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War Related Illness and Injury Study Center


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Our staff consists of physicians, nurse practitioners, physician assistants, psychologists, research scientists, epidemiologists, complementary and alternative medicine practitioners, and environmental health scientists who have many years of experience seeing veterans with post-deployment health concerns. Below is a description of the clinical and research backgrounds of our current DC WRIISC staff members:


Matthew J. Reinhard, PsyD
  • Position: WRIISC Director

Dr. Reinhard is the Director of DC WRIISC. He has been with the WRIISC-DC since 2008 as a clinical neuropsychologist and has seen many Veterans with a variety of post-deployment health concerns. He obtained his BA from Long Island University, his MA and PsyD from Pepperdine University (APA), and interned at the Kaiser Permanente Los Angeles Medical Center (APA). He completed a two-year post-doctoral fellowship in neuropsychology at the University of California-Los Angeles (UCLA), Semel Institute for Neuroscience and Human Behavior. He has recently published neuropsychology research the areas of: PTSD, Complementary and Integrative (CIM) Approaches.   He has also worked as a clinical psychologist in the PTSD treatment program at the Washington DC VAMC. His current area of research interest is brain behavior relationships in PTSD, Gulf War Illness, and CIM. He has an academic appointment at the Associate Professor rank from Georgetown University Medical School Department of Psychiatry.

Contact Dr. Reinhard at: 202-745-8249.

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Nate Allen, BS
  • Position: Grant Manager

Mr. Allen, BS, is a Research Grant Manager at DC WRIISC and graduate of Trinity College, CT. He is currently a research coordinator and primary investigator for WRIISC studies including inhibitory reflex control via eye movements, integrative and alternative medicine for Gulf War Veterans, and the intersection of health and mobile technologies. He hopes WRIISC’s interdisciplinary work with multi-symptom illnesses, TBI, and PTSD will contribute to positive health outcomes for future Veterans.

Contact Mr. Allen at: 202-745-8000, ext. 55474.

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Trisha Nakano Bhagen, CNS®, NBC-HWC, MS, MA
  • Position: Health Coach

Ms. Bhagen is a Certified Nutrition Specialist®, National Board-Certified Health and Wellness Coach, and Experienced-Registered Yoga Teacher. She supports DC-WRIISC through health coaching and nutrition education. She earned a MS Nutrition and Integrative Health, and a MA in Health and Wellness Coaching, both from Maryland University of Integrative Health. Ms. Bhagen earned a MA Teaching from American University. She comes from a 15-year career in education, which included teaching and nutrition education curriculum development. She leads onsite yoga, nutrition education, Whole Health groups, and meditation.

Contact Ms. Bhagen at: 202-745-8249.

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Charity B. Breneman, PhD, MSPH
  • Position: Senior Exercise Physiologist

Dr. Breneman is an Exercise Physiologist with the DC WRIISC. She graduated from Brigham Young University with a BS and MS in Exercise Science. She went on to earn a PhD in Exercise Science with an emphasis in health aspects of physical activity and a MSPH in Epidemiology from the University of South Carolina (USC). Dr. Breneman also completed a postdoctoral fellowship in health services research at the Rural and Minority Health Research Center at USC. Her current area of research includes examining the bidirectional relationship between exercise and sleep, the acute and chronic effects of exercise on post-deployment health, and the individualization of exercise training prescriptions.

Contact Dr. Breneman at: 202-745-8000, ext. 55823

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Ryan Brewster, PhD
  • Position: Clinical Neuropsychologist

Dr. Brewster is a Clinical Neuropsychologist at the DC WRIISC. He completed an undergraduate degree at the University of Miami and an MA and PhD in Clinical Psychology at Georgia State University. Dr. Brewster’s training also included an internship at the University of California-Los Angeles (UCLA) Semel Institute for Neuroscience and Human Behavior and a two-year postdoctoral fellowship in Clinical Neuropsychology (Traumatic Brain Injury/Rehabilitation Track) at the West Los Angeles VAMC. His clinical responsibilities at the DC WRIISC include conducting neuropsychological assessments of Veterans with a wide range of complex neurocognitive and emotional concerns, and supervising postdoctoral fellows specializing in neuropsychology. Dr. Brewster’s current research interests are in the combined application of neuroimaging and traditional neuropsychological assessment to better understand TBI and epilepsy, cognitive rehabilitation following TBI, and disentangling overlapping cognitive and emotional symptoms common in mTBI and PTSD.

