Fifty-five percent of likely voters believe presumptive Democratic Party presidential nominee Joe Biden is in the early stages of dementia, according to a Zogby poll released Wednesday.

President Donald Trump has consistently ridiculed Biden over his verbal gaffes and memory lapses and portrayed him as an old man who would be committed to a retirement home if he were to be elected.

"They are going to put him in a home and other people are going to be running the country," Trump said in early March during a rally in Charlotte, North Carolina.

"Sleepy Joe," Trump added, "he doesn't even know where he is or what he's doing or what office he's running for. Honestly, I don't think he knows what office he's running for."

Biden's age, 77, has been a consistent source of discussion during the 2020 campaign.

The Zogby poll found majorities of Republicans and independents thought Biden had early onset dementia, while nearly a third of Democrats thought this was the case.

The voters most likely to believe Biden was having cognitive issues were staunch Trump supporters.

Zogby conducted polling at shopping checkout and found that the results on the topic of Biden being more or less likely to have dementia were as follows; weekly Walmart Shoppers (64% more likely/36% less likely), weekly Amazon shoppers (67% more likely/34% less likely), and union voters (71% more likely/29% less likely).