Our Team

Kevin NiemanKevin Nieman, Ph.D., LMFT, Director

Dr. Kevin Nieman, LMFT, is the founder and director of Cornerstone Christian Counseling Services (CCCS). Dr. Nieman earned his doctorate in Marriage and Family Therapy from the University of Louisiana at Monroe (ULM), a master’s degree in Marriage and Family Therapy from Harding University, and an undergraduate degree in Business Management from Harding University. Dr. Nieman is a Clinical Member of the American Association for Marriage and Family Therapy (AAMFT), the Oklahoma Association for Marriage and Family Therapy (OKMFT). He is also a member of the American Association of Christian Counselors (AACC). He is an AAMFT Approved Supervisor in Marriage and Family Therapy. Dr. Nieman is also certified to provide Mediation services. He also serves as Adjunct Professor at Southern Nazarene University in their graduate program.

Dr. Nieman has a passion for helping hurting people find hope and healing. Areas of specialty and interest include marriages in crisis, differentiation and self-worth development, and working with CEOs and professional athletes.

Dr. Nieman is married to Lindsey Nieman, M.A. who also provides Marriage and Family Therapy at CCCS. Together they have two beautiful boys. Dr. Nieman is an avid Green Bay Packers Fan.

Lindsey Nieman, M.A., RDN, LD LMFT

Lindsey Nieman, M.A. is a staff therapist at Cornerstone Christian Counseling Services (CCCS). She earned her Master of Arts in Marriage and Family Therapy and an undergraduate degree in Business Management from the University of Louisiana at Monroe (ULM). She also has an undergraduate degree is Nutrition and Dietetics from Louisiana Tech University. Lindsey finished her dietetic internship through the University of Oklahoma Health Science Center. She is a registered dietitian as well as a Licensed Marriage and Family Therapist. Lindsey is a member of the Academy of Nutrition and Dietetics and the American Association of Christian Counselors.

Lindsey is passionate about helping individuals achieve a healthy lifestyle both physically and emotionally/mentally. She combines her knowledge from the nutrition perspective with her Marriage and Family Therapy training to provide her clients with a more complete approach to health. She coordinates healthy lifestyle and cooking classes and groups.

Lindsey is married to Dr. Kevin Nieman, founder and director of CCCS. Together they have two beautiful boys. Lindsey enjoys and is passionate about exercise, gardening, and cooking.

Dawn Brandenburgh, M.Ed., LPC

Dawn Brandenburgh, M.Ed., LPC-S is a staff therapist at Cornerstone Christian Counseling Services (CCCS). She graduated from Ohio University with a Master of Education in Community Counseling. She earned her Bachelor of Science degree in Psychology from Texas A & M University. Dawn worked as a Licensed Professional Counselor in Wisconsin for over 10 years as well as clinically supervised candidates towards licensure before her family relocated to Tulsa in 2013.

Dawn has a passion to help clients who desire an increased awareness and insight into their lives – working towards the goal of healing and the installation of hope – and help them recognize the power and influence they have to make changes in their lives. Early in her career, Dawn worked with at-risk adolescents in various residential facilities. These experiences taught her to look beyond a person’s behavior and instead encouraged her to seek to understand what set of circumstances helped shaped their current behaviors. For some who experienced difficult and/or traumatic events in their lives, they responded to their circumstances by engaging in adaptive behaviors. Dawn works intentionally to help her clients understand that although once helpful and at times life-saving, some of these strategies may no longer be as effective as they once were.

Dawn has experience working with a diverse group of clients, including those who struggle with self-esteem issues (‘people pleasers’), anxiety, depression, unresolved trauma and adjustments to life circumstances (school, empty nest, relationships, job loss, etc.). In her work with clients, Dawn strives to create an atmosphere of non-judgment and safety—with the aim of decreasing resistance and ultimately allowing for client growth.

Dawn is also an Approved Supervisor for candidates seeking licensure as a Licensed Professional Counselor in Oklahoma.

