JCPSLP Vol 22 No 1 2020

Table 2. Participant waiting times and diagnosis (Prospective cohort)

Participant

Age (in months)

Waiting time for speech pathology (weeks)

Waiting time for diagnosis (months)

Group allocation Diagnosis

1

72

1

4

Behaviour

Anxiety

2

65

3

6

ASD

ASD

3

48

4

5

ASD

ASD

4

74

1

3

ASD

ASD

5

65

4

2

ASD

ASD

6

48

4

3

ASD

ASD

7

58

4

6

Behaviour

ADHD

8

63

0

*

ASD

ASD

9

99

4

6

ASD

ASD

10

50

0

3

ASD

ASD

11

48

5

**

WNL

**

12

82

3

6

Behaviour

ADHD

13

62

2

4

Behaviour

ODD

14

68

4

8

Behaviour

ADHD

15

62

0

2

ASD

ASD

ASD: autism spectrum disorder; WNL: within normal limits. Waiting time calculated from time of medical evaluation at DPOP clinic * participant went for private paediatrician assessment, ** participant did not attend the Tumbatin multidisciplinary assessment

Table 3. Participant assessment scores (Prospective cohort)

Group

N

Age (yr;mo)

CELF

CCC-2 GCC

CCC-2 SIDC

1 ASD

9

5;2 ± 11.9

109.9 ± 18.9

58.0 ± 15.5

-12.7 ± 12.1

2 Behaviour

5

6;8 ± 9.3

112.2 ± 11.6

50.0 ± 15.1

3.8 ± 16.0

3 WNL

1

4;0

107.0

58.0

-7

CELF: Clinical Evaluations of Language Fundamentals, Preschool 2 or 4th ed., core language score; CCC-2 Children’s Communication Checklist (2nd ed.), general communication composite, social interaction deviance composite. Figures are listed as mean ± standard deviation

ASD. These children are often referred to as “grey” and historically can take a lot of time and resources prior to diagnosis. Lengthy paths to diagnoses, costly multiple assessments, and delays in accessing early intervention can have profound impacts on the child and their family (Bent, et al., 2020). It is therefore important that new models of care which improve the accuracy and timeliness of the ASD diagnosis are implemented and evaluated. The purpose of this study was to determine if the inclusion of a speech-language pathology assessment resulted in the accurate and timely diagnosis of ASD for children historically difficult to diagnose. A secondary aspiration was to increase the number of children receiving a SLP assessment prior to their formal ASD diagnosis, as recent evidence suggests this does not always occur. Speech-language pathologists play a vital role in a differential diagnostic assessment of ASD and an SLP assessment forms part of a gold-standard assessment.

The children in the behaviour group scored a mean GCC of 50.0 and an SIDC of 3.8. While this second category scored on average lower on the GCC, their SIDC score was higher than the ASD group. The one participant in the WNL category (Participant 11) scored a GCC of 58.0 and an SIDC of –7, which is surprising given their presentation during face-to-face assessment and school observation. A child with typical language and social communication development would be expected to have a higher GCC and a positive SIDC. Assessment scores are illustrated in Table 3. Discussion A differential diagnosis of ASD in preschool and school- aged children with normal intellectual functioning can be challenging. Children can present with social communication difficulties that reflect underlying language, behavioural and/or environmental aetiologies, rather than

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JCPSLP Volume 22, Number 1 2020

Journal of Clinical Practice in Speech-Language Pathology