Brief report: autism and herpes simplex encephalitis

Microbes and Mental Illness: Past, Present, and Future

A review of the association between microbes and mental illness is performed, including the history, relevant definitions, infectious agents associated with mental illnesses, complex interactive infections, total load theory, pathophysiology, psychoimmunology, psychoneuroimmunology, clinical presentations, early-life infections, clinical assessment, and treatment. Perspectives on the etiology of mental illness have evolved from demonic possession toward multisystem biologically based models that include gene expression, environmental triggers, immune mediators, and infectious diseases. Microbes are associated with a number of mental disorders, including autism, schizophrenia, bipolar disorder, depressive disorders, and anxiety disorders, as well as suicidality and aggressive or violent behaviors. Specific microbes that have been associated or potentially associated with at least one of these conditions include Aspergillus, Babesia, Bartonella, Borna disease virus, Borrelia burgdorferi (Lyme disease), Candida, Chlamydia, coronaviruses (e.g., SARS-CoV-2), Cryptococcus neoformans, cytomegalovirus, enteroviruses, Epstein-Barr virus, hepatitis C, herpes simplex virus, human endogenous retroviruses, human immunodeficiency virus, human herpesvirus-6 (HHV-6), human T-cell lymphotropic virus type 1, influenza viruses, measles virus, Mycoplasma, Plasmodium, rubella virus, Group A Streptococcus (PANDAS), Taenia solium, Toxoplasma gondii, Treponema pallidum (syphilis), Trypanosoma, and West Nile virus. Recognition of the microbe and mental illness association with the development of greater interdisciplinary research, education, and treatment options may prevent and reduce mental illness morbidity, disability, and mortality.

Healing autism spectrum disorder with cannabinoids: a neuroinflammatory story

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with a multifactorial etiology. Latest researches are raising the hypothesis of a link between the onset of the main behavioral symptoms of ASD and the chronic neuroinflammatory condition of the autistic brain; increasing evidence of this connection is shedding light on new possible players in the pathogenesis of ASD. The endocannabinoid system (ECS) has a key role in neurodevelopment as well as in normal inflammatory responses and it is not surprising that many preclinical and clinical studies account for alterations of the endocannabinoid signaling in ASD. These findings lay the foundation for a better understanding of the neurochemical mechanisms underlying ASD and for new therapeutic attempts aimed at exploiting the renowned anti-inflammatory properties of cannabinoids to treat pathologies encompassed in the autistic spectrum. This review discusses the current preclinical and clinical evidence supporting a key role of the ECS in the neuroinflammatory state that characterizes ASD, providing hints to identify new biomarkers in ASD and promising therapies for the future.

Prediction and validation of potent peptides against herpes simplex virus type 1 via immunoinformatic and systems biology approach

The human herpes simplex virus type 1 (HSV-1) is an extremely rampant human pathogen, and its infection could cause life-long diseases, including the central nervous system disorders. The glycoproteins of HSV-1 such as glycoprotein B, glycoprotein C, glycoprotein D, glycoprotein H, and glycoprotein L are highly involved in mediating the viral attachment and infection of the host cell. Therefore, immunoinformatic approaches followed by molecular dynamics simulation and systems biology has been used to analyze these glycoproteins in order to propose effective peptide-based vaccine candidates against the HSV-1 infection. The ElliPro and NetCTL.1.2 online tools were employed to forecast the B- and T-lymphocyte (CTL) epitopes for gB, gC, gD, gH, and gL. The 3D coordinates of these epitopes were modeled and docked against the human major histocompatibility complex molecule-1. The outcomes obtained from postdocking analysis along with TAP (Transporter associated with antigen processing), MHC binding, and C-terminal cleavage score assisted in the selection of potential epitopes. These epitopes were further subjected to molecular dynamics simulation and systems biology approach which showed significant results. On the basis of these substantial outcomes, peptides are proposed that could be used to provoke immunity against the HSV-1 infection.