Contact Dr. Brewster at: 202-745-8000, ext. 56800

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Jeremy Chester, BS
  • Position: Data Manager

Mr. Chester, BS, is a Data Manager at DC WRIISC. He has a BS in Biochemistry from Binghamton University. He has worked for the Department of Veterans Affairs since 2016, and he previously served in the United States Marine Corps Reserves for six years, including a one-year active duty deployment in support of Operation Iraqi Freedom. He has conducted research on a variety of topics, including the genetic basis of thyrotoxicosis, the media’s portrayal of Chronic Multi-Symptom Illness, treatments for Gulf War Illness, and the history of translational research in Gulf War Illness. He has published research on thyroid hormone receptor disease. He is currently involved in several research studies with the WRIISC, including treatments for Insomnia in Gulf War Veterans, identifying biomarkers, the course of illness, and targeted treatment approaches for Gulf War Illness, and clinical outcomes of Mefloquine use. He is involved in clinical operations at the WRIISC, including database queries and management and a value stream analysis of clinical operations. He also is involved in WRIISC educational operations, including development of an educational module on depleted uranium exposure and a remote health coaching project.

Contact Mr. Chester at: 202-745-8000, ext. 55769

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Timothy Chun, BS
  • Position: Health Science Specialist

Mr. Chun, BS is a research assistant at the DC WRIISC. He received his bachelor’s degree in Community Health at the University of Maryland, College Park. He has a background in electroencephalogram (EEG) research and will continue this research at WRIISC. Mr. Chun looks forward to expanding his experience in research and to assist the WRIISC team to achieve their goals.

Contact Mr. Chun at 202-745-8000, ext. 55818

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Michelle E. Costanzo, PhD
  • Position: WRIISC DC Research Director

Dr. Costanzo is the Research Director at the DC WRIISC and has a faculty position as a Research Assistant Professor of Medicine at the Uniformed Services University of the Health Sciences (USUHS). She has over 15 years of human subjects research experience with 8 years experience specifically focused in a military research environment (Department of Defense and Veterans Affairs). She has a strong publication history related to post-deployment health topics and expert populations such as elite athletes and physicians, including the 2017 Military Medicine Article of the Year for her work as lead author of the article "Psychophysiological Investigation of Combat Veterans with Subthreshold Post-traumatic Stress Disorder Symptoms."  Specifically, her military-relevant research has utilized psychophysiology and neuroimaging to examine post-traumatic stress disorder and mild traumatic brain injury during fear conditioning, combat-related virtual reality, affective stroop, and telemedicine to reveal insight into the etiology of persistent symptoms associated with deployment. Her recent interest has focused on behavioral interventions aimed at augmenting cognitive control and executive functioning based on neuroscientific understanding of stress, brain structural and functional plasticity that could help Veterans achieve the self-regulation competence to enable them to master patient-driven healthcare. She holds a BS in Neurobiology, Physiology, and Behavior from the University of California, Davis and a PhD in Neuroscience and Cognitive Science from the University of Maryland, College Park (UMD). She was trained in the acquisition and analysis of electroencephalography (EEG) at the UMD as well as in functional Magnetic Research Imaging at the National Institutes of Health (NIH) and the Georgetown University Medical Center. In addition to her scientific training, she has over a decade of experience with research administration and program management, ranging from her work at the National Science Foundation and the White House Office of Science and Technology Policy to her responsibilities as a study manager for NIH, USUHS, Walter Reed National Military Medical Center and WRIISC clinical studies. This has afforded her considerable experience with Federal government program management, budgeting, regulatory compliance and science policy. In addition, she has served as a reviewer for peer-reviewed journals, IRB scientific review and successfully acquired grant funding during her appointment at the VA.  Dr. Costanzo is leading the research team in developing the next generation of rehabilitation, treatment and diagnosis for Veterans through leveraging both clinical and research resources that the VA currently offers and through partnership with other institutions.

