Hearing Impairment And Impact of Hearing impairment

Hearing Impairment

Any deviation from the limits of normal hearing is defined as hearing impairment. Hearing sensitivity of each ear is measured separately and the degree of hearing impairment/ hearing loss is generally classified in five categories and additional category-slight hearing loss is added between the normal hearing and mild hearing loss especially when assessing the hearing sensitivity of the young children. Table 1 shows the classification of severity of hearing impairment.

              

                 Classification                                                                        PTA range in dBHL

Normal Hearing                                                                   -10 to 15

Slight Hearing Loss                                                               16 to 25

Mild Hearing Loss                                                                26 to 45

Moderate Hearing Loss                                                      46 to 55

Moderately – Severe Hearing Loss                                   56 to 70

Severe Hearing Loss                                                            71 to 90

Profound Hearing Loss                                                       91 and more

     

Table 1. Classification of hearing impairment severity

Impact of hearing impairment

                   

Consequences of hearing impairment will depend on the ears involved, degree of hearing loss, type of hearing loss and age at onset of hearing impairment. Usually, it is assumed that if hearing impairment is only in one ear, person may not have any serious problems in terms of listening. However, research has indicated difficulty to localize, reduced speech discrimination and lower speech and language development leading to significant effect on educational, linguistic and auditory perceptual development of children.

Degree of hearing impairment is of major factor leading to the negative impact on the social, educational and economical development of the individual. Mild hearing impairment may not place persons in disadvantageous position to hear and communicate but the higher degree of hearing impairment can put the person daily living in a very difficult position as he/she will need some assistance. Generally, people speak while involved in conversation at 65dBSPL. If a person has hearing impairment of 60dBHL or more he/she will find problems in verbal communication. This level of hearing impairment has been equated as 40% hearing impairment as in persons with disability(Full participation, equal opportunity and protection of rights) act 1995. Thus the definition of hearing disabled as stipulated in the PWD Act 1995 is a person who has minimum of 60dBHL of hearing impairment in the better ear in speech conversation frequencies.

…… Reference is taken from "Sfuran"

Govt. of West Bengal

Understanding Hearing Impairment

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

The Magnitude of the Hearing Impairment

As on 1^st March 2001, Indian population stands at 1,027,015,247 and projected population in 2016 will be 1, 263,543,000. (Census of India, 2001). With the present set of a concept of hearing disability, the Census of India, 2001 counted 1,261,722 people in whom hearing disability exists (Males 53.4% and Females 46.59%). Majority of persons with hearing disability reside in rural India (81.06%) except in the Union territory of Chandigarh. Delhi, and Daman and Diu.

NSS 58^th Round of Survey estimated persons with disability to be 18.49 million (1.8% of the total population). 10% of the persons with disability are likely to have the hearing disability of moderate to profound degree. This number is likely to go high if we have to add hearing disability of lower degree.

…… Reference from Sfuran

Govt. of West Bengal