2024 Stellenbosch Postgraduate Diploma in Occupational Medicine PDF

STELLENBOSCH POSTGRADUATE DIPLOMA IN OCCUPATIONAL MEDICINE - 2024 THEME: Occupational Noise Induced Hearing Loss TOPIC: OCCUPATIONAL NOISE-INDUCED HEARING LOSS (ONIHL) AND THE ROLE OF AUDIOLOGISTS IN REFERRAL, SCREENING, DIAGNOSIS, AND MANAGEMENT. PRESENTERS:...

STELLENBOSCH POSTGRADUATE DIPLOMA IN OCCUPATIONAL MEDICINE - 2024 THEME: Occupational Noise Induced Hearing Loss TOPIC: OCCUPATIONAL NOISE-INDUCED HEARING LOSS (ONIHL) AND THE ROLE OF AUDIOLOGISTS IN REFERRAL, SCREENING, DIAGNOSIS, AND MANAGEMENT. PRESENTERS: PROFS KATIJAH KHOZA-SHANGASE & NOMFUNDO MOROE CoI/Declarations/ Acknowledgements CoI: None Declarations: None Acknowledgements: What’s covered… 1. Introduction & Causes and Risk Factors 2. Clinical Presentation 3. Audiological Evaluation & Referral Process 4. Screening Strategies 5. Diagnosis and Classification PLUS …Case Studies 6. Management and Intervention 7. Preventive Measures 1. INTRODUCTION Hearing Importance in Definition and Prevalence of Occupational Settings: ONIHL Definition Prevalence of ONIHL of ONIHL Overall well-being Type of SNHL caused by prolonged or Global Impact: repeated exposure to high levels of noise in According to the WHO, occupational noise the workplace. exposure is a leading cause of hearing loss Safety Damaging effects of noise on the delicate worldwide, affecting millions of workers structures of the inner ear result in across various industries. permanent hearing impairment, typically South African Context: affecting high-frequency sounds first. Statistics from the Department of Employment and Labour in South Africa indicate that a significant percentage of Communication workers experience NIHL, especially in industries such as manufacturing, mining, construction, and transportation. High-Risk Industries: Industries with high rates of ONIHL often involve machinery, equipment, tools, and processes that generate excessive noise levels, surpassing safe exposure limits. Challenges confronting SA mines: e.g. context Economic and Social Impact ONIHL can lead to: Reduced earning potential, Job dissatisfaction, and Individuals: Career limitations for affected workers ONIHL may necessitate: Job accommodations Rehabilitation services, and Ongoing medical expenses The presence of ONIHL among workers can Workplaces: result in: Decreased productivity, Increased absenteeism, and Higher rates of workplace accidents and errors Managing ONIHL imposes healthcare costs for: Diagnostic evaluations, Healthcare Hearing aid fittings, Rehabilitation services, and Long-term follow-up care. Systems: Additionally, societal costs include: Disability benefits, Compensation claims, and Vocational rehabilitation programmes. CAUSES AND RISK FACTORS Damage to Inner Ear Hair Common Sources of Cells: Occupational Noise Industrial machinery, such as Machinery presses, grinders, and saws, and drills, Equipment: produce high levels of noise during Continuous operation. or Mechanism Engines in vehicles, Intermittent of Damage: aircraft, and heavy Exposure: Engines and equipment generate loud noise, Vehicles: especially in close proximity or enclosed spaces. When exposed to loud noise, Loud noises cause the hair sound waves enter the ear cells to vibrate excessively, Construction tools and stimulate the hair cells in leading to physical trauma like jackhammers, the cochlea. and cell death. chainsaws, and Prolonged or repeated Over time, this damage Power Tools: pneumatic drills exposure to high-intensity accumulates, resulting in emit intense noise noise can damage these SNHL, where the inner ear's levels during use. delicate hair cells. ability to transmit sound signals to the brain is compromised. Risk Factors 2. CLINICAL PRESENTATION Primary Symptoms of ONIHL Progression of ONIHL  Difficulty Hearing Speech in Noisy  Gradual Onset: Environments:  ONIHL typically develops gradually over time with  Individuals with ONIHL may struggle to repeated exposure to hazardous noise levels. understand speech, especially in environments  Initial symptoms may be subtle and overlooked, with background noise. especially in the early stages of hearing damage.  This difficulty can lead to communication  High-Frequency Hearing Loss: challenges, misunderstandings, and frustration.  The initial impact of ONIHL often manifests as difficulty hearing high-pitched sounds, such as  Ringing or Buzzing Sounds (Tinnitus): consonants in speech.  Tinnitus is a common symptom of ONIHL  This high-frequency hearing loss can affect speech characterized by the perception of ringing, clarity and understanding, particularly in noisy buzzing, or hissing sounds in one or both ears. backgrounds.  It can be persistent or intermittent and may  Progression to Speech Understanding: worsen in quiet settings or at night.  As ONIHL advances, individuals may experience  Increased Sensitivity to Loud Noises: challenges understanding speech, especially in noisy or  ONIHL can cause hyperacusis, a heightened crowded environments. sensitivity to loud sounds.  