Circadian Rhythms and Attentional Dysfunction in type1 Narcolepsy

The aim of this investigation was to explore the nature and the severity of circadian abnormalities and attentional deficit in type 1 narcolepsy. In three studies, narcolepsy patients were compared with patients suffering from other central disorders of hypersomnolence and healthy controls on attentional functions and circadian rhythms. Study 1 evaluated the sensibility of actigraphic monitoring in distinguishing the features of daytime and nighttime sleep between adult patients with type 1 Narcolepsy, Idiopathic Hypersomnia and healthy controls. Actigraphy provides a reliable assessment of sleep quality and daytime napping behavior able to distinguish central disorders of hypersomnolence and identify Narcolepsy Type 1 patients. Study 2 describes the features of circadian activity rhythm of narcolepsy type 1 children with recent disease onset. Type 1 narcolepsy children and healthy children were monitored for seven days during the school week, circadian activity rhythms were analyzed through functional linear modeling. Children with type 1 narcolepsy present an altered rest-activity rhythm characterized by enhanced motor activity throughout the night and blunted activity in the first afternoon. The observation of a discrete circadian profile provides new insight on the nature of diurnal variations and suggested that the quantitative assessment of motor activity is a promising behavioral biomarker of Type 1 narcolepsy. The aim of Study 3 was to explore the nature and the severity of attentional Deficits of Narcoleptic patients. This study examined whether narcoleptic patients would exhibit impairments in alerting, orienting, and executive control of attention relative to healthy controls. Narcoleptic patients present a deficit in alerting network, while orienting and executive control networks resulted preserved. Moreover the alerting network efficiency significantly correlate with levels of subjective sleepiness. Results indicates that in narcolepsy the unstable tonic component of alerting process make necessary monitoring and compensation strategies.