Audiology
Sound ◼ A form of energy-produced by vibration ◼ Different velocity in different media ◼ The character: ◼ Frequency (pure tone or complex sound) ◼ Intensity (different from loudness) ◼ Pitch (subjective sensation)
Intensity ◼ Whisper 30 dB ◼ Normal conversation 60 dB ◼ Shout 90 dB ◼ Discomfort of ear 120dB ◼ Pain of ear 130dB
Intensity ≠loudness ◼ Intensity is physical ◼ Loudness is just sensation ◼ Generally more intensity greater loudness ◼ In patients situation is different
Alexander Graham Bell ◼ The inventor of telephone ◼ Bel is use to measure the intensity of sound ◼ dB (decibel) = 1/10 bel ◼ SPL sound pressure level ◼ HL hearing level ◼ nHL normal hearing level
Noise – a complex sound ◼ White noise have all frequency people can hear 20 to 20000 Hz ◼ Narrow band noise with certain frequency ◼ Speech noise frequency in speech range(300-3000Hz) people speech 500-2000Hz audiometric testing 125-8000Hz ◼ Use for masking
Assessment of hearing Three type of hearing loss ➢ conductive hearing loss ➢ sensotineural hearing loss (SNHL) ➢ mixed hearing loss
