Hearing is one of the vital sense organs, which facilitates the social and economic development of the individual. Two ears provide the binaural advantage of hearing so that one can able to localize the source of the sound and judge the distance of the source of the sound. Because of the complex structure of the inner ear, one can able to distinguish minor differences in intensity, frequency and duration of sounds, which is importantly used for discrimination of speech sounds. Thus hearing plays an important role in learning the verbal language. Physiologically ear respond to sounds having the frequency between the 20Hz to 20000Hz when the air pressure equal to or more than 0.0002 dynes per sq. cm is created by any vibrating object. It is also found that binaural hearing thresholds are better than monaural hearing thresholds providing the advantage of ease of listening. Adults with no history of ear problem have a pure tone threshold average for the frequency of 500Hz, 1000Hz, and 2000Hz within 25dBHL. In children, the normal hearing limit shall be 15dBH, as the lower level for normal hearing norms was considered keeping in view of the importance of hearing during the language and speech learning period at an early age.
…… To be continued
Reference from Sfuran
Govt. of West Bengal
No comments:
Post a Comment