By: Jena Pincott
This is how memory loss begins, Sophie tells me: you show up at work, forgetting that you are supposed to be at a breakfast meeting with a client. You blank on the names of your neighbors. Soon enough you walk into a room without any clue as to why you are there. Sophie, a lawyer in her early 50s, who asked to go by a pseudonym, had been suffering from frequent hot flashes and night sweats, both associated with menopause, but the forgetfulness seemed to be in another league. What was happening to her mind?
Lisa Mosconi, director of the Women’s Brain Initiative and associate director of the Alzheimer’s Prevention Center at Weill Cornell Medical College in New York City, might know. She has analyzed thousands of positron-emission tomography (PET) scans of patients entering menopause and has seen how their brain metabolism changes over time. “In premenopause, your brain energy is high,” Mosconi says, showing me a PET scan of a young woman’s brain. It is lit up by many bright red and orange blotch- es representing high glucose metabolism—a proxy for neuronal activity. In perimenopause, which hits women in their mid- to late 40s, brain glucose metabolism slows by 10 to 15 percent or more, and the scan changes: red and orange spots give way to more yel- lows and greens, representing less sugar uptake and lower metabolism. “Then, in postmenopause, brain glucose metabolism slows down 20 to 30 percent, sometimes more,” Mosconi says, showing me the final scan. Now, clearly, the greens have gained territory.
Estrogen is the master regulator of metabolism in the youthful female brain, orchestrating everything from glucose transport and uptake to its breakdown for energy. Mosconi’s scans are rain- bow-colored evidence that decreased levels of the hormone during menopause, which often starts when women are between the ages of 45 and 55, lead to a “bioenergetic brain crisis,” as she describes it. At some point during this seven-plus-year transition period, up to 60 percent of women experience what is known as menopause-related cognitive impairment: bouts of confusion, distractibility and forgetfulness. These memory problems are normal. The generation of synapses requires energy; as estrogen levels and brain glucose metabolism decline, so does the formation of new connections between neurons.