Faculty & Staff

Michael Polydefkis, M.D.
Director, EMG Laboratory
Director, Cutaneous Nerve Laboratory
Associate Professor, Neurology

Michael Polydefkis, M.D., serves as director of the EMG Laboratory and Cutaneous Nerve Laboratory at Johns Hopkins Bayview Medical Center. An associate professor of neurology, he focuses on the treatment of neuromuscular and peripheral nerve disease. Certified by the American Board of Psychiatry and Neurology, and board-eligible in internal medicine, Dr. Polydefkis specializes in diabetes-associated neuropathy. His expertise includes nerve conduction studies, electromyography, and nerve, skin and muscle biopsy reading.

Dr. Polydefkis received his medical degree from The Johns Hopkins University School of Medicine. He became a Howard Hughes Medical Institute research fellow before returning to Johns Hopkins to complete an internship and residency in internal medicine, residency in neurology and a fellowship in neuromuscular diseases.

Dr. Polydefkis’s research interests include the role of nerve growth factor expression in human peripheral nerve regeneration, novel models of human nerve regeneration, identification of factors influencing nerve regeneration in diabetes and HIV infection, and clinical trials of promising neurotrophic agents using novel measures of axonal regeneration. In addition, he has pioneered the use of punch skin biopsy in diabetes and as an outcome measure for clinical trials. This work offers strategies to shorten these trials.

Dr. Polydefkis has received funding from the National Institutes of Health (NIH), the Juvenile Diabetes Research Foundation (JDRF), the Howard Hughes Medical Institute, as well as numerous investigator-initiated trials by pharmaceutical companies. He has served on the board of the Peripheral Nerve Society and is on the editorial board of Experimental Neurology. In addition, he is a member of the grant review committee of the American Diabetes Association and has been an ad hoc reviewer for JDRF and NIH. Dr. Polydefkis has received numerous teaching awards, including the Housestaff Teaching Award from The Johns Hopkins University School of Medicine.

Richard O’Brien, M.D., Ph.D.
Chair, Department of Neurology
Associate Professor, Neurology

Richard O’Brien, M.D., Ph.D., is chair of the Department of Neurology at Johns Hopkins Bayview Medical Center and an associate professor of neurology. He specializes in the treatment of patients with a variety of neurologic conditions, including dementia, stroke, neuropathy and gait disorders.

Dr. O’Brien received his medical degree and Ph.D. from Harvard Medical School, then completed an internship at Massachusetts General Hospital. He also completed a residency in neurology and fellowship in neuromuscular disease at The Johns Hopkins Hospital.

Certified by the American Board of Psychiatry and Neurology, and the American Board of Internal Medicine, Dr. O’Brien has won many teaching awards and holds several NIH research grants. He has spent his life studying how the brain adapts to change and how neurodegenerative diseases alter this process.

Kathleen Burks, CRNP
Nurse Practitioner, Department of Neurology

Kathleen Burks, CRNP, a nurse practitioner in the Department of Neurology, has worked with Dr. Polydefkis since 2004. She has a special interest in the evaluation and treatment of peripheral neuropathy and has worked closely with Dr. Polydefkis on several clinical trials on diabetic and painful neuropathy. She earned a bachelor's degree from Iowa State University and a master's in nursing from the University of Maryland. Burks also completed a post-graduate nurse practitioner degree at The Johns Hopkins University School of Nursing.