Impact of brain injury on menopause and memory
David Stock, post-doctoral researcher at the Toronto Rehabilitation Institute
Early and sudden menopause can put a woman at greater risk of dementia. Studies suggest traumatic brain injury can have the same effect. Now researchers are investigating possible links between the two that could lead to preventative treatments.
David Stock, a post-doctoral researcher at the Toronto Rehabilitation Institute, is trying to find out if traumatic brain injury affects the timing of menopause and, if so, how.
Previous research shows that women who suffer brain injury often have disrupted menstrual cycles, including long periods of time without menstruating. Stock wants to know if brain injury might also trigger early menopause.
During menopause, a woman's estrogen levels decline. That's important because brain regions linked to forming new memories, such as the hippocampus, are chock full of receptors for estrogen. In fact, the hormone is one of the keys to the hippocampus' functioning and this part of the brain is often the first to be targeted by dementia.
Men, on the other hand, don't experience the same drastic decline in estrogen in their brains. Their sex hormone, testosterone, is converted in the brain into estrogen. Since testosterone doesn't significantly drop as men age, their hippocampus keeps working.
Funded in part by the Alzheimer Society Research Program, Stock will recruit women from Toronto-area hospitals who have suffered brain injury. He will then monitor their hormone levels and menstrual cycles, looking for markers of early menopause.
If he finds a trend suggesting a link, and subsequent studies back it up, hormone replacement therapy could be considered.
"I know hormone replacement therapy has been a hot button issue," says Stock. "Large clinical trials in the early 2000s found it to be a risk factor for dementia. But the issue could be about when treatment is prescribed."
If women with brain injury could be screened to see if they were entering menopause early, they could take hormone replacements before their bodies had a chance to adjust to lower levels. Stock hopes to have results to share within three years.