About Sparks Psychological Services

Sparks Psychological Services provides services covering many areas of psychology. Each of our associates has a specific area of expertise. We primarily focus on forensic evaluations and psychological testing. Sparks Psychological Services is based in Cincinnati, Ohio and is available to provide services nationally.


About Our Team


Steve Sparks, Ph.D., ABPP

Steve Sparks, Ph.D., ABPP, psychologist, completed his undergraduate education at the University of Notre Dame, graduating Magna Cum Laude. He received scholarships thereafter and earned both graduate degrees, Master’s and Doctorate, at the University of Cincinnati. He is board certified in forensic psychology by the American Board of Professional Psychology.

Dr. Sparks was formerly the Director of Forensic Services at Forensic and Mental Health Services, Inc., the state-sponsored forensic center in Butler County, Ohio. He is current Adjunct Assistant Professor of Psychology at the Mount St. Joseph University where he teaches Forensic Psychology and former adjunct at the University of Cincinnati. His book chapter Creating and Sustaining an Assessment/Forensic Based Practice was published in 2017 (in Sears. R. & Ossege, J.-Eds.) His work has also been published in the Journal of Applied Social Psychology and the Ohio Psychologist. He has provided psychological assessment services to individuals, private attorneys, forensic psychology centers in Kentucky and Ohio, Ohio Attorney General’s office, the United States Public Health Service, Bureau of Workers’ Compensation,  Social Security Administration,  Catholic Archdiocese of Cincinnati, and the Bureau of Vocational Rehabilitation among many others. He is Past President of the Board of Directors of the Cincinnati Academy of Professional Psychology.

Dr. Sparks specializes in psychological evaluations of many kinds. These services include, but are not limited to cases involving personal, civil, criminal, pre-employment, work-related, neuropsychological, and disability issues. 

Barbra Bergman, Ph.D.

Dr. Bergman was raised in Cleveland, Ohio and graduated with a Bachelor of Arts degree from the Cleveland State University. Her Master’s and Doctorate degrees were conferred at the Ohio State University. She has been a licensed clinical psychologist in Ohio since 1976. Dr. Bergman has practiced as a forensic psychologist for the past 35 years, with experience in evaluation and expert testimony in cases involving adults and children in both civil and criminal courts. Her clinical specialty is assessment and treatment of both victims and perpetrators of sexual abuse and other forms of trauma.

Stephen J Billmann, Psy.D, D. ABSM

Dr. Billmann is a licensed psychologist with more than 20 years of experience. He evaluates individuals for work capacity, diagnostic questions, fitness for duty, and behavioral sleep disorders. He has also treated individuals with a variety of Behavioral Medicine issues. He is board-certified by the American Board of Sleep Medicine.

Dr. Billmann received his Doctor of Psychology degree from Virginia Consortium offered by Eastern Virginia Medical School, William & Mary, Old Dominion University & Norfolk State University. He completed a residency in behavioral medicine at Temple University Hospital and a fellowship at the Sentara-Eastern Virginia Medical School Sleep Disorders Center.


Mark Dallas, Psy.D.

Mark Dallas, Psy.D. Clinical Neuropsychologist completed his undergraduate education at Wittenberg University. He later completed a Masters Degree from Murray State University and his doctorate from Xavier University, both in Clinical Psychology. Dr. Dallas competed his clinical training with a postdoctoral clinical neuropsychology fellowship and an APA accredited internship at the Louis Stokes Cleveland VA Medical Center in Cleveland, Ohio where he was responsible for comprehensive neuropsychological assessment of male and female adult and geriatric inpatient and outpatient veterans in a medical setting using a flexible, syndrome-based approach.

Prior to completing his doctorate, Dr. Dallas worked with older adults at local nursing facilities as a consultant from The Counseling Source. More recently, Dr. Dallas has worked at the Lindner Center of Hope for the past four years serving as their Adult Neuropsychologist working with clients on an outpatient basis and was the primary Neuropsychologist for the short-term, comprehensive inpatient assessment unit The Sibcy House.

