CAOHC Exam Study GUIDE - Questions and Answers

CAOHC Exam Study GUIDE "3 foot rule - Correct Answer 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) - Correct Answer OSHA enforces regulation and NIOSH recommends best practice based on science and research" "Sound pressure level (SPL) versus hearing level (HL) - Correct Answer 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 - Correct Answer 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 - Correct Answer 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) - Correct Answer 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 - Correct Answer 5 dB; for every 5 dB you go over the PEL of 90dBA TWA you half the allowable time of exposure" Unit of measurement for frequency (pitch) - Correct Answer Hertz (Hz)" "Unit of measurement for intensity (loudness) - Correct Answer Decibel (dB)" "Risk of damage from noise - Correct Answer How loud (intensity) and how long (duration)" "Steady-state or continuous noise, e.g. generator - Correct Answer Lasts 1 second or longer" "Impulse or Impact noise, e.g. gunfire or nail gun - Correct Answer Lasts less than one second" "Parts of the outer ear - Correct Answer Pinna and external auditory canal" "Parts of the middle ear - Correct Answer Tympanic membrane, ossicles, eustachian tube" "Eustachian tube (auditory tube) - Correct Answer Tube connecting the middle ear to the pharynx and equalizes middle ear space with atmospheric pressure" "Conductive HL occurs here - Correct Answer Outer or middle ear" "Sensorineural hearing loss - Correct Answer Hearing loss resulting from damage to the inner ear (cochlea) or the auditory nerve" "Noise-induced hearing loss (NIHL) - Correct Answer Condition caused by the destruction of hair cells in the inner ear, 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 - Correct Answer Combination of conductive and sensorineural types in the same ear" "Middle ear bones (ossicles) - Correct Answer Malleus (hammer), incus (anvil), stapes (stirrup)" "Possible early symptoms/signs of noise induced hearing loss - Correct Answer Tinnitus; difficulty understanding in presence of background noise; read visual cues" "Auditory effects of noise - Correct Answer NIHL; tinnitus; hyperacusis" "Non-auditory effects of noise - Correct Answer annoyance sleep disturbance attention motivation stress reactions cardiovascular problems endocrine problems" "OSHA Action Level for noise - Correct Answer 85dBA TWA" "Sound Level Meter A-weighted Scale - Correct Answer 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 - Correct Answer 20 Hz to 20,000 Hz (20 kHz)" "Human speech frequency range - Correct Answer 250 Hz to 4000 Hz" "Elements of a Hearing Conservation Program - Correct Answer Noise hazard assessment; engineering/administrative controls; annual hearing monitoring; annual training/education; hearing protection; recordkeeping" "OSHA Noise Amendment - Correct Answer 29 CFR 1910.95" "Hughson-Westlake Procedure - Correct Answer 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 - Correct Answer Lowest intensity level responded to at least 50% of the time" "Excessive noise levels will impact these test frequencies during a hearing exam - Correct Answer Low frequencies e.g. 500 Hz" "First frequency always tested on an occupational hearing exam - Correct Answer 1000 Hz" "1000 Hz retest - Correct Answer Done as a validity check on first ear tested; thresholds should be within 5dB or should reinstruct patient and start test over" "Presbycusis - Correct Answer A gradual loss of sensorineural hearing that occurs as the body ages" "Hearing protection derating - Correct Answer OSHA recommends to reduce NRR in half" "Hearing protection types - Correct Answer 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 - Correct Answer The one that is worn (consistently and properly)" "Dual hearing protection NRR - Correct Answer After derating add additional 5dB of protection" "Inverse square law for noise - Correct Answer For every doubling of distance away from a noise source you reduce the level by 6 dB" "Noise doubling rule - Correct Answer If you add two identical noise sources you add 3dB to the Level (100 dB + 100 dB = 103 dB)" "Administrative noise controls - Correct Answer Changes made by employer such as changing work schedules to reduce noise hazard risk to employees" "OSHA standard threshold shift - Correct Answer 