Teaching Tree’s mission is to promote life-long learning by embodying the principles of quality and value.
Quality is defined as the adherence to science and maintaining high ethical standards in the pedagogical process without losing empathetic focus on the client. Value is defined as the efficient use of resources by placing effective scientific teaching practices to optimize the number of learning opportunities per any given time.
Teaching Tree’s employees get things done by engaging in a multi-dimensional problem-solving process and data analysis which require self-reflective practice, collaboration, creativity and openness. Our staff learns both from success as well as miraculous mistakes which we define as the courage to go beyond our current comfort zone of what we know and do well.
Our approach is valid as long as it leads to effective actions and meaningful growth, if not – we adapt and modify our programs in response to the environmental feedback. Teaching Tree sprouted in the field of applied behavior science and naturally is rooted in functional contextualism which predicts and changes behavior with ‘precision, scope, and depth’.
Our international staff speak 17 languages! English, German, French, Spanish, Italian, Russian, Polish, Bulgarian, Armenian, Belarusian, Catalan, Farsi, Mandarin, Cantonese, Bahasa Malaysia, Indonesian, and Tagalog.
- Behavior Therapy
- Occupational Therapy
Ashley Gibbs, PhD Candidate, BCBA, OTR/L
Ashley directs our Hochheim clinic as well as oversees all occupational therapy services.
Ashley grew up in Atlanta, Georgia. She graduated from The Medical College of Georgia (now Augusta University) with a Master of Health Science in Occupational Therapy in 2013. After several years of working with children in a multidisciplinary setting and seeing the gains her clients made when they received ABA services, Ashley decided to return to school and graduated from Georgia State University with a Master of Science in Applied Behavior Analysis in 2018. After conducting her first research study as a master’s student, Ashley developed a passion for bridging the gap between research and practice. She is particularly interested in interventions that facilitate generative language and derived relational responding in children with autism and other intellectual and developmental disabilities and has had her work published in multiple behavior analytic journals. Ashley is working on her dissertation as a doctoral candidate in the Educational Psychology program at Georgia State University.
As a BCBA and an OT, Ashley has had experience working with clients from birth to adolescence with a variety of diagnoses and abilities. Ashley believes in treating the whole child and working in collaboration with providers across all disciplines to advance a client’s independence.
Outside of work, Ashley enjoys spending time with her husband and son, reading, and traveling. In the fall, you can find her wearing red and black and cheering for the UGA Bulldogs in NCAA football.
She speaks native English.
Benjamin Brody, MS, BCBA
Ben has worked with children and teenagers with autism from ages one and a half to eighteen. He began this work in 2017 a behavior therapist in Phoenix, Arizona, before completing his Master’s Degree in Psychology with a focus on Applied Behavior Analysis from Capella University in 2020. He is passionate about providing direct therapy to children and teenagers—and designing individualized programs to help them succeed.
Ben enjoys cooking, walking, hiking, biking, chess, and swimming.
He speaks native English and is learning German.
Carla Meikle, MA, BCBA
Carla directs our Kindsbach clinic as well as oversees all ABA services in English.
Carla has almost two decades of experience working with children with special needs and their families. At Carthage College, where she obtained her undergraduate degree in Psychology, she served as Chapter President of Psi Chi and presented research at the American Psychological Association Convention. She obtained her master's degree in Applied Behavior Analysis with an emphasis in Autism and was nominated by her peers to run for President of Four Corners Association for Behavior Analysis. Carla joined Teaching Tree Clinic in 2018 and has been serving as our Clinical Director since soon thereafter.
Carla plays soccer competitively, hikes with her dogs, and travels as much as possible with her husband and two boys.
Carla speaks native English, fluent Spanish, and a bit of German.
David Cole, MS, BCBA
As a researcher, David studied the neuropsychology of fast and slow decision-making in humans and animals. His work has been published in a half dozen journals and has won fifteen grants and monetary awards. A highlight of his academic career was working on a computer game controlled by brainwaves as a visiting researcher at Trinity College Dublin.
