Prevalence of Autism


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Something happened between now and the eighties alright. Something that can definitely account for the increase in prevelance. Simply put – the criteria changed. What constituted autism changed between the eighties and now. Changed drastically. Changed so much in fact that a lot of diagnosticians doubt that Hans Asperger would recognise what is now considered to define Aspergers Syndrome, changed so much that people who were once thought of as AS would be today diagnosed as autistic.
Kevin Leitch
The apparent increase in the number of children with autism has levelled out after peaking in 1992, reports a UK cohort study published last week. The results show that the rise in the number of cases reported previously may have been due to greater awareness of autism and to changes in diagnostic criteria, and the plateau in the prevalence of autism provides further evidence against an association with the MMR vaccination.
Susan Mayor, British Medical Journal
My point, I guess, is that there are so many of us out there, and we are so similar yet so different. Those close to me tease me frequently, saying that I see aspies everywhere, like gay people see gay people everywhere. I get the teasing, mildly sarcastic, "Of course, everyone's an aspie, I'm an aspie, you're an aspie, everyone's an aspie!" Are they? (Sly grin.)
Aspieprincess
The decade of the 1920's may have been the age of jazz, the age of sports, and the age of prohibition, but I don't think it was the age of autism. I think it is unlikely that some genetic mutation suddenly occurred then. I think that social and economic conditions are the cause of the autism "epidemic."
Anne Bevington
Despite heightened media attention on the autism "epidemic," a report published in the July issue of Current Directions in Psychological Science offers three arguments against a true increase in autism prevalence. These include changes in diagnostic criteria for autism, with current criteria being more inclusive than when the diagnosis was first defined in the 1940s; methodological flaws in an unpublished California study widely cited as showing dramatically increased prevalence; and problems in using the U.S. Department of Education's annual "child count" data.
Laurie Barclay, Medscape
espite heightened media attention on the autism "epidemic," a report published in the July issue of Current Directions in Psychological Science offers three arguments against a true increase in autism prevalence. These include changes in diagnostic criteria for autism, with current criteria being more inclusive than when the diagnosis was first defined in the 1940s; methodological flaws in an unpublished California study widely cited as showing dramatically increased prevalence; and problems in using the U.S. Department of Education's annual "child count" data.
Laurie Barclay, Medscape
The changing criteria can make it look like the experts can’t make up their minds. I view the changes as a sign that our understanding of autism is evolving. We now recognize that autism presents itself in a variety of ways. We also recognize that these different manifestations are related to one another. Thirty years ago we didn’t recognize the similarities between a child that was highly verbal, intensely focused on a special interest, and prone to trantrums may have many things in common with a non-verbal child who appears aloof to those around them. Now we do and the benefits to both are huge.
Along the Spectrum
There is a levelling off in the number of autism cases since the early 1990s. Neither this nor the previous increase was related to any change in the rate of MMR vaccination. MMR vaccination was mentioned by a small proportion of all parents (less than 2%) as a possible trigger, but that increased after the 1997 MMR scare. Age at diagnosis has decreased, suggesting changes in diagnostic practice.
Bandolier
What's good, and what's not good, in the world of autism treatment and research? What is good and bad in media coverage of autism and the lives of autistics? Autism Diva rates it.
oddizm
A legal case in Nebraska shows the dangers in creating a government-mandated dragnet that can subject all sorts of children to hours of disagreeable, ineffective or even counterproductive treatment for something they do not have.
Thomas Sowell
Autism is a National Emergency. Because of the tremendous increase we have reported, it is a serious epidemic.
F. Edward Yazbak
Children may not die from Autism or other Pervasive Developmental Disorders, but the cost in medical care, broken families, reduced quality of life and educational resources is so staggering that its impact can barely be comprehended.
Floyd Tilton
An exchange of correspondence with the U.C. Davis M.I.N.D. Institute about autism, vaccinations and "epidemics," and a reply from its Director, who confirms the inappropriateness of the use of "epidemic" to describe autism prevalence.
Kathleen Seidel, neurodiversity.com
Lorna Wing, a veteran autism researcher at the Institute of Psychiatry in London, agrees. In the 1970s she spent a lot of time working with special-needs children in the London district of Camberwell. Wing reckons that at the time, fewer than 10 per cent of autistic children were correctly diagnosed. She also thinks that prisons and institutions are full of autistic adults labouring under wrong diagnoses such as treatment-resistant schizophrenia or ADHD. Ultimately, however, it may be impossible to tell whether there has been a genuine rise in the incidence of autism over the past 30 years. "There is no clear evidence that there has been an increase, but there's no proof that there hasn't," says Charman. Even the arch-sceptic Fombonne accepts this. "We must entertain the possibility," he says. "But we don't have the evidence."
Graham Lawton, New Scientist
In 2002 California experienced an astounding 31 percent one year increase in the number of new children professionally diagnosed with the most severe cases of autism
Stephen Edelson
Once more, blogging the history of Rick Rollens' quarterly press releases on the California DDS numbers. Warning, it's best not to believe any of his interpretations of the numbers, unless you check them yourself and find that he happens to be right. There's some serious spinning going on here. Please read the whole thing and take note of the dramatic and hyperbolic speech.
