Puretone Audiometry Flashcards
What is the range of frequencies that human ears can hear?
20 - 20000 Hz
Describe different sounds
Tones, Noise, Speech
Describe perceptions of sound
Pitch is the perception of frequency
Loudness is the perception of amplitude or intensity
What is psychoacoustics?
Science that deals with the perception of sound
What is the difference between frequency and pitch?
Frequency is the number of cycles per second while pitch is the perception of frequency
What are octaves?
A frequency ratio, 2:1
Doubling of frequency
What is the difference between intensity and loudness?
Intensity is the amount of energy transmitted per second over an area of one square meter (MKS) while loudness is the perception of intensity
Why do we do puretone audiometry testing?
Provides information on the type of hearing loss and also quantifies frequency-specific threshold elevations due to damage in the auditory system. In this way, the amount of loss can be measured separately between the cochlea and the outer/middle ear, provide information on how well the systems are functioning and narrow down which frequencies are affected
Define “hearing”
Ability to perceive acoustic signals/sounds
What are the interoctave rules?
Frequencies between octaves
What are the four threshold testing methods?
Ascending vs Descending
Method of Limits
Method of Constant Stimuli
Hughson-Westlake
Describe the Hughson-Westlake method
Described by Carhart and Jerger, 1959
Variation of method of limits
Often call “down 10 up 5”
Describe the Method of Limits
Tones are presented one at a time, patient responds yes/no after each presentation. Tester controls the level of the stimulus and changes it in fixed steps (ascending or descending).
Ascending runs begin below the subject’s threshold. Descending run begins above the subject’s expected threshold.
Describe the Method of Constant Stimuli
Uses equal number of stimuli at each of several predetermined levels, presented in random order. Yes/No responses are tallied for each level used. Threshold is obtained by calculating the level that corresponds to 50%.
What are false responses?
False-positive means the patient responds when they should not have. Caused by tactile stimulation, confusion between test tones, tinnitus, often behavioral due to misunderstood instructions or tester may inadvertently encourage false positives by presenting tones rhythmically.
False-negative means the patient failed to respond when they should have due to equipment problems or tester errors, tinnitus, or misunderstood instructions, collapsed ear canals or standing waves.
Why do we start with better ear, if known?
Easier to know when to mask
What is the normal range of hearing?
Humans can hear 20-20000 Hz
What is test-retest reliability?
Degree to which test scores remain unchanged when measuring a stable individual characteristic on different occasions.
What is an audiometer?
Electronic instrument used by audiologists to measure hearing function designed to present auditory stimuli.
Audiologists can select the type of signals; characteristics of the sound such as frequency and intensity and transducer through which the signal is routed.
What is an air bone gap?
The difference between AC threshold and BC thresholds
What are the types of hearing loss?
Conductive
Sensorineural
Mixed
Explain high frequency testing
Describe TDH 49
Supra aural headphones
Easy and affordable
Most appropriate to test ears with TM perforation
Describe ER-3As
Insert earphones
Greatest interaural attenuation
Avoid collapsing canals
Lower test-retest variability
Prone to impacts of TM perforation
Describe HDA200
Circumaural headphones
Needed for extended high frequency testing (8-20 Hz)
Cushions sit around the pinna
Describe Radioear B-72
Limited max output
Describe speakers
Patient positioning in the room is critical
Ear-specific information cannot be obtained
For each headphone the __________________ should be centered over the ear canal and the headband should be tightened to make the headphones ________________ to the floor when the patient is sitting upright.
diaphragm
perpendicular