الفهرس 
Introduction
I. Chapter 1: Hearing ImpairmentOnly 14 pages are availabe for public view
 |  | from | 208 |  |  |
| | | from | 208 | | |
Abstract
Disabling hearing loss is defined by WHO as a hearing loss greater than 40dB in the better ear in adults, and a hearing loss greater than 30dB in the better ear in children. The degree of hearing loss may be moderate (41-60 dB loss in the better ear) or severe (61-80 dB hearing loss)(WHO, 2012).The prevalence of hearing impairment worldwide is 5.3%, which represents nearly 360 million persons; ”91% are adults and 9% are children” (WHO, 2012). Whereas the prevalence of hearing impairment in Egypt is (16.02%); almost 10% of school children (6–12 years) are affected. The prevalence of hearing impairment in Dakahlia is 13.69% (Abdel-Hamid et al, 2007).Hearing impairment is the most frequent sensory deficit in human populations. Consequences of hearing impairment include inability to interpret speech sounds, often producing a reduced ability to communicate, delay in language acquisition, economic and educational disadvantage, social isolation and stigmatization. It may be worsened by some medical conditions such as hypothyroidism, diabetes, and possibly hyperlipidemia, among others (Mathers et al, 2000).