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Regression in Autism: What We Know

Posted by National Autism Network , in Autism Awareness, Research and Autism 17 March 2016 · 1,447 views

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Regression in Autism: What We Know New evidence has revealed a “near universal” truth about an aspect of autism that has traditionally been a highly debated topic in the field. We are referring to the presence of regression, or a loss of skills, in autism. There are anecdotal reports from parents about children who seemingly develop typically for the first years of life only to quickly shed their learned skills.  A prominent example is that of Life, Animated author Rob Suskind and his son Owen, who at around three years of age, in the words of his father, “became mute. He suddenly didn’t sleep or eat, and cried inconsolably.”1  Parent reports such as these have traditionally been highly controversial in the field of autism, but new evidence on regression and autism makes “clear that researchers no longer doubt parent reports of the heartbreaking loss of language and social skills seen in some young children with the disorder.”2 Infamously, the idea that regressive skills in autism are linked to vaccines was due to Andrew Wakefield’s now retracted and debunked 1998 study which concluded the MMR vaccine was the root cause of a loss of skills seen in 8 out of the 12 children within the study.3  While the link between vaccines and autism has been wholly disproven, the idea that typically developing children can experience some form of regression, whether it is the subtle loss of mastered skills over a long period of time or the more controversial and incredibly rare dramatic loss of skills in a matter of weeks, is alive and well. In fact, recent research has strengthened the evidence for regression in autism, but suggests the loss of skills are normally less dramatic than parent reports would indicate and are thought to be a result of processes within the developing brain, rather than stemming from influential environmental factors. These new findings also indicate regression occurs over a long period of time (several months) and influences a great percentage children on the spectrum.4 This article will briefly explore the history of how researchers viewed regression in autism and the recent work that has caused the autism community to rethink its view on regression.

A Brief History of Regression in Autism
A loss of skills has been associated with developmental disorders decades before the term “autistic” was coined in the 1940’s. In 1908, Theodor Heller first described dementia infantilis, which “requires that a typically developing child over 2 years of age undergo a severe and mostly irreversible regression of developmental gains, including speech, sociability and self-help skills.”5 Most recently, these symptoms were used to describe a rare disorder known as childhood disintegrative disorder, which made its introduction into the DSM-IV in 1994 only to be absorbed under the umbrella term “Autism Spectrum Disorder” in the most recent edition of the DSM.6-7 While childhood disintegrative disorder was rare, some researchers believe there is enough evidence to identify CDD as a specific subset of autism.7 A 2012 article discussing the removal of CDD from the DSM-V states that “childhood disintegrative disorder represents a process sufficient to cause autism, but that it is different from the mechanism that leads to autism in children without regression… doing away with a separate diagnosis of childhood disintegrative disorder would hinder research efforts into better understanding autism.”5 Although the committee felt there was a lack of evidence to justify CDD as a separate diagnostic category in the DSM-V, there is evidence of children who have undergone dramatic regression at around their 3rd birthday or later, but thankfully it is rare, with the Autism Program at Yale estimating that 1-2 children per 100,000 meet the definition for CDD.8 While the onset of regression in autism passed the age of 3 is rare, research has found that “toddlers who abruptly lose language, social, or other developmental skills are more likely to have severe autism a few years later compared with children who have consistent delays from an early age.”9 A 2010 study conducted by the Interactive Autism Network (IAN) drew from online surveys of parents of 2,720 children with autism, and specifically found that “nearly 30 percent of children who regress never attain conversational speech” and that “at school, nearly 70 percent of children who regress are placed in special education groups, and 56 percent need a professional aide.”9 However, like many findings regarding autism, these results contradict earlier research findings which indicate “at 3-4 years of age, children with autism with early vs. late onset of symptoms, and with vs. without a history of loss of skills (regression) were not found to differ on standardized tests of verbal and nonverbal IQ and observational measures of autism symptom severity.”10 A 2011 study mirrors these findings.