Contact Dr. Costanzo at: 202-745-8000, ext. 56973.

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Lucas E. Crock, MA
  • Position: Health Science Specialist

Mr. Crock is a Health Science Specialist with the DC WRIISC. He has a BS in Psychology from King’s College, Wilkes-Barre, PA, and a MA in Psychological Science from the Catholic University of America in Washington, DC. His background includes conducting research on a variety of topics such as group therapy treatments, moderators for intervention efficacy, and treatments for Gulf War Illness. He is currently involved in multiple studies with the WRIISC examining the efficacy of alternative treatments for Gulf War Illness, telehealth interventions, and treatments for Insomnia in Veterans.

Contact Mr. Crock at: 202-745-8000, ext. 57553.

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Sharon DeMocker, MD
  • Position: Medical Director

Dr. DeMocker is the WRIISC-DC Medical Director. Dr. DeMocker previously headed an Integrative Medical clinic near Asheville, NC for over a decade, which she founded following her training with Dr. Andrew Weil at the University of Arizona, the first postdoctoral Integrative Medicine training center in the country. She completed her residency in Family Medicine through UVA in Lynchburg, with a focus on healthy lifestyle choices to prevent disease, which included her first clinical training with Dr. Weil. During medical school at the Medical University of South Carolina, she was involved in research on the physical and psychological aftermath of trauma. Dr. DeMocker has a strong interest in optimizing health through diet and lifestyle changes, as well as evidence-based, non-pharmaceutical treatments for treating chronic conditions, such as acupuncture, yoga, meditation and bodywork, including physical therapy, myofascial release and Therapeutic Touch. Dr. DeMocker is leading the WRIISC clinical team in expanding access to post-deployment health evaluation services for Veterans with deployment-related health and exposure concerns, and developing and expanding resources to assist VA providers in bringing the highest quality care to our nation’s Veterans.

Contact Dr. DeMocker at: 202-745-8249.

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Arghavan Hamedi, MA
  • Position: Health Science Specialist

Ms. Hamedi, MA, is a Health Science Specialist at the D.C. WRIISC. She has a B.A. in Psychology from Virginia Commonwealth University and an M.A. in Psychological Science from the Catholic University of America. Her research background in cognitive psychology includes examining a variety of topics such as emotion regulation, rumination, and brief mindfulness-based interventions. She was also an advanced cognitive brain trainer and eye-tracking coder. Her clinical research background involves military suicide prevention with active duty service members and investigating the role of attentional biases on suicide ideation. Ms. Hamedi is excited to work with the WRIISC team to help them meet their research goals and provide excellent patient care.

Contact Ms. Hamedi at: 202-745-8000, ext. 56824.

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Kyle J. Jaquess, PhD
  • Position: Research Fellow

Dr. Jaquess is a research fellow at the DC WRIISC.  Dr. Jaquess earned his BA from the University of California, Riverside, in Psychology, his MA from California State University, San Bernardino, in Experimental Psychology, and his PhD from the University of Maryland, College Park, in Kinesiology.  Dr. Jaquess has specific training and expertise in the cognitive-motor neuroscience of human learning and performance.  Dr. Jaquess has conducted research related to changes in neuro-cortical dynamics as a result of practice, differences in expertise, and the application of stress using a psychophysiological approach, and has published several papers in international peer-reviewed academic outlets.  Applying his knowledge of human learning and performance to a medical setting, Dr. Jaquess is currently developing a line of research investigating mechanisms underlying improving and restoring cognitive-motor function in both healthy and clinical populations.

