Search PubMed⌕ Search

Biomedical subjects

A Ebner

Publications and source records attributed to A Ebner.

At least 109 records · Page 6Linked to original sources
PubMed1990

Therapeutic use of right atrial pressures early after the Fontan operation.

In 334 patients undergoing the Fontan operation, the right atrial pressure was 16 +/- 36 mm Hg (mean value +/- SD) 3 h postoperatively, and was on average higher in those who died or had a takedown of the operation than in those who did not (P = 0.0001). Twenty-four hours after operation, the right atrial pressure was 18 +/- 5.5 mm Hg, was higher in those who died or had a takedown than in those who did not (P less than 0.0001); and in those who died or had takedown it was 23.5 +/- 1.66 mm Hg and higher than at 3 h postoperatively (18.7 +/- 0.52). The left atrial pressure 3 h postoperatively was 9 +/- 3.6 mm Hg, and on average was higher in the patients who died or had a Fontan takedown than in those who did not. The continuous relation between right atrial pressure and the probability of death or takedown during the first 24 postoperative hours was such as to recommend consideration of takedown whenever the right atrial pressure reaches 22 mm Hg, and when higher, the recommendation is made with greater urgency.

Adolescent↗
PubMed1989

Nitrous oxide suppresses the electromyographic response evoked by electrical stimulation of the motor cortex.

The influence of nitrous oxide on motor evoked potential (MEP) elicited in rats by cortical and midcervical electrical stimulation was studied and compared with early components of somatosensory evoked potential (SEP) following stimulation of the posterior tibial nerve in 6 rats. We found that nitrous oxide gradually suppresses MEP, depending on the concentration of this inhalation agent. At a concentration of 66 vol% of nitrous oxide, the MEP was completely abolished, whereas the initial component N1-P1 of the SEP was only slightly reduced. We conclude that the descending impulse elicited by electrical stimulation of the corticospinal tract is mainly inhibited at the level of the spinal neuronal or interneuronal system, since (1) neuromuscular transmission is not blocked by nitrous oxide, and (2) MEP suppression is the same following cortical and midcervical stimulation.

Animals↗
PubMed1989

Influence of anesthetics--nitrous oxide in particular--on electromyographic response evoked by transcranial electrical stimulation of the cortex.

The influence of anesthetics usually used for neuroleptic anesthesia--nitrous oxide, fetanyl, flunitrazepam, and thiopental sodium--on motor evoked potentials (MEP) was examined in 15 patients during neurosurgical operations on the spinal cord, in 16 patients in traumatic coma, and in 6 healthy volunteers. MEP were recorded from the contralateral thenar and anterior tibial muscles in response to single transcranial electrical stimuli on the motor cortex. Intraoperatively, during neuroleptic anesthesia we found the amplitudes to be reduced to an average of 11% of the preoperative baselines for the thenar potentials, and to 7% of the preoperative baselines for the anterior tibial muscle potentials, despite a maximum stimulus strength of 750 V. A similar reduction of MEP amplitudes was observed in 6 volunteers during breathing of an oxygen/nitrous oxide mixture (34%/66%), whereas fentanyl, flunitrazepam, and thiopental had only a minor effect on MEP. We conclude that with respect to anesthesia-related suppression of amplitudes, an average of 5 to 15 electromyographic responses should be evaluated for intraoperative monitoring of MEP using the technique described here.

Adult↗
PubMed1988

Motor evoked responses recorded epidurally in a patient with Guillain-Barré syndrome.

The case of a 75-year-old man with Guillain-Barré syndrome is presented. By means of transcranial electrical stimulation and epidural recording at the spinal level L2-3, distinct potentials with a latency of 21ms were obtained when the patient was tetraplegic. At the same time electromyographic responses of the thenar and anterior tibial muscles were absent following both transcranial and peripheral nerve stimulation. The patient recovered partially within 4 weeks. It is concluded that epidurally recorded motor evoked responses allow electrophysiological assessment of the descending pathways even in severe cases of Guillain-Barré syndrome and might contribute to a more accurate prediction of outcome.