As a therapist, a supervisor, a consultant, and a director, David treated toddlers to geriatric patients with diverse psychiatric diagnoses from California to Florida. He developed free graphing software for time-series data that has been adopted by university programs. A highlight of his clinical practice was navigating three adolescents and teenagers from their first words to speaking in sentences in under a year.
In January 2022, David was appointed CEO of Ausblick Therapie GmbH, bringing experience with founding companies, sitting on the boards of nonprofits, and lobbying on Capitol Hill.
David speaks native English, some French, and a bit of German.
Dayra Diaz-Gonzalez, MEd, BCBA
Dayra is a military spouse who is dedicated to helping families. Dayra has been in the field of ABA since 2016, serving young children diagnosed with Autism Spectrum Disorder and their families. She started as a Registered Behavior Technician and maintained this position while she completed her schooling. She attended Arizona State University where she completed a Masters of Education in Curriculum and Instruction with a concentration in Applied Behavior Analysis. She has worked with children and young adults ranging from 2 years of age to 17 years old. She believes in creating individualized programs to help families reach their goals.
Dayra loves to travel. She enjoys trying new foods and spending time with her family.
She speaks native English and native Spanish.
Danielle Trzil, MA, BCBA
Danielle is a Washington State native who found her passion for working with neurodiverse populations while working in a research lab providing parent training. She was inspired by the positive effects of the ImPACT curriculum to families in the Greater Seattle region.
Danielle began working as a behavior technician and assistant behavior analyst before receiving her BCBA credential in 2020. She has experience primarily working with children aged 18 months to 6 years of age with a range of developmental disabilities (including Deaf/hard of hearing, global developmental delays, Down syndrome, and Autism Spectrum Disorder). For the past year and a half, she has been working with a multi-disciplinary team providing services following the Early Start Denver Model in a clinical and preschool setting.
Danielle is passionate about promoting socially significant behaviors and skills in the populations she works with by utilizing naturalistic, developmental/behavioral, and empirically validated practices.
She enjoys spending her free time with her family traveling, going on leisurely hikes, crafting, and being outdoors.
She speaks native English and some American Sign Language.
Diane Fraser, EdD, BCBA-D
Dr. Fraser oversees ABA services in French.
Dr. Fraser was France’s first BCBA. She is the Cofounder of Association Française—Les Professionnels de l’Analyse du Comportement (AF-LPA) and the Verified Course Sequence Coordinator for L'Analyse Appliquée du Comportement. She earned her doctorate in education from Columbia University, has held academic posts at Saint John’s University and Long Island University, and has been invited to deliver several keynote addresses at international conferences. She is the author of Comme Font Les Autres Enfants, a book for parents on how to communicate with their children with autism.
She is an American-born native English speaker and self-taught French speaker.
Emily Berman, MS, BCBA
Interim Clinical Director
Before joining Teaching Tree Clinic in 2018, Emily worked for an ABA company in California, climbing her way from behavior technician to clinical director. During this time, she gained experience working with toddlers, children, and young adults in home, school, and community settings.
Emily has experience in Early Start Denver Model, Pivotal Response Training, attending IEPs, providing community training events, and collaborating with large teams of autism service providers. collaborating with large teams of autism service providers. She always aims to provide individualized ABA service focusing on the highest priorities of the families she works with.
When Emily is not building block towers and facilitating social skills opportunities, you can find h hiking, cooking and exploring new cities.
Emily accepted the clinical directorship of our Frankfurt-Mainz-Wiesbaden clinic until we name a permanent replacement, allowing her to maintain a primary focus on the clients she directly serves.
Emily speaks native English and fluent German.
Eric Shafarman, MA, BCBA
Eric directs our Amberg clinic.
Eric grew up in Stratford, Connecticut. After graduating from New York University, he worked as a teacher’s assistant in NYC public schools, an English teacher in South Korea, and a camp counselor for children with special needs and vacation programs for adults with special needs. In 2014, he entered the field of ABA as a Behavior Technician in Oakland, California, advancing to a Clinical Supervisor position, before developing a school-based therapy center in Dubai, UAE as a Clinical Director.
