Machines You Don’t Want To Hear - Machines You Hear With

Continuous exposure to loud noise can produce hearing loss. Sounds are transmitted as vibrations from the outer ear to the 30,000 delicate hair cells of the inner ear. When exposed to loud sounds, the hair cells vibrate violently. This often results in tinnitus (ringing in the ear) and temporary hearing loss that usually recovers within a day. With continued exposure to loud noise, the temporary hearing loss can become permanent by a destruction of the hair cells. Hearing in the higher pitch range is usually affected first. This often results in a reduction in the clarity of speech, especially in a background of noise. It is, for example, easier to hear men than women and children.

‘Noise and Hearing’ Atlantic Coast Ear Specialists
Author not mentioned
http://www.earaces.com/noise-hear.htm

 

 

 

 
 
During the 20th century, aids for hearing evolved from mechanical to electrical devices. Using an external power source, sounds could now be made louder than was possible with earlier mechanical designs. Consequently, hearing aids were able to provide amplification of sound to those even with severe to profound hearing loss.
 
 

Coincident with the change from mechanical to electrical designs were advances in technology that paved the way for innovative designs of concealed hearing aids and allowed for the manufacture of hearing aids at more affordable prices.

Extract from online exhibit ‘Deafness in Disguise’ of the Becker Medical Library, Washington University, St. Louis, Missouri. 2002
by William Clark, Arnold Heidbreder, Kim Readmond, Brent Spehar, Rosalie Uchanski & Cathy Sarli
http://becker.wustl.edu/ARB/Exhibits/cid/