Core Faculty

Program Director Jay Hinkle, MD is an adjunct assistant professor in the Department of Neurology at UAMS. He is board certified by the American Board of Psychiatry and Neurology in neurology and vascular neurology. Dr. Hinkle received his medical degree from UAMS in 2012 and completed his residency in adult neurology at UAMS in 2016, where he also served as Chief Resident. He went on to complete a vascular neurology fellowship at Johns Hopkins University in 2017. After graduation, Dr. Hinkle joined the neurology team at Washington Regional and the faculty at UAMS. He also serves as a staff neurologist for the ARSAVES telehealth stroke network run by UAMS, and previously served as Medical Director of Stroke Rehabilitation at Encompass Rehabilitation Hospital in Fayetteville.

Associate Program Director Margaret Tremwel, MD, PhD, is an adjunct assistant professor in the Department of Neurology at UAMS. She is board certified by the American Board of Psychiatry and Neurology in neurology and vascular neurology. Dr. Tremwel received her medical degree and PhD in neuroscience from the University of Florida, where she also completed her neurology residency in 2001. She completed a vascular neurology fellowship from UCLA in 2002. She joined Washington Regional in 2014 and serves as the medical director of the hospital’s stroke program. She also serves as the neuro-rehabilitation medical director for Encompass Health in Fayetteville. Dr. Tremwel has served as Principal Investigator or Site Investigator for multiple clinical trials and stroke-related quality improvement initiatives at Washington Regional and is a member of the hospital’s institutional review board (IRB). She is a member and former chair of the Arkansas Acute Stroke Care Task Force.

Caitlin Campbell, DO, specializes in neuro-immunology and multiple sclerosis. She is board certified by the American Board of Psychiatry and Neurology in neurology. She obtained her medical degree from Lake Erie College of Osteopathic Medicine in Florida in 2019. She completed an adult neurology residency at the University of Texas Southwestern in Dallas in 2023 as well as a neuro-immunology fellowship there in 2025. She will lead a neuro-immunology/multiple sclerosis clinic at Washington Regional. 

Alan Diamond, DO, specializes in movement disorders and neuro-palliative care, with a research interest in Parkinson’s Disease and Huntington’s Disease. He obtained his medical degree from the University of Health Sciences College of Osteopathic Medicine in Kansas City in 2000. He completed an adult neurology residency at St. Louis University in 2004, where he also served as Chief Resident, as well as a fellowship in movement disorders from Baylor College of Medicine in Houston in 2005. Dr. Diamond has been with Washington Regional since 2007, as both a staff neurologist and as Director of the Movement Disorders Clinic.

Steven Graham, MD, specializes in general adult neurology and electromyography. He completed his MD at the University of Alabama in Birmingham before completing his residency in adult neurology at Vanderbilt University Medical Center in 1992. Dr. Graham worked in private practice in Nashville after graduation and served as a preceptor for neurology residents and medical students at Vanderbilt. He obtained additional certification in headache medicine from the National Headache Foundation in 2018. Dr. Graham joined Washington Regional in 2019. He leads the neurology continuity clinic for the neurology residency program.  

Dr. Stephen Jones, MD, obtained his medical degree from the University of Texas Health Science Center in Houston and completed a residency in Child Neurology from UAMS in 2020. Since then, he has served as an Assistant Professor of Child Neurology in the Department of Pediatrics at UAMS. Dr. Jones is one of two child neurologists serving as core faculty for our program. Prior to transitioning to Arkansas Children’s Northwest in Springdale, Dr. Jones practiced at Arkansas Children’s Hospital in Little Rock and served on the faculty of the UAMS Child Neurology Residency Program, serving as both a member of the Program Evaluation Committee and the Clinical Competency Committee. At Arkansas Children’s Northwest, he serves as Director of the Headache Clinic.

Sen Sheng, MD PhD obtained his medical degree and a PhD in neuroscience at Peking University Health Science Center in Beijing, China. He completed neurosurgery training with an emphasis in emergency care at People’s Hospital in Beijing, as well as microvascular neurosurgery training at China Meitan General Hospital, also in Beijing. Dr. Sheng completed a neurology residency at UAMS in 2021 and a fellowship in clinical neurophysiology at the University of Pittsburgh in 2022. Prior to residency at UAMS, Dr. Sheng was an attending neurosurgeon in China and completed a postdoctoral program in neurosurgery at Baylor Scott & White Healthcare in Temple, Texas. Dr. Sheng joined Washington Regional in 2023. He is a topic editor for Frontiers in Neurology, Neurocritical and Neurohospitalist Care and on the editorial board for Frontiers in Stroke, Preventative Health and Stroke Complications.

Collin Swafford, DO obtained his medical degree from the University of North Texas Health Science Center in Fort Worth, Texas. He completed a child neurology residency in 2019 at Case Western Reserve University. Following residency, he joined the faculty of the child neurology residency program at the University of Texas Dell Medical Center in Austin. He was the residency program’s Associate Program Director from 2019 to 2022, when he joined the faculty at UAMS and began practicing at Arkansas Children’s Northwest in Springdale, Arkansas. He has a research interest in pediatric vascular neurology and is a peer reviewer for Pediatric Neurology.