P44-S Sensorimotor integration in fibromyalgia

Abstract

Background Fibromyalgia, is a chronic pain disorder, especially common in women, characterised by widespread pain, fatigue, sleep disorders and cognitive dysfunction. Recently prolonged somatosensory temporal discrimination values was shown in fibromyalgia patients compatible with impaired central sensory processing. However knowledge about sensorimotor integration in fibromyalgia is still lacking. Short latency afferent inhibition (SAI) is a phenomenon in which sensory stimulus modulates motor response. SAI is associated with cholinergic system, cognitive functions and sensorimotor integrity. In this study, sensorimotor integration is assessed with SAI paradigm in fibromyalgia patients for the first time. Methods 15 fibromyalgia patients and age-gender matched 15 healthy subjects were included in the study. Severity of pain and other symptoms were evaluated with visual analogue-scale and symptom severity scale respectively, cognitive functions were assessed with neuropsychological tests. Basal motor evoked potential (MEP) was recorded from right abductor pollicis brevis muscle at rest. SAI was obtained by right median nerve direct electrical current stimulation at twice the intensity of sensory threshold, 21 ms in advance of left motor cortical magnetic stimulation. Mean MEP amplitude ratio, recorded after single and conditioned stimulations, were calculated as SAI. Results No significant difference was found between the groups in terms of SAI values (Control group: 40.3 ± 23.4% inhibition; fibromyalgia group: 34.3 ± 25.6% inhibition, p = 0.51). There was no correlation between SAI values and severity of pain and other symptoms and cognitive function scores in the fibromyalgia group. Conclusion Even though sensory processing is impaired, sensorimotor integration and neural pathways that generate and modulate SAI remain intact in fibromyalgia.