Hyperventilation in Patients With Chronic Low Back Pain (HELBP)

Low back pain (LBP) is the leading cause of disability worldwide. Impaired postural control is a key factor in the development and maintenance of LBP. Moreover, the prevalence of LBP is associated with impairments in diaphragm function, symptoms of dyspnea, and dysfunctional breathing. However, the association between LBP (and more specifically postural control) and hyperventilation remains unknown. The main objective of this project is to investigate whether the presence of recurrent non-specific LBP is related to the presence of hyperventilation, when classified either objectively by decreased carbon dioxide values (demonstrating hypocapnia) or by symptoms while showing normal carbon dioxide values. Moreover, the investigators will explore whether psychosocial factors play a role in this relation. Subsequently, the investigators will examine whether hyperventilation in LBP patients is related to impaired postural control, and more specifically to a decreased postural contribution of the diaphragm.

11 point Likert scale evaluating severity/intensity of back pain, ranging from 0 (no pain) to 11 (worst pain imaginable)

Questionnaire evaluating physical and mental components of health related quality of life. 12 items. Total score range 12-56.

Questionnaire evaluating the need for being able to control and predict situations. 15 items, 5 point Likert scale. Total score range 15 - 75

Questionnaire evaluating positive and negative affect. 10 items positive affect, 10 items negative affect, 5 point Likert scale. Total score range per affect: 10 - 50

Questionnaire evaluating assimilative and accommodative responses to problems associated with pain. 14 items, 7 point Likert scale. Total score range 0 - 84

Questionnaire evaluating characteristics linked to alexithymia. 20 items, 3 factors. Total score range 20 - 100

Questionnaire evaluating back specific perceptual awareness. 9 items, 5 point Likert scale. Total score range 0-36

Questionnaire evaluating aversive experiences in adult life. 11 items should be scored with yes or no. If yes a score on a 5 point Likert scale should be given.

Questionnaire evaluating adaptive and maladaptive perfectionism. 35 items, 5 point Likert scale. Total score range 35 - 175

Questionnaire evaluating subjective level of physical activity. 7 questions regarding amount of time spent on certain activities.

Inclusion Criteria Patients: Chronic primary low back pain (>12 weeks) as diagnosed by a medical doctor Inclusion Criteria Healthy controls: No low back pain Exclusion Criteria: Insufficient understanding of Dutch language Previous spinal surgery Chronic Obstructive Lung Disease, Interstitial Lung Disease, pulmonary vascular disease, asthma except for exertional asthma Acute cardiovascular or gastrointestinal disorders Neuromuscular disease interfering with normal lower limb or trunk functioning Acute pain or secondary chronic pain Pregnant and lactating women Major psychiatric conditions Acute lower limb problems Vestibular disorders