Diagnostic Center Team

Amy Allen
Amy Allen, Ph.D., L.MFT, NCSP, School Psychologist
Amy Allen is a Nationally Certified School Psychologist and a Licensed Marriage and Family Therapist. Amy earned her Master's degree in Marriage and Family Therapy and School Counseling at the University of Southern California, then completed her Ph.D. at the University of California, Riverside in School Psychology. She has over 10 years of experience in the field of education and psychotherapy as a children and family therapist, behavioral interventionist/consultant, a university adjunct professor, and a school psychologist. Her ongoing areas of interest and research include empirically-based interventions in schools to support social-emotional learning (SEL) and academic needs, mental health in the Asian American community, and Multi-Tiered System of Supports (MTSS) implementation within a Response to Intervention (RTI) framework.

Alison Pentland
Alison Pentland, Speech-Language Pathologist, Augmentative & Alternative Communication Specialist
Alison Pentland is a speech-language pathologist who specializes in the area of augmentative and alternative communication (AAC). She received her master's degree in communicative disorders and sciences from San Jose State University where she participated in its AAC in Educational Settings grant. Since then, she has worked in homes, schools, and clinical settings, providing AAC assessment, intervention, and consultation for communicators of all ages and their teams. In addition to working at DCN half time, where she leads the AAC Technical Assistance Project, Alison is actively involved in AAC research and education. She serves on the board of directors and chairs various committees for the United States Society for AAC. Alison has presented at state and national conferences and done trainings throughout California and abroad. She is a firm believer that communication access is a human right and is passionate about learning and sharing with others.

Casandra Guerrero
Casandra S. Guerrero, M. Ed., M.S., CCC-SLP, Speech-Language Pathologist
Casandra Guerrero is a Speech Language Pathologist (SLP) with the Diagnostic Center of Northern California. She has a master's degree in Education from University of California, Santa Cruz with a focus in social justice and a master's degree in Communicative Disorders and Sciences from Cal State Northridge. Previous to joining the DCN team she had sixteen years of experience in education, including as a general education teacher, school based SLP, and program specialist. This experience included supporting students in general education, special day classes, transition programs, and with extensive support needs. Casandra has been involved in the California Autism Professional Training and Information Network (CAPTAIN) as a cadre member and leader since 2015. She was a Special Education Local Plan Area (SELPA) regional lead for the Open Access Augmentative Alternative Communication (AAC) project in which she completed the certifications for AAC training and implementation and has a special interest in supporting students with complex communication access needs. She also has a passion for inclusive programming and has extensive experience with training and implementation of peer based inclusion programming, in addition to having worked closely with Special Olympics of Northern California as the lead for a National Banner Unified Champion School. Casandra is excited to continue to support educators and families throughout Northern California gain access to much needed training and resources.

Cecelia Timek
Cecelia Timek, M.A., Education Specialist
Cecelia Timek is an Education Specialist with the Diagnostic Center of Northern California. She has supported individuals in special education for over 20 years. She has worked in early intervention clinics, home settings, assisted living facilities, and schools. Cecelia has worked with students and adults with a wide range of abilities and needs. She is passionate about strength-based assessments and gaining a deep understanding of a learner's profile to best support their educational outcomes. Cecelia currently provides ongoing coaching and support to districts and teachers through technical assistance projects and has recently joined our team of trainers.

Daniel Silberstein
Daniel Silberstein, M. Ed, Education Specialist
Daniel Silberstein is an Educational Specialist with the Diagnostic Center of Northern California. He has a Master's in Education and has worked in the field of special education for over 15 years as a Special Day Class (SDC) teacher and Reading Specialist. Previously, he served as Director of Oakland Unified School District's Reading Clinic, overseeing a program which provided direct reading support to elementary through high-school-aged students in both a clinical and classroom settings. Daniel currently presents trainings for the California Dyslexia Initiative (CDI). Daniel is enthusiastic about sharing strategies for teachers throughout Northern California.

Janet McLellan
Janet McLellan, M.A., Ph.D., CCC-SLP-L, Speech-Language Pathologist
Janet McLellan has worked in the schools for over 30 years as a speech-language pathologist, special education teacher, augmentative and alternative communication specialist, and administrator. She has a Master's in Communication Sciences and Disorders and earned her doctoral degree at the University of North Carolina - Chapel Hill in Special Education and Literacy. She has presented nationally and internationally on topics such as augmentative and alternative communication, language, literacy, and school-based intervention. Her passion is promoting language and literacy learning for all students.

Joey Chapman
Joey Chapman, M. Ed., Education Specialist
Joey Chapman is an Educational Specialist with the Diagnostic Center of Northern California. She has a Master's in Education and has worked in the field of education for over 19 years. Prior to working at the Diagnostic Center of Northern California she was a 3rd grade general education teacher for 5 years and a special education resource specialist for 7 years in San Leandro Unified School District. Joey is inspired to be able to support both new and veteran teachers and is passionate about making sure that learning is accessible and engaging for all students.


