Table 2 Autism Diagnostic Interview-Revised (ADI-R) score differences between the preterm and term ASD groups

Domain A: Qualitative abnormalities in reciprocal social interaction

F value = 6.2 P < 0.001

 A1: Failure to use nonverbal behaviors to regulate social interaction

3.8 (1.9)

3.2 (1.8)

1.7

0.20

1

0.34

 A2: Failure to develop peer relationships

3.9 (2.0)

5.6 (1.8)

10.2

0.002

0.024

0.024

 A3: Lack of shared enjoyment

3.2 (1.8)

3.7 (2.0)

0.9

0.35

1

0.47

 A4: Lack of socioemotional reciprocity

4.1 (2.0)

5.2 (2.3)

3.2

0.08

0.96

0.19

 Total A: A1 + A2 + A3 + A4

14.9 (6.5)

17.6 (6.1)

2.3

0.13

Domain B: Qualitative abnormalities in communication

F value = 1.5 P = 0.20

 B1: Lack of or delay in spoken language and failure to compensate through gesture

2.9 (2.4)

3.9 (2.4)

1.4

0.24

1

0.36

 B4: Lack of varied spontaneous make-believe or social imitative play

3.6 (1.7)

4.0 (1.5)

0.2

0.65

1

0.71

 B2(V)^b: Relative failure to initiate or sustain conversational interchange

2.8 (1.2)

3.4 (1.1)

3.5

0.07

0.84

0.19

 B3(V)^b: Stereotyped, repetitive, or idiosyncratic speech

2.4 (2.0)

3.4 (1.9)

3.1

0.08

0.96

0.19

 Total B(V)^b: B1 + B4 + B2(V) + B3(V)

11.8 (5.4)

14.4 (4.3)

3.8

0.06

Domain C: Restricted, repetitive, and stereotyped behavioral patterns

F value = 1.3 P = 0.28

 C1: Encompassing preoccupation or circumscribed pattern of interest

1.2 (1.4)

1.8 (1.2)

2.9

0.10

1

0.2

 C2: Apparently compulsive adherence to nonfunctional routines or rituals

1.2 (1.5)

1.4 (1.5)

0.1

0.73

1

0.73

 C3: Stereotyped and repetitive motor mannerisms

0.8 (1.1)

1.0 (1.0)

0.5

0.49

1

0.59

 C4: Preoccupation with parts of objects or nonfunctional elements of material

1.0 (0.8)

1.5 (0.8)

4.3

0.04

0.48

0.19

 Total C: C1 + C2 + C3 + C4

4.2 (3.1)

5.6 (3.0)

2.8

0.10