Friday, December 16, 2016

The Gender Gap in Autism: Where are the Girls?

The Gender Gap in Autism: Where are the Girls?

There has been a dramatic increase in reported cases of autism over the past decade. Prevalence rates have risen steadily, from one in 150, to one in 110, and now to one in every 59 children (or 16.8 per 1,000 8-year-olds). According to the CDC's Autism and Developmental Disabilities Monitoring (ADDM) Network, autism is 4 times more common among boys (1 in 37) than among girls (1 in 151). Statistics also indicate that referrals for evaluation of boys are nearly ten times higher than for girls. Moreover, girls are diagnosed with autism at later ages compared to boys. This gender “gap” raises serious questions because many female students with ASD are being overlooked and will not receive the appropriate educational supports and services. 
Why are fewer girls being identified?  Why do parents of girls experience a delay in receiving a diagnosis?  Are there gender differences in the expression of the disorder? Answers to these questions have practical implications in that gender specific variations may have a significant impact on identification practices and the provision of clinical and educational services. Although few studies have examined gender differences in the expression of autism spectrum disorders, we do have several tentative explanations for the underdiagnosis and late identification of girls with ASD. They include the following. 
  • Social communication and pragmatic deficits may not be readily apparent in girls because of a non-externalizing behavioral profile, passivity, and lack of initiative. Girls who have difficulty making sustained eye contact and appear socially withdrawn may also be perceived as “shy,” “naive,” or “sweet” rather than   having the social impairment associated with an autism spectrum disorder.
  • The diagnosis of another disorder often diverts attention from autism-related symptomatology. In many cases, girls tend to receive unspecified diagnoses such as a learning disability, processing problem, or internalizing disorder. A recent survey of women with Asperger syndrome indicated that most received a diagnosis of anxiety or mood disorder prior being identified with an autism spectrum disorder.
  • The perseverative and circumscribed interests of girls with autism spectrum disorders may appear to be age-typical. Girls who are not successful in social relationships and developing friendships might create imaginary friends and elaborate doll play that superficially resembles the neurotypical girl.
  • Although Students with ASD are more likely to be the target of bullying than typical peers, this may not be recognized in girls due to gender differences in preferred modes of aggression. For example, girls may use covert verbal, social, and psychological forms of aggression while boys tend to rely on confrontational and direct modes of bullying. As a result, the more subtle nature of relational and indirect aggression (social exclusion and rejection) used by girls may be taken less seriously than the more obvious, direct aggression exhibited by boys.
  • Although girls may appear less symptomatic than boys, the genders do share similar profiles. Research suggests that when IQ is controlled, the main gender difference is a higher frequency of idiosyncratic and unusual visual interests and lower levels of appropriate play in males compared to females. As a result, the behavior and educational needs of boys are much more difficult to ignore and are frequently seen by teachers and parents as being more urgent, further contributing to a referral bias.
  • Over reliance on the male model with regard to diagnostic criteria might contribute to a gender “bias” and underdiagnosis of girls. Clinical instruments also tend to exclude symptoms and behaviors that may be more typical of females with ASD. For example, assessment instruments such as the Autism Spectrum Rating Scales (ASRS) and Social Responsiveness Scale (SRS) have generally reported higher mean scores for boys than girls. The lower symptom scores for girls may reflect gender differences and expression of the phenotype. Recent research suggests that certain single test items may be more typical of girls than of boys with ASD, and examining symptom gender differences at the individual level might lead to a better understanding of the gender difference in ASD.
  • Apart from biases in reporting or diagnosis, there is significant evidence to suggest that multiple biological factors contribute to the sex differences seen in autism. These include genetic and hormonal differences between males and females that may provide a “protective” mechanism for girls and lead to differences in symptoms and vulnerability to the disorder.
If girls do process language and social information differently than boys, then clinical and educational interventions based largely on research with boys may be inappropriate. As a result, girls may receive less than optimal academic and behavioral interventions. If gender specific variations do exist, then the predictive validity of the diagnosis and developmental course may well differ between the sexes. Unfortunately, the consequences of a missed or late diagnosis can result in social isolation, peer rejection, lowered grades, and a greater risk for mental health and behavioral distress such as anxiety and depression during adolescence and adulthood. As a result, there is an urgent need for research to compare girls with ASD to typical boys and girls to more fully comprehend the implications of being a girl on the autism spectrum. 

