Selective Mutism

by Ivy Ruths, Ph.D

By 12 to 13 months, most infants will have already uttered their first words and by five years of age, children can understand more than 2,000 words. This is the average developmental trajectory for language development; however, in very rare cases a child that has established these milestones and can communicate perfectly well through spoken language, may fail to speak in social situations. This disorder is known as Selective Mutism (SM). SM is a rare disorder, affecting less than 1% of the population. The average age of onset for SM is between 2- and 4-years-old. Parents often believe that their child is shy, quiet, or introverted, and it is not until a child enters school for the first time, that their lack of speech becomes more noticeable and more problematic. Teachers often play a crucial role in differentiating when a child is not simply just shy, but has a problem which may require psychological/behavioral treatment.

SM is often associated with shyness, social isolation and withdrawal, clingy behavior, temper tantrums, or what may look like oppositional behavior. Many of the aforementioned associated behaviors occur in normally developing children in new situations or transition periods, therefore in order to be given a diagnosis of SM, the mutism must last at least one month and this month cannot be limited to the first month of schooling. In addition, the mutism must not be better accounted for by a communication disorder or a lack of knowledge or comfort with the spoken language (e.g. the child must be familiar with the spoken language) and other disorders such as Pervasive Developmental Disorders, should also be ruled out when diagnosing SM. There are several different theories regarding the causes of SM, such as high genetic vulnerability (families of children with SM may have a history of avoidance, anxiety, or shyness) and theories suggesting that SM may be learned through classical or operant conditioning or through vicarious learning. The amount of impairment caused by SM is broad and impacts the child negatively in multiple realms. Socially, children with SM have difficulty making and maintaining friendships. Other children may not understand and interpret the child’s lack of speech as strange. Academically, it is impossible to assess a child’s intellectual ability if he/she is unable to reply to questions, read aloud, or indicate understanding. Treatment, if available, has a much more positive prognosis if delivered early.

Behavioral treatments have been deemed efficacious. Sometimes, medication is also suggested in conjunction with therapy. Behavioral interventions often include contingency management, shaping, stimulus fading, systematic desensitization, and self-modeling. Contingency management occurs when positive reinforcement is given when a child speaks. Shaping refers to providing positive reinforcement for initial approximations of communication such as making eye contact, pointing, or nodding. These behaviors are continually reinforced until they are “shaped” into the desired behavior (i.e. speaking). Stimulus fading involves slowly introducing more people (one at a time) into the room when a child is speaking. For example, a child may be rewarded when he or she speaks when one unfamiliar person is present. As the child becomes more comfortable with the presence of one person, a second unfamiliar person might stand in the doorway while the child continues to be reinforced for speaking. Systematic desensitization involves the use of relaxation skills and the introduction of and habituation to a feared stimulus, in this case, speaking, during an exposure (i.e. the feared situation). Self-modeling consists of making an audio or video recording of the child speaking. Later the recording can be played where the child does not normally speak and watching and hearing himself/herself may help the child become more comfortable with speaking in front of others (this can be especially helpful in the classroom for required presentations). These types of treatments, delivered by a trained behavioral therapist, paired with the support of parents at home and teachers in the classroom, can be effective in helping children with SM overcome their fears of speaking in the classroom, with peers, and with strangers allowing them to reach their full potential socially and academically.