INVESTIGATORS

Alka Khera, MD
NEUROLOGIST, PRINCIPAL INVESTIGATOR

Zaid Shah, DO
INTERNIST, PRINCIPAL INVESTIGATOR
Meet Dr. Shah!
Stay tuned to meet Dr. Shah!

Diana Kerwin, MD, CPI
INVESTIGATOR

Subhan Tabba, MD, MBA
INTERNIST, INVESTIGATOR
Meet Dr. Tabba!
Dr. Subhan Tabba is an Academic Hospitalist at Texas Health Presbyterian Dallas Hospital and has joined Kerwin Medical Center to further his work in Alzheimer’s Disease and Related Dementias (ADRD) research. His focus is not only on finding a cure for these conditions but also on providing more resources for the care partners of dementia patients.
Dr. Tabba earned his Medical Doctorate (MD) from The University of Texas Health Science Center at McGovern Medical School and a Master of Business Administration (MBA) from the University of Houston. He also holds a Bachelor of Science in Cell and Molecular Biology and a Bachelor of Arts in Psychology from The University of Texas at Austin.
A first-generation Pakistani-American, Dr. Tabba is deeply committed to advancing public health and healthcare for marginalized communities. His leadership and advocacy have reshaped policies at local, state, and national levels since 2018. His work has earned him several prestigious accolades, including the National Minority Quality Forum’s 40 Under 40, the Mark Feldman Academic Excellence Award, the Texas American College of Physicians Early Career Physician Award, and the University of Houston Alumni Association Early Achievement Award.
At Kerwin Medical Center, Dr. Tabba continues his mission to drive meaningful progress in dementia research, offering hope to patients and their families. When not working, he enjoys spending time with loved ones, traveling, and playing pickleball.
COGNITIVE ASSESSMENT

Tiffini Hansen
MANAGER OF COGNITIVE RATER SERVICES

Jim Harris, PsyD
NEUROPSYCHOLOGIST, COGNITIVE RATER
Maddie Liggett, MPH
COGNITIVE RATER

Diana Mauricio, MS
COGNITIVE RATER
Meet Diana!
Stay tuned to meet Diana!
PHARMACY AND LAB

Caitlin Feeley, PharmD
RESEARCH PHARMACIST

Tonya Harper, CPhT
PHARMACY TECHNICIAN

Lacey Sands, CPhT
PHARMACY TECHNICIAN
Meet Lacey!
With over 12 years of experience in pharmacy, including 7 years specializing in sterile and non-sterile compounding, Lacey brings a strong foundation of technical expertise and pharmacy regulatory knowledge to the clinical research setting. She has previously held a leadership role with oversight of compounding laboratory operations, with a focus on maintaining compliance.
Lacey is passionate about contributing to clinical research in Alzheimer’s disease and CNS disorders. This work is especially meaningful to her due to a personal connection, having witnessed the impact of Alzheimer’s disease in her grandmother. This experience continues to motivate her commitment to advancing research that improves patient care and quality of life.
Outside of work, Lacey enjoys hiking, backpacking, reading and spending time with her two dogs, Luna and Lily. She values any experience that teaches her something new or gets her out in nature.
OPERATIONS
Jordan Caldwell, CCRC
SITE DIRECTOR
Karen Aleman, CCRC
PROJECT MANAGER
Megha Chadha, MS, CCRC
PHYSICIAN AND COMMUNITY LIAISON

Addy Torres
FRONT OFFICE COORDINATOR - DALLAS PRESBYTERIAN LOCATION
Meet Addy!
As a Front Desk Coordinator, Addy feels fortunate to be the first person patients see when they walk through the door, and she genuinely enjoys creating a welcoming, friendly atmosphere. She finds it incredibly rewarding to be able to interact with our patients, offer support, and engage in meaningful conversations. One of the aspects she loves most about her role is knowing that she's part of a larger team that’s committed to making a difference. Working together toward improving the lives of older adults and their families gives her a real sense of purpose and fulfillment.
Outside of work, Addy loves spending time with her family and friends—especially her nephews, who never fail to bring joy and laughter into her world. She also enjoys exploring new restaurants, baking sweet treats for her loved ones, and relaxing with some coloring to unwind and tap into her creativity.

Jocelyn Valdovinos
FRONT OFFICE COORDINATOR - OAK CLIFF LOCATION
Meet Jocelyn!
Stay tuned to meet Jocelyn!
QUALITY ASSURANCE

Kayla Brown, MS
REGULATORY ASSOCIATE
Meet Kayla!
Stay tuned to meet Kayla!

