Introduction to polysomnography
This chapter discusses a few basic issues: need for polysomnography, types of polysomnography machines available, advantages and limitations of each of these machines; and guidelines for the use of various devices. polysomnography is a good method to assess sleep and sleep disorders. It is useful not only for the clinical diagnosis but for the research as well. A sleep study is used to objectively assess changes in physiological parameters that occur during sleep. During polysomnographic recording, we gather data regarding physiological parameters and try to detect any abnormality. Thus, polysomnography provides objective evidence of different pathologies occurring during sleep. The American Academy of Sleep Medicine (AASM) has proposed guidelines for the use of various types of sleep studies. According to the guidelines, Level III studies, which are also known as Home Sleep Testing (HST) or Out-of-center (OCC) studies, can be done in high-risk patients to verify the presence of sleep apnea.