Using actigraphy to assess sleep and wake rhythms of narcolepsy type 1 patients: a comparison with primary insomniacs and healthy controls

Objective/background: It has been shown that actigraphy may have a discriminant function (DS) for the diagnosis of narcolepsy type 1 patients (NT1), based on a combination of nighttime and daytime parameters. Here, we aimed to test those findings using another actigraph model with a different clinical sample as control (ie, primary insomniacs, PI), carrying out a secondary analysis of previously collected data. Patients/methods: The study sample consisted of 13 NT1 (nine females; mean age 39.38 ± 11.48), 13 PI (nine females; mean age 38.69 ± 10.72) and 13 Healthy Controls (HC) (nine females; mean age 38 ± 10.77). Participants wore the Actiwatch AW64 (Cambridge Neurotechnology Ltd, Cambridge, UK) around the non-dominant wrist for seven consecutive days. Results: Significant differences between groups were observed with a higher number of episodes of wakefulness (wake bouts, WB) in PI than HC, a higher fragmentation index (FI) in NT1 than HC and PI, a higher duration of the longest nap (LNAP) in NT1 than HC and PI and higher DS in PI and NT1 than HC. A new DS (NDS), with LNAP and FI as independent variables, was proposed; which was higher in NT1 than HC and PI. Conclusions: The present study confirms that actigraphy discriminates NT1 from HC. However, considering PI, a new discriminant function NDS which takes into account LNAP and FI is better for this actigraph model.