Autism Diva
If you are keeping track of the trends here in the numbers, you can see that what Rick Rollens is calling a slow-down in the rate of intakes is statistically neglible. After the previoius "tsunami quarter" and after getting some criticism for the inappropriate usage of "tsunami" in letters to the Schafer Autism Report, he still makes reference to a "tidal wave of young children". Autism Diva has a hard time picturing this, it's easier to picture the "hordes of autistic children" from his earlier press release, though the reference is just as weird and demeaning.
Autism Diva
More blogging the history of Rick Rollens' quarter press releases on the California DDS numbers. Beware - his press releases tend to contain highly spun descriptions of the data he finds. Don't believe any of it until you check it out yourself. You can see a change of policy from described here, restricting the services to people who would basically be the ones obviously needing services. This enacting of a stricter policy might be the reason that the rate of increase was slightly lower in the second quarter of this year, the most recent one, which he interprets as a sign that thimerosal use caused an autism epidemic.
Autism Diva
More blogging the history of Rick Rollens' quarterly press releases on the California DDS numbers. This was the tsunami quarter. Never to be forgotten.
Autism Diva
Once rare, autism has reached epidemic proportions in the United States. The increase cannot be attributed to changes in diagnostic criteria, which have actually become more restrictive.
F. Edward Yazbak
The study reported here tests a prediction that autism should occur more often in families of individuals whose occupation requires advanced folk physics but with no requirement of good folk psychology. Physics, engineering, and mathematics are paradigm examples of such occupations. Students in Cambridge University, studying one of these 3 subjects, were screened for cases of autism in their families. Relative to a control group of students studying literature, autism occurred significantly more often in families of students in the fields of physics, engineering, and mathematics.
Simon Baron-Cohen, Patrick Bolton, Sally Wheelwright, Short, Mead, Smith, V. Scahill
The 1990's autism 'epidemic' mentioned has not been proven to exist. The increased rate of autism in the last decade may actually be an increase in autism recognition resulting from broader diagnostic criteria, increased media/public awareness...
Aubrey Stimola
Expansion of what we consider autism results in more frequent use of the label, more research focus on autism spectrum disorders, and a greater likelihood that the disorder will be identified by parents, physicians, school psychologists and professinals.
Jan Blacher, Exceptional Parent
The rates of autism have escalated dramatically. What used to be considered a rare disorder has become a near-epidemic. (WARNING: This website contains anti-Semitic material.)
U.S. House of Representatives, Committee on Government Reform
There is no autism epidemic. On the face of it that sounds ridiculous - just look at the figures. But talk to almost any autism researcher and they will point to other explanations for the rise in numbers. Some say it's still an open question, but others are adamant that the autism epidemic is a complete myth. And if the most recent research is anything to go by, they could be right. Studies designed to track the supposedly increasing prevalence of autism are coming to the conclusion that, in actual fact, there is no increase at all. "There is no epidemic," says Brent Taylor, professor of community child health at University College London.
New Scientist
'There clearly is an increase in prevalence, and some, if not all, of this increase is related to expanding diagnostic classification. Whether or not this explains all of the increase, however, is unknown.'
Erik Strand, Psychology Today
Most experts share the view of Geraldine Dawson, of the University of Washington Autism Center, who states that "there clearly is an increase in prevalence, and some, if not all, of this increase is related to expanding diagnostic classification. Whether or not this explains all of the increase, however, is unknown."
Erik Strand, Psychology Today
This study analyses the prevalence of ASD, comorbidity, educational provision and ability in autistic children in a single health district, born between 1983 and 1996. The number of recorded diagnoses doubled over a 4 year period. This appeared to be due to greater recognition of ASD in more able children, in children initially presenting with ADHD, and possibly in females. ADHD accounted for a substantial proportion of comorbidity. Age at diagnosis appeared to be related to school placement. Cognitive ability levels ranging from more than three standard deviations below the mean to more than one standard deviation above the mean were found in the moderate and severe learning difficulty school population as well as in the mainstream population. Exceptionally low levels of verbal ability were present in a high proportion of mainstream pupils. Measured levels of cognitive function show poor relationship with actual educational placement.
Daphne Keen, Stephanie Ward
Methods of early detection now being explored might facilitate the serial studies of incidence and prevalence that would be needed to demonstrate changes in prevalence in years to come.
Lorna Wing
Although the source of information for many reports on autism for California is the Department of Developmental Services (DDS)' "Quarterly Client Characteristics Report", the numbers reported by DDS are often misunderstood and misrepresented by others. Except for Table 2 of the Report, only persons with a Client Development Evaluation Report (CDER) on file who have "active" status in the DDS system are counted in the report tables. So, numbers reported do not represent all persons with developmental disabilities in the State of California. The numbers can not be used to report the incidence of autism, for example. Also, the quarterly report represents the number of persons with various characteristics in the DDS system as of a point in time.
