JCPSLP Vol 22 No 1 2020

the waiting time to diagnosis. International guidelines recommend that ASD diagnostic assessments start within three months of referral to an autism team (NICE, 2011). Children in the retrospective chart review waited on average 6.1 months from the time of the medical evaluation to the time of diagnosis. While this is less time than the 12-month average reported in recent literature (Bent, et al., 2020), it is double the recommended guideline. The Tumbatin Clinic aims to align the service with best-practice and recent guidelines. Participants in the prospective study waited on average 4.5 months from the initial medical evaluation to the point of formal diagnosis, demonstrating a decrease in time taken to diagnosis. The National Guideline for the Assessment and Diagnosis of Autism Spectrum Disorders in Australia (Whitehouse, et al., 2018) suggests that, in some cases, a single clinician diagnostic evaluation could diagnose children at an earlier stage resulting in earlier access to specific services and support, reduced cost to the health system and better outcomes for the child and their family (Granpeesheh, et al., 2009; Magiati, et al., 2012). The participants in the prospective study were all seen by the speech-language pathologist within 5 weeks of the medical evaluation, and a consensus regarding their diagnostic category was reached shortly thereafter. For some children, given the high degree of accuracy following a combined medical evaluation and speech-language pathology assessment, a stage 2 diagnostic pathway may not be warranted. Some families come to diagnostic services seeking certainty. For these families, an accurate and timely diagnosis and referral to appropriate services would be in the best interests of the family and the child. This possible model of care is represented in Figure 2. Limitations As this study was completed within a clinical setting, the sample size was limited to the number of children meeting criteria who attended within a certain time frame – a convenience sample. It is very important that further research is completed to replicate these findings with a larger sample size and use of controlled, experimental research designs. This study is also limited to children with normal cognition and language level in the preschool and early school years. As such, the results cannot be generalised to all children with suspected ASD. Further studies investigating the importance and effectiveness of a speech-language assessment in the early diagnostic stage for children with suspected ASD at all levels of cognition and ages are needed. As reported in this paper, the benefits of an early diagnosis are many. However, there are some possible disadvantages, which need to be considered. Remaining family-centred and approaching each family on a case-by- case basis will always be a component of best practice. Some families may not be ready or able to comprehend this information in a short space of time, and may continue to be more suited to a longer assessment pathway. Future research using qualitative methodology to capture the perspectives of the family would add depth to this discussion. It is also important to remember that a formal cognitive assessment is part of the gold-standard. A formal cognitive assessment provides vital information from which to interpret all other assessments and should not be skipped, regardless of which diagnostic pathway the child is on.

A thorough understanding of how social communication develops alongside language and cognition is essential in the assessment of ASD. Children with average cognition and language skills may present with social communication difficulties that are subtler than children at lower functioning levels. These social communication difficulties may not be obvious during adult interactions and it is therefore particularly important that children receive a communication assessment across a range of settings as part of the differential diagnostic process (Ozonoff, Goodliun-Jones, & Solomon, 2005; SPA, 2016). Only half of the children in the retrospective chart review reported in this article received a speech-language pathology assessment prior to their consensus team diagnostic evaluation. Many of those who did receive an assessment had to go to private services, where, depending on the professional’s level of experience, assessment procedures can be inconsistent. A lack of information regarding the child’s social communication ability prior to the ASD diagnostic assessment is likely to delay an accurate diagnosis. In our prospective study, we provided all children with a thorough SLP assessment prior to diagnosis, improving the equality of the service and demonstrating that cost-effective, best practice can be achievable within a real clinical setting. Formal and informal language and social communication assessment procedures were completed as part of the prospective study. As expected, all participants scored within the average range or above on the language assessment. There were some group trends with regards to the CCC-2 parent questionnaire of social communication. Overall, children in the ASD category scored lower on the SIDC than the other two groups, although there was wide variation. Only one child in the ASD group scored a positive SIDC score. According to the CCC-2 assessment, a profile of a GCC less than 55 and a negative SIDC is indicative of ASD. However, as this assessment involves parent report, information collected is dependent on the parent’s perspective and therefore may not accurately represent the child’s ability. This highlights that while the CCC-2 certainly added a lot of information not obtained on formal language assessments, it cannot replace direct observations by an experienced speech-language pathologist. Consistent with best-practice guidelines (Ozonoff, et al., 2005), the inclusion of a social communication assessment, language assessment and school observation by an experienced speech-language pathologist is a key component to the early and accurate diagnosis of ASD for children with average cognition and language in the preschool and early- school years. This study further aimed to evaluate if the addition of a speech-language pathology assessment would provide important diagnostic information and facilitate an accurate stage 1 ASD diagnosis. Taken together with the medical evaluation, the information obtained during the speech-language pathology assessment was used to assign participants to diagnostic categories. In all cases, preliminary descriptive diagnostic categories were supported by formal diagnosis. The data shows that following a medical evaluation and speech-language pathology assessment, an accurate stage 1 diagnosis can be made. Finally, this study aimed to describe a possible service delivery option for the future, whereby inclusion of an early speech-language pathology assessment could reduce the number of children attending excessive, inconclusive multidisciplinary team assessments, thus reducing

45

JCPSLP Volume 22, Number 1 2020

www.speechpathologyaustralia.org.au