Attributed grammars in hypnogram analysis

The hypnogram is a schematic representation of sleep dynamics as a sequence of stages along the night. The authors have shown, in previous work, the adequacy of syntactic modeling in automatic sleep analysis. According to this approach, the hypnogram is viewed as expression of a language whose temporal organization is described by stochastic context-free grammars. Here, the authors propose a hybrid model combining syntactic and semantic information, where stage duration is taken into account in terms of attributed grammars. This model enables hypnogram simulation, by means of language generation, and provides improvement in classification accuracy. The method is applied in automatic hypnogram analysis of a control group and a population of dysthymic patients