Autism Diva
The California statistics are based solely on the population served by the state’s regional centers, which coordinate services for persons with developmental disabilities. To many clinicians, it appears that more and more children who, in the past, would never have been referred to the regional centers -- for example, bright but anxious and slightly socially inept kids with average or better IQs and children who, in the past, had been or would have been diagnosed as ADHD, OCD, ODD, anxiety disorder, learning disabilities, psychotic, and so forth -- are now being diagnosed with high-functioning autism and/or Asperger syndrome and referred to the regional centers for services. If children with these other diagnoses "really" had been autistic all along, then they are not contributing any "real" increase to autism.
Autism Diva
The interpretation of the results from the Brick prevalence investigation will not be fully understood until additional prevalence rates have been obtained from other communities and compared to those in Brick Township.
Center for Disease Control Brick Autism Project
The number of persons entering the system with autism has increased dramatically over the past 11 years relative to the other three developmental disabilities, and the accelerated rate appears to be sustaining an upward trend into future years.
California Health, Human Services Agency
The real story is that the autism epidemic is a myth: a combination of skewed statistics, junk science and incomplete reporting... "The [autism] diagnosis is being used more broadly than it used to be. There are some very non-specific diagnoses that have been used in the past: ‘behavioral disorder,’ for example," says the CDC’s Roebuck. "There are kids who 20 years ago would not have been called autistic who now are being called autistic, but they are the same kids."
Chris Bushnell
Our notions of child development are culture bound and too often create a blueprint of age dependent expectations that ordinary parents fear our children cannot meet, rather than a set of required behaviours that our children must master if they are to be considered fully human.
Sami Timimi
OBJECTIVE: To explore variation among the 50 US states in the administrative prevalence of autistic spectrum disorders (ASDs) and factors associated with that variation. DESIGN: This survey study used secondary data from all 50 states obtained from the US Department of Education, Washington, DC, and the American Board of Pediatrics, Chapel Hill, NC. MAIN OUTCOME MEASURE: The outcome of interest was the proportion of children identified with ASD in the academic year 2000-2001. Linear regression was used to examine its association with education and health system characteristics. RESULTS: States ranged in the proportion of children diagnosed with ASD from 0.6 per 1000 to 4.6 per 1000 in 2000-2001. In adjusted analyses, education-related spending, the number of pediatricians in the state, and the number of school-based health centers in the state were positively associated with the administrative prevalence of ASD. CONCLUSIONS: Variation in the administrative prevalence of ASD is associated with education-related spending, which may be associated with better-trained educational staff who can recognize the problem, and more and better trained in-school specialists who can provide screening. It is also associated with the availability of health care resources. Increased access to pediatricians and school-based health centers may lead to improved recognition of ASD. Interstate variability in the identification of ASD should be taken into account when interpreting the results of prevalence studies based on administrative data and the associated system characteristics taken into account by policy makers working to improve the recognition of ASD.
D.S. Mandell et al
Excerpts from and commentary on Differences Among States in the Identification of Autistic Spectrum Disorders, by David S. Mandell, ScD; Raymond Palmer, PhD
Autism Diva
We report an apparent cluster of seven cases of autism spectrum disorder in a network of a few streets in the UK. Clusters do not easily fit the dominant genetic theory of autism. Whilst this could in principle represent the effect of an environmental pathogen, we consider an alternative interpretation: that autism spectrum conditions may be so much more common than was previously thought that finding seven cases in an area of a few streets is not necessarily higher than one would expect from chance. We conclude by highlighting the need for an agewise epidemiological study of autism spectrum conditions, since this cluster is only higher than expected when compared with expected rates for under-5s rather than under-18s.
Simon Baron-Cohen, Kim Saunders, Suniti Chakrabarti
Examination of California DDS data and VAERS reports.
Mark Geier, David Geier
This paper... provides a review of epidemiological studies of pervasive developmental disorders (PDD) which updates a previously published article. The design, sample characteristics of 32 surveys published between 1966 and 2001 are described. Recent surveys suggest that the rate for all forms of PDDs are around 30/10,000 but more recent surveys suggest that the estimate might be as high as 60/10,000. The rate for Asperger disorder is not well established, and a conservative figure is 2.5/10,000. Childhood disintegrative disorder is extremely rare with a pooled estimate across studies of 0.2/10,000. A detailed discussion of the possible interpretations of trends over time in prevalence rates is provided. There is evidence that changes in case definition and improved awareness explain much of the upward trend of rates in recent decades. However, available epidemiological surveys do not provide an adequate test of the hypothesis of a changing incidence of PDDs.
Eric Fombonne
Eric Fombonne
The following is the verbatim text of the Report to the Legislature by The M.I.N.D. Institute on the Principal Findings from the Epidemiology of Autism in California. This document, prepared by Dr. Robert Byrd and colleagues, has not yet undergone peer review.
Robert Byrd, MIND Institute
Disability rights campaigner Kathy Sinnott said the European Autism Information System (EAIS) project, which has €480,000 in EU Commission funding, will discover how common the condition is. The MEP, whose son Jaime suffers from autism, believes there is no reliable data available to determine the incidence of the disorder, which experts say is on the increase.
