Ryan Darby, MD

Ryan
Darby
MD
Assistant Professor of Neurology

Dr. Darby is interested in patients with symptoms at the border zone between neurology and psychiatry. Both neurological and psychiatric patients can share similar symptoms, including delusions, hallucinations, and antisocial and criminal behavior. This suggests that these symptoms may share a common pathway across different diseases. However, these different diseases often have neuroimaging abnormalities in different locations, making it difficult to understand how the same symptom could develop.

To address this problem, Dr. Darby helped to develop a new neuroimaging approach to localize complex behaviors to brain networks, rather than specific brain locations. He first studied this in patients with focal brain lesions, showing that brain lesions in different locations causing the same syndrome were all functionally connected to the same brain network. Dr. Darby’s current work is focused on applying this method to neurodegenerative disorders in order to understand why brain atrophy in different locations can cause the same clinical syndrome. He is using this method in combination with behavioral testing to study criminal behavior in frontotemporal dementia patients and delusions/hallucinations in patients with Alzheimer’s Disease, Parkinson’s Disease, and Lewy Body Dementia. Dr. Darby has received numerous awards for his research, including the Stanley Cobb Award from the Boston Society for Neurology and Psychiatry, the Young Investigator Award from the American Neuropsychiatric Association, the S. Weir Mitchell Award for Outstanding Early Career Investigator from the American Academy of Neurology, and the Norman Geschwind Prize in Behavioral Neurology. His work is generously funded by the Sidney R. Baer, Jr Foundation, the Alzheimer's Association, the BrightFocus Foundation, and the Department of Defense.

For more information on Dr. Darby’s research, please visit his lab website.

Ryan Darby is an assistant professor of neurology at Vanderbilt University Medical Center. He currently sees patients as the director of the Frontotemporal Dementia Clinic in the Department of Neurology at VUMC.

He received his undergraduate degree from Princeton University in psychology and neuroscience, and his medical degree from Vanderbilt University. He trained in neurology at Massachusetts General Hospital and Brigham and Women's Hospital as part of the Partners Neurology/Harvard Medical School program. He then received the Sidney R. Baer, Jr. Research Fellowship in Clinical Neurosciences at the Beth Israel Deaconess Medical Center. He simultaneously completed a clinical fellowship in behavioral neurology and neuropsychiatry at Beth Israel Deaconess Medical Center, Massachusetts General Hospital, and McLean Psychiatric Hospital in Boston.

Sam Sells, MD

Sam
Sells
MD
Assistant Clinical Professor of Psychiatry and Behavioral Sciences

Daniel Claassen, MD, MS

Daniel
Claassen
MD, MS
Professor of Neurology
Division Chief Behavioral and Cognitive Neurology

The theme of my work is to understand the biologic basis of how humans regulate of behavior, and the cognitive processes intrinsic to this nature. My research efforts are focused in patients that suffer from neurodegenerative conditions, and my current studies assess therapeutic outcomes in various neurodegenerative disorders, such as Parkinson, Huntington, and atypical Parkinsonian disorders (PSP and MSA). I also lead a basic research lab which investigates the neurobiological basis neurodegeneration through innovative cognitive neuroscience, neuroimaging tools, and biomarker discovery using patient biofluids. 

For more on Dr. Claassen’s current research, visit the Cognition and Movement Lab page.

Dr. Daniel Claassen is a Professor of Neurology at Vanderbilt University Medical Center, with subspecialty training in movement and cognitive neuroscience. He specializes in the diagnosis and treatment of neurodegenerative disorders characterized by disruptions to cognition, behavior, and movement. He is the chief of the Behavioral and Cognitive Neurology Division.