The previously mentioned IAN study utilized the categorical system developed by Sally Rogers of USC M.I.N.D. Institute, which breaks down autism into three patterns of onset:11

1.    No period of typical development- Autism symptoms are present from birth
2.    Developmental plateau-  Child begins to reach developmental milestones and then stops acquiring new skills
3.    Regression- Child loses skills

Until recently, the percentage of children thought to experience regression in autism has varied, from 13 to 50 percent of all autism cases exhibiting hints at regression.12 A 2010 examination of regression in autism by the Interactive Autism Network determined regression, which was defined as “previously acquired social, communication, or cognitive skills prior to 36 months,” was apparent in 44% of cases.13 However, a recent NIH workshop held in February titled “Loss of Skills and Onset Patterns in Neurodevelopment Disorders: Understanding the Neurobiological Mechanisms” presented evidence that led to the consensus that “regression may represent a near-universal aspect of autism that can affect far more developmental skills than just speech.”2

Research has shown that despite parent reports insisting on a total loss of skills, most the children who undergo a regression of skills “do not have typical development to begin with. Instead, they have early delays and lose some of the skills they had attained.”14 A 2013 study came to this conclusion when they measured skill attainment and loss through “15 socio-communicative items” and found that “regardless of how many skills were developed, the loss of all skills was uncommon, occurring among only 6% of children with [autism].”15 It has been suggested that the primary reason for parents perceiving their child has suffered dramatic and sudden regression is that they are not attuned to the developmental trajectory that accompanies many skills. For example, a skill such as speaking is dependent upon the acquisition of information typically gained in the first year of life, but speech itself usually fails to become apparent until age 2. Parents may fail to notice this trajectory because “if language development is impaired during the first year, a child’s difficulties may not be apparent until the age at which he or she is expected to talk. What presents as a dramatic decline in behavior may actually be a reflection of accumulating abnormal neurobiological functioning, rather than a sudden change.”16 Others have suggested that these children weren’t using language as a communicative tool at all, but they were merely echoing sounds they heard from their parents.17 A 2010 study hints at the notion that parents underestimate regression as researchers recorded a “17 percent regression rate as reported by parents, [but] found that 86 percent of the children showed a decline social skills.”12 Interestingly, a study published in 2013 found regression occurs on average at 1.78 years of age, which coincides almost precisely with the average age of development for speech in children.18 Moreover, evidence from imaging studies suggest that changes in brain development coincide with observable behavioral changes which means “the onset of symptoms that parents are seeing with regression seems to be happening in parallel with the changes in brain development.”4

The Origins of Regression
For years, researchers have been searching for biomarkers that suggest autistic regression could be a distinct subgroup of autism, but have mostly been met with “dozens of contradictory behavioral, physiological, and genetic studies [that] have left the field no closer to finding the answer.”17 However, recent presentations at the international workshop on regression in February are shedding light on potential underlying mechanisms involved in regression and autism. Unlike some past studies which defined regression mainly “as loss of speech without including broader acquisition or loss of other socio-communicative factors,” researchers from the recent workshop suggest regression can affect far more developmental skills than just speech, and “can take the form of subtle losses in motor skills and attention to social cues.”2, 15 Kasia Chawarska, a baby sibs researcher with the Yale Child Study Center and presenter at the February workshop on regression, suggests that “If one looks just at loss of language in toddlers, then regression is evident in about 15 percent of children with autism… But if one looks broadly at other areas of development and at younger children who are not yet speaking, then regression becomes evident in at least 80 percent of children who have autism or will go on to be diagnosed with it.”2