Dr. Dallas’ past and present evaluations include differential diagnosis of dementia, assessment of co-morbid traumatic brain injury (TBI) and psychological conditions, substance abuse, Attention-Deficit/Hyperactivity Disorder (ADHD), comprehensive assessment of decision-making capacity and legal competence, and baseline evaluations to monitor recovery or progression of additional illnesses such as Multiple Sclerosis, Parkinson’s disease, HIV/AIDS and other diseases. Dr. Dallas has more than 10 years of experience in clinical and research work. While a postdoctoral fellow at the Louis Stokes Cleveland VAMC, he participated in research of mild-TBI (mTBI) in polytrauma Iraq/Afghanistan War veterans. He also assisted with recruitment of participants at the Cleveland Clinic for their federally funded study of mTBI veterans. Dr. Dallas is member of the Ohio Psychological Association, the International Neuropsychological Society, and the National Academy of Neuropsychology.

Nick Doninger, Ph.D., ABPP

Nicholas A. Doninger, Ph.D., ABPP is a board-certified in Clinical Neuropsychology with the American Board of Professional Psychology. He received an undergraduate degree in psychology from Boston College and a doctoral degree from Finch University of Health Sciences/Chicago Medical School with a specialization in clinical neuropsychology. Dr. Doninger completed internship training at the Cleveland Veteran Affairs Medical Center and a postdoctoral fellowship in neuropsychology at The University of Chicago Medical Center. He is a licensed psychologist in the state of Ohio and active member of the medical department at Kettering Medical Center in Dayton. In addition, he holds an academic rank of Assistant Professor in the Department of Psychiatry at Wright State University’s Boonshoft School of Medicine.  Dr. Doninger conducts Independent Medical Evaluations for insurance companies through third parties and has worked with organizations to provide evaluations of veterans with claimed disabilities, including Post Traumatic Stress Disorder and Traumatic Brain Injury. His work includes forensic neuropsychological evaluations as part mitigation for capital cases, personal injury claims, and civil capacities.

Amy Garbrecht, Psy.D.

Dr. Amy L. Garbrecht is a full time psychologist with Sparks Psychological Services, LLC and Associates.  Her primary responsibility is to serve as the Assistant Board Chief Clinical Officer for the Mental Health Recovery Services Board of Warren and Clinton Counties.  This position involves completing evaluations for civil commitment (both inpatient and outpatient), providing reports and testimony regarding emergency admissions as well as on-going probate monitoring, and serving as designated liaison and contact for local hospitals, Probate Court, MHRS legal counsel, and Community Mental Health Centers.  Dr. Garbrecht previously completed similar evaluations at hospitals in Montgomery County as a psychologist with The Forensic Psychiatry Center for Western Ohio which is part of Eastway Behavioral Healthcare, Inc.  In addition to serving as an independent examiner for probate court evaluations, Dr. Garbrecht also completed other forensic evaluations. She earned her Psy.D. from Xavier University in 2005.  Dr. Garbrecht also worked as a contract therapist for Adult Recovery Services, providing group and individual therapy for severe and persistently mentally ill adults at Eastway Behavioral Healthcare, Inc.  Previously, Dr. Garbrecht worked as the Program Director for Butler County Juvenile Rehabilitation Center and the Ohio Department of Youth Services as a psychologist with institutional youth and youth on parole.  Dr. Garbrecht is a clinical member of the Association for the Treatment of Sexual Abusers (ATSA), a member of the American Correctional Association (ACA), and the Ohio Psychological Association (OPA).

Dionne Hollis, Ph.D.

Dionne Hollis, Ph.D, LICDC-CS, received her a Bachelor of Arts degree in psychology from Vassar College. She earned her Masters and Doctorate in Clinical Psychology at the University of Cincinnati. She completed her pre-doctoral internship at the Federal Medical Center, Lexington, Kentucky. Dr. Hollis utilizes a multi-theoretical, integrative approach in providing services to adolescents, adults, couples and the elderly. Her professional work experiences have included providing services to stroke, spinal cord injured, traumatic head trauma, orthopedic and geriatric patients, serving as program director of a women’s comprehensive substance abuse treatment facility and maintaining a private practice for several years. Dr. Hollis has also provided consultation to nursing homes, assisted- and independent-living facilities, and physical therapy programs . Specific areas of interest include: women’s issues, substance use/addictive behaviors, cultural issues and health related conditions. Dr. Hollis also has experience in evaluating psychological functioning in children, adolescents and adults, assessing psychological functioning, work related disabilities and fitness for duty. Currently, Dr. Hollis works part-time at SPS providing assessment services.