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 - Correct Answer 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 - Correct Answer 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 - Correct Answer 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 - Correct Answer Automated computer controlled audiometer" "Tinnitus - Correct Answer A jingling; a ringing or buzzing in the ear" "Type of hearing test done by a certified occupational Hearing conservationist (COHC) - Correct Answer Air Conduction Pure Tone Threshold Test" "Hearing Threshold Level (HTL) are recorded on this - Correct Answer Audiogram (can be serial or graphic)" "Baseline Hearing Test Must Be Done Within - Correct Answer 6 months of starting employment (exception for mobile vans is up to 1 year)" "Type of Hearing Loss that is treatable (medically or surgically) - Correct Answer Conductive hearing loss" "Temporary Threshold Shift (TTS) - Correct Answer Brief exposure to intense noise that will ordinarily recover with auditory rest" "Hearing Thresholds Tested are: - Correct Answer 500, 1000, 2000, 3000, 4000, and 6000 Hz; 8000 Hz is optional but recommended." "Audiometric zero is: - Correct Answer 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: - Correct Answer Intensity levels which are measured in Decibels (softest at the top, loudest at the bottom)" "Horizontal axis on a graphic Audiogram shows this: - Correct Answer Frequencies which are measured in Hertz (low to high going from left to right)" "Hearing Baselines are reestablished when you have an STS because: - Correct Answer You don't want to identify the same shift each year" "#Days to notify individual of an STS in writing - Correct Answer 21 days" "OSHA versus NIOSH Noise Permissible Exposure Limit (PEL) - Correct Answer 90 dBA PEL for OSHA; 85 dBA PEL recommended by NIOSH" "OSHA recommendations for Audiometric Records - Correct Answer Maintain for duration of employment; NIOSH recommends duration of employment + 30 years" "Sound Level Meter Microphone Type Required by OSHA - Correct Answer Minimum of Type 2 microphone" "Formable Earplugs are: - Correct Answer Disposable when no longer return to shape and soiled" "Pre-formed earplugs: - Correct Answer Can be washed with mild soap and water and reusable" "Noise muff cushions - Correct Answer 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 - Correct Answer Tests are to be done without hearing aids" "Function of the Outer Ear - Correct Answer Collecting sound and sending it to the eardrum through the auditory canal" "Function of the Middle Ear - Correct Answer 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 - Correct Answer 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 - Correct Answer 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: - Correct Answer Crossover" "The Action Level for OSHA and NIOSH is: - Correct Answer 85 dBA TWA" "Weighting scale required by OSHA for Hearing Conservation Program Noise Assessments: - Correct Answer '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 - Correct Answer C weighted scale; has a flat response with all frequencies equally weighted" "This Hearing Conservation Regulation is the minimum standard - Correct Answer OSHA Noise Amendment" "Best audiometer for testing multiple stations - Correct Answer Microprocessor Audiometer" "Best audiometer for testing difficult-to-test patients - Correct Answer Manual Audiometer" "Calibration of audiometer performed daily with a electroacoustic simulator or human ear is called a: - Correct Answer Biologic calibration" "A check of audiometer performed daily to ensure there are no intermittent problems with hardware is called a: - Correct Answer Functional Check" "Professional Supervisor In a HCP - Correct Answer Responsible for oversight of Audiometric testing; reviews problem audiograms; must be an audiologist or physician" "Elements of a Hearing Conservation Program - Correct Answer Mandatory and includes: exposure monitoring, audiometric testing, hearing protection, employee training, record keeping, and program evaluation" "Noise Controls - Correct Answer At the source (preferred), along the path, at the receiver" "Industrial Hygienist - Correct Answer Responsible for assessment of hazards that may affect workers as well as hazards that may impact the community." "NRR - Correct Answer Noise Reduction Rating; number determined in a laboratory"