The international neurology community mourns the passing of Dr. Mark Hallett, a leader in the fields of movement disorders, neurophysiology, and translational neuroscience. Dr. Hallett’s work helped to elucidate and advance our understanding of human motor control and to establish conceptual frameworks that impact both clinical practice and experimental research worldwide.

Dr. Hallett had unwavering commitment to scientific rigor and talent for bridging bedside observation with sophisticated neurophysiologic investigation. In his nearly 4 decades at the NIH, his research into human motor physiology established him as a pioneer in the application of transcranial magnetic stimulation (TMS) to human neuroscience and trailblazer in establishing the mechanism of disrupted intracortical inhibition and facilitation in human disease. His work in dystonia and other functional movement disorders demonstrated that these conditions arise from specific abnormalities in brain function and attention. His work played a pivotal role in legitimizing functional neurological disorders within academic neurology, alleviating stigma and promoting more rational, compassionate approaches to patient care.

Clinically, Dr. Hallett made seminal contributions across a broad spectrum of movement disorders and inspired neurologists and neuroscientists worldwide. His work in dystonia, tremor, myoclonus, Parkinson’s disease, and functional neurological disorders consistently emphasized mechanism over description, influencing generations of clinicians to think deeply about the neural circuits underlying abnormal movement. In his mentoring, he promoted intellectual generosity, clear thinking, and a culture valuing careful experimentation and open discussion.

Dr. Hallet has been honored with several distinguished awards in recognition of his contributions to neuroscience. These include a Doctor of Medicine honoris causa from the University of Hamburg, Germany; honorary membership in the European Academy of Neurology; and the WFN Medal for Contribution to Neuroscience from the World Federation of Neurology. In addition, he received the International Brain Stimulation Award from the journal Brain Stimulation and the Lifetime Achievement Award from the International Association of Parkinsonism and Related Disorders.

Dr. Hallett is recognized for his professionalism and inclusive approach. In 2004, he assisted in organizing the inaugural International Neurology Forum (INFO) in Vietnam, following the country’s recent opening, under the auspices of the World Federation of Neurology. Subsequent programs were conducted collaboratively with the IAPRD in various countries worldwide.

Dr. Hallett’s legacy is measured not only by an exceptional body of publications and citations, but by his provocative and insightful ideas that have significantly advanced the understanding of both mechanism and patient care. He will be remembered as a scientist of uncommon depth, a clinician of rare insight, and a mentor whose influence will endure for decades.