Mark Holton, MA, LMFT, BCBA,  – Owner

Mark has over 20 years of experience in the behavioral health, mental health and supported employment fields. As a behavioral analyst, licensed marriage family therapist and rehabilitation counselor, Mark enjoys his work and brings all his experience from these treatment fields to the table to create a person centered, evidenced based approach for his clients and the teams he works with. Marks ability to create positive treatment outcomes with his clients has been documented with great success over his career.

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Sarah Holton – Director of Operation, Co-owner

Sarah, born and raised in the four corners, is passionate about the community she grew up in. She was called to this work through the needs of a family member.  Sarah has experience in business and organizational management and a passion for creating avenues for all people to thrive within their communities.


Tonya Shangraw – PhD, BCBA-D, Clinical Director

Tonya is originally from Russia and lives in Alaska. Tonya got her BCBA-D certification in 2012 with a PhD in developmental psychology, offering a great perspective to help with better understanding of typical development and milestones. Tonya has been a Clinical Director for ABA agencies since 2013. Her areas of expertise include language and communication developments, functional assessments, play and social skills development, and working with problem behaviors. She enjoys using natural environment and items that are already in child’s natural environment. While working with clients and families she finds it especially important that all the goals are functional and make sense for the family.


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Pam Bartsch – MA, BCBA

Pam is originally from Southern California and now resides in Southwest Idaho. She has over 11 years of special education experience, working with children with profound disabilities as well as those with a mental health diagnosis. Pam has an extensive background in working with families that have a child with a diagnosis of Autism as well as 11+ years working in the ABA field. Pam’s passion is in working with families to be able to support their children in ways the families did not think were possible and seeing clients growth over time. When not at work, you will find Pam and her family camping, in the summer, playing in the snow in the winter, and on the sports fields in the fall and spring.


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Kaitlyn Cummings BCBA

Kaitlyn is a Board Certified Behavior Analyst living in northwest Florida. An Arkansas native, Kaitlyn graduated from the University of Arkansas in 2016 with a B.A. in psychology and French. After graduating, she began her journey in the field of ABA as a behavior technician and discovered her love for the science of behavior analysis. Kaitlyn earned a master’s of arts degree in applied behavior analysis with an emphasis in autism from Ball State University in May of 2019 and obtained her board certification shortly thereafter. Kaitlyn enjoys targeting functional communication, living, and community skills needed to ensure that clients can reach their highest level of independence, thereby fostering an enjoyable quality of life. In her free time, Kaitlyn enjoys spending time at the beach, paddle boarding, and traveling. Thanks Kaitlyn!


Devon Parson – M.ed, Lead Behaviorist

Independence here in Durango, Devon has over 4 years experience in writing and implementing behavioral support plans for individuals with intellectual and developmental disabilities, Autism and other learning disorders. He holds a Masters degree in Special Education and is currently working on acquiring his BCBA through The University of Colorado Applied Behavior Analysis Program. His dedication and leadership in our local community for people with disabilities is recognized by Fort Lewis College, 9r school district, community center boards, vocational rehabilitation programs, parents, families and the individuals he works with. Thanks Devon!

Karen Silliman – MS, MFT, Office Administrator

With a background of therapeutic experience, Karen joins the PBS team to offer administrative support to staff and clients, with a clear understanding of how the positive impact for PBS clients is tremendous. She enjoys living at 8000 ft. elevation with ongoing spectacular views and high desert opportunities to explore geography, geology and history. Her interests are broad and varied and she enjoys keeping abreast of many arenas of life including little known history and spirituality. Thanks Karen!

Karen Chanda, MS, BCBA

Karen is from Long Island, NY. Karen received a BS in Health Administration, a MS in Special Education and an Advanced Certificate IN Applied Behavior Analysis. As a BCBA she has worked with multiple agencies. In 2020 Karen retired as the Director of Vocational Training and Placement Services at a large non-profit after 20 years of service. She’s held various training opportunities in public and non-public organizations, school systems, and continues to host workshops and trainings related to special education and behavioral interventions. When she is not working, Karen can be found spending time volunteering with Big Brothers and Sisters, animal rescue, and with her husband and daughter at the beach. Thanks Karen!

Tania Isman – Registered Behavioral Technician (RBT)

Tania has been married 16 years with Three children. Tania enjoys being outdoors and going on adventures. She is passionate about getting kids active with yoga and exercise and into the outdoors as much as possible. She recently graduated with a bachelor’s degree in elementary education. Tania hopes to become a BCBA in the future. Thanks Tania!

