A group of brain performance centers backed by Betsy DeVos, the nominee for education secretary, promotes results that are nothing short of stunning: improvements reported by 91 percent of patients with depression, 90 percent with attention deficit disorder, 90 percent with anxiety.

The treatment offered by Neurocore, a business in which Ms. DeVos and her husband, Dick, are the chief investors, consists of showing movies to patients and interrupting them when the viewers become distracted, in an effort to retrain their brains. With eight centers in Michigan and Florida and plans to expand, Neurocore says it has assessed about 10,000 people for health problems that often require medication.

“Is it time for a mind makeover?” the company asks in its advertising. “All it takes is science.”

But a review of Neurocore’s claims and interviews with medical experts suggest its conclusions are unproven and its methods questionable.

Neurocore has not published its results in peer-reviewed medical literature. Its techniques — including mapping brain waves to diagnose problems and using neurofeedback, a form of biofeedback, to treat them — are not considered standards of care for the majority of the disorders it treats, including autism. Social workers, not doctors, perform assessments, and low-paid technicians with little training apply the methods to patients, including children with complex problems.