Prevalence of HSV1/2 Congenital Infection Assessed Through Genome Detection on Dried Blood Spot in Individuals with Autism Spectrum Disorders

BACKGROUND/AIM

Etiopathogenesis of autism spectrum disorders (ASD) remains to be elucidated. Congenital infections, particularly viral infections, have repeatedly been associated with the onset of such disorders. Our study aimed at assessing the prevalence of herpes simplex type 1 and 2 (HSV1/2) congenital infections in patients with ASD.

MATERIALS AND METHODS

In our case-control study, a total of 38 children with ASD were compared to 44 age- and sex-matched controls regarding the presence of HSV1/2 infection though viral DNA polymerase chain reaction performed on dried blood spots collected at birth.

RESULTS

No HSV congenital infection was detected in either group.

CONCLUSION

Our negative finding is in agreement with other studies that failed to demonstrate a definitive role of HSV on the onset of ASD. Further investigation of congenital HSV prevalence in larger and more powerful studies is needed to undeniably discard a role of such virus in the etiopathogenesis of ASD.

Prevalence of Congenital Cytomegalovirus Infection Assessed Through Viral Genome Detection in Dried Blood Spots in Children with Autism Spectrum Disorders

BACKGROUND/AIM

Autism spectrum disorders (ASD) are neurodevelopmental disorders without a definitive etiology in most cases. Environmental factors, such as viral infections, have been linked with anomalies in brain growth, neuronal development, and functional connectivity. Congenital cytomegalovirus (CMV) infection has been associated with the onset of ASD in several case reports. The aim of this study was to evaluate the prevalence of congenital CMV infection in children with ASD and in healthy controls.

PATIENTS AND METHODS

The CMV genome was tested by polymerase chain reaction (PCR) on dried blood spots collected at birth from 82 children (38 with ASD and 44 controls).

RESULTS

The prevalence of congenital CMV infection was 5.3% (2/38) in cases and 0% (0/44) in controls (p=0.212).

CONCLUSION

The infection rate was about 10-fold higher in patients with ASD than in the general Italian population at birth. For this reason, detection of CMV-DNA on dried blood spots could be considered in the work-up that is usually performed at ASD diagnosis to rule-out a secondary form. Given the potential prevention and treatment of CMV infection, this study could have intriguing consequences, at least for a group of patients with ASD.

No evidence of congenital varicella zoster virus infection assessed through dried blood spot in children with autism spectrum disorders

Aim: Several authors have hypothesized an association between congenital viral infections and the onset of autism spectrum disorders (ASD). We aimed to assess the prevalence of congenital varicella zoster virus (VZV) infection in patients with ASD. Patients & methods: Congenital infection by VZV was evaluated in a cohort of 38 children with ASD and in 44 healthy controls. PCR for VZV-DNA performed on dried blood spots collected at birth. Results & conclusion: No VZV infection was detected in both groups. With the limitation of the small sample size of this study, the results are not in favor of a role of VZV in the etiology of ASD.

Maternal Infection During Pregnancy and Autism Spectrum Disorders

We conducted a nested case-control study including 407 cases and 2,075 frequency matched controls to investigate the association between maternal infections during pregnancy and risk of autism spectrum disorders (ASD). Cases, controls, and maternal infections were ascertained from Kaiser Permanente Northern California clinical databases. No overall association between diagnoses of any maternal infection during pregnancy and ASD was observed [adjusted odds ratio (ORadj) = 1.15, 95 % confidence interval (CI) 0.92-1.43]. However, women with infections diagnosed during a hospital admission (ORadj = 1.48, 95 % CI 1.07-2.04), particularly bacterial infections (ORadj = 1.58, 95 % CI 1.06-2.37), were at increased risk of delivering a child with ASD. Multiple infections during pregnancy were associated with ASD (ORadj = 1.36, 95 % CI 1.05-1.78).