Contact Dr. Jaquess at: 202-745-8249

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Walt Jachimowicz, MSN, RN, CNL
  • Position:Nurse Educator

Mr. Jachimowicz is a registered nurse who serves as the Director of Education for the DC WRIISC. He obtained his BSN from Madonna University and his MSN from the University of Detroit Mercy. He has worked for the Department of Veterans Affairs Healthcare System since 1998 and has served in the United States Marine Corps as an active duty reserve officer. Mr. Jachimowicz has many years of experience working in the direct patient care setting and providing education to Veterans and their families. Mr. Jachimowicz has a strong interest in health promotion and disease prevention and set up the DC WRIISC Whole Health Coaching Clinic. Our DC WRIISC Veterans now spend time with health coaches that help them  figure out what their personal health and wellness goals are, how they intersect and affect them holistically and help them develop strategies to meet their wellness goals which may include reducing stress, improving sleep, lowering risk of chronic illness, and/or losing weight.

Contact Mr. Jachimowicz at: 202-745-8000, ext. 52636.

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Mian Li, MD, PhD
  • Position: Neurologist

Dr. Li is a DC WRIISC neurologist who provides clinical care to Veterans seen at the DC WRIISC. His duties include evaluating Veterans with post-deployment health concerns and providing education on war-related illnesses to medical students, residents, and clinical fellows who rotate through the WRIISC. He has been a senior staff fellow at the National Institute of Neurological Disorders and Stroke and has experience in evaluating diseases caused by environmental neuro-toxins. He is currently a clinical Associate Professor of Neurology at the George Washington University. Dr. Li completed his neurology residency at the Albert Einstein College of Medicine in New York and has a PhD in Biomedical Sciences from the Mount Sinai School of Medicine. His research interests include autonomic disorders, brain injuries, and neuro-toxic disorders. Dr. Li is currently the Principal Investigator for two VA Merit studies looking at the autonomic and motor neuron functions of Veterans.

Contact Dr. Li at: 202-745-8000, ext. 56520.

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Nicholas Lezama, MD, MPH
  • Position: Camp Lejeune Family Member Program Clinical Reviewer

Dr. Nicholas Lezama serves as a Camp Lejeune Family Member Program clinical reviewer and WRIISC staff physician. He has a broad background in emergency, aerospace, and preventive medicine. Dr. Lezama is a retired Air Force flight surgeon with 27 years of military service, and he deployed three times in support of Operation Enduring Freedom and Operation Iraqi Freedom. He has served in clinical, command, administrative, and academic positions in the DoD and VA. His expertise and areas of interest include military health, environmental exposures, disaster medicine, aerospace medicine, and aeromedical evacuation. Dr. Lezama received his medical degree from the Boston University School of Medicine and a Master of Public Health degree from the Harvard School of Public Health.

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Antoinette Lomax
  • Position: WRIISC Administrative Officer

Ms. Lomax has been the DC WRIISC Administrative Officer since 2001. She is a longstanding employee of the Department of Veterans Affairs and has considerable experience in organizing clinical programs, overseeing administrative staff and personnel issues, troubleshooting day to day operational issues, and ensuring that budgets and fiscal programs are conducted in accordance with VA regulations. Ms. Lomax also has worked extensively with Veterans to ensure that Veteran feedback is incorporated into strengthening the DC WRIISC program.

Contact Ms. Lomax at: 202-745-8249.

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Keri Maloney, NBC-HWC, MA
  • Position: Health Coach

Ms. Maloney is a board-certified Health & Wellness Coach. She supports Veterans to make positive lifestyle changes, so they can heal and thrive after military service. Ms. Maloney earned a Master of Arts in Health & Wellness Coaching at Maryland University of Integrative Health. She is a U.S. Army and State Department Veteran of the wars in Iraq and Afghanistan. Ms. Maloney served as a legislative assistant in the U.S. Senate and worked on military and Veteran issues. She is a yoga teacher. Ms. Maloney is certified in Mindful Resilience for trauma recovery and leads a weekly meditation class for Veterans on site.

Contact Ms. Maloney at: 202-745-8000, ext. 56310.

