Ten studies (reported in 12 papers) were included: seven randomised controlled trials (RCTs; n=171) and three non-randomised controlled studies (n=96).
The authors stated that the designs of the included RCTs had many shortcomings. All of the included studies had small sample sizes.
In one RCT children in the parent training group had (statistically significant) less severe social communication impairments and better social interaction post-intervention compared with those who received routine care. In one RCT children in the Intensive ABA group had a statistically significant higher IQ post-intervention than the parent training group. In one controlled study parent-reported general behaviour problems and obsessions and rituals were lower amongst children in the parent training group than the control group, though the level of child play was higher in the control group. In another controlled study children receiving routine care were rated by parents as higher in terms of response to their parents, to other adults and to peers compared with the parent training group. Based on two pooled studies there was a benefit in favour of parent training groups on words understood by children (WMD 75.84, 95% CI: 10.95, 140.72, p=0.02) and words said (WMD 69.66, 95% CI: 2.39, 136.94, p=0.04). There was no statistically significant difference between groups on several other child outcome measures.
In one RCT parents and child careworkers in the parent training group had a statistically significant greater knowledge of autism than the control group post-intervention, though the authors suggest this was of limited clinical significance. In one RCT stress and workload during the intervention was rated as higher in the parent training group than in the Intensive ABA group. There was no statistically significant difference between parent training and control groups in any of the other studies assessing parental stress (n=3). In one controlled study information given from mothers, praise, correct responses, direct responses and maternal utterances were greater in the parent training group than in the control group. In one controlled study mothers in the parent training group had lower levels of depression than controls.
There were (statistically significant) better parent interaction strategies with their child in the parent training group compared with the control group in one RCT. There were statistically significant benefits in favour of the pivotal response training group compared with individual target behaviour group on the observed interaction outcomes of happiness, low stress and communication style, though the authors questioned the clinical significance of these. In one controlled study there was less disruptive behaviour during play in the parent training group than in the control group, but poorer interaction between mothers and children during unoccupied periods.