Autism spectrum disorder secondary to enterovirus encephalitis

Millions of children are infected by enteroviruses each year, usually exhibiting only mild symptoms. Nevertheless, these viruses are also associated with severe and life-threatening infections, such as meningitis and encephalitis. We describe a 32-month-old patient with enteroviral encephalitis confirmed by polymerase chain reaction in cerebrospinal fluid, with unfavorable clinical course with marked developmental regression, autistic features, persistent stereotypes and aphasia. She experienced slow clinical improvement, with mild residual neurologic and developmental deficits at follow-up. Viral central nervous system infections in early childhood have been associated with autism spectrum disorders but the underlying mechanisms are still poorly understood. This case report is significant in presenting a case of developmental regression with autistic features and loss of language improving on follow-up. To our knowledge, this is the first published report of enterovirus encephalitis leading to an autism spectrum disorder.

Etiopathogenesis of autism spectrum disorders: fitting the pieces of the puzzle together

Autism spectrum disorders (ASD) are disorders of the central nervous system characterized by impairments in communication and social reciprocity. Despite thousands of studies on this topic, the etiopathogenesis of these disorders remains unclear, apart from a general belief that they derive from an interaction between several genes and the environment. Given the mystery surrounding the etiopathogenesis of ASD it is impossible to plan effective preventive and treatment measures. This is of particular concern due to the progressive increase in the prevalence of ASD, which has reached a figure as high as 1:88 children in the USA. Here we present data corroborating a novel unifying hypothesis of the etiopathogenesis of ASD. We suggest that ASD are disorders of the immune system that occur in a very early phase of embryonic development. In a background of genetic predisposition and environmental predisposition (probably vitamin D deficiency), an infection (notably a viral infection) could trigger a deranged immune response which, in turn, results in damage to specific areas of the central nervous system. If proven, this hypothesis would have dramatic consequences for strategies aimed at preventing and treating ASD. To confirm or refute this hypothesis, we need a novel research approach, which unlike former approaches in this field, examine the major factors implicated in ASD (genetic, infections, vitamin D deficiency, immune system deregulation) not separately, but collectively and simultaneously.

Etiologies of autism in a case-series from Tanzania

Most autism has a genetic cause although post-encephalitis cases are reported. In a case-series (N = 20) from Tanzania, 14 met research criteria for autism. Three (M:F = 1:2) had normal development to age 22, 35, and 42 months, with onset of autism upon recovery from severe malaria, attended by prolonged high fever, convulsions, and in one case prolonged loss of consciousness. In four other cases (M:F = 3:1), the temporal relationship between onset of autism and severe infection was close, but possibly spurious since malaria is common in Tanzania and there were indications of abnormal development in the child or a family member. In seven cases, (M:F = 6:1) autism onset was unrelated to malaria. The excess of non-verbal cases (N = 10) is related local diagnostic practice.

Infection in the first 2 years of life and autism spectrum disorders

OBJECTIVE

The purpose of this work was to investigate the association between infections in the first 2 years and subsequent diagnosis of autism spectrum disorders.

METHODS

We conducted a case-control study among children born at Kaiser Permanente Northern California from 1995 to 1999. Case subjects (n = 403) were children with an autism diagnosis recorded in Kaiser Permanente databases. Control subjects (n = 2100) were randomly sampled from the remaining children without autism and frequency matched to case subjects on gender, birth year, and birth hospital. Information on infections and covariates were obtained from Kaiser Permanente and birth certificate databases.

RESULTS

Overall, infection diagnoses in the first 2 years of life were recorded slightly less often for children with autism than control children (95.0% vs 97.5%). Among specific diagnoses, upper respiratory infections were significantly less frequently diagnosed and genitourinary infections more frequently diagnosed in children with autism. In the first 30 days of life, the frequency of having an infection was slightly higher among children with autism (22.6% vs 18.7%).

CONCLUSIONS

Children with subsequent diagnoses of autism do not have more overall infections in the first 2 years of life than children without autism. Data suggest that children with autism may have modestly elevated rates of infection in the first 30 days and that, during the first 2 years, children with autism may be at higher risk for certain types of infections and lower risk for others. Additional studies that explore the associations between prenatal and early childhood infections and autism may help clarify the role of infection and the immune system in the etiology of autism spectrum disorder.

