Child development and milestones practice

A 30-month-old boy is reviewed after the practice nurse completed an Ages and Stages Questionnaire with his mother. He scores below the cut-off for communication and for problem solving; gross motor, fine motor and personal-social are all above the cut-off. He had four episodes of otitis media in his second year, and his grandmother says he "only listens when he is looking at you". He has lost no skills, has no dysmorphic features and his head circumference is on the 50th centile. Which one of the following is the most appropriate next step?