Characteristics of the studies included
| Study | Trial type | Method of randomisation | Blinding | Duration of follow-up(months) | Diagnostic criteria | Age (years) | Follow-up | AIT interventions | Control condition |
|---|---|---|---|---|---|---|---|---|---|
| ABC, Aberrant Behaviour Checklist; AIT, auditory integration training; ASD, autism spectrum disorder; DSM-IV, Diagnostic Manual of Mental Disorders (4th edn); ICD, International Classification of Diseases; RCT, randomised controlled trial. | |||||||||
| Bettison,13n = 80 | Parallel RCT | Random numbers table | Outcome assessors blinded, investigators not blinded | 12 | Autism or Asperger’s syndrome diagnosed by an independent agency | 3–17 | No loss to follow-up | 2×30 min sessions for 10 consecutive days | As for AIT but music unmodified |
| Edelson et al,14n = 18 | Parallel RCT | Telephone number | Outcome assessors blinded, investigator not blinded | 3 | Autism diagnosed by an independent agency and Rimland Diagnostic E-2 checklist18 | 4–39 | Data from one control participant excluded due to no match in the AIT group | 2×30 min sessions for 10 consecutive days | As for AIT but music unmodified |
| Mudford et al,15n = 16 | Crossover RCT | Geographically divided into groups,then into subgroups alphabetically,by the first letter of their name | Investigators and outcome assessors blinded | 14 | Diagnosis: autism(DSM-IV or ICD-10 criteria) | 5.75–13.92 | 5 lost to follow-up due to lack of cooperation,safety issues,transport problems | 2×30 min sessions for 10 consecutive days | As for AIT, but headphones non-functional and unmodified music played in the room (not through AIT device) |
| Rimland and Edelson,11 n = 17 | Parallel RCT | Last 2 digits of telephone number | Outcome assessors blinded, investigator not blinded | 3 | Autism diagnosed by an independent agency and Rimland Diagnostic E-2 checklist18 | 4–21 | 1 lost to follow-up due to transport problems | 2×30 min sessions for 10 consecutive days | As for AIT but music unmodified |
| Veale,17n = 10 | Parallel RCT | Last 2 digits of telephone number | Outcome assessors blinded, investigator not blinded | 3 | Autism diagnosed by an independent agency | 6–10 (approximately) | No loss to follow-up | 2×30 min sessions for 10 consecutive days | As for AIT but music unmodified |
| Zollweg et al,16n = 30 | Parallel RCT | Random numbers table | Investigators and outcomes assessors blinded | 9 | Cognitive impairment including ASD diagnosed by an independent agency | 7–24 | 28 analysed for ABC at 9 months,22 analysed for loudness discomfort, 14 analysed for pure tone thresholds | 2×30 min sessions for 10 consecutive days | As for AIT but music unmodified |