In general, much information can be extrapolated from the polysomnography; some can be directly related to the sleep, such as the sleep onset latency (SOL), the REM-sleep onset latency, the number of awakenings during the sleep-period, the total sleep duration, percentages and durations of every sleep stage, and the number of arousals. But there can be also other information, crucial for many diagnostics, that are not directly linked with the sleep, such as movements, respiration, cardiovascular parameters. In any case, through the polysomnographic evaluation, other information can be obtained (such as, for example, body temperature or esophageal pH) according to the patient's or the study's needs.