Doubts about regressive autism

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One of the oldest ideas in autism — as old as the naming of the condition itself — is that it comes in two forms: one present from birth, and one that abruptly emerges in toddlerhood. The latter type, or so the idea goes, announces itself through a rapid loss of skills.

In this classic picture of ‘regression,’ a talkative, curious 2-year-old suddenly withdraws. He grows indifferent to the sound of his name. He begins to speak less than before or stops entirely. He turns from playing with people to playing with things, from exploring many objects and activities to obsessing over a few. He loses many of the skills he had mastered and starts to rock, spin, walk on his toes or flap his hands. It’s often at this point that his terrified parents seek answers from experts.

once-clear boundaries have started to fade. Epidemiological studies have found that anywhere from 15 to 40 percent of autism diagnoses fit the regressive type, with estimates varying wildly depending on how regression is defined. And regardless of the definition, estimates of regression’s prevalence (mainly as measured in the United States) have tended to rise as studies have become larger and more rigorous, Ozonoff says. This variability and expansion have both challenged the prevailing view of regression as an exception.

Today, Ozonoff, professor of psychiatry and behavioral sciences at the University of California, Davis MIND Institute, is one of a growing cohort of researchers who say the simple split between regressive and non-regressive autism is almost certainly wrong. Their proposal, which has gained momentum over the past 15 years, is that researchers and clinicians should retire the division for good.

“I think most kids with autism lose some skills, but how many they lose — and when they lose and what they lose — varies across kids,” says Catherine Lord, director of the Center for Autism and the Developing Brain at New York-Presbyterian Hospital in New York City. “I think classifying them as regressive or non-regressive is a waste of time and a misnomer.”

The strength of these early signs varies, and they’re often subtle, but they show up in multiple domains, from movement and eye-gaze patterns to language responses and social interactions. Regression should be seen not as an event but as a process — occasionally sudden but usually protracted, Katarzyna Chawarska, a researcher at the Yale Child Study Center, said at the meeting. Trying to separate the children who regress from those who don’t, she said, “can be like drawing a line in the sand” — an unreliable marker in shifting terrain.

Chawarska’s view echoes the findings of numerous studies that reveal a “range of onset patterns,” as University of Melbourne autism researcher Amanda Brignell and her colleagues explain in a 2016 paper, from ‘early onset’ (early developmental delays, no loss of skills) and ‘delay and regression’ (some early delays, then loss) to ‘plateau’ (no early delays and no loss, but a failure to gain) and ordinary ‘regression’ (no delays before a clear loss). These trajectories differ so much in their timing, speed, depth and effects that it requires a tangle of words and parentheticals to try to squeeze them into a binary framework.

Given all this, Ozonoff argues, we should speak not of regression, but of a variety of onsets: The true clinical picture of how autism begins to present is not two-tone or even spectral, but a complex kaleidoscope of possibilities. “I don’t even call it regression anymore,” she says. “I just think of it as onset: how symptoms start.”

fter 70 years of autism research, there is still no clear definition of what regression is. Psychologists Brian Barger and Jonathan Campbell have wrestled with this problem energetically over the past few years, combing through more than 100 studies. They have concluded that the literature on regression is “without a central conception” and has “no universally agreed-upon central definition.”

They and many others say that these sorts of definitional and measurement problems may mask regression’s true prevalence. Regression may be the norm in children with autism, says Campbell, professor of psychology at the University of Kentucky. “I think you have operational definitional problems. You have measurement problems. And the phenomenon itself is difficult,” he says. “[Regression] might be part of a larger, normal development process. Maybe it’s not specific to autism; maybe there are more kids that go through losses and delays and spurts.”

One challenge in spotting autism’s onset is what scientists call the streetlight effect: the human tendency to look for things where we can most easily see them (whatever’s visible beneath the proverbial lamppost) even though what we seek may lie elsewhere, off in the proverbial dark.

In the case of regression, researchers and parents both tend to focus on language, which usually appears (and sometimes regresses) in the second year of life. But when they focus too much on this one ability, as important as it is, they may overlook or forget gains or losses made earlier in less noticeable areas, such as sensory and motor skills.

The study’s key finding was that at 6 months of age, the children who would later be diagnosed with autism showed subtle but distinctive sensory and motor characteristics that had gone unnoticed. These signs showed up in areas that standard autism screenings don’t assess, and most parents and even professionals might miss them in the absence of other difficulties. The Autism Observation Scale for Infants (AOSI), for instance — which focuses on eye gaze, visual tracking, imitation and other early social-communicative behaviors — picked up no significant differences among the four groups at 6 months. And at 12 months, this same screen detected subtler autism traits only in the group ultimately placed in the ‘severe’ group at 24 months.

final but central problem in the regression literature is its heavy reliance on retrospective studies — those that depend on reconstructing events, rather than observing them as they occur. In these studies, researchers ask parents of a child who’s already been diagnosed or evaluated for autism to remember their child’s development, highlighting any noticeable loss of skills. If the parents recall a typical course of development that suddenly hit a snag, the researchers might deem the child’s autism onset regressive. It’s only during the past decade or so that Ozonoff and others have used prospective studies or home videos to check parent recall. Their work has shown that parents’ memories, like most human memories, can be astoundingly unreliable.

People tend to misremember things such that they fit their current impressions or beliefs — a form of confirmation bias. As a result, they may remember a troublesome teen as a more ornery toddler than she really was, or forget that an agreeable 10-year-old was, at 2, impossibly impossible. Asking parents to remember the progress of a child showing signs of autism is especially perilous.

This illusion may be further magnified by something called the telescoping effect: The more time that passes after a significant event occurs, the more likely a person is, in remembering that event, to move it forward in time. That is, memory draws distant events closer, like a telescope focused on a distant object.