Top hospitals across the country follow different protocols for determining brain death, and often deviate from standards established by the American Academy of Neurology, a new survey finds.

The results, which will be published in the Jan. 22 issue of the journal Neurology, are based on surveys of top neurology and neurosurgery centers identified by U.S. News and World Report.

"We were surprised to find such significant differences among these hospitals in terms of their specified guidelines for brain death determination," said study leader David Greer of the Massachusetts General Hospital Neurology Service. "In reviewing the protocols, we would have anticipated more consistency with the American Academy of Neurology practice parameters."