The Neural Basis of Lumbosacral Proprioceptive Impairment in Recurrent Low Back Pain

Low back pain (LBP) is a well known health problem in Western society that is significantly responsible for socio-economic problems like absenteeism and disability. The lifetime prevalence of LBP is 60-80% and approximately 85% of this LBP has a "non-specific" character whereby the underlying causes and risk factors cannot be demonstrated. While many people recover within a month, most individuals will have recurrence within a year with more severe symptoms. This might be due to insufficient knowledge of the underlying mechanisms. Impaired proprioception, the ability to discern body/limb positions and movements, may cause and maintain LBP shown by an altered postural control strategy. Specifically, patients with LBP rely more on proprioceptive signals from the ankles due to less reliable proprioceptive input of proximal segments. Moreover, they show a decreased variability in postural control and less postural robustness, while variability is a prerequisite for optimal functioning of biological systems. However, further clarification of the neural correlates is necessary. Deficits in proprioception, as found in a subgroup of patient with LBP, are associated with a decreased ability of the brain to process proprioceptive inputs.

The aim of this project is to clarify the evaluation process (e.g. (re)weighting) of proprioception between the sensory input and the motor output. MRI techniques (fMRI and DTI) will be used for a subgroup of LBP patients with a stereotypic ankle steered postural control and a group of healthy controls to determine brain activation during the application of strictly proprioceptive signals in a well established protocol using air-driven fMRI compatible muscle shakers.