|Sleep dysfunction is also known as sleep disorder or somnipathy, it is a medical disorder. Sleep dysfunction effects normal physical, mental, social and emotional functioning of humans. This is normal disorder and usually temporary, may be caused due to stress or other factors. Sleep dysfunction is of many types which include dysomnias, parasomnias, circadian rhythm sleep disorders insomnia and sleep apnea.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.