On-Line vs Off-Line Consolidation Of Motor Skills In Young Primary Insomniacs

Cellini, N. 1 , de Zambotti, M. 2, 1 , Covassin, N. 3, 1 , Sarlo, M. 1 & Stegagno, L. 1

1 Department of General Psychology, University of Padua
2 Center for Health Sciences, SRI International
3 Mayo Clinic, Department of Medicine, Division of Cardiovascular Diseases

In healthy individuals sleep plays a key role in the formation of declarative, perceptual, emotional, and procedural memories. However, a paucity of studies have investigated memory consolidation in sleep disorders. Here, using a finger tapping task, we assessed the two phases of motor memory formation, i.e. encoding and consolidation, in 13 young primary insomniacs (23.31 ± 2.5 yrs) and 13 healthy controls (24.31 ± 1.6 yrs). Participants were tested during the evening and in a morning session after a night of polysomnographic recording. During the pre-sleep evening training insomniacs performed worse than controls in the overall task. However, the learning curve was not different between groups, indicating a similar on-line motor learning. In the morning, insomniacs failed to exhibit any off-line enhancement in motor performance whereas controls improved their performance, indicating an overnight effect on motor skills consolidation. Our results suggest that young adults with insomnia experience an impaired off-line memory consolidation which seems not to be associated with a reduced ability to acquire new motor information.