RECURRENCE PLOTS, ACTIGRAPHY AND DISORDERS OF CONSCIOUSNESS (DOC)

Actigraphy, which stands for measuring acceleration of various body parts, is considered a robust method of assessing circadian rhythms. At the same time, one of hypotheses regarding diagnosis of DOC links the state of the patient to the rhythmicity of his movements – as they may reflect restoration of circadian rhythmicity. However, simple methods of circadian rhythms detection failed us in the past due to how complex and diverse are the data gathered from patients. Recurrence plots, together with quantitative analysis (RQA) are nonlinear methods of assessing dependencies in the data at different time scales and seem promising as a method more sophisticated than standard algorithms used in the actigraphic field. The analysis is conducted on data gathered in the Alarm Clock Clinic in Warsaw. Our exploratory approach focuses mostly on qualitative differences between various stages of DOC which can be observed on generated recurrence plots. Those differences seem very promising, even though the dataset is small and extremely divergent. Standard measures used in RQA allow to cluster one of the stages (Unresponsive Wakefulness Syndrome) – acting like a necessary condition. Altogether preliminary observations made during this study give a glimpse of hope regarding construction of DOC stages classifier based on actigraphic data.