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Response and completion rates
Two-hundred and forty-five potential participants opened the survey, with 173 of these individuals proceeding beyond the first question. Complete responses were obtained for 99 of the respondents who started the questionnaire, resulting in a completion rate of 58%.
Wait-list periods: The wait-list period for an ASD assessment was significantly longer in public/NGO relative to private settings (see table 2). While most of the private diagnostic services (n=52, 88%) start ASD assessments within 3 months of referral, wait times in the public sector were variable, with only 23 of the 50 respondents (46%) reporting wait-list times of 3 months or less (see figure 1). The wait for an MDT assessment (median=12 weeks, SD=25.75, range=1.5–108 weeks) was also longer than for a sole practitioner (median=4 weeks, SD=9.84, range=1–52), Mann–Whitney U=511, p=0.005, perhaps due to the higher number of MDTs in the public sector relative to the private sector.
Total number of public and private services which have wait-list periods of <3 months to more than 12 months.
Assessment sessions and length: Respondents (n=106) completed a median of 2 (range=1–6.5) sessions for ASD assessments with a median assessment length of 90 min (SD=98.15 min, range 30–600 min). There was no difference in the number of assessment sessions completed in the private relative to the public sector (see table 2). However, assessment sessions in the public sector were significantly longer than those in the private sector.
Multidisciplinary assessment: MDTs (n=52) most commonly consisted of one medical and two allied health professionals, usually a psychologist and a speech pathologist. All of the participating occupational therapists were part of an MDT. Most MDTs conducted assessments either in series, together, partially together or in collaboration, that is, each clinician completes an independent assessment, but all assessors meet to make a consensus diagnostic decision (see figure 2). In contrast, sole practitioners (n=49) tended to complete assessments in isolation or in series, that is, assess an individual independently one after the other. Only small numbers of the sole practitioners reported collaborating with other clinicians, with 1 of the 15 (7%) sole practitioners working in isolation and 4 of those working in series (17%) collaborating with external agencies.
Proportion of sole practitioners and MDTs who conduct ASD assessments in isolation, together, partially together, in series or in collaboration with professionals from another discipline. ASD, autism spectrum disorder; MDT, multidisciplinary team.
Multisetting assessment: The majority of the 108 respondents (95%) observed the individual in the clinic in all assessments (median frequency=100% of assessments, SD=31%, range=0–100%). Assessments in the home or school/daycare settings were less frequent, with 47% of respondents including home observations (median frequency=0% of assessments, SD=22%, range=0–100%) and 77% of respondents including observations in the school or daycare (median frequency=20% of assessments, SD=31%, range=0–100%). Only two clinicians (2%), both from the public sector, include clinic and school/daycare observations in more than 75% of the assessments, with 12 clinicians (11%), 4 private practitioners and 8 from the public sector, completing observations in the clinic and home settings. Three respondents (3%), 2 from the private sector and one from the public sector, observed a child in the home and school/daycare settings in more than 75% of the assessments.
Median (SD) and range for the wait-list period, number of assessment sessions and length of assessment sessions for diagnosticians in the private and public sectors
Hearing test: In the Australian clinical pathway, it would be expected that the paediatrician conducts a hearing assessment before referring a child to an allied health team for an ASD assessment.7 Of the paediatricians (n=20) surveyed, only 2 (10%) reported that a hearing test is included in all ASD assessments. Another 2 paediatricians (10%) indicated that they rarely include a hearing test in ASD assessments, 5 reported occasionally or usually (ie, in 30–50% of assessments) and 11 paediatricians (55%) reported to include a hearing test frequently or usually (ie, 70–90% of assessments) where ASD is suspected.
Medical investigations: All of the paediatricians who include medical investigations in ASD assessments reported completing a genetic screen, Fragile X test and neurological and physical examinations. Of the 21 paediatricians, 15 respondents (71%), reported that they include medical investigations frequently or usually (more than 70% of their assessments), with only 4 pediatricians (19%) including medical investigations in all assessments where ASD is suspected.
Assessment measures: A total of 107 participants responded to questions regarding the administration of assessment tools. A developmental history was reported to have been undertaken by 89% of these respondents. Of these, 66 (62%) reported always administering standardised assessments in diagnostic evaluations for ASD, and 21 (20%) reported doing so frequently or usually (in 70–90% of ASD assessments). There was no difference in the proportion of respondents who frequently administer assessments in private (n=51, 88%) relative to public (n=36, 77%) service settings, χ2 (1, N=87)=2.35, p=0.13, Φ=0.15, nor were there differences in the proportion of respondents who administer assessments by state, χ2 (5, N=105)=2.95, p=0.71, Φ=.17.
