About the Owner

Allyssa Mattes, PhD, HSPP

Clinical Neuropsychologist, Owner

Training & Formal Education

Dr. Mattes received her MA and PhD in Clinical Psychology with a specialization in Neuropsychology at Wayne State University in Detroit. She completed residency with a specialization in Neuropsychology at Indiana University School of Medicine. Finally, she completed a two-year post-doctoral fellowship with specialization in Pediatric Neuropsychology and Rehabilitation Psychology at the University of Michigan. She is a member of the National Register of Health Service Psychologists and the Indiana Psychological Association (IPA), and she is currently pursuing board-certification in Clinical Neuropsychology. She is a Star Behavioral Health Provider specially trained in the care of military families as well. She is verified and profiled on PsychTap.com and Psychology Today.

Teaching and Research

Dr. Mattes has conducted research and published in peer-reviewed journals and books on topics including early brain insult and the development of executive functions, parental validity in report of childhood medical complexity, outcome risk associated with neonatal seizures, working memory performance in children with cerebral palsy, and best practices in assessment for rehabilitation neuropsychology. She has taught multiple undergraduate and graduate courses on psychotherapy, neuropsychological assessment, and various aspects of personality functioning and psychopathology. She has also been featured on the TEACH To Go Podcast public education forum.


Dr. Mattes is a midwest native, originally hailing from Michigan, though she lovingly refers to Indiana as “home”. She enjoys spending quality time with her family and pets, being in the great outdoors as much as possible, and constantly finding new opportunities to learn about her favorite larger-than-life topics (the BRAIN, space, and philosophy)!

Philosophy and Approach

Families invest a lot of time, money, and energy into the care of their children. Dr. Mattes makes a point to avoid rash judgements, instead emphasizing a wholistic understanding of the child and family functioning in order to tailor care and provide comprehensive recommendations. Dr. Mattes feels strongly about partnering with the family to address the root of any issue that arises in development, thinking, learning, or behavioral functioning. She full-well understands that a child does not exist in a vacuum, and strong communication with the family is often key to the success of any single member. Dr. Mattes also practices with great empathy, knowing that families are often doing their best with the tools they have available. Adding to her expertise in evidenced-based care, she uses a genuine and humble approach, as she recognizes that parents and families are experts on their own child.

New Day Neuropsychology LLC

Phone: 317-360-0696


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