Table 1 Patient and study characteristics

Bremer (2004)^T0 [16]

U.S.A

49 (29)

Longitudinal

57.8 (13.0)

34.9 (13.2) mo^O

27.9 (6.3)

El Escorial

n.m

Chio (2004) [13]

Italy

80 (49)

Cross sectional

59.8 (12.6; 26–81)

2.1 (1.7; 1–7.8) yr^O

26.6 (9.5; 3–38)

El Escorial

n.m.

Clarke (2001) [15]

Ireland

26 (18)

Cross sectional

63^M (34–86)

31.5 (4–156)^M mo^D

22.5^M (11–36)

El Escorial

n.m

Dal Bello-Haas (2000) [47]

U.S.A

60 (38)

Cross sectional

56.2 (12.2)

n.m

n.m

El Escorial

n.m.

Ganzini (1999) [45]

U.S.A.

100 (61)

Cross sectional

54^M (51.6–56.8)

2.8 (2.0–3.6)^M yr^D

n.m

n.m

n.m

Gibbons (2013) [37]

U.K.

147 (90)

Cross sectional

61 (11; 35–81)

n.m

22.3 (9.5; 4–48)

‘confirmed diagnosis’

n.m

Goldstein (2002) [38]

U.K

31 (19)

Cross sectional

64.0 (11.9)

15.9 (5.2) mo^D

n.m

El Escorial

n.m

Ilse (2015) [10]

Germany

49 (25)

Cross sectional

63.8 (10.0)

35.1 (36.3) mo^O

32.6 (9.2) ^R

El Escorial

33 %

Krampe (2008)^T0 [27]

Germany

31 (19)

Longitudinal

60.3 (10.4; 32.9–79.7)

96.3 (70.5; 22.4–330.4) wk^O

27.0 (6.6; 12–38)

El Escorial

19 %

Lule (2008)^T0 [28]

Germany

39 (19)

Longitudinal

n.m

43.9 (37.5; 0–170) mo^D

19.9 (21.1; 0–39)

El Escorial

n.m

Matuz (2010) [36]

Germany

27 (15)

Cross sectional

55.3 (11.1; 35–73)

36 (4–129) mo^D

17.4 (9.8; 0–36)

‘by a neurologist’

7 %

Matuz ^T0 (2015) [30]

Germany

27 (15)

Longitudinal

55.3 (11.1; 35–73)

43.2 (30.5; 4–129) mo^D

17.4 (9.8; 0–36)

El Escorial

7 %

McCabe (2009) [19]

Spain

120 (72)

Cross sectional

63.2 (12.4)

5.7 (5.8)^O yr

n.m

n.m

n.m

Montel (2012) [46]

France

49 (26)

Cross sectional

63 (12)

45 (28) mo^O

28.2 (9.0)^R

El Escorial

22 %

Pagnini ^T0 (2015) [29]

Italy USA

197 (115)

Longitudinal

^a

^a

30.6(9.9)^SA

‘self-declared’

n.m

Peric (2010) [40]

Serbia

74 (45)

Cross sectional

57 (11)

29 (27) mo^O

34 (8)^R

El Escorial

n.m.

Pizzimenti (2013) [43]

Italy

36 (22)

Cross sectional

63.7 (10.9)

22 (14) mo^O

35.1 (8.7)

El Escorial

22 %

Robbins (2001)^T0 [31]

U.S.A

60 (32)

Longitudinal

58.5 (13.5; 27–83)

n.m

28.1 (6.3; 12–39)

El Escorial

n.m

Simmons (2000) [14]

U.S.A

96 (52)

Cross sectional

57.8 (23–80)

31.8 (2 mo-10 year) mo^O

26.6 (9–39)

‘met the criteria’

n.m

Tramonti (2012) [42]

Italy

40 (30)

Cross sectional

59.1 (10.9; 34–84)

n.m

20.8 (8.3; 7–36)

n.m

n.m

Vignola (2008)^TD [41]

Italy

29 (20)

Cross sectional

63.6 (7.8; 44–78)

11.7 (23.7; 2–43) mo^O

33.1 (4.8; 22–39)

El Escorial

n.m

Winter (2010) [44]

Germany

37 (21)

Cross sectional

59.6 (11.0)

2.3 (1.9) yr^O

n.m

El Escorial

n.m