Logan was a 7-year-old boy referred to our clinic by his mother because of problems with hyperactivity and stereotyped behaviors at home and school. Logan was diagnosed with Fragile X syndrome at the age of 3 years and attended a special-needs preschool for children with neurodevelopmental disorders. This year, Logan began first grade at his local public school and attends most regular classes with the help of a classroom aide. Logan reached developmental milestones at a much slower pace than other children his age. Most notably, he showed marked delays in fine and gross motor skills and generally poor muscle tone and coordination. He was very slow to develop receptive and expressive language and, even today, speaks in simple sentences. His speech is often perseverative and tangential; he often repeats words, phrases, and sounds. Logan was initially diagnosed with global developmental delay. Genetic testing later confirmed the existence of Fragile X. Results of cognitive testing at the beginning of first grade showed that Logan's FSIQ was approximately 50. He showed relative strengths on tasks assessing visual-spatial processing and rote memory, but relative weaknesses on tasks measuring verbal abilities, abstract reasoning, and attention, even compared to other children at his developmental.

1. Logan has Fragile X syndrome. Can he also be diagnosed with intellectual disability? If he meets diagnostic criteria for autism spectrum disorder (ASD), can he also be diagnosed with that condition, too?
2. Why was Logan diagnosed with global developmental delay as a toddler?
3. Logan displays stereotypies, especially when overaroused. What other challenging behaviors are sometimes shown by children with intellectual disability?
4. Do Logan's weaknesses in verbal abilities, abstract reasoning, and attention support the similar structure hypothesis?
5. What causes Fragile X syndrome?
6. Why are girls much less likely than boys to show Fragile X syndrome?
7. Imagine that you want to observe Logan's behavior at school in order to record the number of times he flaps his hands in a given class period. What method of observation might you use to record this frequency?
8. If you were Logan's parent or classroom aide, how might you use positive reinforcement to help him keep his hands at his side and reduce hand flapping?