The Optimal Cut-Off Point for Thai Diagnostic Autism Scale and Probability Prediction of Autism Spectrum Disorder Diagnosis in Suspected Children.

The Thai Diagnostic Autism Scale (TDAS) was developed to diagnose autism spectrum disorder (ASD) under the context and characteristics of the Thai population. Although the tool has an excellent agreement, the interpretation of diagnostic results needs to rely on the optimal cut-off point to maximize efficiency and clarity. This study aims to find an optimal cut-off point for TDAS in the diagnosis of ASD and to compare its agreement with the DSM-5 ASD criteria. This study was conducted on 156 children aged 12-48 months old who were suspected of having ASD and had enrolled from hospitals in the four regions of Thailand in 2017-2018. The optimal cut-off point for TDAS was considered by using receiver operating characteristic (ROC) curves according to the DSM-5 ASD criteria. The areas under the curve (AUCs) for TDAS and ADOS-2 were also compared. Multivariable logistic regression was performed to create a predictive model for the probability of ASD. The AUC of TDAS was significantly higher than that of ADOS-2 (0.8748 vs. 0.7993; p = 0.033). The optimal cut-off point for TDAS was ≥20 points (accuracy = 82.05%, sensitivity = 82.86%, and specificity = 80.93%). Our findings show that TDAS with a cut-off point can yield higher diagnostic accuracy than ADOS-2 and TDAS domain. Diagnosis by using this cut-off point could be useful in practical assessments.

Detection of Electroencephalographic Abnormalities and Its Associated Factors among Children with Autism Spectrum Disorder in Thailand.

Epilepsy often causes more severe behavioral problems in children with autism spectrum disorder (ASD) and is strongly associated with poor cognitive functioning. Interestingly, individuals with ASD without a history of epilepsy can have abnormal electroencephalographic (EEG) activity. The aim of this study was to examine associations between EEG abnormalities and the ASD severity in children. The children with ASD who enrolled at the Rajanagarindra Institute of Child Development, Thailand were included in this study. The severity of ASD was measured by interviewing their parents with the Thai autism treatment evaluation checklist. The short sensory profile checklist was used for screening the abnormality of children in each domain. Ordinal logistic regression analysis was used to examine associations between factors potentially linked to EEG abnormalities. Most of the study participants were boys (87.5%) and the median age was 5 years. Among the 128 children, 69.5% showed EEG abnormalities (41.4% slow-wave and 28.1% epileptiform-discharge). The results show that a larger number of symptoms and increased severity of ASD were independently associated with a higher risk of EEG abnormalities. Our results emphasize the need for guidelines on the presence of EEG abnormalities in children with ASD for the early detection of epilepsy and improving treatment outcomes.

Development and psychometric evaluation of a Thai Diagnostic Autism Scale for the early diagnosis of Autism Spectrum Disorder.

The Thai Diagnostic Autism Scale (TDAS) was developed for use as a diagnostic tool for the early diagnosis of Autism Spectrum Disorder (ASD) in Thai children aged 12-48 months old. TDAS consists of 23 items (13 and 17 items in the observational and interview sections, respectively) classified into seven domains (A1-A3 and B1-B4) according to the criteria in the Diagnostic and Statistical Manual of Mental Disorder, fifth edition (DSM-5). Children with a single score in the A1-A3 domains and at least two of the B1-B4 domains were classified with ASD. The item-objective congruence (IOC) index, confirmatory factor analysis, and Kappa coefficient were used to evaluate the content, constructs, and inter-rater validity levels between the evaluators and concurrent validity between TDAS and physicians' diagnoses, respectively. TDAS showed good overall content validity (IOC range 0.71-1.00), suitable construct validity (root-mean-squared errors of approximation of 0.076 and 0.067, comparative fit indexes of 0.902 and 0.858, and Tucker-Lewis indexes of 0.882 and 0.837 for the observation and interview sections, respectively), and excellent diagnostic agreement between TDAS and the evaluators (Kappa = 1.000) as well as between TDAS and the physicians' diagnoses (Kappa = 0.871). The sensitivity and specificity of TDAS were 100% and 82.4%, respectively. In conclusion, TDAS yielded a high level of content validity, concurrent validity, and inter-rater reliability for the early diagnosis of ASD in Thai children. A large-scale study using TDAS is needed to determine an appropriate cut-off point as well as its efficacy. LAY SUMMARY: The Thai Diagnostic Autism Scale was developed for use as a diagnostic tool for the early diagnosis of Autism Spectrum Disorder (ASD) among Thai children. It contains 23 items in seven domains for the screening via observations and interviews. The psychometric properties of this diagnostic tool provide its reliability and suitability for the early diagnosis of ASD. A large-scale study using it is needed to determine an appropriate cut-off point as well as its efficacy.