There are no epidemiological data on autism for Mexico. This study was conducted to generate a first estimate of ASD prevalence in Mexico. We surveyed children age eight in Leon (Guanajuato). The sample was stratified in two strata: (1) children having special education and medical records (SEMR; N = 432) and (2) children attending regular schools (GSS; N = 11,684). GSS children were screened with the SRS and those with the highest scores were invited to a diagnostic evaluation. The final sample comprised 36 children (80.6 % male) who had confirmed ASD. A third had intellectual disability, 25 % were non-verbal, 69 % had co-occurring behavioral problems. The prevalence overall was 0.87 % (95 % CI 0.62, 1.1 %). This survey provides an estimate for ASD prevalence in Mexico that is consistent with recent studies.

In order to conduct the screening phase of the first epidemiological survey of autism spectrum disorders (ASDs) in Mexico, we needed a screening tool to detect autistic symptomatology in a large sample of school-age children. We used the Spanish version of the Social Responsiveness Scale (SRS). We recruited a clinical sample of 200 children (81% males; mean age: 7.4 years) with a confirmed diagnosis of ASDs and a sample of 363 control children (59.5% males; mean age: 8.5 years) without ASDs. Three-way analyses of variance (ANOVAs) identified a main effect of clinical status (ASDs vs. controls) for both parent and teacher scales, but no gender or age effect. The mean total and subscale raw scores were significantly different between the clinical and control groups for the parent and for the teacher SRS (P < 0.001). The internal consistency of the SRS was excellent. Receiver operating characteristic (ROC) analyses showed excellent discriminant validity of the SRS in the Mexican sample (area under the curve: 0.962 for the parent, 0.960 for the teacher). ROC curves were also used to determine which cutoff would provide the best trade-off between sensitivity and specificity. Mexican SRS scores were significantly higher than in the U.S. and German population for typically developing children but comparable for clinically referred subjects. The SRS is an acceptable screening instrument for epidemiological studies of ASDs in Mexico. Its psychometric properties are excellent and comparable to those derived from North American and other samples.

Links between brain function measures and quality of parent–child interactions within the early developmental period have been investigated in typical and atypical development. We examined such links in a group of 104 infants with and without a family history for autism in the first year of life. Our findings suggest robust associations between event related potential responses to eye gaze and observed parent–infant interaction measures. In both groups, infants with more positive affect exhibit stronger differentiation to gaze stimuli. This association was observed with the earlier P100 waveform component in the control group but with the later P400 component in infants at-risk. These exploratory findings are critical in paving the way for a better understanding of how infant laboratory measures may relate to overt behavior and how both can be combined in the context of predicting risk or clinical diagnosis in toddlerhood.Electronic supplementary materialThe online version of this article (doi:10.1007/s10803-014-2192-9) contains supplementary material, which is available to authorized users.

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