In this edition of Sleep Science Friday, Dr. Adriana Michalak is joined by Dr. Claudia Barth and Dr. Laura Stankeviciute to explore two often underestimated yet critical dimensions of Alzheimer’s Disease: biological sex differences and sleep.
Understanding Alzheimer's Disease
AD is the most common type of dementia, affecting an estimated 7 million people in Europe alone as of 2025 (European Brain Council). The disease leads to degeneration of nerve cells and neuroinflammation due to accumulation of toxic extracellular amyloid plaques (Aβ), intracellular neurofibrillary tangles, and abnormal activation of microglia. These alterations result in neuronal death, brain tissue damage, and progressive brain atrophy, leading to cognitive decline and other behavioural alterations.
Alzheimer's is influenced by both modifiable risk factors—such as diabetes, high blood pressure, physical activity, diet, and sleep—and non-modifiable ones like age, genetics, and biological sex.
Sex-Specific Vulnerability: A Research Gap
Women account for nearly two-thirds of AD cases, yet the impact of hormonal changes remains poorly understood (Barth et al., 2023). Major hormonal transitions such as pregnancy and menopause may represent critical windows of vulnerability in developing AD—a topic we discussed extensively with neuroscientist Dr. Claudia Barth.
The Sleep-AD Connection
As Dr. Laura Stankeviciute stated, sleep is not a lifestyle choice but a biological necessity that must be prioritised and protected. Sleep disruption is both a symptom and driver of AD progression, illustrating a two-way interaction between brain degeneration, cognitive decline, and disturbed sleep (Ju et al., 2013; Bubu et al., 2017). These disturbances affect quality of life for patients and caregivers and often hasten patients' institutionalisation (Petit et al., 2017).
The connection becomes particularly relevant during hormonal transitions related to menopause. During menopause, the number of women reporting sleep problems nearly doubles. Difficulties include falling and staying asleep, frequent awakenings, and daytime fatigue, often intensified by hot flushes and mood disturbances, such as depression (Baker et al., 2019).
Technology and Future Directions
During the interview, we also emphasised incorporating wearable rest-activity pattern measures alongside traditional sleep studies, as sleep unfolds over time, and a single-night polysomnographic recording in the sleep laboratory fails to account for menstrual or seasonal changes. This longitudinal recording is particularly valuable in preclinical AD, as capturing early sleep and circadian disturbances could offer windows for timely, protective interventions.
Co-Creation in Dementia Research
We discussed the vulnerability of caregivers (predominantly women), noting the striking pattern that women are significantly more willing to participate as study volunteers in dementia research, and the importance of engaging participants as partners in science co-creation. As scientists, we are trusted sources of knowledge, but our participants' insights are invaluable in making science meaningful for all.