James S. Powers, MD

James
S.
Powers
MD
Professor of Medicine, Division of Geriatric Medicine
Assoc. Director, VA Geriatric Research, Education & Clinical Center (GRECC)

Director, Middle Tennessee Geriatric Workforce Enhancement Program
Assoc. Director, VA Geriatric Research, Education & Clinical Center (GRECC)
Professor of Medicine, Division of Geriatric Medicine
Adjunct Professor of Nursing
Vanderbilt Primary Care Village at Vanderbilt
Vanderbilt Center for Quality Aging
Geriatric Medicine Fellowship Program Faculty

Education:

M.D., University of Rochester, Rochester, New York
B.A., Wesleyan University, Middletown, Connecticut

Relevant Links:

VUSM Faculty Profile
Division of Geriatric Medicine
Geriatric Medicine Fellowship Program
Department of Medicine

Postgraduate Training:

Residency: Case Western Reserve University Hospitals, 1980 / Cleveland Clinic, 1979

Professional Highlights:

James S. Powers, M.D. received a B.A .cum laude from Wesleyan University (CT.) in 1973 and M.D. with Distinction in Research from the University of Rochester (N.Y.) in 1977 followed by residency in Internal Medicine at Cleveland Clinic and Case Western Reserve University Hospitals 1977-80. He served in the USPHS National Health Service Corps 1980-83 following which he was recruited to Vanderbilt to develop a Geriatric Medicine Program within the Division of General Internal Medicine.

Dr. Powers is author of over 75 papers, books, and book chapters he has devoted his academic career to Geriatric Nutrition, Education, and Healthcare Quality and Safety. He has mentored over 1200 trainees while at Vanderbilt and holds Fellowship in the American College of Physicians, American College of Nutrition, American Geriatrics Society, Gerontologic Society of America, and the Royal Society of Medicine. He serves as the Associate Clinical Director for the V.A. Tennessee Valley Geriatric Research Education and Clinical Center.

Dr. Powers’ research interests include educational outcome evaluation, aging body composition, and models of geriatric care. He is P.I. of the Vanderbilt-Reynolds Geriatric Education Program, Co.-P.I. of the Meharry Geriatric Education Center, and leads numerous clinical demonstration projects for the T.V.H.S. G.R.E.C.C. concerned with falls prevention, caregiver support, and treatment of agitated dementia, and health systems improvement.

Lealani Mae (Leah) Acosta, MD, MPH

Lealani
"Leah"
Acosta
MD, MPH
Associate Professor of Neurology

Dr. Acosta is the principal investigator for Alector Frontotemporal Dementia clinical trial in patients with the progranulin gene mutation and other Alzheimer's disease clinical trial research. As a study physician for Vanderbilt Memory & Alzheimer’s Center, Dr. Acosta performed clinical evaluations, lumbar punctures for cerebrospinal fluid acquisition, and reviewed laboratory findings. She also is a sub-investigator or study physician for other research projects in Alzheimer's disease and other clinical trials at Vanderbilt, such as the Alzheimer's Disease Neuroimaging Initiative, the MIND (Memory Improvement through Nicotine Dosing) Study, and the Bringing to Light the Risk Factors and Incidence of Neuropsychological Dysfunction in ICU Survivors (BRAIN-2). As a Clinician Educator working with medical students, she has served as a Master Clinical Teacher, working one-on-one supervising histories and physicals, and a Portfolio Coach, and currently serves as College Mentor within the Vanderbilt University School of Medicine. She has published research on medical education. Dr. Acosta has been instrumental in protocol implementation for evaluation of normal pressure hydrocephalus, which won the prestigious Vanderbilt University Medical Center Elevate Team Credo Award in 2023, and the lumbar puncture clinic for the neurology residents.

Dr. Lealani Mae (Leah) Acosta is an Associate Professor of Neurology and a board-certified neurologist specializing in neurodegenerative memory disorders. Currently she serves as co-editor of the Humanities section of the journal Neurology. Dr. Acosta joined the Vanderbilt University School of Medicine faculty in 2013. She completed graduate studies, obtaining a master's in public health at Vanderbilt, with her research focused on error frequency and quality in a task of semantic fluency in patients with mild cognitive impairment. 

