Kris Herfkens, PhD, ABPP-CN


Ioan Stroescu, Ph.D., ABPP-CN


Michael Zelson, Ph.D.

Maria Butler, Psy.D.

Bret Booth, Psy.D.

Samantha Sedlak, Psy.D.

Mandy Kellogg

Practice Manager

Dr. Herfkens is a board certified clinical neuropsychologist in private practice in Durham, North Carolina. Her practice is focused on diagnosis and treatment of adult neurocognitive disorders, with a subspecialty focus on geriatrics and MS. In addition, she has over twenty years experience in forensic neuropsychology in both civil and criminal litigation.

Dr. Herfkens received her bachelor’s degree from Carleton College and a doctorate in clinical psychology from the University of Tulsa, where she received an American Psychological Association Dissertation Research Award. Her post doctoral fellowship in clinical neuropsychology was at the University of Alabama at Birmingham School of Medicine.

She currently volunteers with the Greater Carolinas Chapter of the National Multiple Sclerosis Society and is a past chair and current member of the North Carolina Psychology Board.

Dr. Stroescu is a board-certified clinical neuropsychologist with expertise in general adult clinical neuropsychology. He has extensive neurocognitive consultation and clinical assessment experience with dementia and a wide range of neurological disorders, in both in- and out-patient settings.

Prior to joining Triangle Neuropsychology Services Dr. Stroescu was a senior neuropsychologist at NeuroCog Trials, focusing on neuropsychological outcomes in clinical trials of CNS disorders and he continues this work on a part-time basis. Prior to that he was a faculty neuropsychologist and assistant clinical professor at Barrow Neurological Institute in Phoenix, AZ.

He obtained a B.A. in Psychology and Biology from Columbia College in Columbia, MO. He earned his M.S. and Ph.D. with a concentration in Neuropsychology from Saint Louis University. He completed a neuropsychology specialty track internship at the Memphis VA Medical Center and Semmes Murphey Clinic and a post-doctoral fellowship at Emory University School of Medicine. He has authored/co-authored peer-reviewed publications and presentations and is fluent in German and Romanian.

Michael Zelson, Ph.D is a clinical neuropsychologist who has been practicing in outpatient clinic and inpatient rehabilitative settings since 1990. His practice is focused on the neuropsychological evaluation and treatment of adult acquired brain disorders, with particular emphasis on traumatic brain injury and cognitive disorders associated with aging. He is also experienced in assessing cognitive changes due to stroke and cerebrovascular disorders, Multiple Sclerosis and Parkinson’s disease. In addition to neuropsychological evaluation, he provides cognitive-behavioral psychotherapy with expertise in adjustment to illness/disability and psychological approaches to pain management. He earned a Bachelor’s degree in Psychology from the University of Pennsylvania in 1982 and a Doctoral degree in Clinical Psychology from the University of Delaware in 1989. He received post-doctoral experience in neuropsychology at the Institute for Brain Injury Research and Training in Camden, New Jersey. He is a member of the American Psychological Association and the National Academy of Neuropsychology.

Dr. Butler is a clinical neuropsychologist whose approach to neuropsychological assessment has been informed by following human development across the lifespan and conducting evaluations with children, adolescent, and adult populations. Her areas of expertise include neurodevelopmental disorders, Attention-Deficit/Hyperactivity Disorder (ADHD), specific learning disorders, Traumatic Brain Injury (TBI), concussion, epilepsy, and late effects of in-utero exposure. Dr. Butler earned her doctoral degree in Clinical Psychology with a specialty in Neuropsychology and Health Psychology from the American School of Professional Psychology Washington D.C.  She completed her internship in neuropsychology at NeuroRehabilitation Services Goodwill Industries of Northern New England and her fellowship at Mt. Washington Pediatric Hospital/Johns Hopkins Medical System and the University of Maryland Medical System, both CARF accredited institutions. She has trained in several specialty clinics, including the Concussion Assessment and Management Program (CAMP) of Mt. Washington Pediatric Hospital and the Child Development Clinic of Children’s National Medical Center. She has conducted research on evidence-based practices to improve emotional and behavioral regulation and executive functioning skills following moderate to severe TBI, and she has presented research on changes in emotional functioning following stroke.

Dr. Butler conducts comprehensive neuropsychological evaluations, examining the individual’s cognitive, emotional, and social functioning. She values extending interventions and psychoeducation beyond the client’s immediate family system to the school system and other health providers.

Bret A. Booth earned his B.A. at University of Virginia and Psy.D. at the APA-accredited American School of Professional Psychology - Washington, DC (Argosy University). He completed his post-doc training in clinical neuropsychology here in Raleigh, NC serving a primary outpatient neurology population. He has extensive experience over the past decade+ working as a clinical neuropsychologist providing assessment, diagnosis, and treatment recommendations for adult patients with cognitive complaints. Bret A. Booth currently treats cognitive difficulties in patients ages 18 and up, where he specializes in dementia, neurological disorders, neurodevelopmental conditions, chronic health problems, psychiatric illness, psychotropic medication side effects, and traumatic brain injury (note:  he has assisted the Carolina Hurricanes as part of the NHL concussion management program). He has been actively involved in research studies/clinical trials for new medications to benefit neurocognition.

Dr. Samantha Sedlak is a clinical neuropsychologist with experience across the lifespan. She completed her doctorate in Clinical Forensic Psychology at The Chicago School of Professional Psychology. She completed an APA-accredited neuropsychology internship with the Centerstone Consortium, and subsequently completed a two-year neuropsychology post-doctoral fellowship in a private practice setting in Lakeland, Florida. Dr. Sedlak specializes in providing assessment services to a diverse patient population presenting with various psychological, neuropsychological, and medical conditions. She also has specialty training in forensic psychology, including assessments for adult and juvenile criminal and civil cases. Dr. Sedlak is a member of the American Psychological Association Division 40, as well as the North Carolina Psychological Association. In her spare time, she enjoys world traveling and teaching swim lessons to youth and adults.

Mandy is the primary point of contact at TNS for referral coordinators, scheduling, requests for records, and related information. Prior to her move to North Carolina this past spring, Mandy was the Medical Office Manager for San Jose Neurospine in the San Francisco Bay Area and responsible for three practice locations. She is a certified nursing assistant and is completing her BS in Healthcare Administration. Her prior experience also includes serving as a health unit coordinator for Intermountain Healthcare in Salt Lake City, Utah.




Fax: 919- 384-9683

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