Journal Articles

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    Autism in Aotearoa: Is the RAADS-14 a valid tool for a New Zealand population?
    (Hogrefe for the European Association of Psychological Assessment (EAPA), 6/07/2020) Kember S; Williams MN
    Screening measures for autism spectrum disorder (ASD) are important tools for clinicians and researchers. However, where a measure developed and validated for one population is used with another, its performance in this new context must be carefully examined. The RAADS-14, a brief ASD screen developed in Sweden, was evaluated with a sample of New Zealand adults (N = 387), 41 of whom self-reported a prior diagnosis of ASD. The convergent validity of the RAADS-14 (Hypothesis 2) was supported by a strong positive correlation with the AQ-10 (short version of the Autism Spectrum Quotient), r = .81. Discriminant validity (Hypothesis 3) was also supported by a strong negative correlation with the EQ-Short (short version of the Empathy Quotient), r = −.75. However, the measure did not meet inferential criteria for internal consistency (Hypothesis 1), and confirmatory factor analysis (CFA) found a poor fit of the proposed three-factor model (Hypothesis 4) to the data. A cut-off score of 14/42 provided adequate sensitivity (95%) to detect participants with self-reported ASD diagnoses, but not adequate specificity (70%), suggesting a very high rate of false positives should be expected if relying on RAADS-14 scores alone to interpret presence of ASD. In sum, our results do not provide sufficient evidence of reliability and validity to support the use of the RAADS-14 with the New Zealand population. We provide suggestions for refinement of the RAADS-14 that may lead to increased reliability and validity.
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    Vitamin D and omega-3 fatty acid supplements in children with autism spectrum disorder: a study protocol for a factorial randomised, double-blind, placebo-controlled trial.
    (23/06/2016) Mazahery H; Conlon C; Beck KL; Kruger MC; Stonehouse W; Camargo CA; Meyer BJ; Tsang B; Mugridge O; von Hurst PR
    BACKGROUND: There is strong mechanistic evidence to suggest that vitamin D and omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs), specifically docosahexaenoic acid (DHA), have the potential to significantly improve the symptoms of autism spectrum disorder (ASD). However, there are no trials that have measured the effect of both vitamin D and n-3 LCPUFA supplementation on autism severity symptoms. The objective of this 2 × 2 factorial trial is to investigate the effect of vitamin D, n-3 LCPUFAs or a combination of both on core symptoms of ASD. METHODS/DESIGN: Children with ASD living in New Zealand (n = 168 children) will be randomised to one of four treatments daily: vitamin D (2000 IU), n-3 LCPUFAs (722 mg DHA), vitamin D (2000 IU) + n-3 LCPUFAs (722 mg DHA) or placebo for 12 months. All researchers, participants and their caregivers will be blinded until the data analysis is completed, and randomisation of the active/placebo capsules and allocation will be fully concealed from all mentioned parties. The primary outcome measures are the change in social-communicative functioning, sensory processing issues and problem behaviours between baseline and 12 months. A secondary outcome measure is the effect on gastrointestinal symptoms. Baseline data will be used to assess and correct basic nutritional deficiencies prior to treatment allocation. For safety measures, serum 25-hydroxyvitamin D 25(OH)D and calcium will be monitored at baseline, 6 and 12 months, and weekly compliance and gastrointestinal symptom diaries will be completed by caregivers throughout the study period. DISCUSSION: To our knowledge there are no randomised controlled trials assessing the effects of both vitamin D and DHA supplementation on core symptoms of ASD. If it is shown that either vitamin D, DHA or both are effective, the trial would reveal a non-invasive approach to managing ASD symptoms. TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry, ACTRN12615000144516 . Registered on 16 February 2015.
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    Vitamin D and Autism Spectrum Disorder: A Literature Review.
    (21/04/2016) Mazahery H; Camargo CA; Conlon C; Beck KL; Kruger MC; von Hurst PR
    Low vitamin D status in early development has been hypothesised as an environmental risk factor for Autism Spectrum Disorder (ASD), given the concurrent increase in the prevalence of these two conditions, and the association of vitamin D with many ASD-associated medical conditions. Identification of vitamin D-ASD factors may provide indications for primary and secondary prevention interventions. We systematically reviewed the literature for studies on vitamin D-ASD relationship, including potential mechanistic pathways. We identified seven specific areas, including: latitude, season of conception/birth, maternal migration/ethnicity, vitamin D status of mothers and ASD patients, and vitamin D intervention to prevent and treat ASD. Due to differences in the methodological procedures and inconsistent results, drawing conclusions from the first three areas is difficult. Using a more direct measure of vitamin D status--that is, serum 25(OH)D level during pregnancy or childhood--we found growing evidence for a relationship between vitamin D and ASD. These findings are supported by convincing evidence from experimental studies investigating the mechanistic pathways. However, with few primary and secondary prevention intervention trials, this relationship cannot be determined, unless randomised placebo-controlled trials of vitamin D as a preventive or disease-modifying measure in ASD patients are available.