Sleep and time course of consolidation of visual discrimination skills in patients with narcolepsy–cataplexy

Abstract

SUMMAR Y The level of procedural skills improves in normal individuals when the acquisition is followed by a period of sleep rather than wake. If sleep plays an important role in the consolidation process the advantage it provides should be reduced or delayed when its organization is altered, as in patients with chronic sleep disorders. To test this prediction in patients with narcolepsy-cataplexy (NC), who usually have a more fragmented organization of sleep than normals, we compared the initial, intermediate and delayed level of consolidation of visual skills. Twenty-two drug-naive NC patients and 22 individually-matched controls underwent training at a texture discrimination task (TDT) and were re-tested on the next morning (after a night spent in laboratory with polysomnography) and after another six nights (spent at home). TDT performance was worse in patients than controls at training and at both retrieval sessions and the time course of consolidation was different in NC patients (who improved mainly from next-day to 7th-day retrieval session) compared with controls. Moreover, the lessimproving patients at next-day retrieval had a wider disorganization of sleep, probably because of an episode of rapid eye movement (REM) sleep at sleep onset REM, on post-training night more frequently than more-improving patients. These findings suggest that the time course of the consolidation process of procedural skills may be widely influenced by the characteristics of sleep organization (varying night-by-night much more in NC patients than controls) during post-training night.

Different Patterns of Sleep-Dependent Procedural Memory Consolidation in Vipassana Meditation Practitioners and Non-meditating Controls

“…Consolidation of procedural memory -skill learningduring sleep has been studied using a number of tasks, including sequential finger tapping (Benedict et al, 2009;Doyon et al, 2009;Van Der Werf et al, 2009;Dresler et al, 2010;Genzel et al, 2011;Holz et al, 2012b;Wamsley et al, 2012;Antonenko et al, 2013), serial-reaction time task (Galea et al, 2010;Prehn-Kristensen et al, 2011;Ertelt et al, 2012), motor sequence task (Tucker and Fishbein, 2009;Manoach et al, 2010), mirror-tracing task (Smith et al, 2004b;Javadi et al, 2011;Puetz et al, 2011;Holz et al, 2012a), button-box sequence (Wilhelm et al, 2012), visuomotor adaptation task (Doyon et al, 2009); texture discrimination task (Gais et al, 2008;Cipolli et al, 2009), visual discrimination task (Suzuki et al, 2012), and others. These tasks usually involve fine motor skills using the fingers or hand-eye coordination, but do not typically involve balance or bodily displacements.…”

Sleep-Related Declarative Memory Consolidation and Verbal Replay during Sleep Talking in Patients with REM Sleep Behavior Disorder

“…Patients with primary insomnia demonstrated a lower sleep-associated memory consolidation of declarative (verbal and visual memory) memory tasks, while results are more controversial for procedural memory (depending on the test) compared to good sleepers [13]. Patients with narcolepsy show less consolidation of a visual procedural (texture discrimination) task after sleep compared to controls [14]. However, it is not known how parasomnias (including sleepwalking and REM sleep behavior disorder) affect sleep-dependent memory consolidation.…”

Is sleep‐related verbal memory consolidation impaired in sleepwalkers?

“…Patients suffering from moderate obstructive sleep apnea (who experience frequent arousals during sleep stages N1, N2 and REM sleep and reduced brain oxygenation during sleep) demonstrated a reduced overnight improvement in procedural and verbal (but not visual) declarative memory (Kloepfer et al, 2009). Patients experiencing narcolepsy (who exhibit premature entrances into REM sleep and often exhibit difficulty in maintaining sleep continuity) displayed reduced consolidation of visual procedural memory during sleep (Cipolli et al, 2009). In patients suffering from REM sleep behaviour disorder (who experience agitated nightmares during REM sleep), we previously found that they performed overnight consolidation of a verbal declarative task (the FCSRT and the story recall test) equally well as age-matched controls, despite lower cognitive daytime performances and even concomitant Lewy body dementia in one patient (Uguccioni et al, 2013).…”