STUDY ON THE DAILY VARIABILITY OF H/M RATIO IN NORMALS AND PARAPLEGIC PATIENTS
L. Brunati*, M. Ferrarin°, B. Roman*, R. Spadone°, V. Samarani°, A. Mangoni*
IRCCS Fnd. Pro Juventute D. Gnocchi, Neurophysiology Service*, Bioengineering Centre°, Milano, Italy
Purpose: the ratio H/M is an index of spinal motor neuron excitability and it is correlated with the spasticity level in patient. This value is influenced by sovraspinal and spinal pathway. The aim of this study is to evaluate its variability during the day in order to use it in longitudinal studies for the assessment of antispastic treatments.
Method: in this study H reflex was evaluated through the classical procedure explained in literature. The test was performed five times within one session, to compute intrasession variability, and each session was repeated four times during the day, to estimate the intersession variability, for a total of twenty tests in a day. Results: we studied 11 healthy subjects and 9 paraplegic patients with spinal cord injury. Healthy subjects: the mean H/M ratio averaged on all subjects resulted: 0.55±0.21. The intrasession variability, calculated as the mean on all subjects of the SD of each sessions, resulted 0.03±0.02. The variability among the sessions was 0.06±0.03. Paraplegic patients: the mean H/M ratio of all patients was 0.68±0.11. The intrasession variability was 0.03±0.02 and the variability among the sessions was 0.09±0.05.
Conclusion: our data confirm the great variability of H/M ratio both in healthy subjects and in patients. We have found a higher value of H/M ratio in paraplegic patients than in normal but without statistical significance. We have obtained a higher intersession variability in paraplegic than in normal subjects. Therefore we advise to record the range of daily variability of H/M ratio in each patient before treatment application and then to interpret the value obtained after the treatment according to this range of variability.
P-3-01-07
SACRAL DERMATOMAL SOMATOSENSORY EVOKED POTENTIAL IN THE SPINAL CORD INJURED
Jeong-Hwan Seo, Wan-Ho Kim, Yong-Il Shin (Chonbuk National Univ., Chonju, Republic of Korea)
The purpose of this study is to present the method, normal values and clinical significance of sacral dermatomal somatosensory evoked potential(SDSEP) study in spinal cord injured patients. Thirty normal subjects and 33 spinal cord injured patients were enrolled. Using ring electrode, S3 dermatome was stimulated by Viking IV EMG/EP system. Evoked responses were recorded at cortex (Cz'-Fz) by conical needle electrode. The latencies and amplitudes of SDSEP and pudendal SEP responses were obtained and analyzed. In normal control subjects, the P1 latencies of SDSEP at right and left were 34.72±2.68ms and 33.54±1.95ms, the N1 latencies were 43.06±2.31 ms and 42.14±2.29ms, respectively. The P1N1 amplitudes of normal control subjects were 0.73±0.40uV at fight and 0.69±0.22uV at left. The absence or presence of SDSEP and pudendal SEP was coincident in 90% of the SCI patients.
In conclusion, SDSEP study could be used instead of or in combination with PSEP.
