Somnology Somnology Somnology is the scientific study of sleep. It includes clinical study and treatment of sleep disorders and irregularities. Sleep medicine is a subset of somnology. After the invention of the EEG, the stages of sleep were determined in 1936 by Harvey and Loomis, the first descriptions of delta and theta waves were made by Walter and Dovey, and REM sleep was discovered in 1953. Sleep apnea was identified in 1965. In 1970, the first clinical sleep laboratory was developed at Stanford. The first actigraphy device was made in 1978 by Krupke, and continuous positive airway pressure therapy and uvulopalatopharyngoplasty
Scientific pitch notation 0 of SPN marks the low end of what humans can actually perceive, with the average person being able to hear frequencies no lower than 20 Hz. <br> The octave number increases by 1 upon an ascension from B to C. Thus, "A" refers to the first A "above" C and middle C (the small octave's C or simply "c") is denoted as "C" in SPN. Scientific pitch notation is often used to specify the range of an instrument. It provides an unambiguous means of identifying a note in terms of textual notation rather than frequency, while at the same