Women have better verbal memory skills than men – even when they begin experiencing early Alzheimer’s disease, a new study shows.

This greater ability on the part of women may also make it more difficult to diagnose the disease early, the study notes.

Verbal memory refers to the ability to recall information in words and includes hearing, reading, and any other avenue that involves speech and language.

Researchers at the University of California-San Diego studied 254 people with Alzheimer’s disease, 672 people with mild cognitive impairment that included memory problems, and 390 people with no thinking or memory problems.

Participants’ verbal memory skills were tested and PET brain scans measured how well their brains metabolized glucose, which is the primary energy source for the brain. Poor metabolism is a sign of dysfunction in brain cells.

Women scored better than men on the memory tests when they had no, mild or moderate problems with brain metabolism.

Once the participants had more advanced metabolism problems, there was no difference in test scores between women and men.

“Women perform better than men on tests of verbal memory throughout life, which may give them a buffer of protection against losing their verbal memory skills in the precursor stages of Alzheimer’s disease, known as mild cognitive impairment,” says study author Erin E. Sundermann.

If these results are confirmed, memory tests may have to be adjusted to account for the differences in men and women, she adds of the study’s findings, which appear in Neurology.