Parameter
Group
EO
EC
BF
R (mm)
Controls
2.0
1.9
2.3 #,$
(1.7–2.6)
(1.6–2.6)
(1.8–2.8)
OA
2.7**
2.8***
3.2***,##
(2.4–3.4)
(2.2–3.8)
(2.5–4.1)
RA
2.6**
2.8**
3.3***,###,$$
(2.1–3.4)
(2.1–3.4)
(2.7–4.1)
A (cm2)
Controls
139
130
165 ###,$
(97–185)
(99–212)
(107–231)
OA
178*
222**,+
283***,###
(138–250)
(141–367)
(192–406)
RA
186**
236***,++
296***,###,$$$
(144–240)
(160–302)
(182–508)
LRL (mm)
Controls
111
115 ++
117 ##
(96–123)
(103–127)
(104–131)
OA
110
114 +++
149*,###,$$
(95–123)
(101–133)
(110–194)
RA
114
122 ++
149***,###,$$$
(99–129)
(107–149)
(116–213)
FBL (mm)
Controls
147
176 +++
173 ###
(129–170)
(150–210)
(144–216)
OA
166
205*,+++
212 ###,$
(138–209)
(162–297)
(162–247)
RA
176***
230***,+++
225**,###
(157–212)
(186–284)
(180–265)
TL (mm)
Controls
210
238 +++
234 ###
(189–238)
(202–272)
(208–281)
OA
221
279 +++
285*,###
(192–280)
(215–349)
(246–368)
RA
245**
286**,+++
297***,###,$
(206–284)
(248–346)
(248–418)
BF (%)
Controls
–
–
97
(93–99)
OA
–
–
88***
(77–94)
RA
–
–
87***
(77–92)
Figure 1 presents the raw recordings of posturogram trajectories in an RA patient in the EO, EC, and BF conditions. This patient exhibited larger sways in the EC condition compared with the EO and BF conditions.
Fig. 1
Representative trajectories of a rheumatoid arthritis patient in eyes open (EO), eyes closed (EC), and biofeedback coordination (BFC) tests
Table 2 and Fig. 2 demonstrate the results of receiver operating characteristic (ROC) curves in rheumatic patients. LRL motions in the EO, EC, and BF tests resulted in larger area under the curve (AUC) values than other motions did, but the maximum of AUC (>0.75) has been obtained for the BFC parameter. The sensitivity and specificity above 0.75 was achieved when the cut-off point of BFC equaled 92 %.
Table 2
Area under curve (AUC) values of ROC analysis
