Connected scatterplot of developmental outcome. A General Adaptive Composite (GAC) score of 80–100 was defined as ‘average range’, 70–80 as ‘mild’, 60–70 as ‘moderate’, 50–60 as ‘severe’ and all scores < 50 as ‘profound’ cognitive impairment. Each line represents one individual’s decline in developmental score from the left y-axis (baseline developmental scores on a Likert scale) to the right y-axis (follow-up developmental scores as assessed by GAC standard score).