Poor Sleep Rewires the Aging Brain Differently by Age and Sex, New Binghamton University Study Finds

Poor sleep quality affects the brain's internal communication networks in strikingly different ways depending on a person's age and biological sex, according to a new study led by researchers at Binghamton University, State University of New York, with older women showing patterns that resemble the earliest, silent stages of Alzheimer's disease.

The study, published in the journal Neurobiology of Aging under the title "Sleep quality is associated with default mode and salience network connectivity differently across age and sex," analyzed brain scans from two large groups totaling more than 1,300 participants to examine how brain networks connect while at rest in people who reported poor sleep quality. The research was led by psychology graduate student Sepehr Gourabi and Associate Professor of Psychology Ian McDonough, both at Binghamton University, alongside co-authors Selene Tan, Matthew Cribbet and Jeanne Cundiff of the University of Alabama.

The findings revealed distinct patterns depending on a participant's stage of life. In college-age adults, poor sleep quality was associated with overconnected brain regions involved in physical movement, a pattern researchers interpreted as a sign that younger bodies simply weren't physically prepared to fall asleep. In older adults, generally defined in the study as those age 65 and above, that same movement-related connectivity pattern was reversed, with those regions showing under-connection. Instead, older adults with poor sleep exhibited hyperconnectivity in brain regions involved in cognition rather than movement.

McDonough summarized the overall pattern observed in older participants. "We discovered that the poorly slept older brain looks like it is suffering from a general breakdown in its sleep-regulation systems," he said.

The most striking findings emerged among older women specifically. That group showed abnormal hyperconnectivity between the brain's Default Mode Network, which governs internal thoughts and memory, and the Frontal Parietal Network, which supports sustained attention and working memory. According to the study, this pattern of excessive communication between the two networks was directly linked to poorer memory performance among the affected participants, and closely mirrors brain wiring patterns previously observed during the preclinical, symptom-free stages of Alzheimer's disease, McDonough said.

Researchers said the underlying reasons behind these age- and sex-based differences remain unclear. One possibility is that older adults become habituated to a state of heightened arousal over time, or develop coping mechanisms that include greater willingness to use sleep-related medications. Another potential factor is rumination, a pattern of persistent overthinking often associated with anxiety or depression, though researchers noted that anyone can experience rumination depending on their individual circumstances, regardless of a formal mental health diagnosis.

McDonough offered a possible explanation for how this state of mental agitation could interfere with healthy sleep patterns. "One strong possibility is that people who have a lot of running thoughts right before bed are not in a calm state, but rather more of an agitated state," he said.

The research also touched on the complex and still-debated relationship between depression and cognitive decline. McDonough noted that some prior studies have identified a link between depression and dementia, while other research has found that depression can sometimes closely resemble cognitive decline on the surface, with cognitive function improving once the underlying depression itself is treated.

A central unresolved question raised by the study involves the direction of causation between sleep and brain connectivity: do abnormal brain network connections cause sleep dysfunction in the first place, or does poor sleep itself lead researchers to observe those network abnormalities afterward? The study's data offered a partial answer on this point, with researchers finding that hyperconnectivity between the Default Mode Network and Frontal Parietal Network was associated with worsening cognition over time, suggesting that cognitive consequences tend to follow sleep disturbances or increased connectivity between these networks, rather than preceding them, according to McDonough.

Researchers emphasized that growing scientific evidence continues to point toward between-network brain connectivity, particularly involving the Default Mode Network, as an early warning sign of declining brain health more broadly. Because of that connection, the study's authors said getting sufficient, quality sleep remains an important factor in protecting long-term cognitive health across the lifespan.

The study's authors offered different practical takeaways depending on a person's age group. For younger adults, McDonough suggested that efforts specifically aimed at reducing physical and mental arousal before bedtime, such as journaling to help quiet racing thoughts, could prove helpful given the movement-related overconnectivity observed in that age group. For older adults, the researchers said the underlying mechanisms remain considerably less clear, given that heightened arousal does not appear to be the primary driver of the sleep-related connectivity changes observed in that population. McDonough recommended that anyone experiencing ongoing sleep problems consult with their physician for personalized guidance rather than relying solely on general recommendations.

Looking ahead, McDonough suggested that if abnormal brain connectivity changes do in fact precede sleep loss rather than simply result from it, then interventions specifically aimed at strengthening brain network function directly could represent one promising avenue for future treatment approaches. "If connectivity changes do precede sleep loss, then strengthening brain networks could be one solution," he said.

The study adds to a growing body of research examining the relationship between sleep quality and long-term brain health, an area of increasing scientific interest given sleep's established role in memory consolidation, cognitive maintenance, and the clearance of proteins associated with neurodegenerative disease. While the current findings stop short of establishing a direct causal pathway between poor sleep and conditions like Alzheimer's disease, the researchers said the observed similarities between older women's brain connectivity patterns and those seen in preclinical Alzheimer's cases warrant continued investigation into how sleep-related interventions might eventually factor into broader efforts to protect cognitive health as people age.