Sonya Hughes


Sonya Hughes has over 15 years experience in office and office management.  She is the friendly voice at the other end of the telephone and she manages scheduling, appointments, client contracts, billing, and all of the behind the scenes activities that keep our office running smoothly.





Michaela Koveleskie

Michaela Koveleskie, B.A. graduated magna cum laude from Robert E. Cook Honors College at Indiana University of Pennsylvania with a Bachelor of Arts degree in Honors psychology and religious studies. She is in the processing of earning her Masters and Doctorate in Clinical Psychology with areas of interest in geropsychology and health care psychology across the lifespan from Xavier University. She works as a psychometrist for Sparks Psychological Services primarily working with Dr. Stephen Billmann on Disabilities’ Division of Disability Determination (DDD) cases.

Michelle Maegly, Psy.D.

Dr. Michelle Maegly graduated Summa Cum Laude from Muskingum College with a Bachelor of Arts degree in psychology.  She earned her Masters and Doctorate in Clinical Psychology at Xavier University. She completed her doctoral internship at the Veterans Affairs hospital in Lexington, Kentucky and received additional formal training at a large, local community mental health and addiction services agency. Dr. Maegly utilizes a multi-theoretical, integrative approach in providing psychotherapy to adults, couples, and families.  Her experiences include providing services in outpatient community mental health, state psychiatric facilities, VA, and private practice.   Specific areas of interest include: working with survivors of trauma; personality pathology; providing marital/couples services; and values-based psychotherapy, such as Acceptance and Commitment Therapy. Dr. Maegly also has expertise in evaluating psychological functioning in adults and assessing work related disabilities and vocational needs.  Currently, Dr. Maegly works part-time at SPS providing assessment services.

Nicole Purdy-Westrich

Nicole Westrich-Purdy received her Bachelor’s degree in Media Communications, from Ohio University, in Athens, Ohio. There, she also received her Minor in Psychology, and a Certificate in Political Communications. With a background in medical device sales and account management, Nicole is excited to be a part of the SPS office management team. She is one of the two friendly voices you’ll hear at the other end of the telephone. She manages scheduling, appointments, client contracts, and all of the behind the scenes activities that keep our office running smoothly.

Jessica Twehues, Psy.D.

Dr. Jessica Twehues is a licensed clinical psychologist in Ohio and Kentucky. She graduated Magna Cum Laude from Centre College with a Bachelor of Science degree, and she received her Master’s and Doctoral degrees in Clinical Psychology from Xavier University. She completed her doctoral internship in Winnipeg, Canada at the University of Manitoba. Dr. Twehues has provided psychological services, including psychotherapy and psychological assessment, to children, adults, and the elderly. She has worked in a variety of settings, including private practice, mental health agencies, and college counseling centers. Dr. Twehues works part-time at SPS providing assessment services and has particular interest in worker’s compensation and guardianship evaluations.




Celeste Waller-Trimble , Psy.D.

Celeste Waller-Trimble, PsyD. is a 1999 graduate of Wright State University School of Professional Psychology. While a graduate student she became interested in how cultural values and beliefs impact the effectiveness of mental health providers working with culturally diverse populations and how this might impact the mental health disparities seen in minority populations. Since that time she has devoted herself to becoming more aware of her own values and beliefs and how they intersect with how the individuals she serves experience the world. She has a multitude of experience with diverse populations and settings. During her graduate education, she has worked with children and families in community, school, residential, and hospital settings providing treatment and assessment regarding issues ranging from giftedness to severe mental illness. She completed her internship at the Cleveland Veterans Administration Hospital, where she served veterans dealing with Post-Traumatic Stress Disorder, Substance Abuse and many other mental health issues. Upon graduation through 2012 she became a Clinical Supervisor and an Adjunct Assistant Professor where she focused on interpersonal violence in families. She has worked in private practice conducting psychological evaluations, Parenting Evaluations, Social Security Evaluations and Worker’s Compensation Evaluations while also providing treatment to children, adults and families. She currently is working at a state mental health hospital providing treatment and clinical and forensic assessments to civil and forensic patients living with severe mental illness, substance abuse, and or intellectual disabilities. She also facilitates parenting classes part-time through a forensic center for individuals going through divorce proceedings. She increased her diverse work settings by joining Sparks Psychological Services, LLC & Associates part-time in 2017.