Aged↗
PubMed1988

Prognostic value of somatosensory- and motor-evoked potentials in patients with a non-traumatic coma.

A total of 28 patients with non-traumatic coma were studied both with somatosensory- and motor-evoked potentials. While somatosensory-evoked potentials (SEP) have proved to be useful in predicting the outcome in patients with severe brain damage, the aim of this study was to find out whether the additional evaluation of motor-evoked potentials (MEP) could contribute to a better prediction of the outcome than SEP alone. Our results clearly indicate that in terms of prognostic value, SEP are superior to MEP. Nine patients with bilaterally preserved MEP died, while all of the patients with bilaterally preserved SEP and a central conduction time less than or equal to 6.5 ms survived, with a Glasgow outcome score of 1 to 3. Therefore, we cannot recommend the inclusion of MEP in the prognostic evaluation of patients with non-traumatic coma.

Adolescent↗
PubMed1988

[Somatosensory and motor evoked potentials in the prognostic assessment of traumatic and non-traumatic comatose patients].

Somatosensory evoked potentials have proved to be useful for the outcome prediction of comatose patients. To date there are no reliable data with the investigation of motor evoked potentials (MEP) in this question. In the present study 60 patients with traumatic (group I) and 35 with non-traumatic coma (group II) were examined with both electrophysiological tests. It was the aim of this study to find out whether additional recording of MEP could contribute to a better prediction of the outcome than SEP alone. Our results clearly indicate that in terms of prognostic value SEP are superior to MEP. All patients with bilaterally preserved SEP and a central conduction time less than or equal to 6.5 msec (SEP-type Ia) survived whereas all patients with bilaterally absent cortical responses (SEP-type III) died. On the other hand, 12 patients (30.7%) of group I and 11 patients (39.3%) of group II with bilaterally preserved electromyographic responses following transcranial stimulation (MEP-type I) died. Only the bilateral absence of MEP (type III) was an unerring unfavourable prognostic sign. On the whole, we cannot recommend the use of MEP in prognostic evaluation of comatous patients.

Adolescent↗
PubMed1988

[Inflammatory pseudotumor of the bladder].

A case report presents a 30-year-old lady with a pseudotumor of the bladder as large as a fist. The tumor originated from an inflammation around the rest of a suture following appendectomy with a latency of 7 years.

Adult↗
PubMed1986

Event-related brain potentials (P300) and neuropsychological deficit in patients with focal brain lesions.

Sixteen patients with chronic focal brain lesions were investigated with an acoustic P300 test and psychological tests of spatial abilities (Maze Tracing Speed Test, Form Board Test), cognitive speed (Sequential Number Connection Test), categorization (Figure Sorting Test), verbal fluency and vigilance. Neither the psychological battery nor P300 analysis discriminated frontal from retrorolandic brain lesions. Abnormalities of P300 significantly correlated with impairments in those psychological tests which had a spinal component in common. We suggest that abnormality of the P300 with focal brain damage rather indicates higher mental function impairment than direct effects of the lesion.

Adult↗
PubMed1986

[Recurrent urinary incontinence: cystomanometry--conditio sine qua non?].

The value of cystometry in the diagnosis of recurrent urinary incontinence is to differentiate between urge and stress incontinence. This is possible through determination of detrusor hyperactivity characterized by uninhibited detrusor contractions. Cystometry is necessary since neither history nor clinical examination can differentiate between urge and stress incontinence. Both types of incontinence are in many patients found together and factors causing stress incontinence, for instance coughing, may also cause spontaneous, uninhibited detrusor contractions. The diagnosis of detrusor hypoactivity is also important although lack of detrusor contractions is not identical to lack of contractility. In only 50% of patients are detrusor contractions present following correction of the urinary incontinence and increase of urethral resistance. In the other half of the patients, lack of detrusor contractility remains. There is evidence that a so-called micturition-stop-test may allow a prognosis in cases of lack of bladder contractility. Cystometry is, therefore, a conditio sine qua non although it only gives information concerning the function of the detrusor. Concerning the evaluation of the bladder outlet, additional radiological and urodynamic examinations are necessary.

