But he knew from his research that his abnormality was near the brain’s olfactory center. So when he started smelling whiffs of vinegar last summer, he suspected they might be “smell seizures.”

He pushed doctors to conduct an MRI, and three weeks later, surgeons in Boston removed a cancerous tumor the size of a tennis ball from his brain.

At every stage, Keating, a 26-year-old doctoral student at the Massachusetts Institute of Technology’s Media Lab, has pushed and prodded to get his medical information, collecting an estimated 70 gigabytes of his own patient data by now. His case points to what medical experts say could be gained if patients had full and easier access to their medical information. Better-informed patients, they say, are more likely to take better care of themselves, comply with prescription drug regimens and even detect early warning signals of illness, as Keating did.

“Today he is a big exception, but he is also a glimpse of what people will want: more and more information,” said Dr. David W. Bates, chief innovation officer at Brigham and Women’s Hospital.

Some of the most advanced medical centers are starting to make medical information more available to patients. Brigham and Women’s, where Keating had his surgery, is part of the Partners HealthCare Group, which now has 500,000 patients with Web access to some of the information in their health records including conditions, medications and test results.

Other medical groups are beginning to allow patients online access to the notes taken by physicians about them, in an initiative called OpenNotes. In a yearlong evaluation project at medical groups in three states, more than two-thirds of the patients reported having a better understanding of their health and medical conditions, adopting healthier habits and taking their medications as prescribed more regularly.

The medical groups with OpenNotes programs include the Mayo Clinic, Beth Israel Deaconess Medical Center in Boston, Geisinger Health System in Pennsylvania, Harborview Medical Center in Seattle, the Cleveland Clinic and the Department of Veterans Affairs. By now, nearly 5 million patients in the United States have been given online access to their notes.