Clinical and evoked potential changes in acute transverse myelitis following methyl prednisolone

Study design: Observational study with sequential follow-up. Objective: To study the role of somatosensory evoked potential (SEP) and mo tor evoked potential (MEP) in monitoring the effect of methyl prednisolone (MPS) therapy in acute transverse myelitis (ATM). Setting: Tertiary care referral teaching hospital at Lucknow, India. Methods: In the present study, nine patients with ATM whose age ranged betw een 12 and 42 years and three of whom were females have been included. They were subjected to clinical examination, median and tibial SEP and Central motor conduction time (CMCT) to upper and lower limbs. The clinical and evo ked potential studies were repeated after 7 and 90 days of intravenous meth yl prednisolone treatment for 5 days. The outcome was defined on the basis of a 3 month Barthel Index (BI) score into poor (BI<12) and good (BI greate r than or equal to 12). Results: All the patients had varying degrees of leg weakness ranging betwe en grade 0 and 4 on the Medical Research Council scale. Upper limbs were we ak in four patients. Pinprick and joint position sensations in the lower li mb were impaired in all patients. Central motor conduction time to upper li mb was abnormal in two patients and to lower limbs in eight patients. Media n SEPs were normal in all and tibial in two patients. On the seventh day fo llow-up, muscle power improved in six which correlated with CMCT-to tibiali s anterior in five patients. Joint position sense improved in two patients on the seventh day but there was no further improvement at 3 months. Tibial SEP, however, improved in four patients on the seventh day and six patient s at 3 months. Following methyl prednisolone therapy, both sensory and moto r functions improved, but the improvement was more pronounced and more freq uent at 3 months compared to that on seventh day. At a 3 month follow-up, s ix patients had good and three poor recovery. Conclusion: Evoked potential studies provide additional objective means for monitoring the effect of therapy in ATM.