Effectiveness of Bosa (Brief Observation of Symptoms of Autism) as an Alternative Diagnostic Tool for Asd (Autistic Spectrum Disorder) during the Coronavirus Pandemic - a Retrospective Audit

ABSTRACT

Aims By necessity, our trust was unable to complete gold standard ADOS (Autism Diagnostic Observation Schedule) assessments as part of the ASD diagnostic pathway during the Coronavirus pandemic. We, therefore, implemented the BOSA as a stop-gap. This retrospective audit compares the need for further assessments and the outcomes from BOSA assessments against those achieved by our unit when the 'gold standard' ADOS was in use. Our audit standard was to achieve equivalent results pre- and during the pandemic. Methods Data from a random sample of 120 children who completed an ADOS assessment August - December 2019 was compared with data from a random sample of 118 children who completed a BOSA August 2020 - January 2021. Statistical analysis was performed using the 2 tailed Fisher's exact test. Results In school age children, further assessment was significantly more likely to be required when a BOSA assessment was used (25.6% vs. 8.9%, p=0.01). There was a less significant difference between the need for further assessment in the pre-school age group between the ADSO and BOSA groups (14.3% vs. 0%, p=0.048). In this audit, the wait time for a BOSA assessment was 372 days vs. for an ADOS assessment 278 days. However, due to the complex disruption caused by the pandemic, any difference in pathway duration could not meaningfully be evaluated by this audit. An additional ADOS was needed in 14.3% of cases undergoing the BOSA assessment. This will have affected the duration of the assessment process due to delays in arranging and completing further assessments. Children were slightly more likely to receive a positive autism diagnosis using the BOSA. However, this was not statistically significant (p=0.31 for school age, p= 1.0 for preschool age). Conclusion The BOSA assessment seems to be effective when used with pre-school children, with a minimally significant difference in rates of children requiring further assessment and no significant difference in final diagnosis rates. BOSA assessment appears to be less useful in school age children - with a greater proportion then requiring a subsequent ADOS assessment, but, again, with no significant difference in final diagnosis rates. This audit supports the recommendation that the BOSA assessment is not intended to be used long-term or to replace the ADOS, which remains the gold standard assessment. However, in the context of a pandemic, where ADOS assessments were not possible, the BOSA assessment allowed 86% of preschool age and 74% of school age children to receive a confirmed diagnosis (positive or negative), using an assessment method whose diagnosis rates were similar to the ADOS assessment.