Sleep-disordered breathing (SDB) may lead to changes in the brain’s white matter, which may contribute to compromised functional connectivity, a new study suggests.

Chooza Moon, PhD, RN, from University of Iowa College of Nursing, Iowa City, presented the results during a late-breaking abstract session at SLEEP 2018: 32nd Annual Meeting of the Associated Professional Sleep Societies currently underway in Baltimore.

Sleep is important for maintenance of the brain’s white matter, she explained. Sleep promotes myelination and proliferation of oligodentrocyte precursor cells in the central nervous system. SDB and poor sleep quality have been linked to changes in gray matter, but few studies have looked at the impact of SDB on white matter microstructure changes.

The investigators conducted a cross-sectional analysis of polysomnography data and diffusion tensor imaging–assessed white matter microstructure data from 138 adults (mean age, 68 years; 51% male) from the Wisconsin Sleep Cohort Study.

After adjustment for potential confounding factors, more severe SDB (higher apnea-hypopnea index) was associated with lower white matter density and greater axonal degeneration but not with axonal integrity or myelination. Longer wake after sleep onset was associated with lower white matter tract integrity and density, greater demyelination, but higher white matter maturation.

Longer sleep latency was associated with more axonal degeneration but with greater white matter integrity, higher tissue density, and less demyelination. Sleep efficiency and total sleep time were not associated with brain microstructure.

“These findings suggest that the relationship between sleep characteristics and brain microstructure may not be linear,” Moon told attendees. She said further study is needed to clarify the relationship between white matter changes and sleep characteristics.

Approached for comment, AASM board member James Rowley, MD, said this study provides more evidence that SDB “is not good for the brain.”

While some prior studies have found changes in gray matter associated with SDB, this study found changes in the brain’s white matter, “which is what connects everything, so it seems the connections are also being affected, which would have a lot of implications,” said Rowley, from Wayne State University, Detroit, Michigan.

Rowley said it’s also important to note that SDB is undertreated.

“The problem is people probably have it for years before they even think about it or do anything about, so how much of these changes are correctable by the time people get treated isn’t known. The same is true for heart disease and almost anything.”


REFERENCE: SLEEP 2018: 32nd Annual Meeting of the Associated Professional Sleep Societies. Abstract LBA1.