Ireland Online
The autism calamity howlers would have you believe that autism is stalking the nation, godzilla like. But, apparently while children's disability in general is growing (but autism Diva doesn't know if it's growning as fast as the population at large), autism is a very small part of the growth. Autism Diva think the folks screaming, "epidemic" know that retardation is dropping off and SLD is dropping off, and that perhaps the kids who used to go in the "retarded" column are now going in the "autistic" column.
Autism Diva
In their increasingly forlorn looking attempt to get some kind (any kind!) of connection between thiomersal and autism, the Geiers launched a new paper... These sources are terrible. The VAERS is not intended for this purpose, a fact spelled out in big bold type on its page: ".....Therefore, VAERS collects data on any adverse event following vaccination, be it coincidental or truly caused by a vaccine. The report of an adverse event to VAERS is not documentation that a vaccine caused the event."
Kevin Leitch
There is a definite connection between a state’s autism prevalence as reported by the USDE and the criteria that state laws have established for autism eligibility under IDEA. However, because the IDEA criteria have no demonstrated relationship to the medical diagnosis, the USDE numbers are not valid for comparing one state to another or even one year to another within a particular state.
James Laidler
Autism Diva is trying to explain -visually- how it is that it seems that there has been a vast increase in the number of autistic people.
Autism Diva
There is no central register of everyone who has autism - which means that any information about the possible number of people with autism in the community must be based on epidemiological surveys (i.e. studies of distinct and identifiable populations).
National Autistic Society
I see a conspiracy to deny that autistic adults have an opinion in this and other matters of autism. Some and a growing number of autistic adults are sick of hearing that autism is an "epidemic", a "disaster", a "catastrophe" even. They think there is a conspiracy to create the appearance of an autism epidemic. The numbers that are quoted frequently to support the "epidemic", the IDEA derived numbers, are misrepresented. There is an explanation for why it "looks like" there has been an increase in autism. It has to do with the way the numbers are being recorded. But very few people talk about that.
Camille Clark
A child is 3 times more likely to be autistic in Oregon than in Kentucky, Arkansas and Lousiana and almost 3 times more likely in Oregon as in Utah. A kid is more than twice as likely to be autistic in Indiana than in Kentucky and those two states border each other! What's up in Oregon? It must be horrible. Oregon seems to have similar kinds of people as Utah has, maybe there are more hippies in Oregon than in Utah. ...
Autism Diva
The incidence of research-identified autism increased in Olmsted County from 1976 to 1997, with the increase occurring among young children after the introduction of broader, more precise diagnostic criteria, increased availability of services, and increased awareness of autism. Although it is possible that unidentified environmental factors have contributed to an increase in autism, the timing of the increase suggests that it may be due to improved awareness, changes in diagnostic criteria, and availability of services, leading to identification of previously unrecognized young children with autism.
William J. Barbaresi, et al
Changes in the definition of autism, rather than use of the measles, mumps, and rubella vaccine (MMR vaccine), led to increased diagnosis of autism in the United States and probably in Europe, says a study from the Mayo Clinic in Rochester, Minnesota. Before the late 1980s and early 1990s, these children were diagnosed as retarded or having developmental delay, lead author William Barbaresi, a developmental paediatrician, told the BMJ.
Janice Hopkins Tanne, British Medical Journal
"We documented that the number of children [in the UK] diagnosed with `behaviour' and "developmental' disorders, but not autism, tended to decrease by about 20% per year from 1992 to 2000. By contrast, the diagnosis of autism increased by 20% per year during this time period... These data point to the conclusion that the increased incidence of diagnosed autism is primarily a reflection of changes in diagnostic practices, such as improved identification, availability of services, and other similar factors..."
Vittal Katikireddi, British Medical Journal
The study found that the increase in the incidence of autism in Olmsted County, Minn. coincided with broadening of the diagnostic criteria for autism and new federal special education laws including autism as a disability category. Both events occurred many years after immunizations were mandated for school entry. Broader, more precise diagnostic criteria for autism were introduced in 1987. Prior to these new criteria, children with autism may have been given less precise diagnoses such as "developmental delay" or "mental retardation," and children with milder symptoms of autism may not have been identified at all. The 1991 federal special education laws improved the availability of educational services for children with autism.
Medical News Today
Whether we believe the growth is fact or fiction, the reality is that we have an increasing number of individuals with complex support needs who will soon be in need of adult services. Let's make sure we are ready.
Cathy Pratt
The purveyors of the epidemic rhetoric want you to believe that those inhabiting the fringes of Asperger’s Syndrome and the most severely affected autistics pose the same economic and social burden on society and their families. The autistic spectrum is a broad one. As its denizens like to point out, Rainman is no more representative than Spielberg. A question arises with this pervasive 1:166 rhetoric. Widely promoted by autism societies and the parents of autistic children, do they not care that in painting the spectrum as a devastating tsunami, a fate worse than death, a pestilence and so forth, the general public is getting a very negative view of the autistic spectrum and one guaranteed to have a deleterious effect on their autistic children’s future?
Alyric
One in 500 children in America suffer from autism, but the disability is appearing in far greater numbers in certain parts of this country and the United Kingdom, for reasons unknown.
