People with advanced dementia appear to be voting in elections, including through absentee ballots, according to studies in two states. Medical, political and legal experts worry this practice could have an impact on the upcoming presidential election, especially in swing states with large elderly populations, such as Florida.

Studies in Pennsylvania and Rhode Island have found that patients at dementia facilities turned out in greater numbers to vote than the general population.

Some caregivers go into the booth with their patients and essentially vote for them, which has caused experts to raise questions of fraud and abuse.

There is no way to test age competence, according to experts, but many believe there should be some way to prevent people with severe dementia from voting. Critics, however, say this type of practice would be age discrimination and prevent capable people, such as many nursing home residents, from voting in elections that determine issues relevant to them.

A state could deny voting rights to people incapable of grasping what is at stake, but deciding who is capable and who is not would present the biggest challenge, according to Erwin Chemerinsky, political scientist and constitutional scholar at Duke University.

Nearly 4.5 million Americans have Alzheimer’s disease, according to national statistics.