Electromyography↗
PubMed1982

Somatosensory tibial nerve evoked potentials with parasagittal tumours: a contribution to the problem of generators.

Somatosensory evoked potentials following stimulation of the median nerve at the wrist and the tibial nerve at the ankle were recorded in 5 patients with parasagittal tumours, 4 in the fronto-parietal and 1 in the frontal region. Three had intracerebral tumours and 2 parasagittal meningiomas. The extent of each lesion was determined by CT scan, showing a unilateral process involving predominantly the paracentral lobule and adjacent parts of the post- and precentral gyri ("Mantelkante') in 4 patients and a more frontal location of one meningioma affecting mainly the superior frontal gyrus. SEPs recorded from the patients with fronto-parietal tumours showed a uniform pattern with a complete absence of the wave N70 of the tibial SEP elicited by stimulating the nerve contralateral to the lesion. All other waves, including the P40-N50 complex on both sides and the median SEP, were in the normal range. In contrast, the frontal meningioma led to an only slightly altered from of the waves immediately following the initial P40-N50 complex. It is concluded that the tumour abolished the generators of the wave N70 which are apparently located in the cortical somatosensory leg area. Therefore unilateral loss of the wave N70 is indicative of parasagittal lesions. The results may give good evidence that the P40-N50 complex is generated in the thalamus or thalamo-cortical connections.

Adult↗
PubMed1981

Peripheral and central conduction times in hereditary pressure-sensitive neuropathy.

Seven members of a family with histologically proven hereditary pressure-sensitive neuropathy (HPSN) agreed to be examine clinically and electrophysiologically. A sural nerve biopsy specimen taken from the propositus who suffered from a partial brachial plexus palsy showed typical 'sausage-like' myelin sheath thickenings reflecting a failure of axon-adjusted myelination. Reduced motor and sensory conduction velocities involving several nerves were found in the four family members with clinical signs of HPSN. In addition, central conduction times in the auditory and somatosensory pathways were determined measuring the interwave latency I-V in brainstem auditory-evoked potentials and the interpeak latency N14-N20 in median nerve sensory-evoked potentials. Central conduction times in both afferent systems were within normal limits. The absolute delay of peak N14 and N20 in median and P40 in tibial nerve-evoked potentials was probably due to an impaired conduction in the peripheral branch of the bipolar ganglion cell. Whether the central axon branch in the dorsal columns was also involved could not be decided.

Adult↗
PubMed1980

[Brainstem auditory evoked potentials applied to clinical neurology (author's transl)].

Pathological alterations of the brainstem auditory evoked potential in 5 patients suffering from different kinds of brainstem diseases (reversible tumorous infiltration of the brainstem, multiple sclerosis, mesodiencephalic syndrome, apallic syndrome, braindeath) are shown. The alterations resemble the findings of animal experiments reported by Buchwald and Huang 1975: The particular components of brainstem auditory evoked potentials (waves IV-V, III, II and I) may decrease in amplitude or even completely disappear. The components are affected in a sequential reversed order, i.e. if a particular component has disappeared or shows a significant latency increase, the subsequent components are similarly affected. These observations suggest that the particular components are generated by different structures of the afferent acoustic pathway. This underlines the usefulness of brainstem auditory evoked potential recordings in detecting brainstem disorders.

Adult↗
PubMedDate not supplied

Frontal and parietal components of enhanced somatosensory evoked potentials: a comparison between pathological and pharmacologically induced conditions.