Eric has worked across a wide variety of ages and abilities, teaching communication skills to early learners, social skills to teenagers, and vocational skills to adults. He has specialized in early intervention for learners in the range of 2–6 years old and enjoys nothing more than teaching first words and requests, helping learners achieve more control over their lives and achieve their needs and desires in ways that work best for them and their family.
Outside of work, Eric loves traveling, cooking, sports, reading, and chess. A great Sunday for Eric would be playing a round of golf in the morning, attempting to recreate a favorite ethnic dish like Greek Moussaka for dinner, then sharing it with friends and family, followed by watching a basketball game together!
He speaks native English and is learning German.
Gillienne Nadeau, MS, BCBA
Senior Behavior Analyst
Gillienne is from Philadelphia, where she studied theatre and worked as a theatre teacher for children and adolescents. It was in Hawaii in 2011 where she fell in love with behavioral science, eventually earning a master’s degree in Behavior Analysis and Autism Studies from Sage College.
Gillienne loves both the science of behavior and getting to engage with amazing children and teenagers while watching them grow and learn! She is especially passionate about helping children learn through their natural environment and giving them the tools to express themselves as individuals.
Gillienne has supervised experience in the community, schools, homes, and clinics with individuals aged 2–18 years. She has presented research to the Hawaii Association for Behavior Analysis, Learning Disabilities Association of Hawaii, Association for Behavior Analysis International, and The Autism Community in Action.
Gillienne loves dancing, baking, riding her bike, and every cat she meets. She stays involved in theater, performing whenever she can.
She speaks fluent English.
Haley Thielemier, COTA, RBT
Occupational Therapy Assistant & Behavior Therapist
Haley is a military spouse who was born and raised in the small town of Pocahontas, Arkansas. After she graduated with her bachelor’s degree in Interdisciplinary Studies with emphases in Psychology, Health, and Exercise Science, she found work in a specialized daycare for children with special needs. This experience motivated her to return to school to study occupational therapy. She became a Certified Occupational Therapy Assistant in Oklahoma, Missouri, and Georgia. At Teaching Tree Clinic, she both applies her certification as an OTA as well as, more recently, as Registered Behavior Technician.
Haley enjoys traveling around Europe, learning about the local culture, with her husband and two small children.
She speaks native English.
Ivanah Edquiban, MS, BCBA
Ivanah hails from the Philippines, graduating cum laude from the University of the Philippines with a degree in Behavioral Sciences. Sometime later, sitting in front of a computer as a talent acquisition agent, a thought that crossed her mind: She would rather be moving, playing, and working with children.
Six years ago, Ivanah began working a registered behavior technician with children with autism in the Philippines, before completing her master’s degree in applied behavior analysis at Bangor University in the United Kingdom. There, she wrote a thesis on teaching sign language to staff in a nursery using SAFMEDS and Precision Teaching.
Ivanah completed her training to become a BCBA at Teaching Tree Clinic. Since then, she has spent her days working and playing with children and savoring life-changing improvements captured in everyday incremental progress. You could say that this is what reinforces her waking up and walking into work every morning. She cannot imagine doing anything else. She values Teaching Tree Clinic as a place for continued development and learning and where the team cares for the clients and each other.
Ivanah speaks native English and native Tagalog.
Justyna Przeperska, MS, BCBA
German Services Coordinator & Behavior Analyst
Justyna hails from Lower Silesia in Poland. There, her master's degree studies in special education introduced her to the field of autism. That led her to write her thesis on the Picture Exchange Communication System (PECS), introducing her to Applied Behavior Analysis. This brought Justyna to Germany, on an Erasmus Program internship.
In Germany, Justyna quickly settled in, treating children in homes and schools, obtaining her BCBA certification, and pursuing recognition of her training in Poland as a Sozialpädagogin.
She enjoys spending her free time with her son, family, and friends. She also loves cooking, yoga, and the mountains.
She speaks native Polish, fluent German, and a bit of English.
