CAOHC Exam Study

CAOHC Exam Study Unit of measurement for frequency (pitch) - ANS Hertz (Hz) Unit of measurement for intensity (loudness) - ANS Decibel (dB) Risk of damage from noise - ANS How loud (intensity) and how long (duration) Steady-state or continuous noise, e.g. generator - ANS Lasts 1 second or longer Impulse or Impact noise, e.g. gunfire or nail gun - ANS Lasts less than one second Parts of the outer ear - ANS Pinna and external auditory canal Parts of the middle ear - ANS Tympanic membrane, ossicles, eustachian tube Eustachian tube (auditory tube) - ANS Tube connecting the middle ear to the pharynx and equalizes middle ear space with atmospheric pressure Conductive HL occurs here - ANS Outer or middle ear Sensorineural hearing loss - ANS Hearing loss resulting from damage to the inner ear (cochlea) or the auditory nerve Noise-induced hearing loss (NIHL) - ANS Condition caused by the destruction of hair cells, the organs responsible for hearing, as a result of sounds that are "too long, too loud, or too close"; a sensorineural hearing loss Mixed hearing loss - ANS Combination of conductive and sensorineural types in the same ear Middle ear bones (ossicles) - ANS Malleus (hammer), incus (anvil), stapes (stirrup) Possible early symptoms/signs of noise induced hearing loss - ANS Tinnitus; difficulty understanding in presence of background noise; read visual cues Auditory effects of noise - ANS NIHL; tinnitus; hyperacusis Non-auditory effects of noise - ANS annoyance sleep disturbance attention motivation stress reactions cardiovascular problems endocrine problems 3 foot rule - ANS Good rule of thumb to recognize hazardous noise exposure levels/situations: the rule is: if you have to shout at arms length (~3ft), in order to be understood over the background noise, then you're likely exposed to hazardous noise levels & should be wearing hearing protection to prevent NIHL OSHA (Occupational Safety and Health Administration) versus National institute of Occupational Safety and Heath (NIOSH) - ANS OSHA enforces regulation and NIOSH recommends best practice based on science and research Sound pressure level (SPL) versus hearing level (HL) - ANS SPL describes noise measurements taken with a sound level meter or dosimeter; HL describes Threshold levels obtained with an audiometer; 0 dB HL is not equal to 0 dB SPL Noise Dosimeter - ANS A sound measurement device used to record the amount of sound exposure over an extended period of time (usually a work day) Personal vs. Area Sound level meter - ANS Uses a microphone to sense pressure variations in sound waves; the meter converts those pressures directly into decibels; provides a noise measurement that is a snapshot in time. Time Weighted Average (TWA) - ANS An evaluation of exposures that is time-weighted over an established period. It allow the exposure levels to be averaged generally over an eight-hour time period. OSHA exchange rate - ANS 5 dB; for every 5 dB you go over the PEL of 90dBA TWA you half the allowable time of exposure OSHA Action Level for noise - ANS 85dBA TWA Sound Level Meter A-weighted Scale - ANS OSHA requires this scale as it resembles how the human ear responds to sound (humans hear best from 500 Hz to 4000 Hz Human Frequency Response at Birth - ANS 20 Hz to 20,000 Hz (20 kHz) Human speech frequency range - ANS 250 Hz to 4000 Hz Elements of a Hearing Conservation Program - ANS Noise hazard assessment; engineering/administrative controls; annual hearing monitoring; annual training/education; hearing protection; recordkeeping OSHA Noise Amendment - ANS 29 CFR 1910.95 Hughson-Westlake Procedure - ANS Common procedure for obtaining threshold; the audiologist decreases stimulus intensity by 10 dB with a (+) response and increases by 5 dB with a (-) response Hearing threshold level - ANS Lowest intensity level responded to at least 50% of the time Excessive noise levels will impact these test frequencies during a hearing exam - ANS Low frequencies e.g. 500 Hz First frequency always tested on an occupational hearing exam - ANS 1000 Hz 1000 Hz retest - ANS Done as a validity check on first ear tested; thresholds should be within 5dB or should reinstruct patient and start test over Presbycusis - ANS A gradual loss of sensorineural hearing that occurs as the body ages Professional Supervisor In a HCP - ANS Responsible for oversight of Audiometric testing; reviews problem audiograms; must be an audiologist or physician Elements of a Hearing Conservation Program - ANS Mandatory and includes: exposure monitoring, audiometric testing, hearing protection, employee training, record keeping, and program evaluation Noise Controls - ANS At the source (preferred), along the path, at the receiver Industrial Hygienist - ANS Responsible for assessment of hazards that may affect workers as well as