Stability of the ADI-R
scores for the group as a whole and at an individual level; b. exploration of T1 factors that were
associated with ADI-R outcomes at FU.
In line with previous studies (e.g. Bolte and Poustka, 2000; Fecteau et al., 2003; Piven et al., 1996;
Seltzer et al., 2003; Starr et al., 2003), it was predicted that ADI-R scores would decrease between the
ages of 3 and 10 years, indicating an improvement in symptom severity over time.
Method
Recruitment
Initial recruitment was conducted between July 1998 and April 2000 (T1). Parents of children with a
diagnosis of autism or ASD were contacted via the following sources: Local Educational Authorities,
diagnostic and treatment centres and specialist schools across greater London and the UK National
Autistic Society (NAS). In September 2005, all families included at T1 were invited to participate in
the follow-up study (FU).
Participants were included in the current study if they met the following criteria1 at T1: a. chronological
age (CA) 22-54 months; b. enrolled in specialist pre-school provisions (either home-based behavioural
programmes or autism specific nurseries); c. independent professional diagnosis of autism or ASD
prior to participation and meeting algorithm criteria for autism on the ADI-R; d. no additional major
medical diagnoses; e. English the main language spoken at home. Additionally, all children included in
the current study were those who had received an ADI-R assessment at T1 and FU.
Participants
A total of 75 children was assessed between July 1998 and April 2000. Six to 8 years later, 56
participants (72.7% return rate) agreed to take part in the FU study, 35 of whom met all of the inclusion