Pathologically enhanced somatosensory evoked potentials (giant SEPs) were recorded in 10 patients with cortical myoclonus of various origins. With non-cephalic reference electrodes a giant frontal negativity corresponding to normal N30 was found over the contra- and ipsilateral hemispheres which was not simply a phase reversal of the well-known enhanced parietal P25. The preceding far-field P14, parietal N20 and frontal P22 were of normal size. A similar result was found when SEPs were studied during the action of etomidate, an ultrashort-acting non-barbiturate hypnotic which produced a marked increase of the parietal P25 and frontal N30 after intravenous administration. These increased components, on the other hand, were abolished when recording was repeated immediately after application of electroconvulsive shock whereas P14, N20, and P22 remained more or less unchanged in both conditions. Our results indicate that there are neuronal elements in the sensorimotor cortex which are more resistant to influences such as narcotic drugs and seizure activity than others, being highly modifiable by these alterations. It is speculated whether these highly modifiable cortical systems are those in which giant SEPs, as well as pharmacologically increased SEP components, arise.

Adolescent↗
PubMedDate not supplied

Differences of cortical activation in spontaneous and reflex myoclonias.

Frontal and parietal components of somatosensory evoked potentials (SEPs) following median nerve stimulation and scalp potentials preceding myoclonic jerks (jerk-locked averaging, JLA) were compared in 6 patients with cortical reflex myoclonus. Giant potentials were found over the parietal cortex in both conditions. Prominent frontal activity was detected following median nerve stimulation which, however, was absent in jerk-locked averages. Therefore an identical generator of the giant SEP and the JLA is unlikely. As the frontal component is lacking in jerk-locked averaging, the spontaneous jerks produced in our experimental paradigm are believed to be due to spontaneous hyperactivity of the parietal cortex rather than to pathologically enhanced transcortical reflexes.

Adolescent↗
PubMedDate not supplied

Failed surgery for temporal lobe epilepsy: predictors of long-term seizure-free course.

OBJECTIVES: To identify prognostic factors which predict the outcome 2 years after TLE surgery in those patients who were not seizure-free at the 6-month postoperative examination. METHODS: We included 86 postoperative TLE patients who had undergone presurgical evaluation, including video-EEG and high-resolution MRI, and who had seizures between the second and sixth postoperative months. RESULTS: 32% of patients were seizure-free in the second postoperative year. We found that normal MRI findings and secondarily generalized seizures (SGTCS) preoperatively were associated with a non-seizure-free outcome, while rare postoperative seizures and ipsilateral temporal IED with seizure-free outcome. Newly administered levetiracetam showed a significant positive effect on the postoperative outcome independent of other prognostic factors. Five of seven patients who received levetiracetam became seizure-free (p = 0.006). CONCLUSION: One-third of patients who did not become seizure-free immediately after surgery, eventually achieved long-term seizure freedom. We suggest watching for long-term seizure freedom after failed epilepsy surgery especially in patients who had rare postoperative seizures, focal MRI abnormality, ipsilateral temporal spikes, or no SGTCS preoperatively. Levetiracetam may have a positive effect on postsurgical seizures.

Adult↗
PubMedDate not supplied

Clinical features and surgical outcome of medial temporal lobe epilepsy with a history of complex febrile convulsions.

PURPOSE: Temporal lobe epilepsy (TLE) is frequently associated with hippocampal sclerosis (HS) and complex febrile convulsions (CFC). The causal relationship between TLE, HS, and CFC is unclear. There is also contradictory data whether CFC-associated TLE is a distinct epilepsy syndrome and has different surgical outcome than other medial TLEs. METHODS: We investigated 133 patients (aged 16-59 years) with HS-associated TLE. Thirty-six patients with CFC (CFC group) versus 97 patients without febrile convulsions (NFC group) were compared for clinical history, video-EEG recorded seizure semiology, and surgical outcome. RESULTS: In the CFC group the right-sided HS (67% versus 32%) occurred more frequently than in the NFC group (P<0.001). The two groups did not differ according to the clinical features, both groups share the typical symptoms and findings of the medial TLE. In the CFC group, seizure-freedom 2 years after surgery was 91%, while in the NFC group it was only 64% (P=0.023). This difference was significant even after considering the other known predictive factors for medial TLE. CONCLUSIONS: Medial TLE with CFC is not a distinct epilepsy syndrome. The surgical outcome, however, is much more favorable in these patients in comparison with medial TLE patients who had no history of febrile convulsions.

Adolescent↗