Table 1 Participant demographics, behavioral assessments, and outcome assessments by likelihood group. Count is shown for categorical variables. Mean ± standard deviation is shown for continuous variables (age, motion metrics, and behavioral assessments)

N

30

19

N/A

Sex (Female)

8 (26%)

13 (68%)

6.66

0.009**

Age (Months)

9.17 ± 0.31

9.08 ± 0.39

0.88

0.38

Race¹

 White

15

12

0.04

0.83

 Nonwhite

12

7

Ethnicity²

 Hispanic

9

1

2.73

0.10

 Non-Hispanic

21

17

Maternal Education³

 No college

0

0

10.85

0.001***

 Some college or bachelor’s degree

22

4

 Post-graduate education

7

14

Birth Order⁴

 First

0

8

17.41

< 0.001***

 Not first

30

10

Exposure to English (%)

89.5 ± 16.6

92.4 ± 13.9

 0.65

0.52

Mean Absolute Motion (mm)

0.21 ± 0.21

0.36 ± 0.57

1.11

0.28

Mean Relative Motion (mm)

0.07 ± 0.04

0.11 ± 0.11

1.47

0.16

# Motion Outlier Volumes

1.07 ± 2.24

3.53 ± 8.94

1.18

0.25

MSEL T-scores (12 months)

 Gross Motor

49.7 ± 9.4

48.8 ± 15.3

0.21

0.83

 Fine Motor

59.5 ± 9.7

67.7 ± 7.8

3.12

0.003**

 Visual Reception

56.8 ± 6.8

60.5 ± 7.7

1.64

0.11

 Receptive Language

46.8 ± 8.3

53.2 ± 5.2

3.15

0.003**

 Expressive Language

46.67 ± 12.2

51.8 ± 9.2

0.66

0.51

MSEL T-scores (36 months)

 Gross Motor

–

–

–

–

 Fine Motor

51.5 ± 16.3

59.7 ± 12.9

1.79

0.08

 Visual Reception

56.7 ± 18.0

66.5 ± 8.2

2.36

0.02*

 Receptive Language

49.1 ± 14.2

63.0 ± 8.2

3.97

< 0.001***

 Expressive Language

50.8 ± 12.9

61.3 ± 7.2

3.36

0.002**

Vineland (12 months)

 Communication

85.4 ± 21.5

100.3 ± 15.6

2.50

0.02*

 Socialization

85.1 ± 24.3

86.8 ± 34.2

0.13

0.87

Vineland (36 months)

 Communication

95.2 ± 17.0

110.7 ± 8.8

3.76

< 0.001***

 Socialization

92.9 ± 17.1

111.0 ± 8.5

4.44

< 0.001***

AOSI (12 months)

4.93 ± 2.8

3.6 ± 2.1

1.17

0.09

ADOS-2 (36 months)

2.7 ± 1.5

2.2 ± 2.2

0.77

0.45

Outcome Classification

 ASD

6

0

8.76

0.013*

 TD

13

15

 Other Concerns

7

1

MCDI (12 months)

 Words Comprehended

38.5 ± 48.8

66.5 ± 49.1

1.83

0.08

 Words Produced

5.9 ± 9.8

4.1 ± 5.1

0.80

0.43

MCDI (36 months)

 Words Produced

460.3 ± 210.5

590.1 ± 94.6

2.48

0.02*

ESCS (12 months)

 IJA

14.0 ± 8.1

11.6 ± 7.0

0.91

0.37

 RJA

4.4 ± 2.5

8.0 ± 2.9

3.80

< 0.001***