|Hearing impairment, deafness or hearing loss is a partial or total inability to hear. It is caused by many different factors, including but not limited to age, noise, illness, chemicals and physical trauma. There is a diagnosis to determine the severity of the hearing impairment, and it is measured in decibels. It may be ranked as mild, moderate, moderately severe, severe or profound. There are a number of measures that can be taken to prevent hearing loss, but in some cases it is impossible to reverse or prevent. Many new technological advancements have been made to improve the hearing of those who are hearing impaired. However, some of these technologies have caused controversy in the deaf community. Deaf Studies are academic disciplines concerned with the study of the deaf social life of human groups and individuals including anthropology, economics, geography, history, political science, psychology, social studies, and sociology. The Deaf studies comprise the scientific study of the deaf-related aspects of the world. High-impact journals are those considered to be highly influential in their respective fields. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.