Alex Noble – RBT

Alex is originally from Montana and was drawn to the dramatic views and mountains of Durango. She has eight years of experience in working with children of differing abilities. Alex is working towards getting her ABA Master’s Certification and is eager to make an impact in her client’s lives. Outside of work Alex enjoys rock climbing, mountain biking, and photography. Thanks Alex!

Brandee Muzzy – Registered Behavior Technician (RBT)

Brandee is a Registered Behavior Technician with PBS of the 4 Corners. Her dedication and experience working with children with Autism is extensive. Her calmness and effective use of ABA therapy has been supportive and life changing with the children and families she works with. I am truly impressed with her compassion, flexible thinking skills, and her ability to effectively run behavior programs with our clients, families, and staff. Thanks so much Brandee!

Shannon GonzalesBehavior Technician

Shannon was born and raised in Cortez, CO. After graduating high school she moved to the Seattle area where she earned an Associates degree in Early Childhood Education. She moved back to Cortez where she has experience as a lead teacher and paraeducator in a local preschool. Shannon is married with 3 kids, 3 dogs, a cat, a bird and many fish as pets. Shannon likes to spend her time reading, gardening, traveling and being in the mountains with her family. Thanks Shannon!


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BryAnne Goddard – Behavior Technician

BryAnne has lived in the area for over 20 years. She has worked with a variety of children over the past two decades as a teacher, director, and parent educator. She is passionate about helping all children live healthy and happy lives. In her spare time, BryAnne gardens as often as possible and enjoys spending time outdoors with her family.

Arnelda Hathale – Behavior Technician

Arnelda Hathale was born in Tuba City, AZ. but moved to Cortez, CO many years ago. Her empathy and inquisitive nature are a plus. She is a keen observer with loads of patience. Arnelda has experience in the hospitality industry so she understands the value and importance of our clients. The care and personal attention to each and every client’s need is of the utmost important to Arnelda. Our clients deserve it. Thanks Arnelda!

Stacey Watson – Behavior Technician

Stacey is a former thirteen year veteran of Re-1 School District. During that time, Stacey worked in Special Education, teaching children diagnosed with Autism, ADHD, and other Learning Disabilities. I her spare time, Stacey enjoys reading, coloring, painting, working in her yard, hiking, fishing, and time outdoors. Thanks Stacey!

Amanda O’ConnorBehaviorTechnician

Amanda has lived in the four corners area for twenty-five years, and is a mother of three free spirited children, who motivate her every day to be a better person than the day before. Amanda is resilient, patient, and kind. She has a strong desire to help others, and aspires to inspire each step of the way. Thanks Amanda!

Sherry Marcum PBS4C – Job Coach

She has worked successfully with with individuals with special needs for over 20 years. Her experience is seen in the amazing work she does with individuals with disabilities on and off the job. She has a diverse history of training and has worked in many settings with individuals with disabilities. Sherri will be acquiring her national supported employment certification this year. Thanks Sherry!

Bear Messinger, RBT

Bear is from Northern California. He is attending Fort Lewis College, majoring in psychology. His goal is to help people feel better about themselves through greater self confidence, acceptance and socialization. Thanks Bear!

Ellen Fisher, BA, Behavior Technician

Ellen has been living in Durango, Colorado for the past five years after moving from her home state of Washington, where she grew up on the San Juan Islands. In spring of 2021, she graduated from Fort Lewis College summa cum laude with a Bachelors of Arts in Psychology. In the upcoming year, Ellen plans to attend graduate school for social work. In her spare time, Ellen enjoys painting, mountain biking and skiing. Thanks Ellen!

Kathy Flannery, BS, Behavior Technician

Kathy holds a Bachelor’s degree in Family Life Studies. Kathy enjoyed her time working as a Family Educator for Early Head Start for several years as well as a head start teacher for 3 years. She enjoys spending time with her grandkids. Kathy’s Motto is “Tomorrow offers the promise of being better than today if you so choose it to be.” Thanks Kathy!

Payson Veach, Behavior Technician

Payson was born and raised in Cortez, co. He enjoys being outdoors, and also playing different sports. In Highschool Payson spent 3 years in the paraprofessional class learning to work with and help those with different learning abilities. During his experience and education in the special education classroom Payson fell in love with the experience of working in this field. Thanks Payson!