Dialogues in Clinical Neuroscience : New perspectives in autism spectrum disorders (Décembre 2017)
Le numéro de décembre 2017 de Dialogues in Clinical Neuroscience est consacré à l’autisme : New perspectives in autism spectrum disorders.
1. Thibaut F. New perspectives in autism spectrum disorders. Dialogues in clinical neuroscience. 2017 ; 19(4) : 323.
Autism spectrum disorder, a complex developmental disorder, has been found to be one of the most heritable neuropsychiatric disorders. The next step will be to translate these findings into successful treatments for this disorder.
2. Shen MD, Piven J. Brain and behavior development in autism from birth through infancy. Dialogues in clinical neuroscience. 2017 ; 19(4) : 325-33.
Autism spectrum disorder (ASD) is a heterogeneous condition that affects 1 in 68 children. Diagnosis is based on the presence of characteristic behavioral impairments that emerge in the second year of life and thus is not typically made until 3 to 4 years of age. Recent studies of early brain and behavior development have provided important new insights into the nature of this condition. Autism-specific brain imaging features have been identified as early as 6 months of age, and age-specific brain and behavior changes have been demonstrated across the first 2 years of life, highlighting the developmental nature of ASD. New findings demonstrate that early brain imaging in the first year of life holds great promise for presymptomatic prediction of ASD. There is a general understanding in medicine that earlier treatment has better outcomes than later treatment, and in autism, there is an emerging consensus that earlier intervention results in more successful outcomes for the child. Examining early brain and behavior trajectories also has the potential to parse the etiologic heterogeneity in ASD, a well-recognized impediment to developing targeted, mechanistic treatments. This review highlights the current state of the science in the pursuit of early brain and behavioral markers of autism during infancy and examines the potential implications of these findings for treatment of this condition.
3. Chahrour M, Kleiman RJ, Manzini MC. Translating genetic and preclinical findings into autism therapies. Dialogues in clinical neuroscience. 2017 ; 19(4) : 335-43.
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by social deficits and repetitive/restrictive interests. ASD is associated with multiple comorbidities, including intellectual disability, anxiety, and epilepsy. Evidence that ASD is highly heritable has spurred major efforts to unravel its genetics, revealing possible contributions from hundreds of genes through rare and common variation and through copy-number changes. In this perspective, we provide an overview of the current state of ASD genetics and of how genetic research has spurred the development of in vivo and in vitro models using animals and patient cells to evaluate the impact of genetic mutations on cellular function leading to disease. Efforts to translate these findings into successful therapies have yet to bear fruit. We discuss how the valuable insight into the disorder provided by these new models can be used to better understand ASD and develop future clinical trials.
4. Baron-Cohen S, Lombardo MV. Autism and talent : the cognitive and neural basis of systemizing. Dialogues in clinical neuroscience. 2017 ; 19(4) : 345-53.
In 2003, we proposed the hypersystemizing theory of autism. The theory proposes that the human mind possesses a systemizing mechanism (SM) that helps identify lawful regularities (often causal) that govern the input-operation-output workings of a system. The SM can be tuned to different levels, from low to high, with a normal distribution of individual differences in how strongly people search for such input-operation-out-put regularities in any data that is systemizable. Evidence suggests that people with autism are on average hypersystemizers, scoring higher than average on the systemizing quotient and on performance tests of systemizing. In this article, we consider the neural basis behind the SM, since there has been little consideration of the brain basis of systemizing. Finally, we discuss directions for future work in this field.
5. Fernandez BA, Scherer SW. Syndromic autism spectrum disorders : moving from a clinically defined to a molecularly defined approach. Dialogues in clinical neuroscience. 2017 ; 19(4) : 353-71.
Autism spectrum disorder (ASD) encompasses a group of neurodevelopmental conditions diagnosed solely on the basis of behavioral assessments that reveal social deficits. Progress has been made in understanding its genetic underpinnings, but most ASD-associated genetic variants, which include copy number variants (CNVs) and mutations in ASD-risk genes, account for no more than 1 % of ASD cases. This high level of genetic heterogeneity leads to challenges obtaining and interpreting genetic testing in clinical settings. The traditional definition of syndromic ASD is a disorder with a clinically defined pattern of somatic abnormalities and a neurobehavioral phenotype that may include ASD. Most have a known genetic cause. Examples include fragile X syndrome and tuberous sclerosis complex. We propose dividing syndromic autism into the following two groups : (i) ASD that occurs in the context of a clinically defined syndrome-recognizing these disorders depends on the familiarity of the clinician with the features of the syndrome, and the diagnosis is typically confirmed by targeted genetic testing (eg, mutation screening of FMR1) ; (ii) ASD that occurs as a feature of a molecularly defined syndrome-for this group of patients, ASD-associated variants are identified by genome-wide testing that is not hypothesis driven (eg, microarray, whole exome sequencing). These ASD groups cannot be easily clinically defined because patients with a given variant have variable somatic abnormalities (dysmorphism and birth defects). In this article, we review common diagnoses from the above categories and suggest a testing strategy for patients, guided by determining whether the individual has essential or complex ASD ; patients in the latter group have multiple morphologic anomalies on physical examination. Finally, we recommend that the syndromic versus nonsyndromic designation ultimately be replaced by classification of ASD according to its genetic etiology, which will inform about the associated spectrum and penetrance of neurobehavioral and somatic manifestations.