They may require louder speech volumes  Affected individuals may find normal (?amplification) or visual cues to compensate for reduced auditory clarity. environmental sounds uncomfortably loud or painful, impacting their daily activities and social Overall Hearing Sensitivity: interactions. Over time, ONIHL can progress to affect the entire frequency range, leading to a generalized hearing loss that impacts various aspects of daily life, including work, social interactions, and leisure activities.  3. Audiological Evaluation & Referral Process Audiological Evaluation Audiologist's Comprehensive Key role in assessing ONIHL through a series of comprehensive evaluations aimed at determining the extent Role in Evaluations: and nature of hearing loss due to occupational noise exposure. Assessing Gathering detailed information about the individual's ONIHL History Taking: occupational noise exposure history - duration, intensity, and types of noise encountered in the workplace. Individual's symptoms related to hearing, e.g. difficulty Symptom Assessment: understanding speech, tinnitus, hyperacusis, and changes in hearing sensitivity. Audiometric Pure-Tone Audiometry: Hearing thresholds at various frequencies (e.g., 250 Hz to 8000 Hz) - degree and configuration of loss. Testing ONIHL typically exhibit a characteristic high frequency HL - damage to the cochlea from noise exposure (basal turn). Evaluates the individual's ability to understand and repeat Speech Audiometry: words or sentences presented at different volume levels. Speech discrimination & understanding in quiet and noisy environments, simulating real-life communication challenges. Evaluation of middle ear function Tympanometry Evaluates the function of the middle ear and the mobility of the eardrum (TM). Identification of conductive hearing losses. CHL caused by conditions such as fluid in the middle ear (otitis media), eardrum perforations, or problems with the middle ear ossicles (e.g., ossicular chain discontinuity). Referral Process Criteria for Suspected Hearing Loss: Individuals who report symptoms suggestive of hearing loss, e.g., difficulty understanding speech, tinnitus, or Referring increased sensitivity to loud noises Individuals for Individuals with a history of significant occupational noise Audiological Occupational Noise exposure, including prolonged or repeated exposure to loud machinery, equipment, or industrial environments Evaluation Exposure History: Individuals who undergo routine hearing screenings and Abnormal Screening exhibit abnormal results, e.g., elevated thresholds or asymmetrical hearing loss Results: Importance of Occupational Health OHPs, including occupational health nurses, physicians, and safety officers, play a crucial role in identifying individuals Collaboration at risk for ONIHL based on workplace noise exposure for Referrals Professionals (OHPs): assessments, health surveillance programmes, and employee health histories. and Follow- Collaborate with OHPs to facilitate timely referrals for Up Care Audiologists: individuals suspected of ONIHL. Conduct comprehensive audiological evaluations, interpret results, and provide diagnostic assessments and recommendations for management and intervention. Essential partners in the referral process… provide access Employers: to occupational health services, HCPs, and resources for hearing protection. Support follow-up care by ensuring that employees receive appropriate interventions, accommodations, and ongoing monitoring 4. Screening Strategies* Importance of Regular Common Screening Tools Used by Hearing Screenings in High- Audiologists Noise Workplaces Early Detection of ONIHL: Regular hearing screenings NB to detect early signs of Audiometers: ONIHL and monitor changes in hearing thresholds over time. Pure-tone audiometry, conducted in a Early detection allows for timely intervention and Standard diagnostic devices used to measure soundproof booth, assesses an individual's ability preventive measures to mitigate further hearing damage. hearing thresholds at different frequencies (e.g., to hear tones of varying intensity and frequency… 250 Hz to 8000 Hz). valuable information about the presence and severity of hearing loss. Compliance with Regulations: Many occupational safety regulations and standards require employers to conduct periodic hearing screenings for employees exposed to hazardous noise levels. Compliance with these regulations ensures a proactive Otoacoustic Emissions (OAE) Tests: approach to protecting workers' hearing health. Measure the response of the inner ear (cochlea) Often used as a screening tool to assess cochlear to sound stimuli by detecting the emission of function and identify individuals with normal or sound waves produced by healthy outer hair near-normal hearing sensitivity (& middle ear cells. disease). Preventive Action: Hearing screenings help identify individuals at risk for ONIHL and facilitate implementation of HCPs, including education on noise exposure risks, use of hearing protection devices (HPDs), and engineering controls to reduce noise levels. Online Self-Assessment Questionnaires: Administered through web-based platforms or Convenient tools that individuals can use to self- mobile applications… provide preliminary report hearing-related symptoms, exposure to information for audiologists to assess hearing noise, and perceived hearing difficulties. health status and guide further evaluation if indicated. 