Self-Report Tool May Aid Autism Diagnosis

Liam Davenport

August 17, 2015

A novel self-report questionnaire that assesses repetitive behaviors could help clinicians when diagnosing individuals with autism to assess the severity and frequency of such behaviors, new research suggests.

The study results show that individuals with autism score significantly higher than other people on the Repetitive Behaviours Questionnaire–2 (RBQ-2), although a tendency toward repetitive behaviors was observed in neurotypical adults.

"The potential clinical applications of the RBQ-2A [RBQ-2 for adults] include its use as a signposting questionnaire or as a supplement to diagnostic interviews such as the DISCO [Diagnostic Interview for Social and Communication Disorders]," say the investigators.

"Its utility may be especially helpful given that the AQ [Autism-Spectrum Quotient] does not give an adequate or reliable assessment of restricted and repetitive behaviours across typical populations."

The research was published online July 9 in the Journal of Autism and Developmental Disorders.

Repetitive Behaviors More Common

The RBQ-2 was developed from the DISCO and the Repetitive Behaviours Interview and was initially used in the assessment of children and adolescents with autism spectrum disorder.

Responses to 17 of the 20 questions are given on a four-point scale: never or rarely (1), mild or occasional/one or more times daily (2), marked or notable/15 or more times daily (3), and serious or severe/30 or more times daily (4). The three remaining questions are scored on a 3-point scale.

For the current investigation, it was adapted into an adult self-report questionnaire (RBQ-2A) and was examined in two studies. In the first, it was administered to 163 neurotypical UK university students aged 18 to 50 years, alongside the AQ self-report questionnaire.

Two individuals scored higher than the clinical cutoff score of 32 and were excluded. The mean total score among the remaining 161 participants was 1.51 (range, 1.00 - 2.55), although it is noteworthy that at least 14.9% of participants recorded answers of at least "mild or occasional" on each question.

Principal component analysis indicated that two components ― repetitive motor behaviors (RMB) and insistence of sameness (IS) ― accounted for 35.83% of the variance in scores. Importantly, the mean total RBQ-2A score was significantly and positively correlated with mean total AQ score (P < .001).

In the second study, the RBQ-2A was administered to 29 individuals with autism spectrum disorder (mean age, 34.37 years) and 37 neurotypical individuals (mean age, 30.75 years) who lived in Australia. Of the autistic participants, 51.7% were in full- or part-time employment.

Autistic individuals had significantly higher average total scores on the RBQ-2A than neurotypical participants (1.84 vs 1.25; P < .001). RBQ-2A scores were significantly and positively correlated with AQ scores in both autistic individuals (P = .002) and neurotypical participants (P = .01).

Furthermore, the researchers found that autistic participants had significantly higher scores than neurotypical individuals for both the RMB and IS components (P =.001 and P < .001, respectively), with medium and large respective effect sizes. There were no sex differences in scores.

Study author Sue Leekam, DPhil, Cardiff University's chair of autism and director of the Wales Autism Research Center, acknowledged in an interview with Medscape Medical News that the study is "small."

Nevertheless, she said: "It does show that although repetitive behaviors are really quite common in the typical population...they are even more so in those with autism spectrum disorder."

Discussing the clinical utility of the questionnaire, she said: "It's not possible for it to be used as a diagnostic tool because repetitive behaviors are only one of the criteria for autism, and they are also found in other conditions as well."

"What it can be used for, especially once it's been fully trailed and tested, is to supplement the diagnostic process. In other words, it will help clinicians."

Dr Leekham said that the team is currently combining the questionnaire with the DISCO. She explained that it "gives a good range of the different types of repetitive behaviors that an adult might have."

The clinician can then decide how much to probe for further information about those items. "It might help to save a bit of time for the clinician during the clinical process," she added.

She pointed out that the questionnaire has, in various forms, been tested in a number of individuals with autism at different age ranges.

"It always seems that the features fall into these two main groupings of repetitive motor behaviors and what they call insistence of sameness behaviors," said Dr Leekham.

Surprisingly, the current study did not reveal the expected grouping of sensory items with motor behaviors. "We don't quite know the reason for that," she said. "This will be another interesting area to follow up, because sensory symptoms are very common amongst the autism population."

Important Research

Eric Hollander, MD, director, Autism and Obsessive Compulsive Spectrum Program and Anxiety and Depression Program, Albert Einstein College of Medicine, New York City, described the study as a "very worthwhile and important contribution to the literature."

Noting that it may also have an impact in terms of clinical practice, he told Medscape Medical News: "First of all, there's been relatively little work done in adults with autism spectrum disorders, and second, there hasn't been a lot of focus on the restricted and repetitive behavior domain in autism spectrum disorder."

"Much of the research focus has been on the social communication domain, so these are both helpful developments: generating additional work in adults, and then focusing on this target symptom domain."

Dr Hollander explained that the restricted and repetitive behaviors domain is both necessary for an individual to be diagnosed with autism spectrum disorder and an important predictor of whether or not people continue to meet the full criteria for an autism spectrum disorder over time.

He noted that other studies have examined the domain and found the same two components, IS and RMB. He said that the former could be described as wanting things to be the same way and experiencing discomfort owing to deviation from expectations, whereas the latter consists of self-stimulatory types of behavior.

"I think if people are in highly stressful environments where they are bombarded by a lot of sensory input, they may do this as a way to try to gate or decrease the sensory input.

"But I also think that when people are bored and understimulated, then individuals may do these repetitive behaviors to get them up to their optimal level of arousal," Dr Hollander added.

Nevertheless, he said, "we have done some studies that suggested that there were more than just two factors; there were actually four different factors."

"Those factors included obsessive thoughts ― it turns out that adults with autism do have intrusive thoughts or impulses or images and that they are capable of describing them ― and then we found the more typical compulsive behaviors and these self-stimulatory kinds of behaviors."

"We also saw that hoarding was another factor."

For Dr Hollander, one of the important aspects of the questionnaire is that it is self-rated. He said: "Many of the other studies that have been done in children with autism don't ask the questions to the patients, they ask the questions to the parents, and parents have all kinds of different expectations or biases that can influence the parent or caregiver ratings. In fact, one of the things that they showed in these studies, and these are relatively high-functioning adults, is that you can ask them questions.

"It may be that it's not particularly helpful for adults who have severe intellectual disability. They may not be able to do these self-rating scales. But it can be used to try to get a quantitative measure of the severity of the repetitive behaviors in adults with autism.

"It can also be used, I think, in healthy populations or in other patient populations to assess the severity of the receptive behaviors in those individuals as well, and that's helpful," Dr Hollander added.

One coauthor was supported by a joint PhD studentship from the School of Psychology, Cardiff University, and the Economic and Social Research Council. In addition, the second study was partially funded by an APEX Trust for Autism PhD grant. No other relevant financial relatinships have been reported.

J Autism Dev Disord. Published online July 9, 2015. Abstract


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