Sleep disorder in childhood impairs declarative but not nondeclarative forms of learning

Abstract

A large amount of studies have investigated the association between sleep and memory systems. However, remarkably little is known of the effect of sleep disorders on declarative and nondeclarative memory for children. In the present study we examined the effects of sleep disorders on different aspects of memory functions by testing children with sleep-disordered breathing (SDB), which is characterized by disrupted sleep patterns. We used "The War of the Ghosts" test to measure declarative memory and the Alternating Serial Reaction Time (ASRT) task. This enabled us to measure two aspects of nondeclarative memory--general skill learning and sequence-specific learning--separately. Ten children with SDB and 10 healthy controls participated in this study. Our data showed dissociation between declarative and nondeclarative memory in children with SDB. They showed impaired declarative memory, while the sequence-specific and general skill learning was similar to that of healthy controls, in spite of sleep disruption. Our findings suggest that sleep-disordered breathing affects declarative and nondeclarative memory differently in children. Moreover, these findings imply that the disrupted sleep pattern influences the more attention-demanding and cortical structure-guided explicit processes, while the less attention-demanding implicit processes mediated by subcortical structures are preserved.

The effect of Sleep-Disordered Breathing (SDB)on declarative and non-declarative memory processes in children and adults

“…We found that these two types of non-declarative learning and consolidation are intact in children with SDB. Our results on online declarative memory performance are in line with previous studies that found weaker declarative performance in the SDB group in general Csábi et al, 2013). found lower performance on verbal and visual memory tasks in children with SDB compared to healthy controls.…”

“…Our results are in line with our previous study in which the SDB group showed impaired declarative memory performance while the non-declarative learning remained intact compared to the healthy controls (Csábi et al, 2013). using the ASRT task also found intact non-declarative sequence learning in elderly adults with OSA.…”

“…These results indicate that the relationship between online non-declarative memory formation and sleep is similar in children and adults with SDB. The performance difference between declarative and non-declarative tasks in session one can be explained by that the disrupted sleep pattern influences the more attention-demanding and cortical structure-guided explicit processes (story recall), while the less attention-demanding implicit processes (ASRT task) mediated by subcortical structures are preserved (Csábi et al, 2013).…”

“…In this test children are asked to listen and repeat the story after various intervals (immediately or after a determinate interval). The story consisted of 36 sentences; based on the standardized scoring, each sentence is allocated 1 point for the verbatim recalled sentences and 0.5 points for partly correct responses (gist of the sentences; Csábi et al, 2013).…”

“…The authors suggested that this reduced performance may be caused by impaired ability to use adequate learning strategies which either leads to difficulties to learn new information or children with OSA suffer from impaired encoding or altered retrieval. In our recent study (Csábi et al, 2013), we investigated declarative and non-declarative memory performance in one learning session (without consolidation) and showed weaker declarative but intact non-declarative memory performance in children with SDB compared to the controls. These results suggest that the more attentiondemanding declarative learning are more vulnerable to permanent sleep disorder than less attention demanding non-declarative learning.…”