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Biomedical subjects

A Ferbert

Publications and source records attributed to A Ferbert.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Spinal and subcortical somatosensory evoked potentials: a comparison with the localization of spinal, medullary and pontine lesions and in brain death].

The spinal and subcortical median nerve SEPs were recorded in 65 patients with lesions of the cervical cord, medulla oblongata, pons and in brain death. A recording technique including cephalic, non-cephalic and anterior neck referenced leads was used. The location of the lesions corresponded to different types of SEP alterations: Cervical extramedullary lesions compressing the spinal cord corresponded to a prolonged P9-P14 interpeak latency. Cervical intramedullary lesions corresponded to the loss of N13, normally generated in the spinal interneurons. Vascular lesions of the medulla oblongata (Wallenberg's syndrome) showed normal SEPs. Space occupying medulla oblongata lesions corresponded to reduction in amplitude or loss of P14. Pontine lesions showed normal spinal and subcortical SEPs. In brain death P14 showed a graduate decrease in amplitude or alternatively vanished abruptly. The spinal and subcortical SEPs provide a good tool for testing the function of the lemniscal pathways and the spinal interneurons.

Brain Death↗
PubMed1991

[Evoked potentials in diagnosis of ischemic brain stem lesions].

We present an overview on the impact of evoked potentials in diagnosis of ischemic brainstem lesions. Brainstem auditory evoked potentials and somatosensory evoked potentials depict abnormalities, whereas visual evoked potentials are normal in most cases. In patients with basilar artery thrombosis and primary pontine hemorrhage these evoked potentials are mostly abnormal and can indicate the location of the lesion. Furthermore, they are of prognostic value. Whether evoked potentials are abnormal in strokes with branch occlusion of the basilar artery, depends on the location of the infarction. In infarctions of the basis pontis BAEP and SEP may be normal. Hemiparesis in brainstem strokes are associated with abnormalities in transcranial magnetic stimulation. However, no further evaluation of the level of the pyramidal tract lesion is possible by this method. During fibrinolytic therapy of basilar artery thrombosis a continuous monitoring is possible by means of BAEP. Thus, information can be obtained that is not available from neurological examination of the patient under sedative drugs.

Brain Ischemia↗
PubMed1990

Complex hyperkinesia during recovery from left temporoparietal cortical infarction.

A 51-year-old man with preexistent lacunar infarctions in the basal ganglia and pons developed complex involuntary movements of his right arm 1 day after a purely cortical-subcortical ischemic infarction in the territory of the left middle cerebral artery sparing the basal ganglia. The movements were stereotyped and repetitive, affecting hand and fingers or proximal arm muscles alternatively or together. Although hyperkinesia after basal ganglia lesion has been described many times in the literature, it has not yet been reported after cortical-subcortical ischemic infarctions sparing the basal ganglia.

Cerebral Infarction↗
PubMed1990

Brainstem auditory evoked potentials and somatosensory evoked potentials in pontine haemorrhage. Correlations with clinical and CT findings.

Electrophysiological studies were performed on 17 patients with pontine haemorrhage. Most had had massive hypertensive bleeding, leading to death in 12 of them within 3 months. Of the 5 surviving patients, 2 had a poor outcome and 3 a moderately good outcome. Brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials (SEPs) were recorded in all patients, mostly with serial recordings. BAEPs were pathological in all patients. The most important finding was a reduction in amplitude or loss of waves. With a loss of waves after wave II bilaterally all patients died; the 2 patients with a normal amplitude of waves I-V at least on one side, survived in good condition. Further prognostic conclusions were not possible. The correlation with the clinical state was limited and was best for small unilateral tegmental haemorrhages. Eleven of the 17 patients suffered bilateral loss of the N20 component of the median nerve SEP. All these patients died. In patients with unilateral loss of the SEP the outcome could be favourable even if the bleeding extended across the midline. 'Subcortical' SEPs were not significantly altered. EEG findings in 15 and visual evoked potentials in 4 patients showed preserved forebrain electrical activity even in patients in poor condition.

Adult↗
PubMed1990

Loss of brainstem acoustic evoked potentials with spontaneous breathing in a patient with supratentorial lesion.

The loss of brainstem acoustic evoked potentials (BAEP) is considered as a confirmatory test for the diagnosis of brain death in patients with supratentorial lesions. We report a patient with ischemia in the territory of the left middle and anterior cerebral artery, who showed a loss of BAEP waves III-V as a sign of brainstem compression, but maintained spontaneous breathing and EEG activities. We conclude that occasionally BAEP may provide misleading results in the diagnosis of brain death.

