An 18-month-old boy is brought to the office by his mother for a checkup. The patient was born at full term without complications. Growth has been consistently along the 80th percentile for height and weight. The mother reports, "He is healthy and seems happy just playing by himself, but I am concerned about him not talking." She says that he makes some sounds that are unintelligible, has a 1-word vocabulary of "no," and does not yet say "mama," "dada," or "bye-bye." The patient is able to walk and is starting to run. He can scribble and with help can use a spoon to feed himself. On examination, he does not make eye contact, respond to his name, or follow the doctor's gaze when toys are pointed out to him. Hearing testing is normal. Which of the following is the most likely explanation for the patient's behavior?

Question

An 18-month-old boy is brought to the office by his mother for a checkup.  The patient was born at full term without complications.  Growth has been consistently along the 80th percentile for height and weight.  The mother reports, "He is healthy and seems happy just playing by himself, but I am concerned about him not talking."  She says that he makes some sounds that are unintelligible, has a 1-word vocabulary of "no," and does not yet say "mama," "dada," or "bye-bye."  The patient is able to walk and is starting to run.  He can scribble and with help can use a spoon to feed himself.  On examination, he does not make eye contact, respond to his name, or follow the doctor's gaze when toys are pointed out to him.  Hearing testing is normal.  Which of the following is the most likely explanation for the patient's behavior?

Quizplus · Accepted Answer

11ec25c8_d611_5676_bc81_1735c1e477c6_MD0003_00 This child's delayed language development, unresponsiveness to his name, and impaired social communication and interaction are concerning for autism spectrum disorder (ASD). At age 18 months, children should have a vocabulary of approximately 10-25 words, respond to their name when called, and make eye contact and engage in play with others. A key feature of ASD in children this age is the absence of joint attention (ie, spontaneous attempt to share interests with others by eye gazing and pointing at objects). Other signs of autism include insistence on routines, fixated interests (eg, playing exclusively with 1 toy, no interest in others or exploring the world), and repetitive movements (eg, rocking, hand flapping). Language dysfunction in ASD is variable and can range from subtle abnormalities of pitch and odd word choice to absence of functional speech. Language delay without an attempt to compensate through nonverbal means of communication is characteristic of ASD. Management of ASD commonly includes speech therapy, behavioral therapy, educational interventions, and occupational therapy. (Choices B, D, and F) Childhood-onset fluency disorder (stuttering) and speech sound disorder (articulation disorder) are dysfunctions of speech fluency and articulation, respectively. Language disorder is characterized by persistent difficulties in comprehension and production of spoken and written language. These disorders would not explain this patient's impaired nonverbal communication and social deficits. (Choice C) Although differentiating isolated intellectual disability from ASD in young, nonverbal children is often difficult, this patient's deficits in social responsiveness and interaction are more suggestive of ASD. Children with isolated intellectual disability typically exhibit social responsiveness appropriate to their developmental level. (Choice E) Patients with selective mutism have intact verbal and nonverbal communication skills but do not speak in specific settings, typically at school. Educational objective: Impaired development of joint attention is a key feature of autism spectrum disorder in young children. Other possible features include the preference for solitary play, lack of eye contact, and poor response-to-name when called. References: Joint attention interventions for children with autism spectrum disorder: a systematic review and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/26952136) Autism spectrum disorder: primary care principles. (http://www.ncbi.nlm.nih.gov/pubmed/28075089) Joint attention revisited: finding strengths among children with autism. (http://www.ncbi.nlm.nih.gov/pubmed/26148983)

An 18-Month-Old Boy Is Brought to the Office by His