Dawn and her husband have been married since 1996. Together they have two beautiful children, whom they homeschool. Dawn enjoys reading, running and spending time with her family.
Dawn is an in-network provider for many insurance companies.

Mike Blacet, M.S.W., LCSW

Mike Blacet, LCSW earned his Master of Social Work from the University of Oklahoma and is a Licensed Clinical Social Worker in Oklahoma. He is a member of the American Association of Christian Counselors.

Mike is committed to helping others, in cooperation with Christ’s work in them, to overcome obstacles and difficulties in their lives. Mike’s areas of specialty and interest include parent/child relationship problems, attachment issues, anxiety, anger, and spiritual issues.

Mike and his wife Angela have been married since 2001. They are grateful for time together as a family with their two daughters and their son.

Mike enjoys running, reading, studying the sciences, working with his hands, and spending time with family and friends.

Paige Tallent, LPC

Paige Tallent, MHR,LPC earned a Bachelor of Science in Psychology from Northeastern State University and a Master of Human Relations from the University of Oklahoma. Paige has worked in the counseling field since 1999 serving youth, adults and seniors. Paige is a Nationally Certified Counselor; a Licensed Professional Counselor in Oklahoma and an Approved Supervisor for candidates seeking counseling licensure.

Paige is committed to helping individuals, couples and families, find their identity in Christ and their calling as healthy children of God. Paige specializes in trauma recovery; improving relational dynamics within couples and families; encouraging single parent families to heal and excel. Paige is dedicated to suicide prevention and implemented a free suicide prevention service program, Because of Hanah, in Washington County.

Paige is passionate about her family, travel, nature, antique collection and restoration and the art of friendship.

Amber J. Thaxton, M.S, LPC

Amber was raised in sunny California and moved to Oklahoma to pursue her passion to study and become a professional helper. Here in Tulsa she has discovered some of the most warm, unique and loving individuals. Among this great population she met her wonderful spouse John whom she considers her best friend and lover. Together they have a daughter whom will be 1 year old soon and 2 year old Labrador mix. Amber is a wife, mom, therapist, but most importantly a child of God. Amber has experienced the divine move of God and is a woman of great faith who believes that God has given her the will and power to please Him in everything she does.

Encouraging and motivating others is a part of her nature. This passion is coupled with education from Oral Roberts University where she earned a B.A in Psychology and minored in Pastoral care, as well as a masters in Counseling Psychology at Northeastern State University. Ambers is a Licensed Professional Counselor who has experience working with diverse populations, and is inspired to help others whom desire to seek wellness in their mind, body and spirit.

Marc Clayton, M.A., LMFT Candidate

Marc earned his master’s degree in Marriage and Family therapy from Southern Nazarene University. He is a registered Licensed Marriage and Family Therapist Candidate with the State of Oklahoma.
Marc previously worked in the Chemical Dependency Intensive Outpatient Program at Laureate Psychiatric Clinic & Hospital. Marc currently serves as a Recovery Minister at Park Plaza Church of Christ.

Marc is committed to helping individuals and couples find themselves through God’s healing power. Marc will walk with you as you open the door to therapy by sharing your experiences, strengths, and hopes as well as your willingness to accept God’s grace in solving life’s problems. This freedom creates peace, serenity, joy and most importantly a stronger relationship with the Trinity – God, Christ, & Spirit.

Marc and his wife, Jamie, married in March of 2002 and have two beautiful daughters who enjoy camping, hiking, and fishing.

Kelly Stemm, APRN-CNP

Kelly is a Certified Women’s Health Nurse Practitioner. She obtained her Bachelor’s in Nursing at Belmont University in Nashville. Kelly attended Frontier Nursing University for her Master’s degree. She has been trained to provide health services for women that embrace the healthcare needs of a woman throughout her lifespan. Kelly’s goal as a healthcare provider is to make sure every patient feels heard and provide them with care that will give them the means to empower themselves about their health matters. With so many of women’s health needs being extremely personal and difficult, her compassionate care will be sure to put you at ease. Many of her patients have remarked how easy she is to talk to and how comfortable they feel with her. Kelly feels taking care of the entire woman-body, mind, and spirit-is critical to good patient care – holistic care that considers not only the physical aspects of a patient’s illness, but the emotional and spiritual aspects as well. She believes that healing and wholeness are matters of body, mind, and spirit.