A 2004 study aimed to identify the factors involved in the etiology of regressive autism by evaluating 82 children with autism but found that the “results confirmed previous findings of minimal differences in child characteristics, family history, prenatal and perinatal factors, developmental concerns, behavioral concerns, and medical findings in children who regress.”19 A 2006 study attempted to link genetics with an increased risk of regression in ASD but the “genetic linkage study show[ed] that multiplex families – those with two or more children with autism – are no more likely than average to share genes that had been previously linked to regression.”17 Other studies have linked regressive skills in autism to GI issues. A small study published in 2013 focused on dendritic cells, which play a particularly powerful role in the immune response to microorganisms, and found that “children with ASD had significantly more dendritic cells than did typically developing toddlers. Higher levels of one type of dendritic cell (plastmacytoid) related to developmental regression…This later-onset pattern also related to enlargement of the amygdala. Previous studies have likewise linked enlargement of this brain structure with autism.”20 In fact, one of the first publications from the Autism Phenome Project came in the form of a preliminary study that found that “larger brains may be associated with regressive autism, but only in boys.”21 The findings that brain overgrowth is linked to regression were substantiated by presenter Jason Wolff at the aforementioned international workshop as he discussed a study which utilized brain imaging techniques to find an association of “regressive autism with overgrowth of the brain in the first year of life. Often, this period of overgrowth is followed by a marked slowing of growth so that the brain ends up smaller than average by age 3.”2 A presentation from Annette Karmiloff-Smith during the same workshop on regression also points to the developing brain as a potential cause for regression as the loss of skills in autistic regression may stem from too much of the otherwise normal pruning away of excess brain connections during early brain development.2  In her own words she explains that their “hypothesis is that in autism spectrum disorder, there’s an imbalance between the strengthening and pruning away of brain connections. It may be that the threshold is very high for pruning. So that [the brain] prunes away not just the weak connections but also the connections that should be strengthened.”2 However, even Karmiloff-Smith admits that more research needs to be done to determine if “overaggressive pruning” of brain connections is indeed behind regression in autism.2 Others have suggested in most cases “changes in development and loss of specific skills are occurring over an extended period of time. So we should likely be focusing on processes that influence brain development over time.”4 These studies were conducted utilizing baby siblings, which are an invaluable asset to the autism research community. Baby siblings can provide strong scientific evidence related to ASD because “autism tends to run in families, around one in four baby sibs will develop autism by age 3. Another one in five will develop some autism symptoms, though not to the degree that brings a diagnosis of autism.”2 By studying baby sibs, researchers hope to unlock the mysteries of autism, including the prevalence of regression in autism, its underlying mechanisms, and how loss of skills can be prevented in the first place.

This article strives to bring its readers a complete picture of regression in autism and how the phenomenon has been viewed by the researchers within the autism community over the years. However, the picture still remains incomplete, even to researchers. It seems that researchers now agree that regression typically takes place over a period of significant time, rather than just a few weeks, and can take several subtle forms. Based on this information, it is recommended pediatricians not only look to detect the red flags associated with autism during pediatric checkups, but also discuss how the child’s skills are developing between appointments and if there is developmental slowing.4 Those who are interested in exploring regression and autism further should check out the resources below which link to many of the studies or summaries of the studies referenced within this article. The details found within these resources will provide readers with important background information, an idea of potential future research studies focusing on regression, and insights on aspects of regression not discussed in this article, such as the relationship between regressive autism and race.

Resources:
  • IAN Research Report #6: Regression- This is a breakdown of regression in autism from the Interactive Autism Network. The article includes findings from members of their own community with regards to their experience with regression within their children.  
  • Spectrum: Regression- Rather than list each article out one-by-one, this links to Spectrum’s search results for “Regression.” There are over 50 results, but the first dozen or so studies are the most relevant to the topic of regression.