Aged↗
PubMed1990

Clinical features of proven basilar artery occlusion.

Our study describes the early symptoms and signs of 85 patients with either basilar artery occlusion or bilateral distal vertebral artery occlusion documented by selective angiography. The most common prodromal symptoms were vertigo, nausea, and headache, which occurred during the 2 weeks before the stroke. Angiographic findings of 49 patients were classified into proximal, middle, and distal basilar artery occlusions. Twenty-two of these patients had additional vertebral artery lesions. A fourth group was composed of 36 patients with bilateral distal vertebral artery occlusion without opacification of the basilar artery through a vertebral artery injection. Onset was sudden in 20 patients; sudden, but preceded by prodromal symptoms in 11 patients; and progressive in 54 patients. Patients with progressive strokes often had bilateral vertebral artery occlusions. Most patients with acute onset had occlusion of the middle and distal basilar artery. An embolic origin of basilar artery occlusion from an arteriosclerotic vertebral artery lesion was assumed to be an important mechanism. An embolus reaching the basilar artery may not necessarily reach the top of the artery, but may also become lodged more proximally.

Adult↗
PubMed1989

Putaminal haemorrhage after recanalization of an embolic MCA occlusion treated with tissue plasminogen activator.

We present the case of a 42-year-old female, who suffered an embolic occlusion of the right middle cerebral artery (MCA). Recanalization was achieved with tissue plasminogen activator (t-PA) within 7 h after onset of stroke. Post-t-PA infusion angiographic and CT examinations revealed fragmentation of the thrombus and a small putaminal haemorrhage associated with early reperfusion of the MCA. No clinical deterioration was observed and complete recovery occurred within 10 days.

Adult↗
PubMed1989

The complete apallic syndrome--a case report.

In six patients with apallic syndrome the EEG was isoelectric, although the patients were breathing spontaneously and vegetative functions remained stable for a long period of time. No cortical somatosensory evoked potentials could be recorded in four of the patients examined. Cranial CT performed in three patients revealed extensive hypodensity of the cortex, whereas the brain stem showed no major damage. This syndrome is labelled a "complete apallic syndrome". None of our patients, and none of the 23 patients described in the literature, recovered.

Adult↗
PubMed1988

Serial recording of median nerve stimulated subcortical somatosensory evoked potentials (SEPs) in developing brain death.

Subcortical somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded serially in 35 patients during the evolution towards brain death and in brain death. Neuropathological alterations of the central nervous system down to the C1/C2 spinal cord segment in brain death are well known. SEP components supposed to be generated above this level should be lost in brain death, while components generated below should not be altered. Erb's point, scalp and neck potentials were recorded at C3/4, or over the spinous process C7, using an Fz reference. In 10 patients additional montages, including spinous process C2-Fz, a non-cephalic reference (Fz-contralateral shoulder) and a posterior to anterior neck montage (spinous process C7-jugulum) were used. The cephalic referenced N9 and N11 peaks remained unchanged until brain death. N9 and N11 decreased in parallel in amplitude and increased in latency after systemic effects like hypoxia or hypothermia occurred. The cephalic referenced 'N14' decreased in amplitude and increased in latency after the clinical brain death syndrome was observed, while N13 in the posterior to anterior neck montage remained unchanged. The alteration of 'N14' went parallel to the decrease of the P14 amplitude. The subcortical SEPs in the cephalic referenced lead are supposed to be a peak composed by a horizontally orientated dorsal horn generated N13 and a rostrally orientated P14 arising at the level of the foramen magnum. The deterioration of the non-cephalic referenced P14 and of its cephalic referenced reflection 'N14' seems to provide an additional objective criterion for the diagnosis of brain death.

Brain Death↗
PubMed1988

Evoked potentials in basilar artery thrombosis: correlation with clinical and angiographic findings.

