Diagnosis of primary insomnia by actigraphy--improved results by data selection

In spite of the useful information provided by actigraphy in sleep medicine it is still not an independent tool either in the clinical diagnosis or in the follow-up. In the frame of a retrospective study, a simple new method of data reduction was applied with the aim of improving the clinical impact of actigraphy for the diagnosis of primary insomnia.

Actigraphic records with a duration of 1 week produced on 47 subjects who met the inclusion-exclusion criteria. The daily activities during the investigational period were registered by means a self-completed questionnaire. Three parameters (sleep latency, sleep fragmentation and sleep efficiency) and only their three 'worse - as regards insomnia' daily values were analyzed statistically. The study participants comprised 13 healthy controls, 17 healthy 'bad sleepers' and 17 subjects with primary insomnia.

The post-hoc tests did not reveal statistically significant difference in the three parameters between the healthy and 'bad sleeper' groups, but these two groups differed statistically from the primary insomnia group.

The actigraphic analysis of sleep latency, sleep fragmentation and sleep efficacy allows a significant differentiation between subjects with primary insomnia and healthy controls, but not between healthy controls and healthy 'bad sleepers'. Statistical algorithms indicated 'models' for clinically good and bad sleepers. Further studies on large populations are necessary before this method can be introduced in the routine medical care of individuals with primary insomnia.