Best practice recommends that when a girl presents with a combination of social immaturity, restricted interests, limited eye gaze, repetitive behaviors, social isolation, and is viewed as “unusual” or “different” by parents, teachers and peers, the possibility of an ASD should be given consideration. Clinicians and school-based professionals might also question the presence of ASD in girls referred for internalizing disorders such as anxiety or depression. 

Best practice assessment and intervention guidelines are available from: A Best Practice Guide to Assessment and Intervention for Autism Spectrum Disorder in Schools (2nd ed.) and Autism Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and Intervention in Schools. 
Adapted from Wilkinson, L. A. (2016). A best practice guide to assessment and intervention for autism spectrum disorder in schools. London and Philadelphia: Jessica Kingsley Publishers.

Lee A. Wilkinson, PhD, NCSP is a licensed and nationally certified school psychologist, chartered psychologist, registered psychologist, and certified cognitive-behavioral therapist. He is also a university educator and trainer, and has published widely on the topic of autism spectrum disorders both in the US and internationally. Dr. Wilkinson is author of the award-winning books,  A Best Practice Guide to Assessment and Intervention for Autism and Asperger Syndrome in Schools and Overcoming Anxiety and Depression on the Autism Spectrum: A Self-Help Guide Using CBTHe is also editor of a best-selling text in the APA School Psychology Book Series, Autism Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and Intervention in Schools. His latest book is A Best Practice Guide to Assessment and Intervention for Autism Spectrum Disorder in Schools (2nd Edition)

Wednesday, December 7, 2016

Assessment Tools for ASD: Sensitivity Matters


Evidence-based assessment requires using instruments with strong reliability and validity for the accurate identification of children’s problems and disorders, for ongoing monitoring of children’s response to interventions, and for evaluation of the outcomes of intervention. These procedures must also have demonstrated effectiveness in diagnosis, clinical formulation, intervention planning, and outcome assessment. 

Professionals should have an understanding of the basic psychometrics properties that underlie test use and development when assessing children and youth for autism spectrum disorder (ASD). For example, diagnostic validity is an especially important psychometric characteristic to consider when evaluating the quality and usefulness of a screening instrument or more comprehensive measure. It refers to a test’s accuracy in predicting group membership (e.g., ASD versus non-ASD) and can be expressed through metrics such as sensitivity and specificity, and positive predictive value (PPV) and negative predictive value (NPV). 

Sensitivity and specificity are measures of a test's ability to correctly identify someone as having a given disorder or not having the disorder. Sensitivity refers to the percentage of cases with a disorder that screens positive. A highly sensitive test means that there are few false negative results (individuals with a disorder who screen negative), and thus fewer cases of the disorder are missed. Specificity is the percentage of cases without a disorder that screens negative. A highly specific test means that there are few false positive results (e.g., individuals without a disorder who screen positive). False negatives decrease sensitivity, whereas false positives decrease specificity. An efficient screening tool should minimize false negatives, as these are individuals with a likely disorder who remain unidentified. Sensitivity and specificity levels of .80 or higher are generally recommended.  

