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Biomedical subjects

S E Jordan

Publications and source records attributed to S E Jordan.

34 records · Page 2Linked to original sources
PubMed1990

Ischemic brain rescue by transvenous perfusion in baboons with venous sinus occlusion.

We studied brain retroperfusion in nine adult baboons. Experiments in four baboons determined techniques and the safety of retroperfusion, and experiments in three baboons determined the ability of retroperfusion to reverse cerebral ischemia. Two baboons died before retroperfusion. Arterial blood was continuously circulated by an external pumping system from one femoral artery into the intracranial sinuses through specially designed balloon-tipped catheters placed percutaneously into the sigmoid sinuses bilaterally. The balloons intermittently occluded the sinuses. Ischemia was produced by occluding the left middle cerebral artery. Standard and computed electroencephalography with topographic mapping monitored the onset and reversal of ischemia. Retroperfusion rate exceeded 50 ml/min with a mean intrasinus pressure increase of 27 (0-149) mm Hg in all seven experiments. Venograms demonstrated complete or partial filling of the superior sagittal sinus in each experiment. Four experiments without ischemia established maximal balloon occlusion cycles, retroperfusion rates, and sinus pressure changes. These four baboons were neurologically normal after retroperfusion; two had normal magnetic resonance imaging scans. Ischemic changes, detected by electroencephalography following middle cerebral artery occlusion, were reversed with retroperfusion in all three ischemia experiments. Autopsies in the seven baboons demonstrated no parenchymal hemorrhage or edema. Our results suggest that further investigation of retroperfusion, and possibly retroinfusion of agents for cerebral protection, is warranted.

Animals↗
PubMed1989

Computerized electroencephalography in the evaluation of early dementia.

In elderly patients presenting to an ambulatory practice with complaints of cognitive disturbance, early dementia must be differentiated from depression. The present paper describes the application of standard electroencephalography and evoked potential testing (EEG/EP) and computerized electroencephalography with evoked potential mapping (CEEG/EPM) in the analysis of 64 elderly patients complaining of cognitive disturbance. Although previous reports have claimed a sensitivity level of up to 80% for EEG in demented patients, it appears that a lower sensitivity (37% for EEG alone and 61% for EEG/EP) may be expected at the time of early presentation according to the present study. No EEG/EP abnormalities were detected in patients with depression. In demented patients, CEEG/EPM was abnormal in 85% (46 of 54) of cases compared to 10% (1 of 10) of cases with depression. Specific information was obtained from EEG/EP studies that helped differentiate the various causes of dementia in three cases. In CEEG/EPM studies, a pattern of relative suppression of alpha activity or suppressed auditory P300 amplitude in the posterior parietal regions was observed in 11 or 23 (48%) patients with Alzheimer's disease and 2 of 31 (6%) patients with other forms of dementia. None of the depressed patients demonstrated such changes. Based on the present study, it appears that computerized techniques may hold promise as an adjunct to standard EEG evaluation of patients with mild cognitive change in whom diagnosis of dementia or depression is in doubt. Although standard EEG rarely demonstrates characteristic changes that may help differentiate causes of dementia, CEEG/EPM appears to demonstrate, on occasion, abnormalities in the posterior temporal and parietal regions in patients with a diagnosis of probable Alzheimer's disease and rarely in other forms of dementia or depression.

Acoustic Stimulation↗
PubMed1988

Computed electroencephalographic topographic brain mapping. A new and accurate monitor of cerebral circulation and function for patients having carotid endarterectomy.