Alexandra Rockey Fleming
Presents some of the evidence put forward for an increase in the number of cases of people being diagnosed with autism and associated syndromes and some of the research attempting to explain the increase.
Paul Shattock, Paul Whiteley
Asperger's Syndrome is probably neither a syndrome nor a disorder, but a collection of valuable traits that preclude full participation in the weird social antics of NTs, yet enable the kind of creativity, candor and focus required to innovate, invent and engineer the future in ways without which we might still be living in small villages constructed of rock and earthen shelters, and relying on livestock and subsistence farming to survive.
Rod Van Mechelen
To date, the epidemiologic evidence for a secular increase in the incidence of PDDs is both meager and negative. We simply lack good data to test hypotheses on secular changes in the incidence of autism. Because of specific methodologic limitations, the high prevalence rates reported in recent autism surveys cannot be used to derive conclusions on this issue. Prevalence data nevertheless point to the magnitude of the problem, which had clearly been underestimated in the past. But there is no need to raise false alarms on putative epidemics nor to practice poor science to draw the attention to the unmet needs of large numbers of seriously impaired children and adults.
Eric Fombonne
As you can see, caseload in the 3-5 year old group increased during every quarter, at a fairly constant rate, even as exposure to mercury in vaccines was decreasing. Completely the opposite of the picture portrayed by Kirby! Moreover, caseload over this period increased by 38 percent among 3-5 year olds, but by only 34 percent among 6-9 year olds, although even by mid-2005 nearly all of the children in this category were born prior to 1999. If the thimerosal-autism theory were correct, caseloads should have been increasing faster in the 6-9 year old category, in which there has been essentially no change in thimerosal exposure, than among the 3-5 year old category, in which thimerosal exposure has plummeted.
Citizen Cain
"It has long been the scientifically supported belief of SafeMinds that such a trend would be witnessed following the decreased use of Thimerosal, and this trend seems to support our research," continued Redwood.
Joe Giganti
There has been much debate recently over the increase in numbers of children with autism. Has autism truly increased or have diagnostics improved? In other words, are children being diagnosed now that were overlooked 20 and 30 years ago?
Adelle Jameson Tilton
The behavior analytic Law of Effect states: The best predictor of future behavior is past behavior. So, in consideration to that, here are my predictions of how advocates of the autism epidemic will respond in 2007 to a "no decrease" in autism rate according to the DDS; in order of likelihood.
Interverbal
"If the prevalence figure for our new sample had increased from that in the previous study, that might have pointed toward an increase in the incidence of pervasive developmental disorders, consistent with the various claims of an `epidemic of autism,'" the researchers wrote in their study report. "We did not find such an increase, and there was no statistical difference between the two prevalence rates, not even a trend in that direction. It can therefore be safely concluded that, in this area and for children born over the period 1992 and 1998, there was no evidence of a... change in the incidence of pervasive developmental disorders."
Joan Arehart-Treichel
(T)he nature of the statistics kept by the California Department of Developmental Services limits their value... A well-designed epidemiological study might shed more light on whether we’re seeing a real trend (although epidemiology is a poor indicator of causation). Unfortunately, we have yet to see a well-designed study in California or anywhere else. What makes the California DDS statistics so interesting is that -- unlike most of the epidemiological studies we have seen in the past -- these numbers compare apples to apples on a quarter-to-quarter basis. So while the new report doesn’t provide any answers, it definitely raises the question of what may be causing the apparent trend.
Wade Rankin
An increase in the percentage of students identified as needing special education does not necessarily mean that there has been an increase in the percentage of students with disabilities, any more than an increase in reports of domestic violence necessarily means there is more domestic violence.
Jay P. Greene, Education Week
Reports of large increases in autism prevalence have been a matter of great concern to clinicians, educators, and parents. This analysis uses a national data source to compare the prevalence of autism with that of other disabilities among successive birth cohorts of US school-aged children. Cohort curves suggest that autism prevalence has been increasing with time, as evidenced by higher prevalences among younger birth cohorts. The narrowing in vertical separation of the cohort curves in recent years may mark a slowing in the autism prevalence increase.
Craig J. Newschaffer et al
Children with autism vary widely. It was not until 1940 that this constellation of problems with social interaction, communication, and focused interest came to be called autism. And it was not until 1980 that the diagnosis of autism was formalized. In 1994, the diagnosis changed again. Kids diagnosed with autism from 1980 through 1993 had to meet six mandatory criteria. The new 1994 definition offered 16 optional criteria, only eight of which had to be met. Gernsbacher says the 1994 diagnosis made it much easier for a child to be labeled autistic.
Daniel J. DeNoon, Web MD
Autism could have several causes: neurological condition; autoimmune disorder; genetic disorder; nutritional deficiency; environmental reaction; disease caused or triggered by immunizations; or a combination of factors.
Floyd Tilton
Recent studies, like that in California, are tending to give much higher prevalence rates for autism than the traditional figure of 4-5 in 10,000, which, as noted above, was found for classic Kanner's autism very narrowly defined.
Lorna Wing, David Potter
The educational system got a real clobbering with the closing of the major state institutions for the "feeble minded" and the "insane." All those children who were actually not schooled while in institutions, and never released into the general population during their lifetimes, suddenly were taking up classroom seats and frustrating teachers raised on educational theories that all children learn in specific ways.