Positive Predictive Value (PPV) and Negative Predictive Value (NPV) are also important validity statistics that describe how well a screening tool or test performs. The probability of having a given disorder, given the results of a test, is called the predictive value. PPV is interpreted as the percentage of all positive cases that truly have the disorder. PPV is a critical measure of the performance of a diagnostic or screening measure, as it reflects the probability that a positive test or screen identifies the disorder for which the individual is being evaluated or screened. NPV is the percentage of all cases screened negative that are truly without the disorder. The higher the PPV and NPV values, the more efficient the instrument at correctly identifying cases. It is important to recognize that PPV is influenced by the sensitivity and specificity of the test as well as the prevalence of the disorder in the sample under study. For example, an ASD-specific screening measure may be expected to have a higher PPV when utilized with a known group of high-risk children who exhibit signs or symptoms of developmental delay, social skills deficits, or language impairment. In fact, for any diagnostic test, when the prevalence of the disorder is low, the positive PPV will also be low, even using a test with high sensitivity and specificity.
© Lee A. Wilkinson, PhD
Lee A. Wilkinson, PhD, NCSP is a licensed and nationally certified school psychologist, registered psychologist, and certified cognitive-behavioral therapist. He provides consultation services and best practice guidance to school systems, agencies, advocacy groups, and professionals on a wide variety of topics related to children and youth with autism spectrum disorders. Dr. Wilkinson is author of the award-winning books,  A Best Practice Guide to Assessment and Intervention for Autism and Asperger Syndrome in Schools and Overcoming Anxiety and Depression on the Autism Spectrum: A Self-Help Guide Using CBTHe is also editor of a best-selling text in the APA School Psychology Book Series,  Autism Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and Intervention in Schools. His latest book is A Best Practice Guide to Assessment and Intervention for Autism Spectrum Disorder in Schools (2nd Edition).

Savant Skills and the Autism Spectrum


What are savant skills?
There is a long history of reports of individuals who despite having severe intellectual impairments, demonstrate remarkable skills in a particular area. The term “savant” has been variously defined as those individuals who show (a) normatively superior performance in an area and (b) a discrepancy between their performance in that area and their general level of functioning. Some researchers have differentiated “prodigious” savants (e.g., individuals possessing an exceptional ability in relation to both their overall level of functioning and the general population) from “talented” savants (e.g., individuals showing an outstanding skill in comparison with their overall level of functioning). 

