Running head: Early Developmental Regression in ASD 3

ONLINE APPENDIX

Characteristics of regression and subsequent developmental progress reported in recent studies

Study characteristics / Mean duration of skill loss (months) and developmental outcome following regression
Shinnar et al. 2001
Criteria: ‘Any language regression’
Subjects: 177 children with language regression (155 with ASD)
Mean age at regression: 22.8 months / 57% with improved language mean 46 months after regression episode; developmental outcome not reported
Wilson et al. 2003
Criteria: ‘Any language regression’
Subjects: 196 children with language regression (182 with ASD)
Mean age at regression: 21.2 months / Mean interval between onset of regression and review 34.8 months; at that time, 39% children were ‘non verbal’ at follow up, further 45% had ‘reduced verbal output’.
Of 120 children reported to have not preceding developmental difficulties, 61% had some improvement following regression; time between regression and onset of recovery mean 13.4 months
Developmental outcome not reported
Goldberg et al. 2003
Criteria: ADI-R (5 or more words lost) and Regression Supplement Form
Subjects: Regression occurred in 44/132 (33%) children with ASD
ASD
Mean age at regression: Language regression only - 20.7 months; Non language regression - 18.6 months / 75% reported to have some improvement in area of loss. Mean time from loss to regain for children who lost 5 or more words 23.9 months.
Mean IQs reported for regression group only
Lord et al. 2004
Criteria: ADI-R (word loss)
Subjects: Regression occurred in 14/68 (21%) with autism; and 5/28 (18%) with PDD-NOS
Mean age at regression: 16.1 months (children with autism or PDD-NOS) / For word loss vs. no regression groups (significant difference where noted):
Mean time from loss to words to being regained 4.7 months
Verbal IQ: Autism group – similar at age 2 and 5 years for both word loss and no loss groups; PDD-NOS group – statistically significantly higher mean IQ for word loss group than no loss group at both ages 2 and 5 years.
Performance IQ: Autism group – higher at age 2 for no loss group, similar between groups at age 5 years; PDD-NOS group – higher for word loss group at both 2 and 5 years
For both the autism and the PDD-NOS groups: No significant difference between PL-ADOS, ADOS and ADI-R domain scores found for children with and without word loss
When autism and PDD-NOS groups considered together (and children with developmental delay were included), children with loss of any vocalisation had a statistically significantly higher mean ADI-R social domain score and PL-ADOS score (i.e. more impaired)
Luyster et al. 2005
Criteria: ADI-R and telephone interview (word loss)
Subjects: Word loss occurred in 125/351 (36%) with ASD; non language regression occurred in 38 children with ASD
Mean age at regression: 20.2 months (word loss group) / Verbal IQ: word loss group had statistically significantly lower mean verbal IQ (mean 56.7) than non regression group (mean 66.6); non language regression group had non significantly lower verbal IQ (mean 55.2) than non regression group
Performance IQ: Both word loss and non language regression groups had similar mean performance IQs (72.3 and 71.5 respectively) (non regression group mean 80.0)
Both word loss and non language regression groups were significantly more affected than the non regression group on subsets of the MacArthur Communication Development Inventory at both age 24 months and 36 months
Richler et al. 2006
Criteria: Parent interview and ADI-R
Subjects: Children with ASD whose parents reported some loss of skills; regression occurred in 188/351 (53.6%) / Regression group had lower mean VIQ and higher ADI-R social domain scores than non regression group: VIQ 56.7 vs. 66.3, p<0.05); ADI-R social domain score 20.6 vs. 18.9, p<0.05)
Baird et al. 2008
Criteria: ADI-R
Subjects: Word or vocalisation loss in 35/158 (22.2%) children with autism or ASD
Mean age at regression 25.0 months for individuals with word loss / No statistically significant difference between regression and non regression groups in: mean IQ (definite regression 65.0, lower level regression 60.6, no regression 70.3); or Vineland scores (definite regression 43.3, lower level regression 37.5, no regression 46.7)
ICD-10 symptom score significantly greater in the regression than non regression group