Table 1 Demographic, developmental, and clinical manifestations of individuals with SSADHD

Sex, M/F

29 (47%) / 33 (53%)

-

Age, median (IQR)

9.6 (5.4–14.5)

-

Symptom onset (caregiver-reported)

-

0.5 (0.2–0.7)

Diagnosis

-

3.5 (2.0-5.4)

Developmental milestones achieved

Head control

61 (98%)

0.5 (0.3–0.6)

Sitting unsupported

60 (97%)

0.9 (0.6-1.0)

Walking unsupported

56 (90%)

1.6 (1.3–2.5)

First word

54 (87%)

2.3 (1.7-4.0)

Neuropsychologic

FSIQ / DQ, mean ± SD (N = 32)

53.3 ± 13.6

-

Adaptive composite score, median (IQR) (N = 27)

65.0 (56.5–70.0)

-

Autism spectrum disorder diagnosis (N = 30)

17 (57%)

4.0 (2.0–12.0)

REEL-3 receptive age equivalent scores (N = 21)

28.0 (16.0-34.5)

-

REEL-3 expressive age equivalent scores (N = 21)

23.0 (9.7–33.5)

-

MABS percentile rank (N = 20)

13.0 (10.0-22.5)

-

Epilepsy

30 (48%)

9.0 (5.0–12.0)

Drug-resistant epilepsy

11 (18%)

-

EEG- diffuse background slowing (N = 55)

24 (44%)

-

EEG- epileptiform patterns (N = 55)

15 (27%)

Motor and movement

GMFCS 1–3/4–5

53 (85%) / 9 (15%)

-

Hypotonia

40 (64%)

0.25 (0.0-0.5)

Ataxia

25 (40%)

1.5 (1.0–2.0)

Dystonia/Dyskinesia

14 (22%)

1.1 (0.6–10.5)

MRI (N = 39)

No cortical abnormality

28 (71%)

-

T2-weighted hyperintense signal- globus pallidi

18 (46%)

-

T2-weighted hyperintense signal- dentate nucleus

18 (46%)

-

Psychiatric and Behavioral

CBCL/ABCL T-scores, mean ± SD (N = 27)

59.68 ± 8.13

-

OCD behaviors

22 (35%)

4.0 (2.0–9.0)

ADHD diagnosis

28 (45%)

5.0 (4.0-5.1)

Anxiety

25 (40%)

6.0 (3.0–13.0)

Psychosis

3 (5%)

5.0 (4.5–5.5)

Sleep disturbances

Reported sleep disturbances

38 (61%)

1.0   (0.1–1.6)

CSHQ-defined sleep disturbances (N = 32)

25 (78%)

-

Total CSHQ score, mean ± SD (N = 32)

47.8 ± 8.1

-