Meet The Team

Dr. Stephanie Johnson is a licensed clinical and research neuropsychologist who has worked in DC and Virginia, specializing in neurocognitive disorders. With a background in consulting for institutions like the Wisconsin Alzheimer's Institute and Georgetown University Hospital's Stroke Disparities Program, she received extensive training in cognitive disorder diagnosis during her post-doctoral fellowship at the Bryan ADRC at Duke University Medical Center. Joining the medical faculty at Johns Hopkins Hospital, she expanded her research to explore stress' psychological impact on Alzheimer's development in diverse populations, while also providing diagnosis in the Cortical Laboratory. Eventually, Dr. Johnson established two clinics in DC and one in Virginia focused on clinical neuropsychological assessment of neurological disorders. 

Dr. Kierra Evans is a neuropsychology postdoctoral fellow who recently earned her doctorate from The Chicago School of Professional Psychology in Washington, D.C. and completed her APA-accredited internship with the National Psychology Training Consortium in Springfield, Missouri. She has clinical experience with individual and group therapy, case management, DBT skills groups, and assessments.  She has completed neuropsychological assessments in various settings, including private practices, community mental health agencies, and an inpatient forensic hospital. Her expertise and interests lie in conducting neuropsychological and psychological assessments across the lifespan with various conditions, including neurodevelopmental disorders, neurodegenerative disorders, psychiatric disorders, traumatic brain injuries, chronic health conditions, stroke, and learning disabilities. She emphasizes integrating the neurocognitive, emotional, and behavioral aspects of these disorders to help individuals better understand and manage their cognitive and emotional difficulties. Her clinical approach is patient-centered, collaborative, empowering, and culturally aware. Currently, Dr. Evans is working towards obtaining her licensure in Maryland, Virginia, and Washington, D.C. She plans to seek board certification with the American Board of Clinical Neuropsychology following her fellowship. In her personal time, she enjoys spending time with her family and friends, traveling, trying new adventurous experiences, and relaxing.

Dr. Rohma Hassan is a neuropsychology postdoctoral fellow who earned her doctoral degree from The George Washington University Professional Psychology Program in Washington, D.C. She completed her one year internship training at the Albany Psychology Consortium in Albany, New York. She has experience working across the lifespan and with different populations, including inpatient, outpatient, and veteran. She is particularly interested in assessing neurodegenerative and neurodevelopmental conditions, and seeing how these conditions have an impact on an individual's interpersonal experiences. Dr. Hassan is equally passionate about her therapy work, and integrates elements of psychodynamic therapy, feminist theory, and dialectical behavioral therapy.  In both her therapy and assessment work, Dr. Hassan strives to be evidence based while also remaining attentive to individual and social/cultural/systemic factors that bring additional layers to an individual's experience. 

Dr. Charice Williams is a licensed psychologist who believes therapy provides an opportunity to enhance strengths while navigating life’s challenges. She takes a collaborative approach, working closely with clients to understand their concerns and advocate for meaningful change.With over a decade of experience, Dr. Williams specializes in providing therapy and conducting psychological and forensic evaluations for adolescents and adults. Her expertise spans depression, trauma, behavioral challenges, severe mental illness, grief, neurocognitive and neurodevelopmental disorders, and anxiety-related concerns. Grounded in Cognitive-Behavioral Therapy, Dr. Williams emphasizes the powerful connection between thoughts, emotions, and behaviors, while also recognizing the role of contextual and environmental factors. She takes a holistic view of her clients’ challenges and is dedicated to supporting them in achieving growth, resilience, and their ideal selves.

Dr. Troy A. Waller is a Licensed Professional Counselor in the District of Columbia, Maryland, and Virginia with more than 20 years of experience in counseling and mental health. Dr. Waller leverages his entrepreneurial experience as a Psychotherapist and wellness educator to advocate initiatives aimed at maximizing employee resource services to better manage work/life balance and burnout. He has significant experience handling trauma and has served as a corporate consultant for several companies, hospitals, and governmental agencies in the region offering expert advice on how to manage stress and anxiety and preserve strong mental health. Dr. Waller is respected in the Washington DC metropolitan area for his expertise in mental health and psychotherapy. He has been featured in media outlets including Howard University’s popular Radio Show “The Daily Drum”, and TV One’s show “For My Man”, as a consultant. Drawing from his insight of how negative political and economic conditions lead to behavioral and societal problems, Dr. Waller also has been featured in The Washington Post. Dr. Waller has a lifelong commitment to education and empowering the next generation of professionals with the tools they will need to succeed in the mental health profession. In addition to his private practice work, he teaches various psychology courses , including Child Psychology and Psychology at prominent universities in the DC metropolitan area. He has a Master’s Degree in Forensic Psychology and a doctoral degree in Counseling Psychology.

Dr. Jennifer Christman, PsyD, ABBP (Forensics), is a board-certified forensic psychologist and licensed clinical psychologist. Alongside her role at Cognitive Solutions LLC, she serves as the clinical training director and supervisory forensic psychologist for DC Superior Court's Child Guidance Clinic and is the CEO of Forensic Psychology Solutions LLC. With extensive experience as a forensic evaluator spanning state court systems, correction facilities, government agencies, and private practice. Dr. Christman is a social media coordinator for the American Academy of Forensic Psychology. She also sits on the American Board of Professional Psychology Foundation Board of Directors. Dr. Christman expertise is widely recognized through her presentations at local, regional, and national levels. Her contributions to Psychology Today, and appearances on The Forensic Psychologist podcast. 

Ashia has served as a committed employee at Cognitive Solutions for five years, fulfilling the role of Office Administrator. Complementing her professional experience, she possesses two years of academic training in Health Administration. Leveraging her extensive insights gained from years of engagement within the healthcare domain, Ashia has played a pivotal role in shaping the trajectory and success of the company.

Sada is an Administrative Assistant and Executive Function Coach at Cognitive Solutions LLC, where she plays a role in supporting the practice through scheduling, record keeping, and marketing coordination. With a Bachelor’s degree in Psychology, Sada brings both academic knowledge and a genuine passion for mental health to her work. As an Executive Function Coach, she helps clients build essential skills like time management, organization, and self-regulation. Sada is dedicated to fostering a welcoming, supportive, and well-organized environment for both clients and staff, and is proud to be part of a team committed to compassionate, high-quality care.