Prediction of treatment outcome in cocaine dependent males using quantitative EEG.

This study investigates the existence of outcome related neurophysiological subtypes within a population of abstinent cocaine dependent adults. We have previously reported and replicated the existence of a distinctive quantitative EEG (QEEG) profile in such a population, and demonstrated the persistence of this pattern at one and six month follow-up evaluations. This profile is characterized by significant deficits of absolute and relative delta and theta power, and excess of relative alpha power, as compared with age expected normal values. Abnormalities were greater in anterior than posterior regions, and disturbances in interhemispheric relationships were also observed. In the current study, 35 adult males with DSM-III-R cocaine dependence, were evaluated while residents of a drug-free residential therapeutic community, 5-15 days after last use of crack cocaine. Using multivariate cluster analysis, two neurophysiological subtypes were identified from the baseline QEEGs; Cluster 1 characterized by significant deficits of delta and theta activity, significant excess of alpha activity and more normal amounts of beta activity (alpha CLUS) and Cluster 2 characterized by deficits of delta, more normal amounts of theta and anterior excess of alpha and beta activity beta CLUS). No significant relationships were found between QEEG subtype membership and length of exposure to cocaine, time since last use of cocaine or any demographic characteristics. Further, no significant relationships were found between the commonly reported comorbid clinical features of depression and anxiety and subtype membership. However, a significant relationship was found between QEEG subtype membership and length of stay in treatment, with members of the alpha CLUS retained in treatment significantly longer than members of the beta CLUS.

Measurement of spinal cord ischemia during operations upon the thoracic aorta: initial clinical experience.

Paraplegia has been an unpredictable, devasting complication following operations upon the thoracoabdominal aorta for over 30 years. The frequency ranges from 0.5% with operations for coarctation to as high as 15% following surgery for thoracoabdominal aneurysms. Both uncertainty and controversy exist about the value of different protective methods during aortic crossclamping (AXC): heparinized shunts, partial bypass, and reimplantation of intercostal arteries. This report describes the authors' initial clinical experience with a highly sensitive indicator of spinal cord ischemia, somatosensory evoked potentials (SEP) in an attempt to prevent paraplegia associated with surgical procedures on the thoracoabdominal aorta. Seven consecutive patients (one coarctation, five thoracic aneurysms, one thoracoabdominal aneurysm) underwent continuous operative monitoring of SEP. Cortical response to simultaneous electrical stimulation (20 mAmps, 0.6 mSec., 2.3 cps) of both the right and left posterior tibial nerves was recorded before, during, and after AXC, and following operation. When ischemic changes were detected by SEP, increasing distal circulation by different maneuvers (heparinized shunt, femoral-femoral bypass, reimplantation of intercostal arteries) reversed these changes. In two patients with thoracic aneurysms, ischemic changes appeared within three minutes after AXC and all potentials disappeared in nine minutes. Rapid insertion of a graft (AXC 28 and 37 minutes) resulted in SEP return 40 minutes following restoration of flow. These changes were prevented by a heparinized shunt in two patients, femoral/femoral bypass in one, and T8-T9 intercostal reimplantation in one. No SEP changes occurred in the patient with coarctation. No postoperative neurologic complications occurred. Continuous operative monitoring of SEP has exciting possibilities for preventing paraplegia. It is simple, highly sensitive, and seems to provide a precise measurement of adequacy of circulation to the spinal cord.