Age-related differences in sleep-dependent consolidation of motor skills in patients with narcolepsy type 1.

Objective: The influence of post-training sleep on the consolidation process of procedural (ie, visual and motor) knowledge has shown to be less effective in patients with chronic sleep disorders compared with healthy subjects. To ascertain whether the influence of the altered architecture of sleep in patients with narcolepsy type 1 (ie, with cataplexy: NT1) also varies with age, we compared the performance values of 16 children (aged from nine to 14 years) and 16 adults (aged from 24 to 51 years) on finger tapping task (FTT) after daytime and nighttime periods of sleep in the 24 hours following training.

Methods: All patients, who were drug-free and underwent continuous polysomnographic recordings, could take one or more naps after the training session (at 10 a.m.) until one hour before the first retrieval session (at 6 p.m.) and had an undisturbed period of nighttime sleep from about 10 p.m. to two hours before the second retrieval session (again at 10 a.m.).

Results: The pattern of sleep-dependent consolidation was significantly different in the two groups of patients: while performance accuracy was higher in adults compared with children at each session, performance speed improved after daytime sleep in children and after nighttime sleep in adults. The improvement in performance speed, although not related with any sleep parameters in both groups, was positively correlated with the daytime and nighttime total sleep time (TST) in children with greater consolidation gain.

Conclusion: The interaction between time of day and age in the time course of consolidation of new motor skills discloses a different role of daytime sleep (active in children, simply protective from interferences in adults) in NT1 patients and suggests a flexible use of napping in the educational context.