Detecting transient cognitive impairment with EEG pattern recognition methods.

This paper describes an initial evaluation of a new method for assessing transient states of cognitive impairment associated with intoxication or fatigue: neural network pattern recognition applied to features of the electroencephalogram (EEG) recorded from subjects performing a standardized task. Nine subjects performed a working memory task during an extended testing session occurring over the course of one night, and encompassing an alert baseline period, a state of mild acute intoxication, and a state of fatigue compounded by "hangover" or intoxication after-effects. Relative to the alert baseline, task performance was less accurate in the other test conditions, providing evidence of transient cognitive impairment. These states of impairment were associated with changes in spectral characteristics of the EEG. Neural network-based EEG pattern recognition techniques were used to develop and test detectors of these changes. Brief testing data samples originating from the alert baseline condition could be discriminated from those recorded during the state of acute intoxication with 98% accuracy (p < 0.0001), and from those recorded during the state of fatigue/hangover with 92% accuracy (p < 0.001). Furthermore, networks trained on data from a group of subjects were found to accurately classify data from test subjects who were not part of the training group. These results demonstrate the feasibility of using neurophysiological monitoring methods for detecting transient cognitive impairment.     

Pediatric extracranial applications of MR angiography

Extracranial magnetic resonance angiography (MRA) was performed in 20 children to evaluate for various arterial and venous conditions. Time-of-flight and phase-contrast angiograms were constructed using a maximal-intensity-projection algorithm. The accuracy of MRA was comparable to Doppler ultrasound (n = 12) and conventional angiography (n = 3). MRA could provide an excellent mapping of patent (including collaterals) versus thrombosed vessels at sites not evaluated or inaccessible by sonography. Limitations included assessment of small and/or tortuous vessels, severely stenotic lesions, and very slow flow.     

MR spectroscopy using multi-ring surface coils.

A spatially uniform B(1)-field is preferred for MR imaging and spectroscopy. Unfortunately, volume coils are sometimes unavailable, or do not provide adequate RF power or SNR for some applications. In quantitative MRS, mean metabolite concentration cannot be evaluated when the coil response is nonuniform, unless an assumption is made concerning the metabolite spatial distribution. It is well known that standard single-loop surface coils, although offering high SNR characteristics, have poor B(1) homogeneity. New multi-ring surface coils are proposed which produce a locally uniform B(1) field, with sensitivity and power requirements comparable to those of standard surface coils. MR spectroscopy using two and three-ring versions of this "local volume coil" result in spatial localization essentially identical to that obtained with a volume coil but with much improved RF power and SNR characteristics. When compared to standard surface coils, the multi-ring coil offers much improved water suppression and localization, as well as reduced outer voxel contamination, with only a small loss in SNR and moderate increase in SAR. In summary, the multi-ring coil operates midway between the volume coil and the standard surface coil, retaining the most advantageous properties of both. Magn Reson Med 42:655-664, 1999. Published 1999 Wiley-Liss, Inc.     

MR imaging of hypervascular liver tumors: timing optimization during the arterial phase

To analyze the optimal timing strategy for the detection of hypervascular liver tumors during the arterial phase of magnetic resonance (MR) imaging, a test examination after injection of 2 mL of gadopentetate dimeglumine was performed in 47 patients. The time course of the tumor-to-liver contrast-to-noise ratio (CNR) for all studies together was determined relative to the start of injection, the time of peak aortic enhancement, and the time of peak enhancement in the tumor. All studies were grouped together and the highest CNR was transiently observed at the time of peak tumor enhancement. This CNR was significantly higher than those observed at fixed delays after peak aortic enhancement. However, the CNRs at peak tumor enhancement+/-1.5 seconds did not differ significantly from those obtained after peak aortic enhancement. Finally, the CNRs obtained at fixed delays after the start of injection remained significantly lower. In hypervascular liver tumors, a higher CNR can be obtained during the arterial phase when the MR imaging delay is determined relative to the time of peak enhancement in the tumor or the aorta rather than being fixed after the start of contrast material injection. Timing based on the enhancement profile in the tumor rather than in the aorta should be performed only if rapid MR imaging is available with a time resolution of about 1.5 seconds to image the whole liver.     

Cardiopulmonary resuscitation: effect of CPAP on gas exchange during chest compressions