References:
1.    “Life, Animated: A Story of Sidekicks, Heroes, and Autism.” Ron Suskind. (blog). Accessed March 15, 2016. http://ronsuskind.co.../life-animated/.
2.    “Researchers Say Regression in Autism Common, Variable, Maybe Universal.” Autism Speaks, Inc. February 22, 2016. Accessed March 15, 2016. https://www.autismsp...maybe-universal.
3    “Autism and Vaccines.” National Autism Network. May 23, 2012. Accessed March 15, 2016. http://nationalautis...d-vaccines.html.
4.    “New Findings on Regression in Autism: A Researcher’s Perspective.” Autism Speaks, Inc. Accessed March 15, 2016. https://www.autismsp...ers-perspective.
5.    Pelphrey, Kevin and Westphal, Alexander. “In Defense of Childhood Disintegrative Disorder.” Spectrum, April 3, 2012. Accessed March 15, 2016. https://spectrumnews...ative-disorder/.
6.    Charan, Sri Hari. “Childhood Disintegrative Disorder.” Journal of Pediatric Neurosciences 7, no. 1 (Jan-Apr 2012): 55-57. http://www.ncbi.nlm....les/PMC3401658/.
7.    Wright, Jessica. “Rare Regressive Disorder is Not Autism, New Findings Suggest.” Spectrum, May 15, 2015. Accessed March 15, 2016. https://spectrumnews...ndings-suggest/.
8.    “Childhood Disintegrative Disorder.” Yale School of Medicine. Accessed March 15, 2016. http://medicine.yale...mation/cdd.aspx.
9.    DeWeerdt, Sarah. “Dramatic Regression Leads to Severe Autism, Study Finds.” Spectrum, August 3, 2010. Accessed March 15, 2016. https://spectrumnews...sm-study-finds/.
10.   Werner, E., Dawson G., Munson J., and Osterling J. “Variation in Early Developmental Course in Autism and Its Relation with Behavioral Outcome at 3-4 Years of Age.” Abstract. Journal of Autism and Developmental Disorders 35, no. 3 (June 2005): 337-50. http://www.ncbi.nlm....pubmed/16119475.
11.   “IAN Research Report #6: Regression.” Interactive Autism Network (IAN). June 27, 2008. Accessed March 15, 2016. https://iancommunity...report_jun_2008.
12.   Borthwick, Lindsay. “Regression May Mark One-Third of Autism Cases.” Spectrum, September 27, 2016. Accessed March 15, 2016. https://spectrumnews...f-autism-cases/.
13.   Lustig, Megan. “Study Provides New Insights into the Implications of Autism Onset Patterns.” Kennedy Krieger Institute. April 20, 2010. March 15, 2016. http://www.kennedykr...-onset-patterns.
14.   Richler, Jennifer. “Could a 3-Year-Old Just “Disappear?”” Slate, March 24, 2015. Accessed March 15, 2016. http://www.slate.com..._disappear.html.
15.   Thurm A, Manwaring SS, Luckenbaugh DA, Lord C, Swedo SE. Patterns of Early Skill Attainment and Loss in Young Children with Autism. Development and psychopathology. 2014;26(1):203-214. doi:10.1017/S0954579413000874.
16.   Jones, Rebecca. “Workshop Report: Regression in Autism.” Simons Foundaion Autism Research Initiative (SFARI). April 17, 2012. Accessed March 15, 2016. https://sfari.org/up...ssion-in-autism.
17.   Hughes, Virginia. “Contradictory Results on ‘Regressive’ Autism Divide Researchers.” Spectrum, May 16, 2008. https://spectrumnews...de-researchers/.
18.   Barger, B.D., Campbell, J.M., and McDonough, J.D. “Prevalence and Onset of Regression Within Autism Spectrum Disorders: A Meta-Analytic Review.” Journal of Autism and Developmental Disorders43, no. 4 (April 2013): 817-28. Accessed March 15, 2016. http://www.ncbi.nlm....pubmed/22855372.
19.   Christopher, J.A., Sears, Lonnie L, Williams, Patricia Gail, and Hersh, J. “Familial, Medical and Developmental Patterns of Children with Autism and a History of Language Regression.” Abstract. Journal of Developmental and Physical Disabilities 16, no. 2 (May 2004): 163-170. Accessed March 15, 2016. https://www.research...uage_Regression.
20.   “Immune Changes Linked to Regression, GI Distress & Repetitive Behaviors.” Autism Speaks, Inc. Accessed March 16, 2016. https://www.autismsp...itive-behaviors.
21.   DeWeerdt, Sarah. “Study Links Brain Size to Regressive Autism.” Spectrum, December 12, 2011. Accessed March 16, 2016. https://spectrumnews...ressive-autism/.