Correlation of somatosensory evoked potentials and long loop reflexes in patients with multiple sclerosis

Based on the results of somatosensory evoked potentials (SEPs) and long loop reflexes (LLRs) obtained from the 50 upper limbs of 25 normal controls by stimulating the median nerve, four regions were set up in a latency correlation diagram between N20 and LLR, which were assumed to mainly represent the afferent and the efferent functions, respectively. Seventy upper limbs of patients with multiple sclerosis, differently marked according to the presence or absence of pyramidal sign and/or impaired vibration sense, were plotted on the diagram. The regions to which the patient belonged turned out to be reasonably compatible with the neurological status of the patient. Simultaneous measurements of SEPs and LLRs are therefore useful to evaluate the afferent and efferent pathways in the central nervous system.