She attended The George Washington University, graduating summa cum laude in psychology. She completed graduate studies in psychology, philosophy, and physiology at Oxford University in Oxford, UK. On returning to the United States, she finished both her medical education and residency training in Neurology at the University of Virginia in Charlottesville, VA. She completed fellowship in Cognitive and Behavioral Neurology at the University of Florida in Gainesville, FL, under the mentorship of Dr. Kenneth Heilman, focusing on creativity. Her interest in this topic stems in part from her own hobbies of poetry, drawing, and calligraphy. Her range of publications reflects these varied interests, including peer-reviewed research articles and creative writing, primarily poetry.

Sumi Misra, MD, MPH

Sumi
Misra
MD, MPH
Associate Professor of Medicine
Division of General Internal Medicine and Public Health

Dr. Misra is the section chief of palliative care at the Veterans Administration Hospital (VA) and is a board-certified geriatrician and palliative care physician who leads key aging-related programs at the VA and VUMC. With her training and experience, Dr. Misra is uniquely poised to lead the ENHANCE project.

Mohana Karlekar, MD

Mohana
Karlekar
MD
Associate Professor of Medicine
Division of General Internal Medicine and Public Health

Dr. Karlekar is the section chief of palliative care at Vanderbilt University Medical Center. She serves in leadership roles in palliative care at the local, regional, and national levels and has served as chair of the Tennessee State Palliative Care Council and Quality of Life Council since its inception in 2019.

Ralf C. Habermann, MD, MMHC

Ralf
C.
Habermann
MD, MMHC
Assistant Professor of Medicine
Division of Geriatric Medicine, Autonomic Dysfunction Center
Tennessee Valley Healthcare System Nashville campus
Medical Director
Bethany Center for Vanderbilt Primary Care Village, Kindred Hospice, and Mur-Ci Homes

Patient Care Interests- Geriatric medicine, palliative care, rehabilitation and healing, and autonomic dysfunction.

Education

  • Fellowship- Vanderbilt University Medical Center, 2000
  • Residency- Rhode Island Hospital, Brown University, 1995
  • MD- Freie Universitat Berlin, Germany
  • Master of Management Healthcare- Vanderbilt University

Publications

Mariu Carlo Duggan, MD, MPH

Mariu
Carlo
Duggan
MD, MPH
Assistant Professor of Medicine
Division of Geriatric Medicine

Program Director, Geriatric Medicine Fellowship Program
Medical Director, Acute Care of the Elderly (ACE) Unit, 7 Round Wing
Assistant Professor of Medicine, Division of Geriatric Medicine
Critical Illness, Brain dysfunction, and Survivorship (CIBS) Center

Education:

M.D., Medicine, Vanderbilt University, Nashville, Tennessee
M.P.H., Vanderbilt University, Nashville, Tennessee
B.S., Harvard University, Cambridge, Massachusetts

Relevant Links:

VUSM Faculty Profile
Division of Geriatric Medicine
Geriatric Medicine Fellowship Program

Megan Simmons, DNP, PMHNP

Megan
Simmons
DNP, PMHNP-BC
Director, Psychiatric-Mental Health Nurse Practitioner (Lifespan) Specialty
Assistant Professor of Nursing and Psychiatry
megan.simmons@vanderbilt.edu

https://nursing.vanderbilt.edu/people/bio/megan-simmons

Dr. Simmons joined the Vanderbilt University School of Nursing faculty in 2013. She has been a board certified Psychiatric-Mental Health Nurse Practitioner (PMHNP) since 2005 when she graduated from Vanderbilt?s MSN program. 

Since 2006, Dr. Simmons has practiced as a consultant in long-term care facilities providing psychiatric assessment and medication management services. 

She obtained her DNP from Vanderbilt University in 2013, and her scholarly project assessed the off-label usage of antipsychotic medications in Middle Tennessee nursing homes. 

Dr. Simmons is active in multiple professional organizations, and serves as the chair of the Geropsych Focus Group within the Gerontological Advanced Practice Nurses Association. 

Her current research interests include geriatric psychopharmacology, mental health care of older adults and long-term care residents, and treating behavioral and psychological symptoms of dementia.