Ten studies were included (n appeared to be 141): one randomised controlled trial (n=17); four controlled trials (n=66); three case series (n=47); one case study (n=6); and one single-subject study (n=5). Sample size ranged from five to 28.
All studies described patients or used comparable treatment groups and all used valid outcome measures. Two studies reported blinded assessment of outcome, two reported treatment fidelity and three used intention-to-treat analysis.
Treatment intensity (five studies, n=68):
For chronic aphasia, all eight effect sizes from four group studies reported greater effects of higher intensity treatment on language impairment. The single-participant study reported mixed effects. Results of treatment intensity on communication activity/participants were mixed for chronic aphasia.
For acute aphasia, effect sizes from one study (n=17) favoured more intensive treatment.
Effects for maintenance of treatment effects in patients with chronic aphasia were mixed in one single-subject study.
CILT (five studies, n=70):
For chronic aphasia, nine of 16 effect sizes from five group studies were large and reported greater effects of higher intensity treatment on language impairment.
For chronic aphasia, eight of 11 effect sizes from three studies reported greater effects of CILT compared to control on language impairment.
Both studies that assessed maintenance reported that the effects of CLIT in chronic aphasia were maintained (at one month and six months respectively).