hazards that may impact the community. NRR - ANS Noise Reduction Rating; number determined in a laboratory Hearing protection derating - ANS OSHA recommends to reduce NRR in half Hearing protection types - ANS Noise reduction devices worn over the ear (noise muffs) or inside the ear canal (earplugs) in work or recreational settings with high noise levels Best hearing protection - ANS The one that is worn (consistently and properly) Dual hearing protection NRR - ANS After derating add additional 5dB of protection Inverse square law for noise - ANS For every doubling of distance away from a noise source you reduce the level by 6 dB Noise doubling rule - ANS If you add two identical noise sources you add 3dB to the Level (100 dB + 100 dB = 103 dB) Administrative noise controls - ANS Changes made by employer such as changing work schedules to reduce noise hazard risk to employees OSHA standard threshold shift - ANS 10dB average change at 2000 Hz, 3000 Hz, and 4000 Hz, when compared to a baseline , in one or both ears OSHA Recordable Standard Threshold Shift for Hearing Loss - ANS 3 criteria: 10dB average shift at 2, 3, and 4kHz, compared to baseline, AND 25 dB average HL at 2, 3, and 4 kHz in the same ear on current audiograms, AND determined to be work-related Collapsing ear canal - ANS Occurs naturally in some individuals during audiometric testing-earphones cause auricle to move forward collapsing the canal and causing an artificial hearing loss; Insert earphones should be used Cochlea - ANS 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 - ANS Automated computer controlled audiometer Tinnitus - ANS A jingling; a ringing or buzzing in the ear Type of hearing test done by a certified occupational Hearing conservationist (COHC) - ANS Air Conduction Pure Tone Threshold Test Hearing Threshold Level (HTL) are recorded on this - ANS Audiogram (can be serial or graphic) Baseline Hearing Test Must Be Done Within - ANS 6 months of starting employment (exception for mobile vans is up to 1 year) Type of Hearing Loss that is treatable (medically or surgically) - ANS Conductive hearing loss Temporary Threshold Shift (TTS) - ANS Brief exposure to intense noise that will ordinarily recover with auditory rest Hearing Thresholds Tested are: - ANS 500, 1000, 2000, 3000, 4000, and 6000 Hz; 8000 Hz is optional but recommended. Audiometric zero is: - ANS 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: - ANS Intensity levels which are measured in Decibels (softest at the top, loudest at the bottom) Horizontal axis on a graphic Audiogram shows this: - ANS Frequencies which are measured in Hertz (low to high going from left to right) Hearing Baselines are reestablished when you have an STS because: - ANS You don't want to identify the same shift each ear #Days to notify individual of an STS in writing - ANS 21 days OSHA versus NIOSH Noise Permissible Exposure Limit (PEL) - ANS 90 dBA PEL for OSHA; 85 dBA PEL recommended by NIOSH OSHA recommendations for Audiometric Records - ANS Maintain for duration of employment; NIOSH recommends duration of employment + 30 years Sound Level Meter Microphone Type Required by OSHA - ANS Minimum of Type 2 microphone Formable Earplugs are: - ANS Disposable when no longer return to shape and soiled Pre-formed earplugs: - ANS Can be washed with mild soap and water and reusable Noise muff cushions - ANS 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 - ANS Tests are to be done without hearing aids Function of the Outer Ear - ANS Collecting sound and sending it to the eardrum through the auditory canal Function of the Middle Ear - ANS 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 - ANS 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 - ANS Conductive hearing loss When sound presented to the poorer ear crosses through the skull and is picked up by the better ear, this phenomenon is referred to as: - ANS Crossover The Action Level for OSHA and NIOSH is: - ANS 85 dBA TWA Weighting scale required by OSHA for Hearing Conservation Program Noise Assessments: - ANS A weighted scale; response resembles how the human ear responds to sound (humans hear best from 500-4000 Hz) This weighting scale is best for determining hearing protection attenuation - ANS C weighted scale; has a flat response with all frequencies equally weighted This Hearing Conservation Regulation is the minimum standard - ANS OSHA Noise Amendment Best audiometer for testing multiple stations - ANS Microprocessor Audiometer Best audiometer for testing difficult-to-test patients - ANS Manual Audiometer Calibration of audiometer performed daily with a electroacoustic simulator or human ear is called a: - ANS Biologic calibration A check of audiometer performed daily to ensure there are no intermittent problems with hardware is called a: - ANS Functional Check