Analysis of descriptive electrophysiological parameters in contralateral interlimb reflexes on tetraplegic patients

Abstract

Study design: Cross-sectional study. Objectives:The present study aims to analyze and correlate the interlimb reflexes (ILRs), through a standard methodology, in tetraplegic and healthy subjects. The study of the connectivity between the injured spinal cord and the ILR transmission empowers new rehabilitation pathways for tetraplegic patients. Setting: University Hospital-UNICAMP, Campinas, Brazil. Methods: A total of 15 chronic tetraplegic patients and 10 healthy subjects were analyzed with the same methodology. Two tests were performed: (i) In test 1, the stimulus was applied to the right-arm radial nerve and the electromyography (EMG) signal collected in contralateral left tibial muscle. (ii) In test 2, the stimulus was applied to the left-leg fibular nerve and EMG collected in contralateral limb biceps, exploring the opposite direction of the pathway. In both tests, the subjects were stimulated with intensities from 5 to 30 mA (5 mA step) and 40 × 500 μs current modulated pulses. Reflexes were detected from the averaging of the 40 EMG sweeps. Results: Each group was analyzed with regard to the reflexes' incidence, amplitude and latency. ILRs were found with similar prominence in both groups. A correlation between the ILR amplitude and the subject injury level was verified. Significant differences were found in the correlation of ILR latency with stimulation charge between healthy and tetraplegic subjects. Conclusion: The ILR transmission parameters of healthy and tetraplegic subjects were studied. The results obtained strongly suggest a different ILR transmission between healthy and tetraplegic subjects, reinforcing the hypothesis of nerve regeneration after injury.