Katrin Hechler-Massel, MS, BCBA
Senior Behavior Analyst
Katrin started her journey in the field of ABA 10 years ago and has absolutely loved being a BCBA since 2014. She has had the pleasure of working with children, teenagers, and adults on the autism spectrum, as well as with individuals with other development and learning disabilities. Most recently, Katrin worked for HMHI Autism Spectrum Disorder Clinic and Neurobehavior Home Program at the University of Utah. She previously provided ABA services in homes, schools, and clinics.
In her free time, Katrin enjoys spending time with her wonderful family, everything food, going on hikes and camping, and listening to records.
She speaks native German and fluent English.
Katya Shchurskaya, MA, BCBA
Katya began her career as a language instructor at Minsk State Linguistic University. A few years later she started looking into Applied Behavior Analysis, as her own son was developing with a speech delay, and immediately fell in love with the science. Her keen interest in the area grew into a new profession – she completed the ABA program and obtained her Master’s degree in
Psychology in 2020. For some time, Katya combined her teaching job at the university with work with children with special needs implementing behavior analysis in both settings, but eventually transitioned to the latter. She is truly passionate about her work, as both its process and result give her immense joy and inspiration.
Katya is a constant learner, has a vibrant curiosity for new places, people and experiences. In her
free time, she enjoys travelling, hiking and reading.
She speaks native Russian and Belarusian, fluent English, and some Italian.
Cofounder, Chairperson, & IT Specialist
After studying distributed IT systems, Leif worked for 10 years as an IT consultant in a large German bank. Bored with the high level of abstraction and dissatisfied with the lack of connection to the real world, he quit his job and moved on with the intention of spending time in the forest, away from the modern world—a plan that was thwarted by his wife, who hired him as an employee for their clinic. The clinic flourished and eventually became Ausblick Therapie GmbH, where he served as interim executive director during the start-up and transition period before handing that role over to David Cole, so he could finally devote himself to contemplation and meditation in his cabin in the woods.
He lives with his family in the Palatinate Mountains, loves good food and its preparation, eccentric music, and time in nature. He explores approaches to holistic health for himself and his family and is interested in the intersection of Western science and psychology, Eastern mysticism, and shamanism.
Leif speaks native German and fluent English.
Mallori Ratcliff, MS, BCBA
In 2015, Mallori was voted Idaho Falls, Indiana’s top woman to know for her work with children and adolescents suffering from severe depression and suicidal ideation/self-harm. That same year, she was published in the United States Psychiatric Rehabilitation Association quarterly review, a culmination of research projects and awards she won for her research into personality and behavior. In particular, she has studied addictions and dual diagnoses, including Intellectual and developmental disabilities (IDD) and severe mental illness.
The majority of Mallori’s career has been spent working with neurodiverse individuals and their families. She has worked as a therapist, a supervisor, a consultant, and a program director, developing mental health and drug and alcohol programs in the United States that treated low-income individuals and their families. She has also worked as a direct support worker in the field/community, in the home, in the clinic, in schools and via telehealth. A highlight of her clinical practice has been working with individuals who were dually diagnosed with severe mental health and IDD, helping them to stabilize and lead fulfilling lives.
Mallori speaks native English, some Spanish, and a bit of German.
Miriam Quarterman, RBT
Miriam is a German native born in Heidelberg. She is a mother to 3 children with a background in elementary school education. She moved to the Rheinland Pfalz region during her time as a military spouse and returned after a few years in the frozen tundra known as North Dakota. While living in the United States, she worked as a Support Parent for Early Intervention, served families of children with special needs as a member of the Family Voices of North Dakota, became involved with the Children's Hemiplegia and Stroke Association, and lobbied the governor to establish a national Pediatric Stroke Awareness Day.
Miriam is a mother of an autistic son who survived an in utero stroke. So, she understands the parents' side of Autism. And it was her son who inspired her to become an RBT.
Miriam has a love for food so naturally she enjoys cooking and baking, so much so that she started a small bakery. When Miriam is not working at the center or baking she enjoys spending time with her family, including their dog and cat.
Miriam speaks native German, fluent English, some Spanish, and some French.
