Quick Dips

Birthday Home Videos
in the Service of Science

Suppose that you are concerned with a serious, but relatively rare disorder of childhood. This disorder is suspected to be present from birth, but is rarely sufficiently obvious in its effects to permit a reliable diagnosis before age three to four years. Suppose also that you know that the earlier treatment is begun, the more likely it is that the child will recover.

Clearly, if you can find some reliable predictive symptoms which occur in the first years of life which permit both tentative diagnosis and early treatment to begin, this would be a major development for individuals and families affected by this problem.

The disorder being described is autism, a pervasive developmental disorder marked by intellectual handicap, an extreme lack of responsiveness to other people, gross deficits in language development, and abnormalities of behaviour such as echolalia (repeating words or advertising jingles over and over), extreme perseveration in activities, and stereotyped behaviour (e.g., hand flapping, rocking, whirling). The long-term outlook for autistic children, even when diagnosed in their preschool years and given the benefit of special education services, is not good, and only a minority grow up into something approaching normal adulthood. Most continue to exhibit severe problems in areas of social interaction, intellectual performance, and personal independence.

A growing body of research has, however, shown that if autistic children can be identified early and given intensive behavioural treatment (about 30 hours per week) for two or more years, starting before age 5 (and preferably by 2 or 3 years old) very positive outcomes can be achieved.

About half the children so treated end with IQ scores in the normal range, many are able to attend regular schools, and a large number show substantial improvements in social behaviour and general self-care abilities. Some make such large gains over all areas of functioning that they become indistinguishable from their regular peer group. Catherine Maurice's book Let Me Hear Your Voice: A Family's Triumph over Autism (Knopf, 1993) gives a moving account of how two autistic children were rehabilitated to normality in this way.

In research to date, the best outcomes have been seen with children who began intensive treatment early, at age 2 or 3. The dilemma is that while we need to intervene early for maximum effectiveness, it is difficult to detect those in need of help early enough. We need some way of reliably diagnosing autism in the first two years of life. Since there are no physical or physiological markers of autism -- it cannot be diagnosed by a blood test or CAT scan -- we must look for behavioural symptoms.

One way of doing this might be by recruiting a group of newborn infants and tracking them over their preschool years. The early records of those who subsequently became autistic could be reviewed to see what early signs reliably predicted autism. The problem with this kind of prospective research is that because autism is rare, a huge sample would need to be followed, and this would be very expensive.

An alternative might be to interview parents of newly-diagnosed autistic children to see what they can remember about their child's early behaviour. Interesting although such information is, it is subject to too much bias and memory loss to be satisfactory.

Several researchers have recently realized the potential of family home video recordings for gaining information about the early behaviour of autistic children. Videos made at the child's birthday parties, or other family social occasions involving siblings and other children, provide a window to the past. Even better, the situations where the videos are made are typically social situations, and there is good reason to suppose that abnormalities in social interactions are some of the earliest signs of autism.

Peter Dowrick, a New Zealander now working at Children's Seashore House, a treatment and research facility of the University of Pennsylvania Medical School, and a group of colleagues, have recently coded home videos of 25 children with autism and 25 age-matched children whose development was typical. The videos were made when the children were between 12 and 30 months old. The raters were blind as to the children's diagnosis.

A combination of three social behaviours (e.g., looking at faces) and six communicative behaviours (e.g., says one or more words; shows object to another person) reliably predicted the later diagnosis of autism/pervasive developmental delay. Some of the observed differences in behaviour were very large: on average, typically-developing children used words on 37 occasions given 100 opportunities to do so, autistic children did so 9 times per 100 opportunities. Typical children followed verbal instructions 24 times per 100 opportunities, autistic children 2 times per 100 opportunities. Showing or handing an object to another person was fairly rare for all children, but was never observed in autistic children. Interestingly, in non-social behaviours, where the children were interacting with objects rather than people, there were no differences between diagnostic groups.

Dowrick and his colleagues suggest that a child who by the age of 30 months engages in social behaviour when given the opportunity less than 20% of the time, who almost never attempts to show or hand an object to another child or adult, and who uses words in a social situation less than once per 5 minutes should be very carefully monitored. The parents of such children can also be given the option of beginning early intervention. The predictive validity of these symptoms is not, of course, perfect. However, since early intervention is not likely to be harmful, while delayed intervention may lead to less effective rehabilitation, we can be much more tolerant of false positives (diagnosing possible autism when the child is not) than of false negatives (saying not autistic when the child is).

Neville Blampied, Psychology Department, University of Canterbury