Quantifying motor control of the lumbar spine by a dynamic sitting device; a pilot reliability study

Abstract

Abstract: Introduction: Nearly everyone is affected by low back pain at some point in time. The presence of pain can cause adaptive or protective altered movement and motor control impairments. Ongoing mal-adaptive motor control behaviour can lead to a chronic state of pain. A significant cause of non specific chronic low back pain is lumbar segmental instability. Patients with lumbar segmental instability demonstrate an inability to reposition the lumbar spine accurately. A newly introduced dynamic sitting device measures how accurately a subject completes different tracks by using lumbar stabilizing muscles, and thereby provides insight into the ability to coordinate lower back muscles. The present study was set up to estimate the reliability and agreement parameters over the test scores given by the TBT. Methods: Four therapists tested six patients (mean age: 43,8 SD ±7,7 years) with low back pain, on two days with at three-week intervals. Whilst sitting on a dynamic sitting device the patients had to cover a presented track. The movements in the lower back were measured by a computer, the precision with which the movements were made was scored. The inter-rater reliability was calculated using intraclass correlation (ICC), test retest data were analyzed using a paired t-test for four different tracks. Results: The number of completed cycles showed a good to excellent reliability (ICC: 0.87-0.90). Differences in time spent between opposite sides of the track gave good reliability scores (ICC: 0.72-0.97). Over three weeks a significant (p<0.05) improvement was found in the number of cycles covered. Conclusion: It is legitimate to compare scores measured by different raters. This instrument seems useful to objectively quantify the ability to reposition the lumbar spine. Future research needs to focus on a larger sample size of patients with LBP to enforce knowledge about this instrument as a diagnostic device.