To determine the usefulness of computed electroencephalographic (EEG) topographic (CET) brain mapping to monitor neurologic function during carotid endarterectomy (CEA), 46 consecutive patients having CEA were monitored preoperatively, intraoperatively, and immediately postoperatively by CET brain mapping and simultaneous 16-lead EEG. Preoperative studies revealed that 7 of 16 asymptomatic patients, 5 of 11 patients with amaurosis fugax, and 8 of 12 patients with transient ischemic attacks (TIAs) had abnormal CET brain mapping suggestive of previous subclinical stroke. EEG was abnormal in only 8 of the 20 patients with abnormal CET brain mapping. Intraoperatively during carotid cross-clamping, ischemic changes were seen on CET brain mapping in 23 patients whereas EEG detected these changes in only 13 patients. Ischemic changes detected by intraoperative CET brain mapping were more likely to occur in patients with previous stroke (six of seven) than in patients without previous stroke (17 of 39), p less than 0.05. Patients with changes detected by intraoperative CET brain mapping had an average carotid back-pressure of 38 mm Hg, in contrast to 57 mm Hg for patients without CET brain mapping changes, p less than 0.05. After endarterectomy, CET brain mapping revealed new ischemic changes in one patient who awoke with a mild stroke and in one patient who had TIAs and amaurosis fugax within 6 hours of surgery. We conclude that CET brain mapping is a sensitive, accurate, and useful noninvasive monitor of cerebral circulation and function for patients having CEA.(ABSTRACT TRUNCATED AT 250 WORDS)

Blindness↗
PubMed1987

The centrifugal effect and other spatial artifacts of topographic EEG mapping.

Topographic maps of EEG can contain artifacts that are foreign to clinical electroencephalographers trained to read traditional EEG records. Several spatial artifacts are described and discussed here, including the centrifugal effect, ring enhancement, spatial aliasing, electrode hills and holes, color-step effects, and restriction of minima/maxima to electrode sites. Users of quantitated EEG with topographic maps should be aware of these artifacts and should have a high suspicion for other analogous artifactual spatial phenomena when interpreting individual patient records.

Color↗
PubMed1987

Evaluation of stroke using EEG frequency analysis and topographic mapping.

Frequency analysis and topographic mapping of EEG were studied in 20 consecutive patients with mild stroke and in 20 age-matched normal subjects. Abnormally large increases in delta and decreases in alpha activity were seen over the scalp in 17 of 20 patients and in no normal subjects. Theta was unreliable by itself. The scalp area so localized appeared correct in each case compared with signs, symptoms, and neuroimaging studies. These computerized EEG analysis techniques were abnormal significantly more often than routine EEGs. The results obtained here with simple techniques agree with past studies done with more complex types of EEG analysis.

Aged↗
PubMed1987

Autonomic activity in the carpal tunnel syndrome.

The authors report the results of autonomic testing in patients with the carpal tunnel syndrome. Galvanic skin response (GSR) and skin temperature measurements in 46 patients and 32 normal controls were recorded and were statistically analyzed by computer. The findings were then correlated with the results of nerve conduction studies and duration of symptoms. Definite sympathetic changes were documented by a temperature increase in the affected index fingers of patients. These changes occurred in six patients who had symptoms for less than six months as well as in patients who had symptoms for more than six months. Nerve conduction studies were positive in 48% of patients with symptoms for less than six months and in 80% of patients with symptoms for six months or longer. There was no statistical difference between galvanic skin response measurements in the patients and the controls.

Adolescent↗
PubMed1983

An unusual late complication of acrylic spinal fusion: case report.

The authors report an unusual complication after posterior cervical spine fusion utilizing methyl methacrylate and metallic pins. Eight months postoperatively, the patient noticed a subcutaneous foreign body in the right side of the neck. Radiographic and operative findings confirmed the clinical impression of migration of one of the metallic pins.

Aged↗
PubMedDate not supplied

The etiology of valgus angulation after metaphyseal fractures of the tibia in children.

We conducted a retrospective study of proximal metaphyseal fractures of the tibia in children who developed valgus deformities. We reviewed the cases in an effort to determine the most likely etiology of post-fracture tibia valga, which occurs despite careful treatment and follow-up. We reviewed seven major theories presented in the literature regarding the etiology of this problem. Our conclusion was that all the theories were not prerequisites for the development of valgus angulation, but rather may be secondary mechanisms. We suggest that the most likely primary mechanism is an increased vascular response causing an asymmetric growth stimulation of the medial metaphysis of the proximal tibia.

