par Deconinck, Nicolas ;Soncarrieu, Marie-Vinciane ;Dan, Bernard
Référence Pediatric Neurology, Nova Science Publishers, Inc., page (65-90)
Publication Publié, 2012-05
Partie d'ouvrage collectif
Résumé : Autism spectrum disorder (ASD) is a group of devastating developmental conditions whose prevalence was reported as increasing over the last decades. This may be related to changes in diagnostic criteria, comorbidity with other developmental disabilities or a true increase in cases. Diagnosis rests essentially on behavioral presentation and developmental history. Difficulties in communication and reciprocal social behavior are the core characteristics of ASDs. Motor and behavioral stereotypies, though prevalent, are not specific to ASDs and are often not observed before the age of 2. The etiology and pathophysiological mechanisms of ASD remain largely unknown, although environmental toxins and genetic factors have been implicated. Early diagnosis of ASD is of utmost importance because early intervention is especially effective in the experience of many professionals although not evidence based. Diagnosis for ASD is commonly made at approximately 3 years or older. There have been significant advances in our knowledge of the early signs of ASD through the use of retrospective videotape analysis, parental report and screening studies. However, there has been a lack of prospective methods to study early features in children who go on to develop ASD. There remains little research on the prospective identification of these children in a community-based sample before 18 months. Recently however some studies were able to identify early neurological signs and developmental predictors, which differed according to the age at assessment and allowed rather accurate identification of children with ASDs. By recruiting younger siblings of children with ASD, who are at much higher risk for developing ASD, some authors could demonstrate a prolonged latency to disengage visual attention from two competing stimuli and a delayed expressive and receptive language during the first year of life. A characteristic pattern of early temperament, with marked passivity and decreased activity level at 6 months, followed by extreme distress reactions, a tendency to fixate on particular objects in the environment, and decreased expression of positive affect by 12 months was aloso quite specifically recognized. By examining early medical and behavioral characteristics of NICU children later diagnosed with ASD, some authors showed that ASD neonates showed persistent neurobehavioral abnormalities and higher incidences of visual asymmetric visual tracking and upper limb muscle tone deficits. At 4 months, children with an eventual diagnosis of ASD specifically showed a continued visual preference for higher amounts of stimulation, behaving more like newborns. Looking at early social attention and communication skills with adapted scales in children before the age of 18 months in very large communitybased settings, authors were able to identify children at "risk " for ASD with a positive predictive value around 80 %. In this review, we review recent advances and discuss the validity of organizing early detection program for ASD in the context of a daily medical practice with the questions and hurdles raised by this approoach. © 2012 by Nova Science Publishers, Inc. All rights reserved.