5. Diagnosis and Classification* ONIHL Diagnosis Based on Classification of ONIHL Severity Levels Audiometric Findings Mild ONIHL (26-40 dB HL): Slight to moderate hearing loss, typically affecting Noise-Induced high-frequencies Audiometric findings of Damage May experience difficulty understanding speech in elevated hearing Pattern: noisy environments and may benefit from hearing thresholds, esp at Compare the individual's conservation strategies and regular monitoring. specific frequencies Characteristic pattern of audiometric results to commonly affected by hearing loss - "notch" or normative data or age- noise-induced damage. dip in hearing specific standards to Moderate ONIHL (41-55 dB HL): High frequencies (e.g., thresholds at the high determine the presence and severity of ONIHL. Moderate hearing loss, impacting speech 3000 Hz, 4000 Hz, 6000 frequencies on the understanding and communication abilities, Hz, and 8000 Hz) audiogram. Comparison to especially in challenging listening situations. Elevated Normative Hearing aids and assistive listening devices may Hearing be recommended to improve auditory function. Data: Thresholds: Severe ONIHL (56-70 dB HL): Significant hearing impairment, affecting speech understanding, social interactions, and daily activities. Management strategies may include hearing aids, communication training, and workplace accommodations to optimize communication and participation. Profound ONIHL (71+ dB HL): Profound hearing loss, where individuals have limited residual hearing and may rely on alternative communication modalities such as sign language, lip reading, or cochlear implants for auditory rehabilitation. 6. Management and Intervention* Audiologists' Role in Developing Personalized Management Plans Assessment and Evaluation: Personalized  Conduct comprehensive assessments to Recommendations: determine the extent and impact of  Based on assessment results - develop ONIHL on an individual's hearing personalized management plans tailored abilities, communication skills, and to the individual's specific needs, quality of life. preferences, and lifestyle factors. Hearing Conservation Programmes: Collaborate with employers to implement HCPs. HCPs include education on noise hazards, proper use of hearing protection devices (HPDs), and regular audiometric monitoring. Hearing conservation programmes Importance of Hearing Protection Devices (HPDs) and Engineering Controls  e.g., earplugs and earmuffs …crucial in reducing noise exposure and protecting hearing health in high-noise environments. HPDs:  Audiologists educate individuals on the selection, fitting, and proper use of HPDs to ensure maximum effectiveness in noise reduction. Audiologists collaborate with occupational safety professionals and engineers to implement engineering controls, Engineering e.g. sound barriers, acoustic enclosures, and noise- Controls: reducing machinery (“buying quiet”), to minimize noise levels in the workplace. These controls complement HPDs and contribute to a safer work environment with reduced noise exposure risks.  Rehabilitation Options for Individuals with ONIHL Hearing Aids: Residual hearing and mild to moderate ONIHL - hearing aids to amplify sounds, improve speech clarity, and enhance communication abilities. Cochlear Implants: Severe to profound ONIHL with limited benefit from hearing aids - cochlear implants may be considered. Audiologists provide pre- and post-implantation evaluations, programming, and rehabilitation services for cochlear implant recipients. Auditory Training: Auditory training programmes to help individuals with ONIHL improve listening skills, speech understanding, and auditory processing abilities. May include exercises, speech perception tasks, and adaptive strategies to optimize communication in challenging listening environments. Communication Strategies: Audiologists teach communication strategies such as lip reading, speechreading, and sign language to individuals with ONIHL who rely on visual cues for communication. These strategies enhance communication effectiveness and promote social inclusion for individuals with hearing loss. 7. Preventive Measures Significance of Preventive Measures Implementing Crucial in identifying engineering controls, areas with hazardous administrative measures, noise levels and assessing and workers' risk of ONIHL. personal protective Audiologists and equipment (PPE) occupational health professionals collaborate Examples: to: sound barriers, measure noise levels, acoustic enclosures, determine exposure noise-reducing machinery, durations, and job rotation, and Noise identify high-risk zones Workplace work scheduling to limit requiring intervention. Exposure noise exposure durations Noise Assessments Controls: : Artificial Employee Intelligence/ Education on Providing comprehensive education and training Machine Hearing programmes to employees on Learning Protection: the importance of hearing protection, proper use of hearing protection devices (HPDs), and adherence to safety protocols (promotes a culture of hearing conservation and empowers workers to protect their hearing health) Advocacy for Regular Audiometric Monitoring Adherence to Regular Periodic