Low-contrast response deficits and increased neural noise in children with autism spectrum disorder.

A battery of short-duration neurophysiological tests were designed and implemented using visual evoked potentials (VEPs) to examine specific neural mechanisms in children with and without autism spectrum disorder (ASD). Contrast-sweep conditions (bright or dark isolated-checks) were used to elicit steady-state VEPs to examine the integrity of ON/OFF pathways. Children with ASD displayed deficits in low-contrast responses at the stimulus frequency of 12.5 Hz, notably under conditions that emphasized activity in the magnocellular pathway. Signal-to-noise ratios were weaker in the ASD group, particularly for the OFF pathway. There were no group differences in the amplitude of responses. In addition, the ASD group displayed significantly higher levels of neural noise than controls. For the response at the stimulus frequency, the ASD group produced a relatively constant level of noise across the contrast range tested, with higher levels than controls at low contrasts and approximately equal levels of noise at moderate to high contrasts.

The autism mental status exam: sensitivity and specificity using DSM-5 criteria for autism spectrum disorder in verbally fluent adults.

The phenotypic heterogeneity of adults suspected of autism spectrum disorder (ASD) requires a standardized diagnostic approach that is feasible in all clinical settings. The autism mental status exam (AMSE) is an eight-item observational assessment that structures the observation and documentation of social, communicative and behavioral signs and symptoms of ASD. Previous findings indicate high classification accuracy when compared to the autism diagnostic observation schedule in a non-stratified population of high-risk patients suspected of having ASD. This protocol investigates the sensitivity and specificity of AMSE scores using DSM-5 criteria for ASD in a sample of high-risk verbally fluent adults. Findings indicate an optimized sensitivity of 0.91 and a specificity of 0.93 for this group. Because of its high clinical utility, the AMSE holds promise as a diagnostic assessment tool that can support one's clinical diagnosis of ASD in high-risk adults.

Brief report: the Autism Mental Status Examination: development of a brief autism-focused exam.

The Autism Mental Status Examination (AMSE) described here is an eight-item observational assessment that prompts the observation and recording of signs and symptoms of autism spectrum disorders (ASD). The AMSE is intended to take place seamlessly in the context of a clinical exam and produces a total score. Subjects were independently administered the AMSE and the Autism Diagnostic Observation Schedule (ADOS). The ADOS was used to estimate the most effective criterion cut-off on the AMSE. A score of five or greater produced excellent sensitivity and good specificity in a high-risk sample. Internal consistency was acceptable and inter-rater reliability was good to excellent. Preliminary findings indicate excellent classification accuracy and suggest that the AMSE provides a rapid and reliable observational assessment in a high-risk population.