Changes of Cortical Somatosensory Evoked Potentials following Angular Rotations of the Cervical Spine in Rats

OBJECTIVE: To evaluate changes of the spinal cord conductivity by investigating the cortical somatosensory evoked potentials (SEPs) after angular rotations of the cervical spine in the rats. METHOD: Ten rats (Sprague-Dawley, 300~350 gm) were used. The trunk and head were fixed in the instrument for measuring rotational angles of the cervical spine. P1 latencies and P1-N1 amplitudes of the SEPs were obtained by stimulation of the posterior tibial nerve at the left hind paw. Thin scalp needle electrodes were placed subcutaneously at the 3 mm posterior to the vertex and nasion. We measured the parameters of the potentials at each 10o angular loading and compared the values measured immediately with those 5 minutes after each rotation. RESULTS: P1 latencies were 19.9+/-5.5 msec at rest, 20.1+/-5.8 msec at 90 degrees, 20.5+/-5.8 msec at 100 degrees, 21.2+/-6.2 msec at 120 degrees and 21.7+/-6.1 msec at 130 degrees, which were significantly prolonged above 100 degrees rotational loadings (p<0.05). The potentials disappeared at 140~170 degrees in some rats. The P1 latencies were prolonged according to increasing of the head rotational angles, however, P1-N1 amplitudes were not significantly decreased until absence of the potentials. There was no significant difference of the P1 latencies and P1-N1 amplitudes between potentials recorded immediately after rotational loading and at 5 minutes after rotation. CONCLUSION: P1 latencies of the SEPs according to the head rotation were significantly prolonged over 100 degrees loadings in the rats. This result suggested possible impairment of the spinal cord conductivity over 100 degrees rotational loading of the cervical spine in the rat.

Effect of Bilateral Contraction of Proximal Arm Muscle on Electromyographic Activity in Hemiplegic Patients

OBJECTIVE: Reaction time is known to be longer for bilateral activities than for unilateral ones. However, bilateral isometric training is a common technique for motor recovery in relatively early stage of recovery following stroke. Moreover, few studies elucidated the response time of proximal arm muscle. This study was designed to investigate the effects of bilateral shoulder abduction on electromyographic (EMG) timing in hemiplegic subjects. METHOD: EMG signal of 18 subjects with hemiplegia was recorded during isometric contraction of shoulder abductor along the audible beep. Each subject performed three sets of contraction: unilateral contraction of each side and simultaneous bilateral contraction. EMG parameters included initiation delay, termination delay, and root mean square (RMS). RESULTS: When subjects performed bilateral contraction simultaneously, initiation and termination delays and RMS of paretic arm significantly increased in the affected arm than nonaffected side. Compared with unilateral contraction, initiation and termination delays did not differ significantly although RMS was significantly reduced. In addition, side-to-side difference of termination delay significantly decreased. CONCLUSION: These results demonstrated that bilateral isometric training of proximal arm muscle could be performed for motor recovery after stroke with no compromise of movement timing. Furthermore, movement control would be expected to be enhanced.

Repetitive Stimulation Test after Sciatic Nerve Section in the Rat

OBJECTIVE: To evaluate changes of the parameters of the compound muscle action potentials (CMAPs) in repetitive stimulation test of the distal segment after section of the rat sciatic nerve. METHOD: Twenty rats (Sprague-Dawley, 400~450 gm) were used. Under anesthesia, one side of sciatic nerve at the 1 cm distal to the ischial tuberosity was sectioned. Following section the proximal end of the distal segment of the nerve was fixed to adjacent muscle by suture. An active stimulating wire electrode was placed at 1 cm distal to the proximal end of the distal segment. Recording electrodes were mounted at the soleus subcutaneously. Recordings of the repetitive stimulation of the sciatic nerve from the soleus were obtained at 4-hours intervals until complete conduction absence. RESULTS: Mean time of complete absence of the CMAPs in the distal segment after section of the sciatic nerve was 70.0 +/-12.5 hours. There was no significant change in the amplitude or area of the CMAPs in low rate or high rate repetitive stimulation. CONCLUSION: Our results suggested that sufficient amount of acetylcholine was released in response to repetitive stimulation after nerve section in the rat.

Percutaneous Endoscopic Jejunostomy in a Traumatic Brain Injured Patient with Subtotal Gastrectomy; A case report

To present a case of Percutaneous Endoscopic Jejunostomy in traumatic brain injured patient with subtotal gastrectomy. A 54-year-old man who injured a left subdural and intraventricular hemorrage by a falling. The patient had a history of the subtotal gastrectomy and suffered significant gastroesophageal reflux and recurrent aspiration pneumonia during nasogastric tubal feeding. The traditional Percutaneous Endoscopic Gastrostomy was inappropriate procedure for him because of significant alteration of gastric anatomy, insufficient volume of remnant stomach, and continuous gastroesophageal reflux. Direct percutaneous endoscopic placement of a jejunostomy tube was performed and we provide adequate enteral nutritional support in a traumatic brain injured patient with subtotal gastrectomy and gastroesophageal reflux.