'There is no objective measure of brain fog,' said Dr. Pauline M. Maki. 'This is a subjective term that women use to describe the constellation of symptoms that they experience.'
Dr. Maki is a professor of psychiatry, psychology, and obstetrics and gynecology at the University of Illinois at Chicago. She presented 'Hormone therapy and cognition: current evidence and clinical implications' at The Menopause Society 2026 Annual Meeting, held October 20 to 24, 2026, in San Diego, California. Her talk was part of the plenary symposium: menopause and longevity medicine: what we know, what we don't know, and what we shouldn't promise.' She reviewed cognition across the transition, hormone therapy trials, and dementia prevention.
How cognition may change across the menopause transition
In longitudinal studies, verbal learning and memory decline on average from the pre- to the perimenopause. A menopause symptom, she noted, worsens with ovarian aging independent of chronologic aging or after surgical removal of the ovaries. Cognitive performance stays in the normal range for most women, although about 10% experience a clinically significant change that can persist into the postmenopause. No single cognitive profile exists at midlife. In her group's analysis, 12% of women showed an attention deficit/hyperactivity disorder–like pattern.
What hormone therapy trials and symptom data may mean for cognition and dementia
Dr. Maki ran the first trial of hormone therapy in early postmenopausal women, expecting a cognitive benefit. 'And then I looked at my results, and I was wrong,' she said. Larger trials using different formulations later reached the same conclusion: in younger postmenopausal women, hormone therapy showed neither cognitive benefit nor harm. Later in life, conjugated equine estrogen (CEE) plus medroxyprogesterone acetate was associated with cognitive harm, whereas oral estradiol with vaginal progesterone appeared neutral. None of the four large trials in younger women recruited women with moderate to severe vasomotor symptoms.
She suggested a shift in focus 'from the absence of estrogen to the presence of symptoms that are very likely to affect brain function.' A woman who reports memory problems at midlife is often also dealing with hot flashes, low mood, or poor sleep. In a trial of stellate ganglion blockade, a nonhormonal treatment, reductions in physiologically measured hot flashes correlated with improvements in verbal memory. 'This isn't a hormone story. This is a symptom story,' she said.
She then turned to whether hormone therapy can prevent dementia, including Alzheimer disease. Early oophorectomy is the exception: estrogen used until the typical age of menopause offset the higher risk. Women's Health Initiative (WHI) death-certificate data showed fewer Alzheimer disease deaths with CEE, but 'you will hear people favorably talk about the WHI when it's convenient, and this is one of them,' she said. Four large observational studies and randomized trials of Alzheimer disease biomarkers did not support hormone therapy for dementia prevention.
Dr. Maki closed with The Menopause Society's 2022 position statement: hormone therapy is not recommended at any age to prevent or treat cognitive decline or dementia, initiation after age 65 years increased dementia risk, and estrogen may benefit cognition immediately after bilateral oophorectomy but is neutral in the early natural postmenopause
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Abbreviations: CEE, conjugated equine estrogen; WHI, Women's Health Initiative.