IMFAR 2011: Onset Patterns in Autism: Correspondence Between Home Video and Parent Report

Any omissions or errors are my own contributions. -SR

S. Ozonoff, UC Davis MIND Institute


The study was a collaborative effort between UC Davis’s MIND Institute and the University of Colorado.

We usually think of autism onset in terms of two categories:

  1. Autism symptoms that appear early in life, before 1st birthday, or
  2. A child who loses previously acquired skills after the first birthday

Ozonoff’s study used home videos that were coded using objective methods to see when symptoms were first apparent, and how they unfolded over time.

The study looked at two questions:

  1. Are two categories sufficient to describe onset?
  2. How do home video and parent reports correspond?

For the home video method, parents gave the researchers all home video in which child appeared, from age 6 months through the second birthday.

The researchers focused on four social/communication behaviors:

  1. Eye contact
  2. Social smiles
  3. Joint attention
  4. Language

In some cases, parent reports showed good concordance with videos regarding language loss, but much more moderate concordance with social loss. In other cases, kids didn’t regress — they just weren’t making expected gains.

The reachers actually saw three primary onset trajectory models, not two:

  1. Early onset
  2. Regressive
  3. Plateau — typical levels of social communication level off at 6 months, with no progress over time

The team used a statistical method to show how many trajectories there were, and what their shapes were.

When the statistics were reviewed, two categories appeared insufficient for describing autism onset. Three might be insufficient as well.

Parent reports were very different than video evidence, statistically. Parents were good observers and reporters of their children’s current behavior, but poor reporters of kids’ behaviors in past compared to present behaviors.

Resulting questions:

  1.  Can we improve parent reporting?
  2. Can we come up with other ways to report onset?

We need to make sure we are putting kids into the right group!

SR disclosure: My family participated in MIND Institute studies on autism and regression that included supplying home videos.