Sleep Stability and Memory Function in Children Are Linked, CPC Analysis Shows

Cardiopulmonary coupling (CPC) analysis of sleep stability might be a useful risk biomarker for memory function among children, according to study findings published in Sleep Medicine.

While it is well known that sleep impacts neurocognitive development among children, it is unclear how decreased sleep stability is related to memory impairment. Researchers therefore used CPC to assess the relationship between sleep stability and memory among children with sleep-disordered breathing (SDB).

Researchers enrolled 152 children aged 5 to 12 years (average [SD] age, 8.2 [1.7] years; 65% male) who visited the Sleep Center of Beijing Children’s Hospital in China from June 2022 to March 2023. Participants were assessed via an overnight CPC sleep study and memory tests before and after sleep. In the CPC analysis, high frequency coupling (HFC) as a percentage of total sleep time was used as a measure of stable sleep, and a sleep quality index (SQI) was used that integrated HFC, sleep duration, and sleep fragmentation. Researchers used the cyclic variation in heart rate as a sleep apnea indicator (SAI).

The investigators categorized the participants into 3 groups based on their HFC percentages: low for HFC below 60%, moderate for HFC from 60% to 80%, and high for HFC above 80%. Children in the low HFC cohort had lower sleep efficiency, a higher proportion of wakefulness, higher non-rapid eye movement (NREM) stage 1 sleep, and a higher obstructive apnea-hypopnea index (OAHI) relative to the children in the high HFC group (all P <.05).

The investigators also found that the HFC percentage had a negative association with the apnea-hypopnea index (AHI) and obstructive AHI (OAHI), which in turn had a negative relationship with sleep quality index (SQI) and a positive link with SAI (all P <.01). In contrast, the low frequency coupling (LFC) percentage had a positive correlation with AHI and OAHI (all P <.01). Notably, the sensitivity and specificity of HFC and LFC were not statistically significant.

The researchers then evaluated the relationship between sleep breathing measures and memory test results. They found that AHI, OAHI, and SAI had no significant associations with memory test results.

An age-adjusted analysis of the association between the CPC measures and memory test results found that SQI had a positive relationship with delayed recall test scores and the recognition consolidation rate (all P <.05). The HFC percentage also had a positive correlation with delayed recall test scores (P <.05), delayed recognition (P <.05), as well as the recognition consolidation rate (P <.01).

In contrast, the LFC percentage (P <.01) and SAI (P <.05) had a negative relationship with the recognition consolidation rate. Further, the LFC percentage had negative associations with delayed recall test scores and delayed recognition scores (all P <.05).

Study limitations include potential sampling bias, the inability to extrapolate long-term effects due to the short study duration, and use of a small sample from China, which limits the study’s generalizability.

“[S]leep stability and quality assessed via CPC was positively correlated with memory function in children with OSA,” the study authors concluded. “HFC therefore might be a better index to evaluate the influence of diverse sleep pathologies on memory function.”

Disclosure: A study author declared affiliations with organizations or entities with financial interests related to this research. Please see the original reference for a full list of author disclosures.

This article originally appeared on Pulmonology Advisor