The polysomnography is an overnight exam that monitors many different bio-physiological signals during sleep. A correct evaluation of the polysomnography recordings is essential to identify possible sleep disorders. Still nowadays the evaluation procedure, called sleep scoring, is carried out manually by a sleep physician or by a technician, who visually inspect the polysomnography traces of the whole night. It can be a quite tedious and time-consuming activity. Many automatic sleep scorings systems are available, but the vast majority remain unused. According to the international standards the detection of some well-defined patterns (sleep spindles, k-complexes, vertex waves…) is needed to score the PSG and to assign at each part of the recording the correct sleep phase.