Patricia E. Clark
The rate of reported pervasive developmental disorders has increased, and the authors found a rate of 62.6 per 10,000 in a previous study of preschoolers in Stafford, U.K. They conducted another survey in 2002 to estimate the prevalence in children in a later birth cohort and to compare it to previous findings from the same area. Screening for developmental problems included 10,903 children ages 4.0 to 6.0 years who were living in a Midlands town on the survey date. Children with symptoms suggestive of pervasive developmental disorders were intensively assessed by a multidisciplinary team using standardized diagnostic interviews, psychometric tests, and medical workups. The rate of pervasive developmental disorders is higher than reported 15 years ago. The rate in this study is comparable to that in previous birth cohorts from the same area and surveyed with the same methods, suggesting a stable incidence.
Suniti Chakrabarti, Eric Fombonne
Although the evolution of the prevalence of cerebral palsy is now well documented, much less is known about the evolution of the prevalence of other disabilities such as mental retardation, sensorial defects, autism and psychosis. The aim of this paper is to determine those trends. A population-based survey was carried out in 1992-1993 in three French 'departments'. All disabled children born between 1976 and 1985 and receiving a special education and/or financial assistance were systematically registered. The comparison of three cohorts of children born in 1976-1978, 1979-1981 and 1982-1984 using the test for trend in proportion showed a significant decrease (P = 0.03) in the prevalence of severe mental retardation, after exclusion of Down syndrome. This decrease was significant for severe mental retardation associated with psychosis. The time trend prevalence for cerebral palsy increased (P = 0.03) but was irregular. The time trend prevalence of other disabilities (other motor defects, severe sensorial disabilities, autism and psychosis) did not change significantly. A detailed analysis of severe mental retardation and cerebral palsy was performed by geographical area, age at first registration and type of disability. The increase in prevalence of cerebral palsy is possibly due to earlier registration of disabled children. The decrease in prevalence of severe mental retardation does not seem to be due to recruitment bias, but there is a possibility of classification bias.
C Rumeau-Rouquette et al
The current social context seems to exert a stronger influence on the debate than the scientific arguments. Although claims about an epidemic of autism and about its putative causes have the most weak empirical support, the subsequent controversy has put autism on the public agenda. In recent years, children with autism, their families, and professionals involved in their care and in research have seen welcome and legitimate increases in public funding. Yet, ironically, what has triggered substantial social policy changes in autism appears to have little connection with the state of the science. Whether this will continue to be the case in the future remains to be seen, but further consideration should be given to how and to why the least evidence-based claims have achieved such impressive changes in funding policy.
Eric Fombonne
The prevalence of autism appears to have stabilised. There is no evidence for a new phenotype of autism ("new variant", or "regressive autism"). The claims that MMR vaccine is involved in the initiation of autism, and/or with regression, and/or with bowel problems associated with autism, are not supported by any credible scientific evidence, while there is compelling and increasing evidence showing no association.
R. Lingam et al, Archives of Disease in Childhood
The prevalence of autism in Brick Township seems to be higher than that in other studies, particularly studies conducted in the United States, but within the range of a few recent studies in smaller populations that used more thorough case-finding methods.
Jacquelyn Bertrand et al
Concern has been raised about possible increases in the prevalence of autism. However, few population-based studies have been conducted in the United States. The rate of autism found in this study was higher than the rates from studies conducted in the United States during the 1980s and early 1990s, but it was consistent with those of more recent studies.
Marshalyn Yeargin-Allsopp, Catherine Rice, Tanya Karapurkar, Nancy Doernberg, Coleen Boyle, PhD; Catherine Murphy
Our finding agrees with current lifetime prevalence figures suggested by Powell et al. Thus estimates of prevalence from the early 1970s may have seriously underestimated the prevalence at that time. Confirmation of this suggestion would require contemporary assessment of the individuals involved.
Helen Heussler et al, British Medical Journal
The study aimed to establish prevalence of the broader autistic spectrum, including Asperger syndrome, in 5- to 11-year-olds in Cambridgeshire, UK. Cases of diagnosed autism spectrum condition (ASC) in children who were in Cambridgeshire schools and aged between 5 and 11 years on 31 December 1999 were sought using public records, screening instruments, educational psychology and special educational needs coordinator (SENCO) records. We report a prevalence of ASC in the age group 5-11 years of almost 0.6 percent (57 in 10,000). This is 11 times higher than the rate of classic autism but in line with other recent national and international rates for the broader spectrum. In the responding mainstream schools the prevalence was 0.33 percent. In the responding special school population it was 12.5 percent. The overall sex ratio of the children with ASC replicated findings for classical autism of 4:1 (M:F), but in those children being educated in mainstream schools the sex ratio was 8:1 (M:F).
Fiona Scott, Simon Baron-Cohen, Patrick Bolton, Carol Brayne
This lack of a preeminent environmental or regional causality suggests that there is a relationship between the recorded growth of autism and the public infrastructure.
