New Parameter in Multiple Sclerosis Analysis

Changes in motor evoked potentials in patients with multiple sclerosis (MS) during the process of magnetic stimulation were analysed. Several specific muscle responses were studied and a new multiplication factor (MF) was defined as the ratio between average latency times or central motor conduction times (CMCTs) and average times with a reference in healthy group and corresponds to each grade of Kurtzke Disability Status Scale. This parameter shows a great utility in the assessment of motor dysfunction, correlating with the severity and nature of MS with a special role both in disease diagnosis and tracking of the evolution of pathological processes from the early illness stages until Kurtzke scale value of 6. The variation of multiplication factor values on each appropriate muscle response is presented, depending on the specific magnetic stimulation and the Kurtzke scale. Four multiplication factor types were defined by taking into account CMCTs and respective latency times for cortical, cervical and lumbar stimulations.