1. NOISE INDUCED HEARING LOSS
DR. J. OPOKU-BUABENG
CONSULTANT OTORHINOLARYNGOLOGIST
KATH /KNUST.

2. Outline Anatomy / Physiology of Human Ear Causes of Hearing loss NIHL
Pathology
Degree of Hearing loss
Signs of Hearing loss
Audiological findings
Preventive measures
Rehalitation

3. Anatomy / Physiology

4. Causes of Hearing Loss 1. Congenital 4.4% 2. Infection / Injury 17.1%
3. Age (Presbyacusis) 28.0%
4. Prolonged loud noise (Industrial deafness) 33.7%
Others 16.8%
Source: League for Hard of Hearing
Hearing impairment Disability Handicap
Psychosocial effects / impacts

5. Noise Induced Hearing Loss
Noise-induced hearing loss (NIHL) is hearing impairment resulting from exposure to high decibel (loud) sound.
Dependent on the following features of the sound:
1. Intensity
2. Duration
3. Type of Noise exposure

6. Types of NIHL Acute acoustic trauma Gradual developing NIHL
NIHL caused by acute acoustic trauma refers to permanent cochlear damage from a one-time exposure to excessive sound pressure. This form of NIHL commonly results from exposure to high-intensity sounds such as explosions, gunfire, a large drum hit loudly, and firecrackers.
Gradually developing NIHL can be caused by multiple exposures to excessive noise in the workplace or any source of repetitive, frequent exposures to sounds of excessive volume, such as home and vehicle stereos, concerts, nightclubs, and personal media players.

8. Intensity / Source of Noise
Currently, the World Health Organization estimates that nearly 360 millions people suffer from moderate to profound hearing loss from all causes.
According to a 2015 review, “Hearing loss due to recreational exposure to loud sounds” by the WHO World Health Organization (WHO), an estimated 1.1 billion young people may be at risk for hearing loss caused by unsafe listening practices.

9. Pathology Adaptation Reversible injury TTS – Hours to days
Irreversible injury PTS – can be because of repeated attacks of TTS or a single loud noise exposure.
TTS – there is Metabolic cochlea pathology
PTS – mainly cause a Structural cochlea pathology

10. Normal / Damaged Cochlea Hair Cells

12. NIHL / Exposure period

13. Grade of Hearing Impairment

14. Signs of Hearing loss

15. Audiological findings
Both NIHL caused by acoustic trauma and gradually-developed- NIHL can often be characterized by a specific pattern presented in audiological findings. NIHL is generally observed to affect a person's hearing sensitivity in the higher frequencies, especially at 4000 Hz. "Noise-induced impairments are usually associated with a notch-shaped high- frequency sensorineural loss that is worst at 4000 Hz, although the notch often occurs at 3000 or 6000 Hz, as well".

16. Prevention Public education / awareness
Enforcement of social interventions by EPA, Law Enforcement Agencies, etc.
Labour regulations with the use of protective devices.
Hearing Conservation Programme

17. Public education
The best, first option for protecting hearing is lowering the volume of sound at its source.
Secondly, limiting the time of exposure to loud noise can reduce injury.
Finally, physical protection from the noise can reduce its impact.

18. Workers in general industry who are exposed to noise levels above 85 dBA are required by the Occupational Safety and Health Administration (OSHA) to be in a hearing conservation program (HCP), which includes noise measurement, noise control, periodic audiometric testing, hearing protection, worker education, and record keeping.

19. Protective devices
Ear plugs
Ear muffs

20. Aural Rehabilitation
BTE Hearing aid

21. ITC Hearing aid

22. THANK YOU