Hyperbaric oxygen therapy may improve symptoms in autistic children

Autism is a neurodevelopmental disorder that currently affects as many as 1 out of 166 children in the United States. Recent research has discovered that some autistic individuals have decreased cerebral perfusion, evidence of neuroinflammation, and increased markers of oxidative stress. Multiple independent single photon emission computed tomography (SPECT) and positron emission tomography (PET) research studies have revealed hypoperfusion to several areas of the autistic brain, most notably the temporal regions and areas specifically related to language comprehension and auditory processing. Several studies show that diminished blood flow to these areas correlates with many of the clinical features associated with autism including repetitive, self-stimulatory and stereotypical behaviors, and impairments in communication, sensory perception, and social interaction. Hyperbaric oxygen therapy (HBOT) has been used with clinical success in several cerebral hypoperfusion syndromes including cerebral palsy, fetal alcohol syndrome, closed head injury, and stroke. HBOT can compensate for decreased blood flow by increasing the oxygen content of plasma and body tissues and can even normalize oxygen levels in ischemic tissue. In addition, animal studies have shown that HBOT has potent anti-inflammatory effects and reduces oxidative stress. Furthermore, recent evidence demonstrates that HBOT mobilizes stem cells from human bone marrow, which may aid recovery in neurodegenerative diseases. Based upon these findings, it is hypothesized that HBOT will improve symptoms in autistic individuals. A retrospective case series is presented that supports this hypothesis.

Autistic disorder and viral infections

Autistic disorder (autism) is a behaviorally defined developmental disorder with a wide range of behaviors. Although the etiology of autism is unknown, data suggest that autism results from multiple etiologies with both genetic and environmental contributions, which may explain the spectrum of behaviors seen in this disorder. One proposed etiology for autism is viral infection very early in development. The mechanism, by which viral infection may lead to autism, be it through direct infection of the central nervous system (CNS), through infection elsewhere in the body acting as a trigger for disease in the CNS, through alteration of the immune response of the mother or offspring, or through a combination of these, is not yet known. Animal models in which early viral infection results in behavioral changes later in life include the influenza virus model in pregnant mice and the Borna disease virus model in newborn Lewis rats. Many studies over the years have presented evidence both for and against the association of autism with various viral infections. The best association to date has been made between congenital rubella and autism; however, members of the herpes virus family may also have a role in autism. Recently, controversy has arisen as to the involvement of measles virus and/or the measles, mumps, rubella (MMR) vaccine in the development of autism. Biological assays lend support to the association between measles virus or MMR and autism whereas epidemiologic studies show no association between MMR and autism. Further research is needed to clarify both the mechanisms whereby viral infection early in development may lead to autism and the possible involvement of the MMR vaccine in the development of autism.

Aetiology of autism: findings and questions

BACKGROUND

Although there is good evidence that autism is a multifactorial disorder, an adequate understanding of the genetic and non-genetic causes has yet to be achieved.

METHODS

Empirical research findings and conceptual reviews are reviewed with respect to evidence on possible causal influences.

RESULTS

Much the strongest evidence concerns the importance of susceptibility genes, but such genes have yet to be identified. Specific somatic conditions (such as tuberous sclerosis and the fragile X anomaly) account for a small proportion of cases. Over recent decades there has been a major rise in the rate of diagnosed autism. The main explanation for this rise is to be found in better ascertainment and a broadening of the diagnostic concept. Nevertheless, some degree of true rise cannot be firmly excluded. However, the epidemiological evidence on the main hypothesized environmental explanation, namely the measles-mumps-rubella vaccine, is consistently negative.

CONCLUSION

Progress on the elucidation of the causes of autism will be crucially dependent on the combination of epidemiology with more basic science laboratory studies.

Childhood autism: a circuit syndrome?

BACKGROUND

Autism is a disorder that can lead to life-long disability. Currently, the etiology of autism is unknown, and although there are treatments for some of the behavioral abnormalities, there is no cure.