BACKGROUND: Conventional cardiopulmonary resuscitation (CPR) includes 80-100/min precordial compressions with intermittent positive pressure ventilation (IPPV) after every fifth compression. To prevent gastric insufflation, chest compressions are held during IPPV if the patient is not intubated. Elimination of IPPV would simplify CPR and might offer physiologic advantages, but compression-induced ventilation without IPPV has been shown to result in hypercapnia. The authors hypothesized that application of continuous positive airway pressure (CPAP) might increase CO2 elimination during chest compressions. METHODS: After appropriate instrumentation and measurement of baseline data, ventricular fibrillation was induced in 18 pigs. Conventional CPR was performed as a control (CPR(C)) for 5 min. Pauses were then discontinued, and animals were assigned randomly to receive alternate trials of uninterrupted chest compressions at a rate of 80/min without IPPV, either at atmospheric airway pressure (CPR(ATM)) or with CPAP (CPR(CPAP)). CPAP was adjusted to produce a minute ventilation of 75% of the animal's baseline ventilation. Data were summarized as mean +/- SD and compared with Student t test for paired observations. RESULTS: During CPR without IPPV, CPAP decreased PaCO2 (55+/-28 vs. 100+/-16 mmHg) and increased SaO2 (0.86+/-0.19 vs. 0.50+/-0.18%; P < 0.001). CPAP also increased arteriovenous oxygen content difference (10.7+/-3.1 vs. 5.5+/-2.3 ml/dl blood) and CO2 elimination (120+/-20 vs. 12+/-20 ml/min; P < 0.01). Differences between CPR(CPAP) and CPR(ATM) in aortic blood pressure, cardiac output, and stroke volume were not significant. CONCLUSIONS: Mechanical ventilation may not be necessary during CPR as long as CPAP is applied. Discontinuation of IPPV will simplify CPR and may offer physiologic advantage.     

Perineal one-stage pull-through for Hirschsprung's disease

PURPOSE: The aim of this study was to present the strategy of a one-stage repair of Hirschsprung's Disease (HD) performed via a transanal approach. METHODS: Ten consecutive neonates and one toddler underwent transanal repair for biopsy-proven HD. A rectosigmoid transition zone was suggested by contrast enema in all patients. The mean age at operation for the neonates was 4 days. A mucosal dissection was begun 0.5 cm proximal to the dentate line. Once the correct plane was established, up to 15 cm of bowel can be resected without ligating vessels or performing a transabdominal dissection. The proximal extent of dissection was delineated by the presence of ganglion cells seen on frozen section analysis. RESULTS: The mean operating time was 105 minutes. There were no intraoperative or postoperative complications. All children had the presence of ganglion cells confirmed postoperatively on permanent sections. The mean hospital stay was 2 days. All children averaged three to six bowel movements per day without oral or enema therapy. CONCLUSIONS: The perineal one-stage operative pull-through (POOP) procedure for Hirschsprung's disease is a quick and easy adaptation of a well-described technique of transanal mucosectomy. Long-term follow-up will be required to determine whether bowel function is better that that seen after traditional staged repairs.     

Development and evaluation of an abridged, 5-item version of the International Index of Erectile Function (IIEF-5) as a diagnostic tool for erectile dysfunction

An abridged five-item version of the 15-item International Index of Erectile Function (IIEF) was developed (IIEF-5) to diagnose the presence and severity of erectile dysfunction (ED). The five items selected were based on ability to identify the presence or absence of ED and on adherence to the National Institute of Health's definition of ED. These items focused on erectile function and intercourse satisfaction. For 1152 men (1036 with ED, 116 controls) analyzed, a receiver operating characteristic curve indicated that the IIEF-5 is an excellent diagnostic test. Based on equal misclassification rates of ED and no ED, a cutoff score of 21 (range of scores, 5-25) discriminated best (sensitivity=0.98, specificity=0. 88). ED was classified into five severity levels, ranging from none (22-25) through severe (5-7). Substantial agreement existed between the predicted and 'true' ED classes (weighted kappa=0.82). These data suggest that the IIEF-5 possesses favorable properties for detecting the presence and severity of ED.     

Mid-third forearm fractures in children: an unorthodox treatment

Twenty children with fractures of both bones in the middle third of the forearm were immobilized in extension after closed reduction. Unlike distal-third fractures, these fractures are prone to develop rotary and angular deformities that may lead to permanent functional impairment and visible deformity. Mid-third forearm fractures with the radius fracture proximal to the ulnar fracture are even more troublesome. Nineteen patients had no clinical deformity at cast removal, and by 1 year, there was no difference in forearm rotation. Extension casting can be used initially for proximal fractures or to salvage forearms that lost reduction in flexed elbow casts. Extension cast application is easy while the reduction is maintained, whereas the problems are often encountered while applying a flexed elbow cast. This unorthodox treatment is safe and effective and may alleviate the need for surgical intervention.     

Why does postpsychotic IQ decline in childhood-onset schizophrenia?

OBJECTIVE: The authors' goal was to examine whether the postpsychotic decline in full scale IQ during adolescence for patients with childhood-onset schizophrenia is due to a dementing process or simply failure to acquire new information and skills. METHOD: Linear regression was used to determine the rate of change for scaled and raw scores on subtests of 31 patients with childhood-onset schizophrenia. The resulting slopes were examined and related to changes in the patients' brains determined by magnetic resonance imaging. RESULTS: Three postpsychotic subtest scaled scores declined significantly: picture arrangement, information, and block design. In contrast, there was no decline in the non-age-corrected (raw) scores for any subtest. A significant correlation was found between decrease in hippocampal volume and a smaller increase in raw score on the information subtest. CONCLUSIONS: The decline during adolescence in the full-scale IQ of patients with childhood-onset schizophrenia does not reflect dementia but, rather, an inability to acquire new information and abilities.