In 28 patients with vertebro-basilar or basilar artery thrombosis brain-stem auditory evoked potentials (BAEPs) and somatosensory evoked potentials (SEPs) have been recorded. Visual evoked potentials (VEPs) were recorded in 7 of these 28 patients. In 24 patients the diagnosis was angiographically proven and in 4 patients Doppler sonography and computerized tomography suggested this diagnosis. The BAEP and SEP findings were correlated to clinical and angiographical signs. BAEPs could be classified into 6 different patterns. In more than half of the patients different BAEP patterns from the two ears could be found. A pathological IV/V complex was most often found in comatose patients and in patients with a basilar artery occlusion distal to the anterior inferior cerebellar artery. Prolonged interpeak latency of I-III was mainly found in alert or drowsy patients with caudal occlusions. The frequent occurrence of a BAEP with only wave I preserved, or with no waves preserved, in patients with brain-stem functions suggests that BAEPs are not useful in the diagnosis of brain death when basilar artery thrombosis is suspected. SEPs were either absent bilaterally or else severely altered on one side in all comatose patients. In alert patients, including those with 'locked-in' syndrome, SEPs were never absent bilaterally. Increased N13-N20 interpeak latency was an uncommon finding in this series. There was no correlation between the SEP and the angiographically proven location of the occlusion. In the 'locked-in' syndrome both SEP and BAEP findings were non-uniform. Normal SEPs were sometimes found in combination with severely altered BAEPs, suggesting partial deafferentation. Since basilar artery thrombosis is now a treatable condition, early diagnosis and documentation of functional deficits moves into a more important clinical area than heretofore.

Adult↗
PubMed1988

Intra-arterial thrombolytic therapy improves outcome in patients with acute vertebrobasilar occlusive disease.

In this retrospective analysis we report our treatment experience in 65 consecutive patients with clinical signs of severe brainstem ischemia with angiographically demonstrated thrombotic vertebrobasilar artery occlusions who received either local intra-arterial thrombolytic therapy (urokinase or streptokinase) (43 patients) or conventional therapy (antiplatelet agents or anticoagulants) (22 patients). We analyzed the data with respect to cerebral artery occlusion patterns, posttreatment arterial recanalization, and the clinical categories of favorable/unfavorable outcome and survival/death. In subgroup analyses, recanalization in patients who received thrombolytic therapy correlated significantly with clinical outcome; in 19 of 43 patients, recanalization was demonstrated angiographically, while in 24 patients the occlusion persisted. All patients without recanalization died, but 14 of the 19 patients displaying recanalization survived (p = 0.000007), 10 with a favorable clinical outcome. Only three of the 22 patients who received conventional therapy survived, all with a moderate clinical deficit. When we compared the treatment groups, highly significant differences in both outcome quality (p = 0.017) and survival (p = 0.0005) were found to depend on establishing recanalization. Our data support the concept that technically successful thrombolysis of vertebrobasilar artery occlusions is associated with beneficial clinical outcome.

Acute Disease↗
PubMed1988

Local intra-arterial fibrinolytic therapy in acute carotid territory stroke. A pilot study.

The possibility that intra-arterial local infusion of fibrinolytic agents may achieve recanalization of previously occluded carotid territory arteries in acute stroke was tested in a prospective angiography-based open pilot study at two centers. Fifteen of 20 patients with acute symptoms (mean treatment-onset interval 7.6 hours) demonstrated complete recanalization; 10 of the 15 patients exhibited clinical improvement of varying degree by the time of hospital discharge. Four of the 20 patients suffered hemorrhagic transformation of the infarcted territory without clinical deterioration or demise. Because of the study format and the limited number of patients, dose responses for recanalization and risk relations were not established. We conclude that local intra-arterial fibrinolytic therapy may lead to cerebral arterial recanalization in acute carotid territory thrombotic stroke. The particular implications and limitations of this approach are discussed.

Acute Disease↗
PubMed1988

Combined SPECT imaging of regional cerebral blood flow (99mTc-hexamethyl-propyleneamine oxime, HMPAO) and blood volume (99mTc-RBC) to assess regional cerebral perfusion reserve in patients with cerebrovascular disease.

In 53 patients with cerebrovascular disease (CVD), regional cerebral blood flow (CBF) and blood volume (CBV) were imaged by SPECT within one session. Slice division (CBF: CBV) yielded distribution of regional cerebral perfusion reserve (CPR). Semiquantitative evaluation was obtained from manually set ROIs by interhemispherical ratios (for CBF, CBV and CPR), using 2 SD from a normal group (n = 10) as a threshold. Sensitivities were 59% for CBF, 94% for CBV and 83% for CPR. Combined sensitivity was 98%. Establishing three constellations for CBF, CBV and CPR, regionally normal CBFs but quantitatively increased CBVs (+69%) and decreased CPRs (-31%) were found in relatively early stages of CVD. Very advanced cases showed decreased CBFs (-65%), CBVs (-40%), CPRs (-49%) and a surrounding penumbra. In 87% (46/53 patients), such rheologically postulated constellations could be demonstrated. We conclude that combined CBF and CBV SPECT, assisted by CPR images, is a promising tool to detect CVD and to assess its individual regional severity.

Aged↗