Christopher A. Kearney's book, Helping Children with Selective Mutism and their Parents: A Guide for the School-Based Professionals, is a behaviorist's approach to dealing with selective mutism. The book does a great job of detailing typical causes of selective mutism and techniques for treating the various causes. One of the most important ideas is that selective mutism needs to be treated by the community- family, school, friends are all important components to the treatment plan. A therapist will experience most success by going into the child's comfort zone and slowly rewarding speech. The lower functioning a child, the longer the approach will take. While Shipon-Blum's book focuses on purely anxiety based causes, Kearney acknowledges that oppositional behaviors may contribute to the disorder.
Below is a graphic that summarizes the ideas in the text. The main causal factors are in the purple blobs in the center. They often occur in combinations. Kearney stresses that underlying issues need to be addressed prior to behavioral interventions. A child who has been taunted about stuttering is not likely going to be willing to speak until the taunting is eliminated and stuttering is reduced and/or normalized. A child who has been beaten for talking or making a noise will not talk until the threat is removed. Furthermore, children who do not speak English competently may be reluctant to speak around proficient speakers until their proficiency improves.
Kearney shares that treatment is often slow and progress gradual. Records of progress can keep the entire team motivated when plateaus occur.