REVIEW SUMMARY

While this article will review the clinical, anatomic, and pathologic features seen in autism, the primary focus will be to present a new and provocative unifying theory regarding the underlying mechanisms causing this disorder. Current research advances, some controversial, will be discussed, and a novel definition of autism as a "circuit syndrome" will be presented. The work elaborated here will tie many of the disparate findings together, based on the idea that autism arises from abnormalities of the cerebellolimbic circuitry. Some of the more alternative theories of autism, such as mercury toxicity, linkage to the measles, mumps, and rubella vaccine, and the use of secretin will be discussed. Finally, pharmacologic treatment options will be reviewed.

CONCLUSIONS

Autism is not single disorder but represents dysfunction of the cerebellolimbic circuitry that can arise from many different etiologies.

Treatment of late onset autism as a consequence of probable autommune processes related to chronic bacterial infection

Two cases are described of children who at first developed normally, but before the age of three developed autistic symptoms following the reactivation of a chronic oto-rhinolaryngologic infection. The clinical and laboratory data of the cases support the aetiological hypothesis of an autoimmune process. Adrenocorticotrophic hormone (ACTH), prescribed in the first months of the disease, cured one case. The other patient, who was two years old when autistic symptoms appeared and was treated only six years later, showed a partial but definitive improvement with the immunosuppressive treatment. This report proposes that reactivation of a chronic bacterial infection be included among the aetiologies of Late Onset Autism, and demonstrates that, when the aetiological hypothesis of an autoimmune process based on clinical and laboratory data is considered, an immunosuppressive treatment, particularly with ACTH, can be very effective and also safe.

Measles-mumps-rubella vaccine and autistic spectrum disorder: report from the New Challenges in Childhood Immunizations Conference convened in Oak Brook, Illinois, June 12-13, 2000

BACKGROUND

Parents and physicians are understandably concerned about the causes and treatment of autism, a devastating disease that affects the entire family. Although much has been learned about autism, there are many gaps in our knowledge about what causes the disorder and how it can be prevented. Autistic symptoms occur along a spectrum, often referred to as autistic spectrum disorder (ASD). Concern has been raised about a possible association between measles-mumps-rubella (MMR) vaccine and inflammatory bowel disease (IBD) and ASD, especially autism with regression. Also, increased requests for educational services related to ASD have raised concerns about possible increases in the incidence of ASD.

METHODS

On June 12-13, 2000, the American Academy of Pediatrics (AAP) convened a conference titled "New Challenges in Childhood Immunizations" in Oak Brook, Illinois. At this conference, parents, practitioners, and scientists presented information and research on MMR vaccine and ASD. Attendees included representatives from select AAP committees and sections as well as federal and other organizations that address related issues. The multidisciplinary panel of experts reviewed data on what is known about the pathogenesis, epidemiology, and genetics of ASD and the available data on hypothesized associations with IBD, measles, and MMR vaccine. Supplemental information was requested from authors who have proposed the hypotheses and other experts in relevant areas.

RESULTS

Autism is a complex disorder of uncertain and probably multiple etiologies. Genetic predisposition to ASD may involve as many as 10 genes. Many experts believe that the abnormal brain development in autism occurs before 30 weeks' gestation in most instances. In utero rubella is a known cause of autism. Animal model data support the biologic plausibility that exposure to yet unrecognized infectious or other environmental agents could cause ASD. Several factors may contribute to apparent increases in incidence of ASD in recent years. Most data indicate increased recognition and reporting as primary factors, but the epidemiologic data are insufficient to determine if there has been a true increase in the incidence of ASD. Increased reporting of ASD in recent years has occurred long after the introduction of MMR vaccine in the United States in 1971 and widespread use of this vaccine in the 1970s for routine immunization of children at 12 to 15 months of age. Appropriate detailed studies are needed to define the true incidence and prevalence of ASD. Epidemiologic studies in Europe indicate no association between MMR vaccine and ASD. Some children with ASD have gastrointestinal symptoms, but an increased rate of any specific gastrointestinal disorder in children with ASD has not been established. Studies to detect evidence of measles virus in intestinal tissue specimens from patients with IBD or autism with gastrointestinal symptoms have not used uniform techniques. Several laboratories have found no evidence of measles viruses in tissue specimens from patients with IBD, but 2 groups have found evidence of measles virus using different techniques. A group that found evidence of measles virus in affected tissue specimens from patients with IBD has also reported detecting portions of measles virus in peripheral blood lymphocytes and intestinal tissue specimens from patients with autism and gastrointestinal disorders. Finding a portion of a virus using molecular techniques does not constitute evidence for a causal relationship, because some viruses persist in unaffected hosts. Additional controlled studies in several laboratories are needed to determine if portions of measles virus persist in intestinal and other tissues of people with and without gastrointestinal disease and/or ASD.