Participants who reported administering assessments (n=105) were asked to indicate which types of assessments are included in diagnostic evaluations for ASD. Since some measures are restricted to particular disciplines, it was unsurprising that there was variability in the proportions of clinicians administering cognitive, language and adaptive assessments and measures of ASD symptomatology (see table 3). In addition, only 50 respondents (47%) administer the ADOS and 41 (39%) the ADI-R. Thirty-two respondents (30%) use the ADOS and the ADI-R together in diagnostic evaluations for ASD.
Of the 105 respondents who indicated that they administer assessments as part of diagnostic evaluations for ASD, only 8 (8%) reported that they complete an assessment battery comprising measures of developmental, cognitive, language, adaptive skills and ASD symptomatology. The numbers increased only marginally when we examined developmental and cognitive assessments separately, with 11 respondents (10%) completing a developmental assessment in addition to measures of language, adaptive skills and ASD symptoms, and 14 (13%) completing a cognitive assessment in addition to these other measures. Taking the profession-specific assessments separately showed that 27 psychologists (53%) administered cognitive and adaptive assessments in addition to measures of ASD symptomatology, and 14 speech pathologists (56%) administered language assessments in addition to measures of ASD symptomatology.
To account for clinicians who may review the results of assessments that are administered by other disciplines, we also asked participants to indicate whether they review assessment results. Sixty-seven (68%) respondents reported that they review assessment results. There were no differences in the proportion of respondents from each profession, χ2 (4, N=98)=6.29, p=0.18, Φ=0.18, or state; χ2 (5, N=98)=2.31, p=0.80, Φ=0.15 who review the results of assessments. Finally, we investigated whether respondents who do not regularly administer assessments (ie, in <30% of assessments), review assessment results instead. Six of the 17 respondents (35%) who do not regularly administer assessments always review assessment results. A further 3 respondents (18%) who do not regularly administer standardised assessments often review these results of assessments that have been administered in other settings.
Two respondents, both sole practitioners, reported that they do not administer standardised assessments in diagnostic evaluations for ASD. These respondents reported that they do not administer standardised measures because they are not part of everyday practice, or because they have already been administered at another service. In addition, one respondent reported that the standardised measures are not required because diagnostic decision-making is outlined in the Diagnostic and Statistical Manual Fifth Edition.
Assessment of co-occurring neurodevelopmental or mental health conditions: Only 23 of the 105 respondents (22%) who administer standardised assessments include additional measures of behaviour or psychopathology. The majority of these clinicians were psychologists (see table 3).
Facing uncertainty in diagnosis: Forty-seven of the 97 (48%) participants who responded to this question reported that they make provisional ASD diagnoses when faced with diagnostic uncertainty. There was no difference in the proportion of provisional diagnoses between the private and public settings, χ2 (1, N=97)=2.53, p=0.11, Φ=0.16, or across the states, χ2 (7, N=97)=12.8, p=0.08, Φ=0.36. Of the respondents who make provisional diagnoses, 34 (72%) reported that this label is rarely used, with the remaining 5 (11%) and 2 (4%) reporting that provisional diagnoses are given occasionally and sometimes respectively. Provisional diagnoses were reportedly given when individuals demonstrated subthreshold symptoms, were very young or would benefit from intervention. Thirty-nine respondents (83%) reported that they reassess individuals with provisional diagnoses within a mean of 13 months (SD=7.96 months).
From 94 respondents, 16 (17%) reported that they have diagnosed ASD when the person did not meet full criteria for the condition. Fifteen of these respondents (88%) reported that this has rarely occurred (<10% of their assessments), with the remaining respondents indicating that it has been occasional (about 30% of assessments). While there was no significant difference in the proportion of overdiagnosis coming from each state, χ2 (7, N=94)=2.41, p=0.79, Φ=0.16, a significantly higher proportion of respondents who made a diagnosis when the individual did not meet criteria came from the private (81%) relative to the public (19%) sector, χ2 (1, N=94)=4.50, p=0.035, Φ=0.22. When asked about the reasons for making the ASD diagnosis, 14 (88%) clinicians reported that they thought that the individual did have ASD, but that the assessment did not reveal the individual's actual diagnostic status. Other commonly reported reasons for the diagnosis were to ensure that the child could access early intervention (n=6), school support (n=5) or disability services (n=3).
Proportion of respondents (N=105) from each discipline who administer developmental, cognitive, language, adaptive, ASD or psychometric assessments