Laurel Nowden, MBA, CCRP
QUALITY ASSURANCE ASSOCIATE
Meet Laurel!
Stay tuned to meet Laurel!
CLINICAL RESEARCH

Maddie Euckert
CLINICAL RESEARCH COORDINATOR II
Meet Maddie!
Maddie is a Clinical Research Coordinator II at Kerwin Medical Center with nearly five years of experience in clinical research across multiple specialties.
She is driven by the opportunity to contribute to meaningful advancements in Alzheimer’s disease and is passionate about supporting patients and their families throughout the clinical trial journey. Maddie works closely with patients, investigators, and sponsors to help ensure studies are conducted with both precision and compassion. She currently manages multiple trials across two locations, helping translate research into real progress for those affected by neurodegenerative disease.
Maddie earned her degree in Psychology from Texas A&M University, with a focus in neuroscience and a certificate in Applied Behavioral Health. She began her career at UT Southwestern and has since gained experience in both academic and startup research environments.
Outside of work, Maddie enjoys concerts, music festivals, and all things beauty, as well as spending time with friends and being near the water whenever she can.

Amarpreet Dhaliwal
CLINICAL RESEARCH COORDINATOR
Meet Amarpreet!
Stay tuned to meet Amarpreet!

Mallory Freeman
CLINICAL RESEARCH COORDINATOR
Meet Mallory
Stay tuned to meet Mallory!

Darah Sanchez
CLINICAL RESEARCH COORDINATOR
Meet Darah!
Darah joined Kerwin Medical Center as a Clinical Research Coordinator supporting the execution of multiple ongoing clinical studies. In this role, she contributes to study coordination, regulatory documentation, and daily research operations in close collaboration with investigators and the research team. Her work includes managing study workflows, maintaining accurate study documentation, and supporting protocol-driven procedures to ensure clinical trials are conducted in compliance with regulatory standards and site processes.
She is committed to maintaining high standards of organization, reliability, and operational consistency within the research program.
Outside of work, Darah enjoys staying active, reading, and spending time with loved ones.

Roberto Moreno
CLINICAL RESEARCH COORDINATOR
Meet Roberto!
Roberto earned his Bachelor’s degree in Biology from the University of Texas at Dallas and is currently pursuing a Master’s degree at the University of Texas at Arlington. He has a strong background in cancer research, beginning his career studying the effects of heme sequestration in non-squamous non-small cell lung cancer (nsq-NSCLC). He subsequently contributed to early-phase oncology research, conducting first-in-human studies of multiple Phase 1 investigational agents targeting a spectrum of advanced solid tumors, including colorectal cancer, non-small cell lung cancer, melanoma, pancreatic cancer, and rare solid tumors. In 2026, he joined Kerwin Medical Center to focus on Alzheimer’s research, bringing his expertise in translational science and early drug development to neurodegenerative disease studies.
Outside of research, Roberto enjoys spending time with his wife, whether outdoors camping, exploring new restaurants and cuisines, or watching a football game. He also appreciates indoor activities and discovering new experiences. He balances his professional work with a love for adventure, good food, and football.

Ashna Adhikari
CLINICAL RESEARCH COORDINATOR
Meet Ashna!
I’m Ashna and I’m a graduate from the University of Texas at Dallas with a Master’s in Applied Cognition and Neuroscience. Upon graduation from the Master’s program in 2023, I continued to work at the University of Texas at Dallas doing research on the impacts of TBIs and MS on verbal retrieval. Eventually I want to earn my PhD in Clinical Neuropsychology, because I love research and want it to be accessible to everyone. It’s with this in mind that I joined Kerwin Medical Center, I want as much exposure to different populations as I can get, so that I know where I can help.
In my free time I enjoy having an active social life, hanging out with my family, and going to as many events as Dallas has to offer.

Gabi Mireles
RESEARCH ASSISTANT
Meet Gabi!
Gabi joined the KMC team in October of 2024. Here's what she has to say:
I genuinely enjoy being part of a team that makes a difference in people’s lives. With years of experience working with the older community, I’ve developed a strong passion for providing support and creating meaningful connections. One of my favorite aspects of my role is the opportunity to interact with patients face-to-face, ensuring they feel comfortable and cared for.
As a natural people person, I thrive on building relationships and making every individual feel heard and valued. Whether I’m assisting patients or collaborating with colleagues, I love fostering a positive, welcoming environment. For me, it’s all about making a real impact and improving the patient experience every step of the way.