CONCLUSIONS

Although the possible association with MMR vaccine has received much public and political attention and there are many who have derived their own conclusions based on personal experiences, the available evidence does not support the hypothesis that MMR vaccine causes autism or associated disorders or IBD. Separate administration of measles, mumps, and rubella vaccines to children provides no benefit over administration of the combination MMR vaccine and would result in delayed or missed immunizations. Pediatricians need to work with families to ensure that children are protected early in the second year of life from these preventable diseases. Continued scientific efforts need to be directed to the identification of the causes of ASD.

Exclusion of linkage to the HLA region in ninety multiplex sibships with autism

Several studies have suggested a role for the histocompatibility complex of loci (HLA) in the genetic susceptibility to autism. We have tested this hypothesis by linkage analysis using genetic marker loci in the HLA region on chromosome 6p in multiplex families with autism. We have examined sharing of alleles identical by descent in 97 affected sib pairs from 90 families. Results demonstrate no deviation from the null expectation of 50% sharing of alleles in this region; in fact, for most marker loci, the observed sharing was less than 50%. Thus, it is unlikely that loci in this region contribute to the genetic etiology of autism to any significant extent in our families.

Epilepsy surgery in children with pervasive developmental disorder

Pervasive developmental disorder (PDD) is occasionally associated with medically intractable complex partial seizures. The outcome of PDD was explored in three males and two females who underwent epilepsy surgery at 32 months to 8 years of age (mean = 4 years) after onset of epilepsy at 1 week to 21 months of age (mean = 11 months). Four children had temporal lobe resections (three right, one left; two for focal cortical dysplasia, and two for tumors), and one had a right temporoparieto-occipital resection (for focal cortical dysplasia). Each child underwent repeated evaluations by a pediatric neuropsychologist and psychiatrist. Fourteen to 47 months (mean = 23 months) after operation, one child with persistent seizures had moderate developmental and behavioral improvement, three children (two seizure free, one with rare staring spells) had mild developmental and behavioral improvement, and the remaining child (seizure free) experienced a worsening of her PDD. The four children with mild-to-moderate improvement in postoperative cognitive and behavioral development still demonstrated persistent delay. Cognitive gains were confirmed by neuropsychologic testing in the oldest patient but were not reflected in test results from the three younger children, who had more modest improvement. The child with worsening of her PDD had cognitive and emotional deterioration to babbling, echolalia, aggressiveness, decreased social interaction, and increased mouthing of objects beginning several months postoperatively. These results suggest that families should be counseled that PDD symptoms in children with focal epileptogenic lesions may or may not improve after epilepsy surgery, even if the surgery is successful with respect to seizure control.

Autism and visual agnosia in a child with right occipital lobectomy

OBJECTIVES

Autistic disorder is a developmental handicap with an unknown neurological basis. Current neuropsychological models for autism suggest an abnormal construction of visual perceptual representation or a deficit in executive functions. These models predict cerebral lesions in the temporo-occipital or frontal regions of autistic patients. The present study aimed at studying the presence of symptoms of autism and visual agnosia in a 13 year old girl who had a right temporo-occipital cortical dysplasia that was surgically removed at the age of 7.

