About Us

John A. Bertelson, MD, FAAN is a board-certified behavioral neurologist and serves as Principal Investigator at Senior Adults Specialty Research. He is a nationally recognized expert in Alzheimer’s disease, Lewy body dementia, and other disorders of cognition, with extensive experience across clinical care and clinical research.

Dr. Bertelson received dual undergraduate degrees in chemical engineering and biochemistry from Rice University and earned his medical degree from the University of Texas Health Science Center at Houston. He completed his neurology residency at the Mayo Clinic, followed by advanced fellowship training in Behavioral Neurology and Neuropsychiatry at Harvard Medical School/McLean Hospital and in Neuroimaging at the Dent Neurologic Institute.

Dr. Bertelson has served as an investigator on numerous clinical trials, has been part of the Senior Adults Specialty Research leadership team since 2016, and brings more than 20 years of experience caring for individuals with cognitive and neurological disorders in Central Texas.

Meredith Barron, PhD, is a licensed psychologist and President of Senior Adults Specialty Research, with more than 20 years of experience in clinical research and neuropsychological assessment. She earned her PhD in Counseling Psychology and a master’s degree in Counselor Education from The University of Texas at Austin and completed an APA-accredited clinical internship and postdoctoral fellowship in the Department of Psychiatry at the University of Texas Health Science Center at San Antonio.

Dr. Barron has been involved with Senior Adults Specialty Research since its inception in 2002 and has served in senior clinical and research leadership roles since 2010. Engaged in clinical trials since 1999, she has served as a Sub-Investigator, senior clinical leader, and expert rater across Phase II–IV studies in Alzheimer’s disease and related neuropsychiatric conditions, spanning prevention through moderate-stage disease.

As President, she provides strategic and operational leadership while remaining actively engaged in study oversight, rater training, quality assurance, and participant care. She is committed to advancing ethical, high-quality clinical research and improving outcomes for individuals and families affected by Alzheimer’s disease.

Larisa Schertz, RN, is the Site Director at Senior Adults Specialty Research and brings more than two decades of experience in psychiatric nursing and Alzheimer’s disease clinical trials. She is a registered nurse with extensive expertise in site operations, participant safety, regulatory affairs and the execution of complex Phase II–IV clinical trials.

Ms. Schertz has worked with Senior Adults Specialty Research in clinical research roles since 2004 and has served as a Research Coordinator, Site Manager, Rater, and now Site Director. She has played a central role in the successful conduct of numerous Alzheimer’s disease and neuropsychiatric clinical trials, with experience spanning prevention, early symptomatic, and moderate-stage disease. Her responsibilities have included participant screening and assessment, neuropsychiatric rater, study coordination, and ongoing protocol and regulatory compliance.

Prior to her work in clinical research, Ms. Schertz practiced as a psychiatric nurse in inpatient and emergency psychiatric settings, bringing a strong foundation in behavioral health and patient safety to her research work. As Site Director, she oversees daily site operations, staff coordination, study implementation, and quality assurance, helping to ensure consistent, high-quality research conduct and participant care.

Cherie Simpson, PhD, APRN, CNS-BC, is a board-certified Clinical Nurse Specialist in Adult Health and Sub-Investigator at Senior Adults Specialty Research with extensive experience in Alzheimer’s disease clinical care and research. She earned her PhD in Nursing from The University of Texas at Austin and holds advanced training as a registered nurse and clinical nurse specialist.

Dr. Simpson has been involved in Alzheimer’s disease research and geriatric psychiatry for nearly two decades and has worked with Senior Adults Specialty Research since 2005. She has served as a Research Nurse, Sub-Investigator, and Principal Investigator across Phase II–IV clinical trials in Alzheimer’s disease, mild cognitive impairment, and neuropsychiatric symptoms of dementia. Her research experience includes prevention, early symptomatic, and moderate-stage Alzheimer’s disease studies, including trials incorporating biomarker confirmation and longitudinal outcomes.

In addition to her clinical trials expertise, Dr. Simpson has a strong academic background and previously held a tenure-track faculty appointment at the University of Texas at Austin School of Nursing. Her scholarly work focuses on dementia caregiving,
sleep, caregiver burden, and behavioral and psychological symptoms of dementia, and she has published extensively in peer-reviewed journals.

Dr. Simpson remains actively engaged in both clinical research and patient care specializing in cognitive health, bringing a holistic, patient-and family-centered approach to Alzheimer’s disease research. Her longstanding involvement with Senior Adults Specialty Research provides continuity in clinical oversight, research quality, and participant care.