Dana Lee Baker
The rate of autism in the Atlanta area in 1996 was higher than U.S. rates during the 1980s and early 1990s, according to results of a study published in the Jan. 1 issue of The Journal of the American Medical Association. However, the rate is consistent with that reported in more recent studies. "Debate continues about whether the overall prevalence of autism has increased or whether past rates underestimated true prevalence," write Marshalyn Yeargin-Allsopp, MD, from the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, and colleagues.
Laurie Barclay, Medscape
Better ascertainment of diagnosis is likely to have contributed to the observed temporal increase in rates of diagnosis of PDD, but we cannot exclude a real increase.
Lian Smeeth et al
There has been concern that the incidence of autism and other pervasive developmental disorders (PDDs) is increasing. Previous studies have been smaller, restricted to autism (excluding other pervasive developmental disorders such as Asperger's syndrome), included boys only, or have not been based on a national sample. We investigated time trends in the rates of diagnosis of pervasive developmental disorders. We analysed the rates of first diagnosis of pervasive developmental disorders among people registered with a practice contributing to the United Kingdom General Practice Research Database during the period 1988 to 2001. We included 1410 cases from over 14 million person-years of observation. The main outcome measures were rates of diagnosis of pervasive developmental disorders by year of diagnosis, year of birth, gender and geographical region... Better ascertainment of diagnosis is likely to have contributed to the observed temporal increase in rates of diagnosis of PDD, but we cannot exclude a real increase.
Liam Smeeth et al
There is little risk and great potential benefit to be derived from acknowledging the likelihood that as many adults as children could be diagnosed with autistic spectrum conditions if they so desired. It is no more speculative and far more compassionate to entertain such a reasonable notion than it is to categorically deny its possibility. There is no harm done to autistic children by acknowledgement of the existence of adults on the autistic spectrum. Such acknowledgment should not jeopardize the search for justice of families who have evidence that their children have been injured by vaccines.
Kathleen Seidel, neurodiversity weblog
If we assume that overall, there has been less usage thimerosal in vaccines, we can predict that the age cohorts of children after year (2000) will be lower or equal in number of children receiving services compared to the immediately previous year. The overall pattern that would emerge would be a "wave" that slowly travels across the graph as the years go by. It is also logical to predict that this pattern would being to be seen by at least 2004 for the youngest age groups (ages 3 and 4). This is not seen via the graph. The predictions have "flunked" so to speak. The IDEA autism rise is still going and will very likely continue until it reflects the prevalence rate of the epidemiology as predicted by Gernsbacher, Dawson, & Goldsmith (2005).
Interverbal
The Department of Disability Services (DDS) has published their quarterly report. In that report the numbers of service categories the DDS provides services for are listed. These reports are issued once every quarter. It has become habit for various persons to review these reports for autism and to chart the number of supposed new cases and compare to the number of supposed new cases at the same time, the last year. Various blogs have also featured this topic at different points. The purpose of the current review is to provide a graphical display of these number and justification for this presentation. It is also to provide criticism for the way these numbers have been displayed in the past. It is finally, to provide a discussion for what these numbers indicate.
Interverbal
The questions “Is there an increase in the actual prevalence of Autism” and “Why is there a change in the number of cases we identify” might be inter-related and could have the same starting point for an answer. This involves an exploration of the data being used to show an increase. These include epidemiology, the Individuals with disabilities Education Act yearly reports to Congress, and California Department of Disabilities Services statistics.
Interverbal
The epidemiology establishes the prevalence for the autism spectrum. It can be the most precise method we posses. However it is not without problems or complications. While, these data seem to be the most correct, they still deserve a careful and critical look.
Interverbal
It is inaccurate to label the change between given quarters as "new intakes". This is due to change in service categorization (Autism Diva, 2005). This is comparable to what occurs in the IDEA data sets; we are dealing with a assignment to service categories rather than strict descriptive label.
Interverbal
DEA (1990) created Autism, as a service category in U.S. special education. The IDEA definition is characterized as an assessment of need, not a diagnosis by eligibility alone (Autism Watch, September 15, 2004). This is further complicated by the fact that the States have some freedom to make their diagnostic criteria for Autism more permissive. This seems to be exactly what the States of Oregon and Minnesota have done (Autism Watch, September 15, 2004). These two states have the most students receiving services under the Autism category. In Oregon and Minnesota the diagnostic criteria is permissive when compared to other States. Oregon requires a general agreement from multidisciplinary team that a child meets criteria for Autism, as opposed to an additional separate diagnosis from a professional certified to use the DSM-IV (Autism Watch, September 15, 2004).
Interverbal
The purpose of the DDS system is to take care of and help "developmentally disabled" Californians. Because the line is so tremendously fuzzy between PDD, NOS and Asperger's syndrome and "Autistic disorder" many, many, many doctors are willing to "fudge" a child's diagnosis if the child NEEDS the help that the DDS can offer. No, the DDS is not set up to help autistics who are close to functioning normally. It is possible to have a child or adult with an Asperger's diagnosis who is as functionally disabled as one who didn't speak until age 3 and has an "autistic disorder" diagnosis. It is the real world functioning that should matter and does matter to most doctors.
