Robert J. Schwartzman, 81, a renowned neurologist, emeritus professor, former residency training director and chairman of the department of neurology at three Philadelphia universities, and a caregiver to former President Gerald Ford after his stroke in 2000, died Wednesday, Aug. 4, of a heart attack at his home in Marco Island, Fla.

For 31 years, Dr. Schwartzman chaired the departments of neurology at Thomas Jefferson University, Hahnemann University School of Medicine, and Drexel University College of Medicine.

Renowned for pioneering research and testing of chronic pain, he oversaw labs that made groundbreaking discoveries, steered international conferences that reshaped medical guidelines, and inspired countless others to build on his work.

“He was a master neurologist and clinician in the truest sense,” said fellow neurologist S. Ausim Azizi.

A doctor quoted at painnewsnetwork.org called his death a “huge loss for science and humanity.”

Dr. Schwartzman was an expert on complex regional pain syndrome (CRPS), the use of ketamine as a treatment for chronic pain, and many other neurological issues. At Jefferson, he and others founded the first CRPS clinic in the United States.

Esteemed as a professor and mentor, he trained more than 350 residents over 40 years and took as much pleasure in their success as his own. Former students noted his “wicked great sense of humor,” “fatherly” presence, and “true understanding of life” in an online tribute.

He published Neurological Examination: An Illustrated Guide to the Neurological Examination in 2006 and Differential Diagnosis in Neurology in 2007, and his name is attached to nearly 200 articles and papers.

His 1982 paper, Neurologic Complications of Disseminated Intravascular Coagulation, has relevance to current COVID-19 researchers, and he showed his optimism about the future of treatment, and the lure of neurology as a vocation, in a 2011 video interview at Drexel.

“It’s dramatic,” he said of the inroads he and others achieved in treating pain and disease. “Anybody that is not a neurologist now is silly,” he said of the profession.

Dr. Schwartzman personally treated thousands of patients in their sometimes desperate efforts to find relief from chronic, severe pain. He sent patients abroad, sometimes going with them, when new treatments, including the “ketamine coma,” were not yet permitted in the United States.

When Ford suffered a stroke during the 2000 Republican National Convention in Philadelphia, Dr. Schwartzman was one of his local physicians and accompanied the former president on his return to California.

His impact will live on through patients like me,” a former patient said in an online tribute. Another wrote, “Not a week goes by that I don’t think of him with gratitude.”

Born Nov. 28, 1939, in Washington, Dr. Schwartzman graduated from Harvard and then the University of Pennsylvania School of Medicine in 1965. He had an internship and residency in internal medicine at Duke University Hospital, a residency in neurology at Penn, and a fellowship at the National Institutes of Health.

He was an associate professor of neurology at the University of Miami from 1971 to 1978 and professor of neurology, chief of the division of neurology, and program director at the University of Texas Health Science Center in San Antonio from 1978 to 1982.

He was chair of neurology at Jefferson from 1982 to 1995, at Hahnemann from 1995 to 2002, and at Drexel, after it took over Hahnemann in 2002, until 2013. He won numerous awards and honors from all three universities, and from national organizations, and retired to Florida in 2013.

Independent and opinionated, Dr. Schwartzman preferred written over electronic medical records, and, a collaborator at heart, resisted isolating himself as a researcher or teacher. He used his Facebook page as a forum for neurologists to meet and converse on important issues.

He liked boating, tennis, and nature, especially the Florida Everglades. He was disarming to family, friends, and patients. “He made everyone feel special,” said fellow doctor Philip Getson.

His wife of 55 years, Denise, said: “He was so special to me. I miss him desperately.”

In addition to his wife, Dr. Schwartzman is survived by son David; daughters Jane and Nancy; two grandchildren; two brothers; and other relatives.

Services were private.

Donations in his name may be made to the Audubon Corkscrew Swamp Sanctuary, 375 Sanctuary Rd. W, Naples, Fla. 34120.