Brain Cortical Mapping by Simultaneous Recording of Functional Near Infrared Spectroscopy and Electroencephalograms from the Whole Brain During Right Median Nerve Stimulation

To investigate relationships between hemodynamic responses and neural activities in the somatosensory cortices, hemodynamic responses by near infrared spectroscopy (NIRS) and electroencephalograms (EEGs) were recorded simultaneously while subjects received electrical stimulation in the right median nerve. The statistical significance of the hemodynamic responses was evaluated by a general linear model (GLM) with the boxcar design matrix convoluted with Gaussian function. The resulting NIRS and EEGs data were stereotaxically superimposed on the reconstructed brain of each subject. The NIRS data indicated that changes in oxy-hemoglobin concentration increased at the contralateral primary somatosensory (SI) area; responses then spread to the more posterior and ipsilateral somatosensory areas. The EEG data indicated that positive somatosensory evoked potentials peaking at 22 ms latency (P22) were recorded from the contralateral SI area. Comparison of these two sets of data indicated that the distance between the dipoles of P22 and NIRS channels with maximum hemodynamic responses was less than 10 mm, and that the two topographical maps of hemodynamic responses and current source density of P22 were significantly correlated. Furthermore, when onset of the boxcar function was delayed 5–15 s (onset delay), hemodynamic responses in the bilateral parietal association cortices posterior to the SI were more strongly correlated to electrical stimulation. This suggests that GLM analysis with onset delay could reveal the temporal ordering of neural activation in the hierarchical somatosensory pathway, consistent with the neurophysiological data. The present results suggest that simultaneous NIRS and EEG recording is useful for correlating hemodynamic responses to neural activity

Cryosurgical Retraction in the Removal of Intracranial Vascular Tumors : Technical Note

We describe a technique using a cryoprobe as a retractor in the removal of intracranial vascular tumors. This simple method is safe and effective especially for the extraction of tumor embedded in the brain tissue

Japan Carotid Atherosclerosis Study : JCAS (EBM of Neurosurgical Disease in Japan)

The recent randomized trials, North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial, and Asymptomatic Carotid Atherosclerosis Study, have demonstrated the effectiveness of carotid endarterectomy to reduce the incidence of cerebral infarction in patients with symptomatic and asymptomatic high-grade carotid artery stenosis. However, no studies on Japanese patients have been done until now, and recent progress in endovascular stent treatment has been made. The present prospective, multicenter (not randomized) trial, the Japan Carotid Atherosclerosis Study, has started to analyze present practice and propose treatment guidelines for Japanese patients. Here, the protocol and early results of 565 patients registered until the end of January 2004 are presented

Vertebrobasilar Insufficiency in a Patient with Persistent Trigeminal Artery and Stenosis of the Ipsilateral Carotid Bifurcation : Case Report

A 69-year-old female with frequent episodes of vertigo was found to have persistent trigeminal artery and ulcerative stenosis of the ipsilateral carotid bifurcation. The clinical symptoms, pathogenesis, and treatment of this anomaly are discussed