Autism Diva
Recent news about the link between certain vaccines and autism has brought the disorder into the public eye yet again. Although the results of these reports are controversial, there is consensus that the disorder is on the rise. In 1999, the Department of Developmental Service documented a 273% increase in reported cases of autism in California from 1987 to 1998. Researchers have begun to provide clues about the genetic side of the disorder, but no study has been able to give the full story behind the causes. What do we know about the rise in autism? What do we need to find out? What can be done in the meantime?
City Visions Radio
Here is Rollens latest quarterly press release. This time we don't have a tsunami of young children with autism or even a "staggering tidal wave" of young children with autism. No, now we have a dramatic slow-down in the increase. Not that the total numbers are less this quarter but that the increase is smaller than it has been... Translation: The flood of autistic children has slowed down a lot but it's still horrific. Don't stop feeling panicked yet!
Autism Diva
District revenue was associated with higher proportions of children identified with autistic disorder at baseline and increasing rates of identification when measured longitudinally. Economically disadvantaged communities may need assistance to identify children with autistic spectrum disorders and other developmental delays that require attention.
Raymond F. Palmer et al
The new study, which involved 10,903 preschool children in the United Kingdom, confirmed the elevated autism rate, but clearly demonstrated that autism prevalence is not increasing. "This study provides the most robust estimate of childhood autism to date, and suggests that epidemic concerns are unfounded," says Dr. Fombonne.
Canada NewsWire
AIM: To quantitatively examine the influence of study methodology and population characteristics on prevalence estimates of autism spectrum disorders. METHODS: Electronic databases and bibliographies were searched and identified papers evaluated against inclusion criteria. Two groups of studies estimated the prevalence of typical autism and all autism spectrum disorders (ASD). The extent of variation among studies and overall prevalence were estimated using meta-analysis. The influence of methodological factors and population characteristics on estimated prevalence was investigated using meta-regression and summarised as odds ratios (OR). RESULTS: Forty studies met inclusion criteria, of which 37 estimated the prevalence of typical autism, and 23 the prevalence of all ASD. A high degree of heterogeneity among studies was observed. The overall random effects estimate of prevalence across studies of typical autism was 7.1 per 10,000 (95% CI 1.6 to 30.6) and of all ASD was 20.0 per 10,000 (95% CI 4.9 to 82.1). Diagnostic criteria used (ICD-10 or DSM-IV versus other; OR = 3.36, 95% CI 2.07 to 5.46), age of the children screened (OR = 0.91 per year, 95% CI 0.83 to 0.99), and study location (e.g. Japan versus North America; OR = 3.60, 95% CI 1.73 to 7.46) were all significantly associated with prevalence of typical autism. Diagnostic criteria, age of the sample, and urban or rural location were associated with estimated prevalence of all ASD. CONCLUSIONS: Sixty one per cent of the variation in prevalence estimates of typical autism was explained by these models. Diagnostic criteria used, age of children screened, and study location may be acting as proxies for other study characteristics and require further investigation.
J.G. Wiliams, C E.G. Brayne, J.P.T. Higgins
No sound scientific evidence indicates that the increasing number of diagnosed cases of autism arises from anything beyond purposely broader diagnostic criteria, coupled with deliberately greater public awareness and intentionally improved case finding.
M.A. Gernsbacher, M. Dawson, H.H. Goldsmith
Over all, the largest number of autistic kids in the system are White, and they are overrepresented compared to Hispanic kids when one looks at the overall population of the state. But for some reason there is a larger portion of African American autistic kids compared to the total number of African American handicapped kids... This is more evidence of the inequalities of the system and the fact that different criteria are being used to label kids in the school systems, and also further evidence that these numbers can't be used to track autism "epidemiology".
Autism Diva
Concerns have been raised over observed increases in the number of children who are given a diagnosis of a neurodevelopmental disorder. The goal of this study was to examine trends by age and calendar year in the diagnosis of two of these disorders, autism and attention-deficit hyperactivity disorder (ADHD), in the context of other psychiatric disorders in a sample of hospitalized children. Increases in rates of diagnosis of etiologically unrelated mental disorders suggest that there have been changes in diagnostic practices over time, increases in community prevalence of these disorders, and increased likelihood of hospitalizations for different mental disorders.
David S. Mandell, et al
While only speculatively, it can be suggested that there is a rural/suburban bias in the incidence of ASD. This fits with the hypothesis of the possibility of environmental factors (such as OP pesticides) contributing to the formation of IAG.
Bob Budd
Many autism advocacy groups use the data collected by the US Department of Education (USDE) to show a rapidly increasing prevalence of autism. Closer examination of these data to follow each birth-year cohort reveals anomalies within the USDE data on autism. The USDE data show not only a rise in overall autism prevalence with time but also a significant and nearly linear rise in autism prevalence within a birth-year cohort as it ages, with significant numbers of new cases as late as 17 years of age. In addition, an unexpected reduction in the rise of autism prevalence occurs in most cohorts at 12 years of age, the age when most children would be entering middle school. These anomalies point to internal problems in the USDE data that make them unsuitable for tracking autism prevalence.
James Laidler

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