Feeling stiffness in the back: a protective perceptual inference in chronic back pain

doi:10.1038/s41598-017-09429-1

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Sci Rep. 2017; 7: 9681.

Published online 2017 Aug 29. doi: 10.1038/s41598-017-09429-1

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Table 1

Return to: Feeling Stiffness in the Back

Demographic and baseline questionnaire data.

Demographic variables	Study 1a and 1b			Study 2
Demographic variables	CLBP & stiffness (n = 15)	Healthy controls (n = 15)	p-value	CLBP & stiffness (n = 10)	Healthy controls (n = 10)	p-value
Age (years)	27.1 (8.3)	28.9 (8.3)	0.54	23.4 (4.8)	25.7 (5.4)	0.33

Gender	11M, 4F	10M, 5F	0.69	7M, 3F	6M, 4F	0.64

Height (cm)	176.5 (11.1)	170.2 (11.1)	0.14	176.0 (11.2)	170.5 (13.5)	0.33

Weight (kg)	74.5 (16.5)	73.5 (15.3)	0.85	73.1 (16.5)	71.3 (13.3)	0.80

Current pain	34.3 (15.5)	1.2 (2.2)	<0.001	16.5 (18.4)	0.6 (1.6)	0.02

Avg pain last 48 hrs	36.7 (16.8)	0.6 (1.4)	<0.001	23.0 (17.7)	0.6 (1.6)	0.003

Duration of pain (years)	6.4 (5.1)	n/a	n/a	6.2	n/a	n/a

Current stiffness	43.0 (17.2)	2.0 (2.4)	<0.001	20.8 (16.8)	1.2 (2.1)	0.005

Avg stiffness last 48 hrs	41.3 (19.3)	2.3 (3.7)	<0.001	26.8 (19.2)	1.7 (3.3)	0.003

Body drawing (count)
• Complete/accurate	2	7	0.046	1	4	0.12

• Incomplete/inaccurate	13	8	0.046	9	6	0.12

Modified ODQ	31.2 (15.7)	1.3 (2.5)	<0.001	22.0 (9.7)	0.4 (0.8)	<0.001

Back Beliefs Questionnaire:
Inevitability	29.9 (6.6)	29.9 (5.5)	0.77	20.3 (16.0)	20.9 (15.6)	0.74

State STAI-short form:
Pre-testing	11.0 (4.0)	7.9 (1.7)	0.01	10.7 (4.1)	8.3 (2.1)	0.13

Post-testing	9.9 (3.4)	7.6 (1.6)	0.03	10.4 (3.7)	7.7 (1.9)	0.06

All values are mean (SD) unless otherwise specified. Pain and stiffness measures rated using a 0–100 numerical rating scale (NRS), where higher values represent more pain/stiffness. Body image drawings of the back assessed perception of the back^³² and were coded as either complete/accurate or incomplete (missing parts of the back) or inaccurate (large deviations in drawing of the back). Modified Oswestry Disability Questionnaire (ODQ) has a minimum score of 0 and a total possible score of 100, higher scores represent higher levels of disability^⁶⁷. Back Beliefs Questionnaire has a minimum score of 9 and maximum score of 45 where lower scores represent increased negativity in back beliefs^⁶⁸. Spielberg State-Trait Anxiety Inventory (STAI) short form has a minimum score of 6 and a maximum score of 24; higher scores indicate higher levels of state anxiety^⁶⁹.