Savant skills have been reported much more frequently in males than in females and have been identified in a wide range of neurological and neurodevelopmental disorders. The most commonly reported savant skills are mathematical skills (calendrical calculations, rapid arithmetic and prime number calculations), music (especially the ability to replay complex sequences after only one exposure), art (complex scenes with accurate perspective either created or replicated following a single brief viewing) and memory for dates, places, routes or facts. Less frequently reported are “pseudo-verbal” skills (hyperlexia or facility with foreign languages), coordination skills and mechanical aptitude.
Research
Research in the past 10 years has generated some controversy about the actual incidence of savant syndrome in autism. Once thought to be rare in people with autism, found in no more than 1 out of 10 individuals, research over the past few years suggests savant skills may be more common than previous estimates. Although there have been many single case or small group studies of individuals with autism who possess savant abilities or exceptional cognitive skills, there have been few systematic, large-scale investigations in this area. Inconsistencies in definition and wide variation in diagnostic criteria, ages and ability levels of the cases reported are problematic, as is a paucity of valid information on rates of savant skills in ASD. The objective of this research study was to investigate the nature and frequency of savant skills in a large sample of individuals with autism who had been initially diagnosed as children.
The total sample was comprised 137 individuals, first diagnosed with autism as children, who were subsequently involved in an ongoing, longitudinal follow-up study. Cognitive assessments (Wechsler Scales) were completed for all participants (100 males and 37 females) between the ages of 11 and 48 years (mean age of 24). Parental report data on savant skills were obtained approximately 10 years later at a subsequent follow-up.  Cognitive ability ranged from severe intellectual impairment to superior functioning. Savant skills were judged from parental reports and specified as “an outstanding skill/knowledge clearly above participant’s general level of ability and above the population norm.”
Results
Of the 93 individuals for whom parental questionnaire and cognitive data were available, 16 (17.2%) met criteria for a parent-rated skill, 15 (16.8%) had an exceptional cognitive skill and 8 (8.6%) met criteria for both. There were 14 calendrical calculators (one also showed exceptional memory and another also showed skill in computation and music). There were four others with computational skills (in one case combined with memory and in another case with music). Visuospatial skills (e.g., directions or highly accurate drawing) were reported in three individuals. One individual had a musical talent, one an exceptional memory skill and one had skills in both memory and art. The subtest on which participants were most likely to meet the specified criteria for an area of unusual cognitive skill was block design followed by digit span, object assembly and arithmetic.
There was a sex difference (albeit statistically non-significant) in the prevalence of savant skills. Almost one-third (32%) of males showed some form of savant or special cognitive skill compared with 19 percent of females. No individual with a non-verbal IQ below 50 met criteria for a savant skill and contrary to some earlier hypotheses; there was no indication that individuals with higher rates of stereotyped behaviors/interests were more likely to demonstrate savant skills.
Discussion
In total, 39 participants (28.5%) met criteria for a savant skill. Cognitively, 23 individuals (17% of total sample) met criteria for one or more exceptional area of skill on the Wechsler Scales. Combining the two, 37 per cent of the sample showed either savant skills or unusual cognitive skills or both, a far higher proportion than previously reported. These results suggest that the rates of savant skills in autism are significant, particularly among males, and although these estimates are higher than reported by other researchers, the findings parallel those of previous studies. Based on these findings, it appears likely that at least a third of individuals with autism show unusual skills or talents that are both above population norms and above their own overall level of cognitive functioning. It should be noted that these data offer no support to claims that savant skills occur most frequently in individuals with autism who are intellectually challenged or that individuals with higher rates of stereotyped behaviors/interests are more likely to demonstrate savant skills.
Apart from the need for further research examining the underlying basis of savant skills and why certain individuals go on to develop any area of exceptional skill and why these skills encompass such different areas, there is a more practical and pressing question; “how can these innate talents be developed to form the basis of truly ‘functional’ skills?” In the present study, only five individuals with exceptional abilities (four related to math and one related to visuospatial ability) had succeeded in using these skills to find permanent employment. For the majority, the isolated skill remained just that, leading neither to employment nor greater social integration. As the authors conclude, “The practical challenge now is to determine how individuals with special skills can be assisted, from childhood onward, to develop their talents in ways that are of direct practical value (in terms of educational and occupational achievements), thereby enhancing their opportunities for social inclusion as adults.”
Key References

Howlin, P., Goode, S., Hutton, J., & Rutter, M. (2009). Savant skills in autism: Psychometric approaches and parental reportsPhilosophical Transactions of the Royal Society B: Biological Sciences, 364, 1359–1367. doi:10.1098/rstb.2008.0328 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2677586/

Marsa, L. (2016). Extraordinary minds: The link between savantism and autism. https://spectrumnews.org/features/deep-dive/extraordinary-minds-the-link-between-savantism-and-autism/

Treffert D. (2000). Extraordinary people: Understanding savant syndrome. Ballantine Books: New York, NY.

Treffert, D. (2009). The Savant Syndrome: An Extraordinary Condition. A Synopsis: Past, Present, Future. Philosophical Transactions of the Royal Society B: Biological Sciences, 364, 1351–1358.

Lee A. Wilkinson, PhD, NCSP is a licensed and nationally certified school psychologist, registered psychologist, and certified cognitive-behavioral therapist. He provides consultation services and best practice guidance to school systems, agencies, advocacy groups, and professionals on a wide variety of topics related to children and youth with autism spectrum disorder. Dr. Wilkinson is author of the award-winning books,  A Best Practice Guide to Assessment and Intervention for Autism and Asperger Syndrome in Schools and Overcoming Anxiety and Depression on the Autism Spectrum: A Self-Help Guide Using CBTHe is also editor of a best-selling text in the APA School Psychology Book Series,  Autism Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and Intervention in Schools. His latest book is A Best Practice Guide to Assessment and Intervention for Autism Spectrum Disorder in Schools (2nd Edition).




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