutations and deletions in mitochondrial DNA Noise Reactive oxygen species are believed to play a major role in cochlear aging, and they are also generated in response to noise exposure. Genetic Predisposition Male sex and race blacks consistently demonstrate 60% to 70% lower odds of hearing loss compared with whites Presbycusis has been found to cluster strongly in families. more pronounced for the strial atrophy pattern of hearing loss (flat audiogram) than the sensory phenotype (high-frequency loss) Proposed genes in recent studies include those that code for glutathione peroxidase and superoxide dismutase, two antioxidant enzymes active in the cochlea Health Comorbidities smoking and circulatory disorders such as hypertension, cardiovascular and cerebrovascular disease, and diabetes

9. Pathophysiology Histologic changes associated with aging occur throughout the auditory system from the hair cells of the cochlea to the auditory cortex in temporal lobe of the brain. Elucidation of pathophysiology of presbycusis is still incomplete.

10. Saxen , Gacke and Schuknecht Studied histologic changes in cochlea of human ears with presbycusis Identified 4 sites of aging in cochlea and divided presbycusis into 4 types based on these sites Histologic changes correlated approximately with symptoms and auditory test results

11. Sensory presbycusis Epithelial atrophy with loss of sensory hair cells as well as supporting cells in the organ of corti . Originates in basal turn of cochlea and slowly progress towards the apex. Affects first few millimeters of basal turn. Sharp drop in high frequency threshold, begins after middle age. Abrupt downward slope of audiogram begins above speech frequency, speech discrimination is preserved.

12. Histologically atrophy may be limited to only the first few millimetres of basal end of cochlea Process is slowly progressive over time Due to accumulation of lipofuscin pigment granules at the basal end of cochlea

13. Neural presbycusis Most common type. Atrophy of the spiral ganglion and nerves of osseous spiral lamina in the basal turn Organ of Corti is largely intact Schuknecht estimated that 2100/35000 neurons are lost every decade. Loss begins early in life and may be genetically predetermined. Effects not noticeable until old age because PTA not affected until 90% of neurons are gone.

14. Gradual hearing loss with moderate slope in high frequencies Disproportionate decline in speech discrimination Often refractory to amplification May be observed before hearing loss is noted because fewer neurons are required to maintain speech thresholds than speech discrimination

15. Metabolic ( strial ) Results as atrophy of stria vascularis . Normally maintains the chemical and bioelectrical balance and metabolic health of cochlea Hearing is represented by a flat hearing curve because entire cochlea is affected Speech discrimination is preserved Affects younger population (30 – 60 years) with slow progression and may be familial

16. Mechanical (i.e. cochlear conductive) Atrophy of the spiral ligament Primarily affects the apical turn Cystic degeneration may cause detachment of the organ of Corti from the lateral cochlear wall Bilateral symmetric loss with upward slope in high frequencies Preserved speech discrimination

17. INTERMEDIATE Change in characteristics of the cochlear duct that are not evident on light microscopy but alter function at sub microscopic level. Changes in intracellular organalles involved in cell metabolism,decrease in synapse numbers and changes in endolymph composition have all been implicated in this category.

18. MIXED Some combination of other five.

19. Clinical features Presentation varies Physological -Old patient at least in their fifties. H/O :Slow and insidious hearing problem Description involves loss of clarity rather than loss of volume. Difficulty in hearing conversation particularly in presence of background noise. Sometimes tinnitus may be the only presenting feature.

20. EXAMINATION Otological examination will be normal.

21. INVESTIGATION Audiology with PTA and speech discrimination Most commonly, the audiogram shows a hearing loss which tend to be worse at higher frequency. As the condition advances there tends to be progressive loss of be loss of middle( 1 and 2 KHz) and even low frequencies.(250 & 500hz).

22. DIAGNOSIS Age >60yrs. Normal examination finding. Symmetrical High frequency hearing loss.

23. MANAGEMENT NON SPECIFIC: PSYCHOLOGICAL AND PRACTICAL MEASURES. SPECIFIC

24. Specific management Binaural hearing aids. Tinnitus management. Tinnnitus retraining therapy Cognitive directive counselling. Sound therapy

25. recent emphasis has been placed on personal sound amplification products (PSAPs) and low-cost, community-based hearing interventions for older adults. Aside from amplification, correction of health factors that may impact age-related hearing loss—such as smoking, hypertension, and cholesterol levels—should also be considered. Cochlear implantation may play a role in treating older adults with severe to profound sensorineural deafness.

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