METHODS

Neuropsychological evaluation included Wechsler and Kaufman intelligence scales, a test of word fluency, digit span, Corsi block, California verbal learning, Trail making, Benton facial recognition, Snoodgrass object recognition tests, Rivermead face learning subtest, and developmental test of visual perception. The ADI-R was used to show current and retrospective diagnosis of autistic disorder. Neuroimagery included brain MRI, single photon emission computed tomography (SPECT), and PET.

RESULTS

Brain MRI showed a right occipital defect and an abnormal hyperintensity of the right temporal cortex. PET and SPECT disclosed a left frontal hypometabolism together with the right occipital defect. Neuropsychological testing showed a visual apperceptive agnosia and executive function deficits. Psychiatric study confirmed the diagnosis of autistic disorder.

CONCLUSIONS

Although the possibility that autism and visual agnosia were dissociable factors in this patient cannot be excluded, the finding of both deficits supports the possibility that occipito-temporal lesions can predispose to the development of autism.

Autism and the immune system

As our knowledge of the interactions of the immune, nervous and endocrine systems progresses, complex links with the origin and course of psychopathology in childhood are revealed. In this article the neuroimmunological literature on autism is reviewed. Relevant aspects of immune functioning and the neuroendocrine-immune network are described. We present the immunological findings in autistic patients within two related conceptual frameworks: a viral and an autoimmune hypothesis. Interpretation of data is hampered by conceptual and methodological differences between studies. Both the clinical significance of the immune changes and the causal connection between immune changes and psychopathological phenomena in autism remain to be elucidated. Recommendations for further research are given.

Validity and neuropsychological characterization of Asperger syndrome: convergence with nonverbal learning disabilities syndrome

The authors investigated the validity of Asperger Syndrome (AS) by comparing the neuropsychological profiles in this condition and Higher-Functioning Autism (HFA). Diagnostic assignment followed a stringent procedure based on ICD-10 research criteria for the two disorders. The groups had comparable age and Full Scale IQ distributions. The groups differed significantly in 11 neuropsychological areas. The profile obtained for individuals with AS coincided closely with a cluster of neuropsychological assets and deficits captured by the term nonverbal learning disabilities, suggesting an empirical distinction from HFA.

No association between prenatal exposure to influenza and autism

We examined the relationship between the number of autistic patients, obtained from the register of the National Autism Society (NAS), born each month between January 1953 and December 1988 in England, and the occurrence of influenza epidemics one to nine months before birth. The relative risk of developing autism, for exposure to influenza during gestation, was assessed by a Poisson regression model. Our results indicate that exposure to influenza epidemics during gestation is not associated with autism.

Medial temporal lobe structures and autism: a review of clinical and experimental findings

Although substantive understanding of brain dysfunction in autism remains meager, clinical evidence as well as animal brain research on the effects of early damage to selective brain system have now yielded enough knowledge that some provisional hypotheses concerning the etiology of autism can be generated. Basically, the underlying premise of this review is that a major dysfunction of the autistic brain resides in neural mechanisms of the structures in the medial temporal lobe, and, perhaps, more specifically the amygdaloid complex. This review begins with a summary of clinical evidence of the involvement of the medial temporal lobe structures in autism. The major behavioral disturbances seen in monkeys that had received neonatal lesions of the medial temporal lobe structures are then described. From this survey it can be seen that distinct patterns of memory losses and socioemotional abnormalities emerge as a result of extent of damage to the medial temporal lobe structures. The potential value of the experimental findings for an understanding of neural dysfunction in autism as well as directions of future research are discussed in the final section of the review.

Susceptibility to social influence in adults with Asperger's syndrome: a research note

Asch's line judgement task was used to compare the susceptibility to social influence of adults with Asperger's syndrome with that of two groups of controls one of which was matched on verbal IQ. There was no overall difference between the three groups' mean rate of conformity but in contrast to both groups of controls, the subjects with Asperger's syndrome were significantly more likely to adopt a consistently conforming or nonconforming strategy. There were also significant differences between the groups in their interaction with the other participants. The implications of the findings are discussed in the context of current theories of autistic social dysfunction.