Dr. Rhonda Voskuhl, a neurology professor at UCLA, has proposed a "10-year rule" to help women distinguish between memory lapses caused by menopause and early signs of dementia or Alzheimer's disease. Many women experience cognitive changes during perimenopause and menopause due to oestrogen loss, and these temporary memory blips are often mistaken for serious neurological decline. Voskuhl recommends that women compare their current cognitive function to their baseline from a decade ago, noting that subjective cognitive decline—where patients notice changes despite normal neurological tests—is often overlooked, affecting approximately one in nine adults.

The key distinction lies in how memory loss impacts daily function. Menopausal brain fog typically involves inconsistent, temporary lapses such as misplacing items or slower processing speed, whilst overall reasoning and independence remain intact; symptoms often worsen with stress or poor sleep. By contrast, early dementia causes persistent, progressive memory loss that interferes with basic tasks like managing finances or driving safely. Experts advise women to trust their own observations of cognitive changes and seek full medical evaluation, including brain scans and vascular screenings, to rule out underlying conditions such as thyroid imbalances or blood vessel disease. Research suggests women who begin hormone therapy in their 50s may have a 23 per cent lower dementia risk.