Selective Mutism has been described as a social communication anxiety disorder (The Selective Mutism Group, n.d.). Though its prevalence is considered rare in the DSM-IV (APA, 2004), research by Bergman et al (2002) showed that 1 in 143 elementary school-aged children met the diagnostic criteria for Selective Mutism.
DIR / Floortime in Assessing and Treating Selective Mutism