Risk of bias assessment
| 1. Randomised controlled trials | |||||||
| Cochrane Collaboration Tool Risk of bias items | |||||||
| Study (year) | Sequence generation | Allocation | Blinding of participants and personnel | Blinding of outcome assessment | Outcome data | Selective reporting | Other threats to validity |
| Brooke16 (1992) | U | U | L | L | L | L | H |
| Mooney32 (1993) | U | U | L | H | L | U | H |
| Schneider42 (1999) | U | U | U | U | H | L | H |
| Meythaler41 (2001) | U | U | L | L | U | U | H |
| Meythaler43 (2002) | U | U | U | U | L | H | H |
| Baños39 (2010) | U | U | L | L | L | L | H |
| Yablon33 (2010) | U | U | L | L | L | U | H |
| Giacino40 (2012) | U | L | L | L | L | L | L |
| Hammond35 (2014) | L | L | L | L | U | L | L |
| Tramontana44 (2014) | H | H | L | L | H | L | H |
| Johansson46 (2014) | U | H | H | H | H | L | H |
| Beresford37 (2015) | U | U | L | L | H | L | H |
| Hammond17 (2015) | L | L | L | L | U | L | L |
| Fann45 (2017) | L | L | L | L | L | L | H |
| Hart47 (2017) | U | U | L | L | L | L | L |
| 2. Observational studies | |||
| Study (year) | Newcastle-Ottawa Quality Assessment Scale No of stars awarded | ||
| Selection* | Comparability† | Outcome‡ | |
| Rao50 (1985) | ** | ** | |
| Maturana Waidele38 (2009) | ** | ** | |
| Mysiw49 (2006) | ** | *** | |
| Kooda51 (2015) | ** | ** | |
| Anderson48 (2016) | ** | ** | |
| Gramish36 (2017) | *** | * | |
For Cochrane Collaboration’s Tool: For Newcastle-Ottawa Quality Assessment Scale.
*Maximum four stars.
†Maximum two stars.
‡Maximum three stars.
H, high risk of bias; L, low risk of bias; U, unclear risk of bias.