Optimal Radial Motor Nerve Conduction Study Using Ultrasound in Healthy Adults

OBJECTIVE: To obtain reference values, to suggest optimal recording and stimulation site for radial motor nerve conduction study (RmNCS), and to analyze the correlation among RmNCS parameters, demographics and ultrasonography (US) findings. METHODS: A total of 55 volunteers participated in this study. We hypothesized that ‘lateral edge of spiral groove (A)’ was the optimal stimulation site, and the ‘largest cross-sectional area (CSA) of extensor indicis proprius (EIP) muscle (B)’ was the optimal recording site. The surface distance between ‘A’ and the lateral epicondyle of the humerus divided by upper arm length, was named the spiral groove ratio. The surface distance between ‘B’ and the ulnar styloid process divided by forearm length, was named the EIP ratio. Using US, we identified these sites, and further conducted RmNCS. RESULTS: Data was collected from 100 arms of the 55 volunteers. Mean amplitude and latency were 5.7±1.1 mV and 5.7±0.5 ms, respectively, at the spiral groove, and velocity between elbow and spiral groove was 73.7±7.0 m/s. RmNCS parameters correlated significantly with height, weight, arm length, and CSA of the EIP muscle. Spiral groove ratio and EIP ratio were 0.338±0.03 and 0.201±0.03, respectively; both values were almost the same, regardless of age, sex and handedness. CONCLUSION: We established a reference value and standardized method of RmNCS using US. Optimal RmNCS can be conducted by placing the recording electrode 20% (about one-fifth) of forearm length from the ulnar styloid process, and stimulating at 34% (about one-third) of the humeral length from the lateral epicondyle.

Can Short-Term Constraint-Induced Movement Therapy Combined With Visual Biofeedback Training Improve Hemiplegic Upper Limb Function of Subacute Stroke Patients?

OBJECTIVE: To Investigate the synergic effects of short-term constraint-induced movement therapy (CIMT) and visual biofeedback training (VBT) in subacute stroke patients. METHODS: Thirty-two subacute stroke patients were enrolled and randomly assigned to one of three groups: short-term CIMT with VBT, VBT only, and control groups. We applied CIMT for an hour daily during VBT instead of the ordinary restraint time, referred to as 'short-term' CIMT. Short-term CIMT with VBT group received simultaneous VBT with CIMT, whereas the VBT the only group received VBT without CIMT for an hour a day for 2 weeks. The control group received conventional occupational therapy (OT) alone. Patients underwent the Purdue Pegboard Test, the JAMAR grip strength test, the Wolf Motor Function Test, the Fugl-Meyer Assessment (upper extremity), Motricity index and the Korean version of Modified Barthel Index test to evaluate motor functions of the hemiplegic upper limb at baseline, post-treatment, and 2 weeks after treatment. RESULTS: No significant differences were observed between short-term CIMT with VBT and VBT only groups. Both groups showed significantly higher scores compared to the control group in the WMFT and FMA tests. However, the short-term CIMT with VBT group showed significant improvement (p<0.05) compared with the control group in both grasp and pad pinch at post-treatment and 2 weeks after treatment while the VBT only group did not. CONCLUSION: Short-term CIMT with VBT group did not show significant improvement of hemiplegic upper limb function of subacute stroke patients, compared to VBT only group. Larger sample sizes and different restraint times would be needed to clarify the effect.