CAOHC Exam Prep - Questions with Verified Answers Collapsing ear canal Occurs naturally in some individuals during audiometric testing-earphones cause
... [Show More] auricle to move forward collapsing the canal and causing an artificial hearing loss; Insert earphones should be used Cochlea A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses; damage from hazardous noise occurs here. Microprocessor audiometer Automated computer controlled audiometer Tinnitus A jingling; a ringing or buzzing in the ear Type of hearing test done by a certified occupational Hearing conservationist (COHC) Air Conduction Pure Tone Threshold Test Hearing Threshold Level (HTL) are recorded on this Audiogram (can be serial or graphic) Baseline Hearing Test Must Be Done Within 6 months of starting employment (exception for mobile vans is up to 1 year) Type of Hearing Loss that is treatable (medically or surgically) Conductive hearing loss Temporary Threshold Shift (TTS) Brief exposure to intense noise that will ordinarily recover with auditory rest Hearing Thresholds Tested are: 500, 1000, 2000, 3000, 4000, and 6000 Hz; 8000 Hz is optional but recommended. Audiometric zero is: 0 dB HL; this is not an absence of sound HL scale has been normalized to healthy adult hearing Vertical axis on a graphic Audiogram shows this: Intensity levels which are measured in Decibels (softest at the top, loudest at the bottom) Horizontal axis on a graphic Audiogram shows this: Frequencies which are measured in Hertz (low to high going from left to right) Hearing Baselines are reestablished when you have an STS because: You don't want to identify the same shift each ear #Days to notify individual of an STS in writing 21 days OSHA versus NIOSH Noise Permissible Exposure Limit (PEL) 90 dBA PEL for OSHA; 85 dBA PEL recommended by NIOSH OSHA recommendations for Audiometric Records Maintain for duration of employment; NIOSH recommends duration of employment + 30 years Sound Level Meter Microphone Type Required by OSHA Minimum of Type 2 microphone Formable Earplugs are: Disposable when no longer return to shape and soiled Pre-formed earplugs: Can be washed with mild soap and water and reusable Noise muff cushions Should completely cover ear and seal against the face; cushions should be replaced when damaged and no longer seal effectively. Hearing Aids and Hearing Test Tests are to be done without hearing aids Function of the Outer Ear Collecting sound and sending it to the eardrum through the auditory canal Function of the Middle Ear Amplification of sound; lever action of the ossicular chain and the mismatch in size of eardrum and oval window amplify sound about 10 times Function of the Inner Ear Convert mechanical sound waves to neural impulses that can be recognized by the brain for hearing and balance This type of hearing loss is treatable Conductive hearing loss [Show Less]