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Chmaika Mills, PhD
  • Position: Neuropsychology Fellow

Dr. Chmaika Mills is currently completing a two-year postdoctoral fellowship in clinical and research neuropsychology at the War Related Illness and Injury Student Center (WRIISC) at the Washington DC Veterans Affairs Medical Center. She graduated from the University of Maryland College Park in College Park, MD with a BS in psychology. She earned her MS in Clinical and Counseling Health Psychology from Philadelphia College of Osteopathic Medicine in Philadelphia, PA and her PhD in clinical psychology, with a specialization in adult neuropsychology, from Howard University in Washington, DC. Dr. Mills completed her pre-doctoral internship, with an emphasis in neuropsychology, at the Washington DC VA Medical Center in Washington, DC. Her clinical experiences include neuropsychology and psychotherapy in military and community populations with complex psychiatric and medical histories. Her research interests include traumatic brain injuries, neurocognitive functioning and evaluation, performance/symptom validity tests, mood disorders, and health-related behaviors.

Contact Dr. Mills at: 202-745-8000, ext. 55644.

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Michelle Kennedy Prisco, MSN, ANP-C
  • Position: Environmental Exposure Specialist

Ms. Prisco is an adult nurse practitioner who serves as the environmental exposure specialist DC WRIISC. She obtained her BBA from the University of Notre Dame and her MSN from Yale University. She has worked at the Department of Veterans Affairs since 1994 and was an Army Nurse Corps Officer in the United States Army Reserve. She has published a number of articles in the areas of post-deployment health and infectious disease. Ms. Prisco currently is the lead research investigator working on a VA grant exploring Veterans’ knowledge, attitudes, and perceptions regarding deployment environmental exposures. Ms. Prisco was the Principal Investigator for a VA Merit Grant that explored how complementary and alternative medicine affected combat Veterans with PTSD-related sleep difficulties. She also was a co-investigator for a VA funded study that looked at developing an Environmental Exposure Assessment Tool for combat Veterans returning from Iraq and/or Afghanistan. Ms. Prisco’s research interests include public policy issues, environmental exposure concerns, web-based educational programming, and complementary and alternative medicine. She also is the DC WRIISC webmaster.

Contact Ms. Prisco at: 202-745-8000, ext. 56235.

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Rachel Stewart, PhD, LICSW
  • Positions:
    • Social Worker
    • Statistical Support

Dr. Rachel Stewart is a Licensed Independent Clinical Social Worker in the District of Columbia. After receiving her BA degree from the University of Notre Dame, Dr. Stewart went on to receive her MSW and PhD from the National Catholic School of Social Service at Catholic University. Dr. Stewart worked for many years in the private sector specializing in serious mental illness in the hospital, residential, and outpatient settings. Since coming to the VA, Dr. Stewart has served primarily in the Emergency Department where she was instrumental in the development and implementation of the Fast Track program. Dr. Stewart is honored to continue learning from her colleagues and the Veteran community at the Washington, DC WRIISC.

Contact Dr. Stewart at 202-745-8000, ext. 54647.

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WenGuo Yao, BS, MS
  • Position: Clinical Coordinator

Mr. Yao holds a bachelor’s degree in biology and a master’s degree in computer science. He plays a key role in coordinating clinical referrals participating in the War Related Illness and Injury Study Center’s National Referral Program.

Contact Mr. Yao at: 202-745-8000, ext. 57554.

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Alex Zajdel, BA
  • Position: Research Assistant

Mr. Zajdel, BA, is a Research Assistant at the DC WRIISC. He graduated from Queens University of Charlotte with a Bachelor’s degree in Psychology. He is a research assistant for the GW-CAM study that is exploring the effects of iRest Yoga Nidra and Auricular Acupuncture in Veterans experiencing fatigue, pain, and cognitive issues. Mr. Zajdel is excited to work with Veterans as he expands his understanding and experience in the field of research and integrated health and wellness, while supporting WRIISC to meet their goals of providing excellent patient care.

Contact Mr. Zajdel at: 202-745-8000, ext. 55768.

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