Kelly is a native of Oklahoma. When she is not in the office, Kelly enjoys spending time with her husband and their 10 year old son, usually at a hockey event. Kelly is currently working towards a post-master’s Family Nurse Practitioner certificate. She hopes to be able to take care of your entire family by June 2019.

Sonia Marshall CYT, Relax & Renew® Trainer

Sonia is a Yoga Instructor and Graphic Artist. She earned her 200 hr. YTC in Hatha Yoga from Yoga Spirit Academy in Tulsa, earned a Bachelors Degree in Commercial Art from Oral Roberts University, and in 2015 she was certified as a Relax & Renew@ Trainer in Dallas TX, with Judith Lasater.

She began practicing yoga to manage chronic back pain, stress and anxiety, and through regular practice she discovered how yoga can help to heal the body and mind. From her personal experience, she is inspired and passionate about sharing the practice of yoga with others.

Sonia teaches with a gentle approach, with a focus on body awareness.

Sonia and her husband have been married for 18 years. She has lived in Tulsa for 26 years and enjoys camping with her husband and their two dogs, Stella and Hadi. She loves experimenting with new recipes, traveling, and music.

Becky Weathers, Office Manager

Becky Weathers is our office Manager. Before coming to Cornerstone, she worked in the health insurance industry for nearly 27 years and then in the medical industry for a little over 3 years. Becky loves working with people and hopes to make a positive difference each day. Becky and her husband Clyde have been married for 25 years and have 3 beautiful daughters. In her spare time, Becky enjoys traveling and spending time with her family.

Deidra Nickel, LPC

Deidra Nickel earned her M.A. in Marriage and Family Therapy from Southern Nazarene University. She is a registered Licensed Professional Counselor with the State of Oklahoma.

She has a passion for helping families, especially women, determine who they are in Christ and their purpose as they navigate life’s struggles and hardships.

Deidra enjoys singing at church, spending time with her family and friends, classical music, and riding with her husband on his Harley.

Mary Catherine Corbell, Intern

Mrs. Corbell is originally from south Arkansas and moved to Tulsa after getting married. She received her Masters degree in Mental Health Counseling in 2013. Mrs. Corbell has worked in a variety of settings with children and adolescents. She began her career working at a neurodevelopmental therapy center in Atlanta. She enjoys co-leading a trauma group for young children. This groups mission is to educate and support parents, guardians and advocates with evidence based practices. When we can understand how trauma impacts the brain then we can learn to take steps towards becoming part of the solution. Her passion is to apply her extensive practical therapy and experience to help children and young adults reach the highest potential that God has for them.

Gregg Nelson, Intern

Gregg Nelson is currently an intern staff therapist here at Cornerstone. He will then work toward obtaining his licensure as a Licensed Professional Counselor. He is currently pursuing his Professional Counseling degree from Liberty University and will graduate in the fall of 2018. He received his Bachelors of Arts Degree in Biblical & Theological Studies from Regent University in 2012. He holds specialized certification in the field of Spiritual Care in Crisis Intervention from the International Critical Incident & Stress Foundation, Inc. and is involved with numerous Critical Incident Stress Management (CISM) teams across the country. He is a certified Gottman Seven Principles Program Leader, is an ordained minister, serves on the Board of Directors of numerous nonprofit organizations as a consultant and is a member of the American Association of Christian Counselors (AACC).

Gregg is dedicated to individuals, couples and leaders to help Educate, Equip, Encourage and Empower their lives, relationships and careers. He works along side his clients to find hope and healing through knowing who they are in Christ and discovering their identity and value in Him. Gregg’s areas of specialty include spiritual, relationship, leadership, pre-marital, couples, loss, grief, stress and crisis/trauma issues.

Gregg enjoys traveling, networking, volunteering, reading, going to his son’s swim meets and spending time with friends & family.