Natana Gill, MA, RBT
While studying to be an actor at university, Natana had the chance to teach drama in after-school programs. She fell in love with teaching, finding that she enjoy her students' on- and off-stage successes more than her own. A few years later, when she observed a class at the Texas School for the Blind, she knew she had found her calling. Natana obtained a master's degree in Special Education from Texas Tech, spending the next 8 happy years working with students of all ages with a wide range of abilities, and diagnosis, including autism.
Although moving to Germany has been a wonderful adventure for Natana, it also meant leaving her students behind. She is excited for the opportunity to work with the learners at Teaching Tree Clinic, because in some ways, it feels like coming home. Natana now has nearly 20 years of experience working with children in a variety of roles, not least including nanny, puppeteer, library storyteller, and Mad Science instructor.
Natana loves to read, spend time with her family exploring villages, and learning to weave.
Natana speaks native English.
Nilofar Sediqi, MEd, BCBA
Senior Behavior Analyst
Nilo was raised in Hamburg, Germany, moving to California when she was 13 years old. There, in 2015, she began her career as an RBT, before pursuing her master’s degree in Special Education with an emphasis in Applied Behavior Analysis from George Mason University.
In addition to pediatrics, she has worked with adults with psychiatric diagnoses ranging from developmental disabilities and substance abuse, both in group homes and as a consultant for a Mobile Crisis response team.
Nilo is passionate about giving a voice to those she serves as well as a naturalistic approach to build skills and decrease problem behaviors. She believes everyone is unique and any treatment approach should be individualized to meet each learner’s needs. She sees the potential in the individuals she serves and works hard to help them live a rich and fulfilling life.
Nilo enjoys traveling, spending time with her family, and discovering new places when she is not to be found at our Hochheim clinic.
She speaks native English, fluent German, and fluent Farsi.
Noemi Lovera, MS, BCBA
Noemi was born and raised in San Jose, California. After graduating with her bachelor’s degree in sociology in 2015, she found work with neuro-divergent children in a school setting. Ranging from 3 to 16 years old, most of the students had limited verbal and social skills and high levels of aggression. It was here that she was introduced to mentors and colleagues who showed her how ABA could be used to design individualized treatment precisely and efficiently for each student.
Over the next several years, she immersed herself in her newfound passion, while traveling summers to Southeast Asia to volunteer teaching English, supporting local special needs programs, and building housing and other infrastructure. She began a master’s degree in Behavioral Psychology from Pepperdine University in Los Angeles, California, and in 2021, she passed her board examination as a behavior analyst.
Noemi enjoys visiting new countries, learning local customs, eating food from all over the world, and playing soccer in her free time.
She speaks native English, fluent Spanish, and a bit of Japanese.
Samantha Cimirro, MOT, OTR/L
Samantha Cimirro was born and raised in New Jersey, USA. She graduated Summa Cum Laude with a bachelor's degree in Psychology from Stockton University. While pursuing a PhD in Clinical Psychology, she met an occupational therapist at a residential school for children and adults with severe and profound disabilities. She was inspired. She changed course and spent the next 2 years working full-time and taking night classes to qualify for the Masters of Occupational Therapy program at The University of St. Augustine for Health Sciences.
Samantha graduated 2 years later with high honors and proceeded to work with pediatrics to geriatrics in homes, schools, and private and state facilities. As Teaching Tree Clinic's occupational therapist, she intends to continue to expand her training and become a certified feeding specialist. Having struggled with sensory processing differences as a child, especially in the area of eating, gives her the perspective to understand and empathize with what her clients and their family are going through.
These days, Samantha enjoys spending time with her own child and her husband.
Samantha speaks native English.
Sara Melià Carreras, RBT
Office Manager & Behavior Therapist
Sara was born on a small island called Menorca. She has split her time between Spain and Germany for the past 3 years, but she is ready to set down roots in Germany.
Sara studied tourism and, for 5 summer seasons, worked with children as an entertainer. It fulfills her, helping and making families happy, be it as an entertainer or as a therapist.
Sara loves nature, animals, and traveling.
Sara speaks native Spanish and Catalan, excellent English, some German, and a bit of Italian.
