Selective Mutism: The Role of Speech-Language Pathologists

Selective mutism is an infrequent childhood communication disorder that often first manifests itself at school. A child with selective mutism may not be able to speak with teachers and/or peers at school, however, is able to speak fluently with parents and siblings at home. School based speech language pathologists (SLPs) often are the first consulted when a child does not speak at school. This article discusses the definition of selective mutism, characteristics, etiology, and the role of SLPs in assessment and treatment as a part of an interdisciplinary team.                    

What is selective mutism?

The Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM–5; American Psychiatric Association, 2013) defines selective mutism as a childhood anxiety disorder in which a child is unable to speak in socially expected situations (i.e., at school) despite having the ability to speak in other situations (i.e., at home). The child’s inability to speak should be present for at least one month beyond the first month of school and hinders the child’s ability to access the school curriculum and interact with peers and adults. The failure to speak is not as a result of the child’s lack of expressive language skills or as a result of a childhood onset fluency disorder. Additionally, selective mutism is not as a result of a language (i.e., autism) and/or psychological disorder (i.e., schizophrenia). However, selective mutism may co-occur with other communication disorders (Giddan, Ross, Sechler, & Becker, 1997). The onset of selective mutism is typically before the age of five years old, more commonly affecting girls, and with an incidence of less than one percent of the population (Muris, Hendriks, & Bot, 2016).


Children with selective mutism may exhibit some or all of the following general characteristics with varying degrees of severity (list is not exhaustive):

  • Refusal to speak

  • Speak only in a whisper with certain people

  • Separation anxiety from parent

  • Symptoms of anxiety

  • Avoidance behavior

  • Depression

  • Poor eye contact

  • Frozen or blank facial expression

  • Temper tantrums

(Giddan et al., 1997; Martinez, Tannock, Manassis, Garland, Clark, & McInnes, 2015)


A single cause of selective mutism has not yet been identified, however, varying theoretical models include the following etiological factors:

  • Unresolved psychic conflicts

  • Genetics

  • Trauma

  • Maladaptive family dynamics

  • Dysfunctional reinforcement

(Viana, Beidel, & Rabian, 2009)


Due to the multi-faceted nature of selective mutism, the diagnosis of selective mutism should include a comprehensive multimodal approach involving the school psychologist, teacher, and SLP(Krysanski, 2003). A thorough developmental history, including pre and post natal, should be obtained from the parent and from medical records in order to rule out conditions that are characterized by the lack of speech. It is essential to obtain a thorough history of symptoms as well when and under what circumstances the child is mute. The psychologist conducts a parent interview and completes various checklists to assess for selective mutism and other disorders. The teacher provides information about the child in the classroom setting. This may include a report of circumstances in which the child is more or less likely to speak as well as the effectiveness of strategies that have been previously implemented (Viana, Beidel, & Rabian, 2009).

A speech and language assessment may be complicated due to the child’s mutism, however, it is necessary for the SLP to perform an assessment to determine the type and severity of the child’s impairment. Observing the child in a variety of school settings is needed to understand the child’s ability to use non-verbal communication and note the extent to which the child warms up to unfamiliar individuals (Yeganeh, Beidel, Turner, Pina, & Silverman, 2003). Nonverbal assessments of receptive language, standardized and informal, have been used successfully with children with selective mutism. If the child is verbal with the SLP, assessment of expressive language, standardized and informal, may be possible along with an assessment of voice, speech sound production, and fluency. If the child does not speak with the SLP, one useful assessment strategy is to have the parent provide an audio or video recording of the child speaking at home in order to evaluate phonetics, mean length of utterance, tone, rhythm, and quality of responses (Dow, Sonies, Scheib, Moss, & Leonard, 1995).

Receptive and expressive language (if able to assess) tend to be in the average range along with typical articulation, however, narrative length and detail maybe be diminished. Also, pragmatic abilities away from home may appear to be below average (McInnes, Fung, Manassis, Fiksenbaum, & Tannock, 2004). It is important to note that assessments results may need to be interpreted with caution due to responses that may have been influenced by behaviors typified in children with selective mutism (Middendorf & Buringrud, 2009, November).     


It is recommended that the SLP provide treatment as a part of the interdisciplinary team consisting of the child, parents, teacher, slp, and psychologist (Krysanski, 2003). It should be noted that Viana, Beidel, & Rabian (2009) report that literature on the treatment of selective mutism are single case studies with only a small number of controlled trials for the treatment of selective mutism. Behavioral interventions have been shown to be effective and often consists of a combination of different strategies. These include:

  • Contingency management -  positive reinforcement upon verbalization or approximation

  • Shaping - reinforcement provided for approximations then shaped into desired outcome

  • Stimulus fading - upon mastery of each step, gradual increase of the number of unfamiliar individuals in the room as well as approximation to the child

  • Systematic desensitization - relaxation techniques combined with exposure to situations of increased anxiety

  • Self modeling - audio or video recording edited to show the child speaking in settings where the child does not speak

(Amari et al., 1999; Kehle, Madaus, Baratta, & Bray, 1998; Watson & Kramer, 1992)

Additionally, a pilot study on Social Communication Anxiety Treatment (S-CAT) has just been published (Klein, Armstrong, Skira, & Gordon, 2017). Utilizing behavioral and cognitive strategies, the main goal of S-CAT is to reduce a child’s anxiety about speaking and avoidance behaviors as well as reduce enabling parental behaviors. 33 children/families, who sought services at a private clinic, completed the study with a median age of 6.8 years and median age of onset of 2.86 years. By the end of the 9 week treatment, results from the Selective Mutism Questionnaire, a standardized parent questionnaire, indicated that 95% of children showed gains in speaking frequency at school, with unfamiliar people in public settings, and with family friends in the home. Parents also reported their child experienced relief from anxiety and withdrawal, however teachers did not report a decrease. Family compliance was found to be the biggest challenge and achievement. There are limitations regarding external validity since only one therapist provided the interventions. Authors report that the results of this pilot study are strong and future direction includes validating S-CAT as an evidence-based intervention. This study was funded by the Selective Mutism Research Institute.

Ivan Campos, M.S., CCC-SLP, is a pediatric bilingual speech-language pathologist in Southern California. He is cofounder of and serves as Community Engagement Director. He can be reached at

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American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.

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Giddan, J. J., Ross, G. J., Sechler, L. L., & Becker, B. R. (1997). Selective mutism in elementary school: Multidisciplinary interventions. Language, Speech, and Hearing Services in Schools, 28(2), 127-133.

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Klein, E. R., Armstrong, S. L., Skira, K., & Gordon, J. (2017). Social communication anxiety treatment (S-CAT) for children and families with selective mutism: A pilot study. Clinical child psychology and psychiatry, 22(1), 90-108.

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Watson, T. S., & Kramer, J. J. (1992). Multimethod behavioral treatment of long‐term selective mutism. Psychology in the Schools, 29(4), 359-366.

Yeganeh, R., Beidel, D. C., Turner, S. M., Pina, A. A., & Silverman, W. K. (2003). Clinical distinctions between selective mutism and social phobia: an investigation of childhood psychopathology. Journal of the American Academy of Child & Adolescent Psychiatry, 42(9), 1069-1075.