Kristin Moore
Kristin Moore, Psy.D., Clinical Psychologist
Kristin Moore received her doctorate degree in clinical psychology from John F. Kennedy University. Her specialty is in the area of child and adolescent psychology, and she has provided mental health and psycho-diagnostic assessment services to children, adolescents, and their families in California community mental health clinics and hospitals for over a decade. Her interests include trauma, mood disorders, and bilingual and projective assessment.


Liz Arenas
Liz Arenas, M.S., CCC-SLP, Speech-Language Pathologist
Liz is a bilingual speech-language pathologist with the Diagnostic Center of Northern California. She has worked in private clinics, home settings, and schools (public, private, and charter) in Arizona and California. Liz has over 26 years of experience working with children from early intervention to high school transition with a variety of communication abilities and needs. She has served as a member of state-level committees to inform practices when working with dual- language learners. Her experience has allowed her the opportunity to collaborate with professionals and families while conducting assessments, creating intervention plans, and informing services in the schools.

Michelle Kooyman
Michelle Kooyman, M. Ed., Education Specialist
Michelle Kooyman is an Educational Specialist with the Diagnostic Center of Northern California. She has a master's degree in education and holds teaching credentials for Deaf and Hard of Hearing as well as for Extensive Support Needs (previously, Moderate Severe Disabilities). She has over 25 years of experience working in both deaf and hearing academic settings as a paraprofessional and a teacher in a high school regional program, a special day class, a transition program for students aged 18 to 22, and co-teaching in a high school special day class. Her passion is to support students so that they thrive with confidence.

Natalie Corona
Natalie Corona, M.S., L.E.P., School Psychologist
Natalie Corona is a bilingual school psychologist with the Diagnostic Center of Northern California. She has a master's degree in Educational Psychology with a focus on Clinical and Child School Psychology from California State University, East Bay. She has worked in special education for over a decade as an instructional assistant, school psychologist, and administrator. She has expertise working with all age levels (preschool-transition) and ability levels. Her interests and areas of passion include executive functioning, working with students with significant needs, and helping early career teachers and school psychologists develop their skills.

Natalia Jocic
Natalie Jocic, M.S., LEP, ABSNP, School Psychologist
Natalie Jocic is a school psychologist and diplomate in school neuropsychology. For over 20 years, she has worked with neurodiverse and neurotypical students as a behavior technician, school psychologist, school counselor, and program specialist. This experience ranged from supporting early childhood to continuing education programs; assessing and providing services to students in general education, autism, counseling enriched programs, etc.; and collaborating with families and school districts on best practice assessment and intervention.

SM
Samson Mai, M.A., School Psychologist
Samson Mai is a School Psychologist with the Diagnostic Center of Northern California. He has a master's degree in education from Fresno Pacific University. He has worked in education for over 15 years as an English teacher abroad, as a school psychologist and an assistant director of a non-public school. Samson has experience working with all ages and ability levels around Northern California, including being part of the team that established the counseling enriched program for a local Bay Area middle school. His passion for mindfulness and meditation, allows him to fully engage and be present while supporting students and families. He strives to help families and school teams understand the strengths and challenges of their students, and how to best make progress from where they currently are.

Sharon Reyes
Sharon L. Reyes, M.S., CCC-SLP-L, Speech-Language Pathologist
Sharon Reyes has been working at Diagnostic Center Northern California for seven years. She obtained her master's degree from Cal State Hayward (now Cal State East Bay). Her previous work experience in Speech-Language Pathology includes school-based services (students ages 3 to 22), early intervention, hospital and skilled nursing facility (SNF) settings. Sharon has special interests in working with deaf and hard of hearing students, helping families make the transition between early intervention and school-based services as well as promoting Interprofessional Practice to better support students.

Tara Zombres
Tara Zombres, M.Ed., NCED, BCBA, Education Specialist & Behavior Analyst
Tara is a Behavior Analyst and Education Specialist at the Diagnostic Center-North. When in the classroom, she taught students with a wide variety of disabilities, specializing in working with students with extensive support needs. She has a master's degree in Curriculum and Instruction in Special Education and a graduate certificate in Applied Behavior Analysis. Her areas of expertise are providing engaging and appropriate instruction for students with complex needs, developing educational programs for students with severe emotional and behavior disorders, conducting functional behavior assessments for students with severe behavior problems, teaching students with Autism using Evidence Based Practices and designing comprehensive programming for students with emotional and behavioral disorders. She sits on the planning committee for the national Advancing School Mental Health conference and is a member of the California Department of Education School Mental Health Policy Workgroup. Tara is a Board-Certified Behavior Analyst (BCBA) and a Nationally Certified Educational Diagnostician and has been a PENT leader since 2017. She is currently a Ph.D. candidate in Applied Behavior Analysis at The Chicago School of Professional Psychology. Her goal as a professional is to forever keep in mind that empowering children changes the world.