Table 2.

Descriptive and psychometric FOGQsa data

		Total sample n = 225		Clinical sample n = 36		Postal survey sample n = 189
Item		Mean (SD)	Corrected Item-total correlations n = 214	Mean (SD)	Corrected Item-total correlations n = 35	Mean (SD)	Corrected Item-total correlations n = 179
1	"Walking during worst state"	1.6 (1.1) 2 missing	0.68	1.7 (1.2) 1 missing	0.87	1.6 (1.1) 1 missing	0.64
2	"Gait difficulties affecting daily activities and independence"	1.1 (1.1) 2 missing	0.68	1.2 (1.1) 1 missing	0.76	1.1 (1.2) 1 missing	0.68
3	"Feet getting glued to the floor"	1.1 (1.4) 1 3 missing	0.83	1.7 (1.4)	0.82	1.0 (1.4) 2 missing	0.84
4	"Duration of longest freezing episode"	0.87 (1.3) 7 missing	0.89	1.6 (1.6)	0.91	0.73 (1.1) 7 missing	0.90
5	"Duration of typical start hesitation"	0.76 (1.1) 6 missing	0.88	1.2 (1.4)	0.85	0.67 (1.1) 6 missing	0.89
6	"Duration of typical turning hesitation"	0.76 (1.1) 5 missing	0.83	1.1 (1.4)	0.78	0.68 (1.1) 5 missing	0.85
		Total score n = 214		Total score n = 35		Total score n = 179
	Mean (SD)	6.1 (6.2)		8.6 (7.2)		5.6 (5.9)
	Median, q1-q3	4.0, 1.0-4.0		8.0, 2.0-14.0		4.0, 1.0-9.0
	Min-max	0-22		0-22		0-22
	% scoring minimum (0)/maximum (24)	19/0		17/0		20/0
	Reliability, Cronbach's alpha (95% CI)	0.93 (0.91-0.94)		0.94 (0.90-0.97)		0.93 (0.91-0.94)

FOGQsa: Freezing of Gait Questionnaire, self administered version. Each item is scored between 0-4, and the total score thus ranges between 0-24. Higher scores denote more severe FOG.

Some participants left certain items blank. Total scores could therefore be computed for 214 out of the 225 (95%).

¹ On item 3, 126 scored 0, i.e. they never experienced freezing episodes, whereas 96 out of the 214 (45%) scored at least 1 and could be defined as "freezers".

Out of the 96 reporting freezing episodes, 51 did so "often- about once a day" and 11 "always- whenever walking".