Autismo

Autism

Autism is a disorder of neural development[->0] characterized by impaired social interaction[->1] and communication[->2], and by restricted and repetitive behavior. These signs all begin before a child is three years old. Autism affects information processing in the brain[->3] by altering how nerve cells and their synapses[->4] connect and organize; how this occurs is not wellunderstood. It is one of three recognized disorders in the autism spectrum[->5] (ASDs), the other two being Asperger syndrome[->6], which lacks delays in cognitive development and language, and Pervasive Developmental Disorder-Not Otherwise Specified[->7] (commonly abbreviated as PDD-NOS), which is diagnosed when the full set of criteria for autism or Asperger syndrome are not met.
Autism has a stronggenetic basis, although the genetics of autism[->8] are complex and it is unclear whether ASD is explained more by rare mutations[->9], or by rare combinations of common genetic variants. In rare cases, autism is strongly associated with agents that cause birth defects[->10]. Controversies[->11] surround other proposed environmental causes[->12], such as heavy metals[->13], pesticides[->14] orchildhood vaccines[->15]; the vaccine hypotheses are biologically implausible and lack convincing scientific evidence. The prevalence[->16] of autism is about 1–2 per 1,000 people worldwide; however, the Centers for Disease Control and Prevention[->17] (CDC) reports approximately 9 per 1,000 children in the United States are diagnosed with ASD. The number of people diagnosed with autism has increaseddramatically since the 1980s, partly due to changes in diagnostic practice; the question of whether actual prevalence has increased is unresolved.
Parents usually notice signs in the first two years of their child's life. The signs usually develop gradually, but some autistic children first develop more normally and then regress[->18]. Early behavioral[->19] or cognitive intervention can helpautistic children gain self-care, social, and communication skills. Although there is no known cure, there have been reported cases of children who recovered. Not many children with autism live independently after reaching adulthood, though some become successful. An autistic culture[->20] has developed, with some individuals seeking a cure and others believing autism should be accepted as adifference and not treated as a disorder.
Characteristics
Autism is a highly variable that first appears during infancy or childhood, and generally follows a steady course without remission[->21]. Overt symptoms gradually begin after the age of six months, become established by age two or three years, and tend to continue through adulthood, although often in more muted form. It is distinguished not bya single symptom, but by a characteristic triad of symptoms: impairments in social interaction; impairments in communication; and restricted interests and repetitive behavior. Other aspects, such as atypical eating, are also common but are not essential for diagnosis. Autism's individual symptoms occur in the general population and appear not to associate highly, without a sharp line separatingpathologically severe from common traits.

Social development
Social deficits distinguish autism and the related autism spectrum disorders[->22] (ASD) from other developmental disorders. People with autism have social impairments and often lack the intuition about others that many people take for granted. Noted autistic Temple Grandin[->23] described her inability to understand the socialcommunication[->24] of neurotypicals[->25], or people with normal neural development[->26], as leaving her feeling "like an anthropologist on Mars".
Unusual social development becomes apparent early in childhood. Autistic infants show less attention to social stimuli, smile and look at others less often, and respond less to their own name. Autistic toddlers differ more strikingly from social...