Table 1.

Quality Assessment of included studies.

Study	Randomisation (appropriate description?)	Concealment (appropriate description?)	Patient blinding (appropriate description?)	Withdrawals and dropouts	Comparable baseline groups	Total (max 8)
Wolkenstein 1996 [16] & Horak 1993 [18] 1998 [17]	1	0	0	0*	0	2
Langer & Hauswald 1989 [19]	1	0	0	1	0*	2
Ng et al 2004 [21]	1 (1)	1 (0)	1 (1)	1	1	7
Magnusson et al 2004 [15]	1 (1)	0	1 (1)	1	0	5
Williamson et al 1996 [23]	1 (1)	1 (1)	1 (1)	1	0*	7
Petti et al 2002 [20]	1 (0)	0	0	1	1	3
Xue et al 2002 [22]	1 (0)	0	1 (1)	1	0	4

* Information unclear

A score of 1 was given for each parameter fulfilled in the text with an additional point for adequate description of randomisation, allocation concealment and blinding. A 0 was scored where no description or detail was given.