Noise Occupational Audiometric Level Safety Monitoring: Measurements: Regulations:  To detect early signs of  To assess the Regulations, such as ONIHL and monitor effectiveness of noise OHS standards for changes over time. control measures, permissible exposure  Proactive approach  To identify areas of limits (PELs), allows for concern, and hearing conservation  timely intervention,  To ensure compliance programs (HCPs), and  adjustment of with occupational safety audiometric testing prevention strategies, regulations (e.g., OHSA requirements and standards, Occupational Ensure that employers  identification of Health and Safety Act, prioritize hearing health individuals requiring Regulations). and implement additional support or  Enables employers to comprehensive accommodations implement targeted measures to prevent interventions and ONIHL among workers. maintain a safe working environment. CASE STUDIES* Case Study 1: Assessment and Management Challenges  John works in a manufacturing plant exposed to high levels of noise from machinery. Scenario:  He undergoes audiometric testing and is diagnosed with moderate ONIHL, characterized by a high-frequency hearing loss and difficulty understanding speech in noisy environments. Assessment  John experiences challenges in accurately reporting his hearing difficulties due to concerns about job security and stigma associated with Challenges: hearing loss.  His audiogram reveals notches at high frequencies, indicating noise-induced damage. A multidisciplinary team comprising audiologists, Management occupational health professionals, and human resources (HR) personnel collaborates to address John's case. They implement hearing conservation measures, provide Strategies: counselling on hearing protection, and offer communication strategies and workplace accommodations (e.g., quieter workstations, amplified phones) to support John's communication needs. Case Study 2: Successful Outcome and Follow-Up Care Karabo, a construction worker, experiences gradual Scenario: hearing loss and tinnitus due to long-term exposure to loud equipment and tools. He undergoes audiometric testing and is diagnosed with severe ONIHL. Successful Karabo receives comprehensive rehabilitation services, including fitting of hearing aids and participation in auditory training programmes. Outcome: He also benefits from workplace modifications, such as noise-reducing barriers and regular audiometric monitoring. The multidisciplinary team conducts regular follow- Follow-Up up assessments to track Karabo's progress, adjust interventions as needed, and provide ongoing support and education on hearing conservation. Care: Karabo's successful outcome highlights the effectiveness of a collaborative approach in managing ONIHL and optimizing outcomes for individuals with hearing loss in occupational settings. Suggestions for Multidisciplinary Approaches Establishing Collaborative Partnerships: Collaborations between audiologists, occupational Open communication, shared goals, and mutual health professionals, employers, and employees to support in implementing preventive measures and address ONIHL comprehensively – COMPLEX managing ONIHL cases. INTERVENTIONS. Conducting Workplace Assessments: Regular noise assessments, workplace ergonomics To identify at-risk individuals, assess environmental evaluations, and employee health screenings. noise hazards, and implement targeted interventions. Providing Education and Training: Educational workshops, training sessions, and awareness campaigns on hearing conservation, noise Empower employees to take proactive steps in exposure risks, proper use of hearing protection protecting their hearing health. devices (HPDs), and early signs of ONIHL. Implementing Policy and Compliance Measures: Advocate for adherence to occupational safety Ensure that policies and procedures are in place to regulations, HCPs, and audiometric testing promote a safe and healthy work environment requirements. conducive to hearing preservation. Conclusion Key Takeaways Significance Importance of Vigilance Education and Awareness Collaboration and Multidisciplinary Approaches Further Initiatives Further research initiatives to deepen our understanding of ONIHL mechanisms, risk Development and implementation of robust occupational safety regulations, factors, prevention strategies, and standards, and guidelines that rehabilitation approaches. prioritize hearing conservation set permissible exposure limits (PELs) promote adherence to best practices in noise control and management Research Policy Advancements: Development: Training and Public Capacity Awareness Building: Campaigns: …professional development … educational initiatives, and opportunities, and capacity-building outreach programmes to initiatives for raise awareness about the impact of audiologists noise exposure on hearing health occupational health professionals encourage early detection of safety officers hearing loss employers promote proactive measures for (to enhance their knowledge, skills, preventing ONIHL in various and competencies in addressing industries and occupational ONIHL effectively) settings. WITS. FOR GOOD Where are audiologists??? WITS. FOR GOOD [email protected] [email protected]