6. Zwick GP. Neuropsychological assessment in autism spectrum disorder and related conditions. Dialogues in clinical neuroscience. 2017 ; 19(4) : 373-9.
Neuropsychological assessment provides a profound analysis of cognitive functioning in people with autism spectrum disorder (ASD). Individuals on the autistic spectrum often show a high level of anxiety and are frequently affected by comorbidities that influence their quality of life. Yet, they also have cognitive strengths that should be identified in order to develop effective support strategies. This article presents an overview of five cognitive areas that are essential for neuropsychological evaluation (ie, intelligence, attention, executive function, social cognition, and praxis) and explores the underlying causes of behavioral problems in persons with ASD. Furthermore, it stresses the importance of meticulous neuropsychological testing with regard to cognitive remediation, a method that can help to enhance single cognitive processes in a targeted manner. Objective test results suggest it might be possible to promote an improved sense of coherence. In line with the salutogenic model, this may be fundamental for human health and well-being.
7. Schottle D, Briken P, Tuscher O, Turner D. Sexuality in autism : hypersexual and paraphilic behavior in women and men with high-functioning autism spectrum disorder. Dialogues in clinical neuroscience. 2017 ; 19(4) : 381-93.
Like nonaffected adults, individuals with autism spectrum disorders (ASDs) show the entire range of sexual behaviors. However, due to the core symptoms of the disorder spectrum, including deficits in social skills, sensory hypo- and hypersensitivities, and repetitive behaviors, some ASD individuals might develop quantitatively above-average or nonnormative sexual behaviors and interests. After reviewing the relevant literature on sexuality in high-functioning ASD individuals, we present novel findings on the frequency of normal sexual behaviors and those about the assessment of hypersexual and paraphilic fantasies and behaviors in ASD individuals from our own study. Individuals with ASD seem to have more hypersexual and paraphilic fantasies and behaviors than general-population studies suggest. However, this inconsistency is mainly driven by the observations for male participants with ASD. This could be due to the fact that women with ASD are usually more socially adapted and show less ASD symptomatology. The peculiarities in sexual behaviors in ASD patients should be considered both for sexual education and in therapeutic approaches.
8. Stepanova E, Dowling S, Phelps M, Findling RL. Pharmacotherapy of emotional and behavioral symptoms associated with autism spectrum disorder in children and adolescents. Dialogues in clinical neuroscience. 2017 ; 19(4) : 395-402.
Autism spectrum disorder (ASD) is characterized by impairment in social communication and restricted patterns of behavior. Although there is no pharmacological treatment approved by the US Food and Drug Administration (FDA) for the core symptoms of ASD, there is mounting support in the literature for the management of behavioral symptoms associated with this developmental disorder, in particular, irritability and hyperactivity. Aripiprazole and risperidone are currently approved by the FDA for the treatment of irritability in youth with ASD. Though not FDA-approved, methylphenidate and guanfacine are effective for the management of hyperactivity in children with ASD. Selective serotonin reuptake inhibitors are often used in clinical practice to target anxiety and compulsions ; however, there is little evidence to support its use in this population. There is a great need for further research on the safety and efficacy of existing psychotropic medications in youth with ASD, as well as the development of new treatment modalities for the core and associated behavioral symptoms.
9. Davidson M. Vaccination as a cause of autism-myths and controversies. Dialogues in clinical neuroscience. 2017 ; 19(4) : 403-7.
Despite significant progress in the study of the epidemiology and genetics of autism, the etiology and patho-physiology of this condition is far from being elucidated and no curative treatment currently exists. Although solid scientific research continues, in an attempt to find explanations and solutions, a number of nonscientific and pure myths about autism have emerged. Myths that vaccines or mercury are associated with autism have been amplified by misguided scientists ; frustrated, but effective parent groups ; and politicians. Preventing the protection provided by vaccination or administration of mercury-chelating agents may cause real damage to autistic individuals and to innocent bystanders who as a result may be exposed to resurgent diseases that had already been « extinguished. » That such myths flourish is a consequence of the authority of scientific evidence obtained by scientific methodology losing ground to alternative truths and alternative science. This article presents a narrative of the origin of the myths around autism.