Child↗
PubMedDate not supplied

Acute and chronic brain injury in United States National Team soccer players.

We designed a study to determine whether chronic encephalopathy occurs in elite, active soccer players resulting from repetitive heading of the soccer ball. Studies have suggested that the cumulative effects of heading a ball can cause a chronic brain syndrome similar to dementia pugilistica, which is seen in professional boxers. Twenty of 25 members of the U.S. Men's National Soccer Team training camp (average age, 24.9; average years of soccer, 17.7), who completed a questionnaire on head injury symptoms and had magnetic resonance imaging of the brain, were compared with 20 age-matched male elite track athletes. The soccer players were surveyed about playing position, teams, number of headers, acute head injuries, and years of playing experience. An exposure index to headers was developed to assess a dose-response effect of chronic heading. The soccer and track groups were questioned regarding alcohol use and history of acute head traumas. Questionnaire analysis and magnetic resonance imaging demonstrated no statistical differences between the two groups. Among the soccer players, symptoms and magnetic resonance imaging findings did not correlate with age, years of play, exposure index results, or number of headers. However, reported head injury symptoms, especially in soccer players, correlated with histories of prior acute head injuries (r = 0.63). These findings suggest that any evidence of encephalopathy in soccer players relates more to acute head injuries received playing soccer than from repetitive heading.

Acute Disease↗
PubMedDate not supplied

Preembolization functional evaluation in brain arteriovenous malformations: the superselective Amytal test.

PURPOSE: To describe our experience with the use of Amytal injected through a superselective catheter prior to planned embolization of cerebral arteriovenous malformations. MATERIALS AND METHODS: 109 superselective tests were performed with 30-mg injections of Amytal. All patients were evaluated by both clinical examination and EEG. RESULTS: Twenty-three of these tests were positive. There were no prolonged neurologic complications of the Amytal test. We also examined the value of EEG monitoring compared to clinical monitoring during the Amytal test. Of the 23 positive Amytal tests, only 12 showed a change on clinical exam (52%). This meant that almost half of the positive Amytal tests would have been falsely called negative (false negative rate of 10%). There were also three positive Amytal tests with changes on clinical examination without any change on EEG. CONCLUSION: The superselective Amytal test can be done safely as part of the interventional neuroradiologic procedure. Clinical and EEG monitoring of the patient are essential.

Adolescent↗
PubMedDate not supplied

Preembolization functional evaluation in brain arteriovenous malformations: the ability of superselective Amytal test to predict neurologic dysfunction before embolization.

PURPOSE: To describe the incidence of neurologic dysfunction following embolization of supratentorial AVMs, and to correlate findings with results of preembolization Amytal tests. MATERIALS AND METHODS: Data from 147 embolizations of supratentorial AVMs following Amytal tests in 30 awake patients were analyzed retrospectively. RESULTS: Of five embolizations done after a positive Amytal test, two were followed by neurologic complications. Eighty-two embolizations done as single embolizations immediately after a negative Amytal test were associated with no neurologic complications. The remaining embolizations were parts of multiple series of embolizations, each beginning with an Amytal test and followed by a number of embolizations without catheter movement or repeat Amytal testing. Since any prior embolization in the series might reduce the sump effect of the AVM, embolic agent delivered later in the series could potentially reach functional brain tissue not fully tested by the Amytal test. Therefore, repeat embolizations (not immediately preceded by an Amytal test) were considered separately. In 60 repeat embolizations, six (10%) were associated with some neurologic complication. CONCLUSIONS: Repeat Amytal testing might detect the loss of sump effect as the AVM is embolized. We conclude that use of data from superselective Amytal tests adds to the safety of AVM embolizations and that repeat Amytal testing potentially could be valuable when serial embolization of a vessel is planned.

Adolescent↗