Ability of toddlers to recognise TV images. Clinical utility of this milestone is not established.

Editor—Lloyd and Brodie propose that the ability of an 18 month old child to recognise television images may be a useful milestone in the assessment of development.1 Their data derive from the examination of two conditions only: Down's syndrome and normality. To extend the concept to include learning disabilities in general, language disorders, and autism is not necessarily valid. The authors found that their milestone had a high degree of specificity (96%): very few normal children were unable to recognise television images. The sensitivity of the milestone—its ability to detect Down's syndrome—was 81%. One fifth of children with Down's syndrome were not detected. We do not know how sensitive the milestone is to learning disability generally, language disorders, or autism. We cannot assume that the findings with the group of children with Down's syndrome can be generalised. Therefore, the clinical utility of this developmental milestone has not yet been established.