Atypical selective mutism in the context of sibling rivalry: an early childhood case report

Introduction

Selective mutism (SM) is a disorder characterized by a persistent failure to speak in specific social situations where speech is expected, despite the individual possessing developmentally appropriate language comprehension and the ability to speak comfortably in secure environments (e.g., at home). With a prevalence of under 1% in the general population, it is observed more frequently in females. If not intervened upon early, this condition severely impairs social and academic functioning. It is frequently accompanied by anxiety disorders, most notably social anxiety disorder. This case report presents an early childhood SM patient exhibiting atypical clinical features, including intermittent periods of mutism even with his parents.Informed consent was obtained from the family for this poster presentation.

Case Presentation

A 3-year-and-9-month-old male patient was applied to the pediatric emergency department with his mother due to an inability to speak that had been ongoing for 12 hours. Prior to this acute presentation, the patient communicated verbally in a developmentally appropriate manner using 3-to-4-word sentences. However, he had recently been experiencing day-to-day fluctuating periods of mutism at home lasting up to 5-6 hours, followed by a sudden return to normal communication.

During the initial outpatient evaluation, the patient remained mute but maintained eye contact, participated in play, and actively utilized non-verbal communication. He was well-adjusted with peers at daycare but refused to speak to his teacher. The Denver II Developmental Screening Test revealed that his personal-social, fine motor, gross motor, and language skills were consistent with his chronological age.

Significant sibling rivalry was noted regarding his 1.5-year-old younger brother. Notably, prior to the mutism episodes, the patient told his parents, “I became a baby too, I cannot speak.” Additionally, the mother exhibited a highly anxious demeanor during clinical interviews. Pediatric neurology examinations conducted to rule out organic etiologies, such as acquired aphasia and Landau-Kleffner Syndrome, revealed no underlying pathology.

Diagnosed with atypical SM without identifiable comorbidities, the patient was referred for play therapy after comprehensive psychoeducation was provided to the family. Interventions focused on regulating mother-child interactions within the context of sibling rivalry. During follow-up appointments, the patient began initiating communication with the clinicians.

Discussion and Conclusions

SM is a multifactorial disorder emerging from the reciprocal interaction of temperamental traits, genetic predispositions, neurodevelopmental factors, and environmental influences. Although the family history lacked a diagnosed anxiety disorder, the mother’s highly anxious attitude likely impacted the child’s stress tolerance and exacerbated SM symptoms. While literature frequently reports SM cases rejecting communication with authority figures, the intermittent mutism toward parents in this case highlights the condition’s clinical heterogeneity.

The paroxysmal episodes of speech loss following typical language development necessitated the meticulous exclusion of organic syndromes, such as Landau-Kleffner Syndrome. In conclusion, early childhood SM can exhibit atypical fluctuations influenced by psychosocial stressors, such as the birth of a sibling. The careful exclusion of organic etiologies combined with holistic, multidisciplinary interventions addressing family dynamics holds significant potential to improve the clinical course.

References

Ercan ES, Bilaç Ö, Perçinel Yazıcı İ. Çocuk ve Ergen Psikiyatrisi 1. Cilt. Akademisyen Kitabevi;2020. s.397-406