Digital analysis and technical specifications.

Digital acquisition and analysis of sleep data has become more common over the past 20 years. Many investigators have developed strategies to record and analyze sleep in a quantitative way. Initially, digital recording and analysis were restricted by technical limitations. With current technology, the technical limitations of computer acquisition, data storage, and analysis are less constraining, and the development of recommendations for the specifications and scoring of sleep can be more clearly guided by the goal of characterizing physiologic phenomena. In order to develop recommendations and specifications regarding digital acquisition and analysis, a literature search, evidence review, and standardized consensus process focused on 5 questions regarding computer-assisted sleep recording and analysis. These questions included: (1) the reliability of computerized scoring of sleep stages, (2) the analysis of elemental events and waveforms, (3) the physiological and/or clinical significance of digitally-analyzed signals, (4) the importance of proposed changes in standardized scoring that could incorporate digital analysis, and (5) the potential advantages and disadvantages of computerized sleep recordings. Of 154 studies identified by the search, 119 were found to be suitable for evidence review. The evidence review suggested that computer scoring and quantitative analysis of sleep is still in the formative stage of development. For many technical specification decisions, little or no direct evidence was found, although basic engineering principles or standard practices provided some rationale which was utilized to develop the recommendations formulated during the subsequent UCLA/Rand standardized consensus process.