Sasha Cress, MEd, BCBA
Behavior Analyst & Onboarding Coordinator
Sasha is military spouse residing in the Kaiserslautern Military Community. She is committed to promoting hands-on learning for children of all abilities and through all stages of the learning process. She believes that every child is a capable learner and deserves a positive and supportive environment to foster their physical, emotional, intellectual, and social needs.
Sasha has worked with children in diverse roles, from early childhood educator to paraprofessional in special education classrooms to primary school instructor. She joined Teaching Tree Clinic as Registered Behavior Technician under the mentorship of Veneta Dimitrova before obtaining her certification as a Board Certified Behavior Analyst.
Sasha holds a bachelor’s degree in Communications from Grand Canyon University and a MEd in Curriculum and Instruction with an emphasis in Applied Behavior Analysis from Arizona State University.
Sasha speaks native English.
Sonia Roach, MA, BCBA
Sonia is military spouse residing in the Kaiserslautern Military Community. She has worked with students ranging from preschool to high school as a para-educator, a Special Education teacher, and now a Board Certified Behavior Analyst. She believes that every child is capable of learning and developing—socially, emotionally, and academically—when provided a nurturing environment. In her experience, these environments entail collaboration with other professionals, including occupational therapists, speech pathologists, and educators.
Sonia graduated with an undergraduate degree in psychology, holds a teaching credential in early childhood special education, and obtained her master’s degree in in curriculum and instruction with an emphasis in applied behavior analysis.
Sonia speaks native English, native Spanish, and a bit of German.
Stephen Buckley, MS, BCBA
Stephen hails from Ireland, and it is there that for many years he lived alongside the children, teenagers, and adults with disabilities with whom he worked as a carer. He found that the people he worked with grew and became happier when they experienced encouragement from carers who showed interest, compassion, and empathy for them. However, he eventually noticed that many of people he worked with also appeared to be “stuck.” Over the years, they did not significantly expand their activities, access to educational opportunities, social circles, or self-help skills. Indeed, they would even regress, like by engaging in self-harm behaviours.
After researching therapies that offered to increase the self-help and social skills of people with disabilities, Stephen learned of a scientifically validated method proven successful with all types of individuals to improve all types of socially significant behaviour. In 2015, he returned to school to obtain a second master’s degree, this time in Applied Behaviour Analysis.
As a trainee, Stephen introduced ABA-based strategies to a large residential centre in Ireland that had come under scrutiny for poor practices, cultivating a culture of Positive Behavioural Support. Since then, his practice has centered on consulting with German families with infants and children with autism.
Stephen speaks native English and some German.
Tenny B. Chalian, MA, BCBA
Senior Behavior Analyst
Tenny has been in the field if Applied Behavior Analysis since 2009. She obtained her Master’s degree in Psychology with an emphasis in Behavioral Clinical Psychology from California State University, Northridge. She worked with individuals with autism and other developmental disabilities at home, school and community setting for several years.
She also has experience working as an Autism Program Specialist at the Behavioral Health Department at one of the largest health plans in Los Angeles.
She believes that teamwork makes the dream work, specially when helping families that have kids with special needs. She loves conducting different types of functional analysis and doing assessments in general.
She is passionate to teach new skills to her clients and make meaningful changes using safe and dignified treatment plans.
Tenny loves to travel with her husband as well as take a long walk or hike in nature and learn something new everyday.
Tenny speaks fluent English, excellent German, and native Armenian and Farsi.
William (Billy) Moulden, MA, BCBA
After earning his Bachelors Degree in psychology, William began working at Eden Autism in New Jersey where he discovered his career. He has worked in the field of ABA for 6 years starting as a Teaching Assistant working with middle school age children. William earned his Masters degree in Applied Psychology focusing on Applied Behavior Analysis at Rider University in New Jersey. He completed his training to become a BCBA at the adult services program of Eden Autism. William has worked with both Children adolescents and adults with a primary diagnosis of Autism from age 6 to 70.
William enjoys baking and going for long walks with his dog.
He speaks native English and some German.