Lesson 2: CAUSES OF HEARING DAMAGE ARC 507: ENVIRONMENTAL CONTROL III (ACOUSTICS AND NOISE CONTROL ) Department of architecture Federal university of technology, akure. Contents. Introduction . Noise Induced Hearing Damage . Acoustic Trauma Temporary Threshold Shift
Lesson 2: CAUSES OF HEARING DAMAGE
ARC 507: ENVIRONMENTAL CONTROL III
(ACOUSTICS AND NOISE CONTROL)
Department of architecture
Federal university of technology, akure
This topic explains the main adverse health effects of noise: damage to the hearing mechanism, known as noise– induced hearing loss (NIHL); and tinnitus.
Also covered are other agents that can damage hearing: ototoxic substances; diseases; and the ageing process.
Temporary Threshold Shift (TTS)
It is defined as a temporary change in hearing level that recovers between exposures, resulting from sound levels over about 70 - 75dB(A).
Growth and Recovery of TTS
TTS for Different Noise level
Permanent Threshold Shift (PTS)
This is permanent damage to the ear as a result of continued or repeated exposure to excessive noise over a period of time.
Progression of NIPTS for 90 and 100db(A)
This is the term given to noises which are heard in the ears’ or ‘in the head’ – ringing, buzzing, hissing, whistling, pulsing or other sounds which do not come from an external source
Nosoacusis is defined as hearing damage resulting from diseases and infections, ototoxic medications, or trauma (blows) to the head.
Many systemic and hereditary diseases can cause hearing loss. Among these are: rubella, meningitis, diabetes, renal disease, rheumatoid arthritis and Meniere's disease.
Median audiogram for male
Median audiogram for female
This is defined as noise – induced hearing loss from non-occupational noise, for example, high level music, recreational shooting, and other noisy hobbies such as carpentry and drag racing.