The polysomnogram assay: a method to represent the overnight polysomnogram in a condensed format

We present the polysomnogram assay (PSGA), a new representation format for the polysomnogram (PSG), designed to assist in the interpretation of overnight PSG studies. The technique condenses the PSG record by a factor of 30 while preserving the ability to portray PSG features of diagnostic relevance, including sleep architecture, arousals, movement, leg jerks, cyclic alternating pattern, and increased breathing effort. The PSGA patterns associated with these events are described and illustrated by examples. The new format considerably reduces the effort required to evaluate sleep quality and continuity, making it more practicable for the polysomnographer to interpret the entire overnight PSG study. The compressed time scale also facilitates analysis of relatively long PSG episodes and allows assessment of signal activity surrounding critical PSG events. The PSGA appears capable of improving identification of arousals, leg jerks, and upper airway resistance, and may be especially amenable for automatic analysis of PSG data.