S-1-10-02
MAGNETIC STIMULATION AND SPINAL REFLEXES AS TOOLS FOR INVESTIGATION OF THE MOTOR SYSTEM:
Thomas W. Findley (UMDNJ-School of Osteopathic Medicine, Stratford, NJ)
We studied motor reorgaization and excitability of alpha motoneurons to la input in subjects with unilateral lower limb amputation, studying muscles at rest and during voluntary contraction. The absence of chafes in the excitability of the alpha motoneuron pool in the presence of motor reorganization targeting muscles proximal to the stump suggests that reorganization occurs proximal to the alpha motoneuron pool. We noticed a trend towed reduction of conduction time during voluntary contraction, and found in subsequent studies with normals that the peripheral conduction time in response to Transcranial Magnetic Stimulation (TMS) was related to the activity of the target muscle and to the fastest conduction velocity of the target nerve. We then found that merely thinking about a specific movement without any voluntary contraction had facilitatory effects on the motor evoked potential, but this effect was less than that of voluntary contraction. Most recently, we have investigated reciprocal inhibition in the forearm during weak isometric wrist flexion or extension, and during thinking about wrist extension of flexion. Voluntary contraction of the agonist muscle did not produce inhibition of most antagonist muscles in response to TMS. Consistent but generally non-statistically significant inhibition of antagonist muscles to TMS was seen by thinking about agonist movement. However, we found clear inhibition of H reflex in wrist flexors during thinking about wrist extension, but of lower magnitude than the inhibition seen with voluntary wrist extension. Facilitation induced in the TMS study was stronger than that obtained with H reflex, while stronger inhibitory responses were observed in the H reflex study. Variations in H reflex amplitude appear to be largely mediated by motoneuron excitability at the spinal cord level, whereas motor evoked responses to TMS appear to be affected by a combination of motor cortex and spinal cord influence.
S-1-10-03
ASSISTING PARAPLEGIC INDIVIDUALS TO WALK BY MEANS OF ELECTRICALLY INDUCED MUSCLE CONTRACTIONS: GAIT PERFORMANCE AND PATIENT COMPLIANCE
H. A. Cerrel-Bazo M.D., A Rizzetto P.T., D. Pauletto P.T.., Lucca M.D., L. Caldana M.D.
Centro di Neuroriabilitazione e Ricerca di Villa Margherita, Arcugnano, Vicenza, Italy
Purpose: To evaluate the drop-out ratio and patient compliance of those spinal cord injury (SCI) subject using the electrically induce walking system (EIWS).
Materials and Methods: 30 SCI subjects participated on a CCE (computer controlled exercise) program preparatory to the FGP (functional electrical stimulation gait program). The EIWS is a hybrid system composed of the Parastep system and an articulated AFO. Metabolic and cardio-pulmonary responses were also analysed for those home EIWS users that return to our research facility.
Results:
1. Drop-out rate: 4 SCI subjects
2. Home environment walking: 14 SCI. The average MCWD (maximum continue walking distance) (m) at a SPMS (self preferred maximum speed) prior to home departure was 444.28. The mean SPMS (m/min) was 14.5. The mean daily walking distance at home (m) was 442.85. The mean daily time (min) was 90.71.
3. FGP: 12 SCI subjects are in the final phase of the gait program.
4. Follow-up evaluation and cardiopulmonary and metabolic expenditure: 5 SCI were
able to return to our research facility. The treadmil MCWD (m) at a SPMS mean: 842.4. Mean treadmill maximum continue walking time (min): 49.9. The EIWS users were able to perform walking under the anaerobic threshold, O2 Pulse (b/min) mean 10.53. O2 cost (mL/Kg.m) mean 1.18, O2 are (mL/Kg.min) mean 20.38%. Maximum heart rate mean 73.95.
5. Total length of time walking with the EIWS after the completion of FGP: 14-39 months. No drop-out rate.
Conclusion: The Parastep system on well selected and trained SCI individuals has an excellent user compliance.
