The Clinical Significance of Somatosensory and Motor Evoked Potential in Myelopathy

BACKGROUND: Myelopathies are classified as intramedullary and extramedullary one on the basis of location of lesion. Though there are some characteristic clinical findings which can differentiate extramedullary from intramedullary lesions, it is not easy to tell extramedullary from intramedullary lesions in complicated cases. We performed this study to figure out the relationships between anatomic location (intramedullary or extramedullary), clinical parameters (motor and sensory symptoms and signs), and electrophysiologic findings in myelopathy. We also investigated the diagnostic value of motor evoked potential (MEP) compared with that of somatosensory evoked potential (SSEP) in myelopathy. The amplitude changes of compound muscle action potential (CMAP) after motor cortex stimulation have a lot of intra-individual and inter-individual variability, so were not used to determine pyramidal tract dysfunction in clinical ground. We analyzed CMAP amplitude changes in myelopathy. METHODS: Fifty-six patients with myelopathy demonstrated in MRI were studied. We defined abnormal CMAP amplitude changes as intra-individual inter-side amplitude ratio more than 50%. RESULTS: Lower MEP showed abnormal findings in 93% of tests and lower SSEP, 37% (p<0.05). The correla-tions between clinical parameters and electrophysiologic findings were higher in lower MEP (71%) than lower SSEP (42%) (p<0.05). CONCLUSIONS: The results of this study suggest that MEP is more useful than SSEP for detecting spinal cord dysfunction but as false positivity of lower MEP was considerable, MEP and SSEP are reciprocal diagnostic method for myelopathy. SSEP and MEP do not have significant diagnostic values in differentiating extramedullary from intramedullary myelopathy. The inter-side CMAP amplitude difference may indicate subclinical spinal cord dysfunction.

Increased Cerebrovascular Resistance in Liver Cirrhosis and Ascites / 대한간학회지

BACKGROUND/AIMS: Portal hypertension in cirrhosis is associated with a hyperdynamic circulation, which is characterized by hypervolemia, high cardiac output, arterial hypotension and low peripheral vascular resistance. These circulatory abnormalities are thought to be secondary to a splanchnic arteriolar vasodilation related to the increase in portal pressure. Studies assessing regional hemodynamics in patients of cirrhosis with ascites have shown vasoconstriction in the renal circulation and in peripheral vascular territory. This study was designed to assess the cerebral vascular resistance in cirrhotic patients with ascites. METHODS: The resistive index in the middle cerebral artery and in a renal interlobar artery were measured by Doppler ultrasonography in 12 cirrhotic subjects without ascites, 23 cirrhotic subjects with ascites, and 8 healthy subjects. The arterial blood pressure and plasma renin and norepinephrine concentration, which reflect the activity of the renin-ngiotensin and sympathetic nervous systems respectively, were also measured. RESULTS: The resistive index in the middle cerebral artery were significantly higher in cirrhotic patients with ascites (0.58 +/- 0.04, mean +/- standard deviation) than in cirrhotic patients without ascites (0.53 +/- 0.02, p<0.01) and in control subjects (0.50 +/- 0.05, p<0.01). The resistive index in the middle cerebral artery showed direct correlation with renal resistive index (r = 0.52, p<0.01), plasma renin activity (r = 0.44, p<0.01) and norepinephrine (r = 0.33, p<0.05). The resistive index in the middle cerebral artery showed an inverse correlation with mean arterial pressure (r = -.59, p<0.01). CONCLUSION: The results suggest that in patients of cirrhosis with ascites, independent of the amount of ascites, there is a cerebral vasoconstriction which is related with the arterial hypotension and the overactivity of vasoconstrictor systems.

Localized soft tissue tumors around the knee

No abstract available.