Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BRAIN STEM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1996

Neuroimaging of pediatric brain stem diseases other than brain stem glioma.

A wide variety of both neoplastic and non-neoplastic lesions affect the pediatric brain stem. Of these, inflammatory and infectious, along with occult vascular malformations produce the greatest concern regarding the interpretation of imaging studies that could lead to inappropriate therapeutic modalities in the treatment of the patient. Awareness of the differential diagnosis and, when appropriate, the judicious use of follow-up examination are warranted.

Brain Diseases↗
PubMed1976

Auditory brain-stem responses in brain death.

Auditory brain-stem responses were measured by far-field recording techniques in 27 patients fulfilling the criteria of brain death. The responses were either absent or consisted of the presence of just the initial component (Wave I). Wave I, when present, was of normal amplitude but prolonged in latency. Four patients were followed over several days from a state of coma with evidence of preserved brain-stem and cerebral functions to a clinical state compatible with brain death. Auditory brain-stem responses were initially intact and then showed a decrease in amplitude and a prolongation of latency of the later components until finally Wave I was alone. Auditory brain-stem responses are an objective measure of one of the sensory pathways traversing the brain-stem and can be used to evaluate the functional states of the brain-stem in patients in whom the question of brain death has been raised.

Adult↗
PubMedDate not supplied

[Lateralization and level of brain stem lesions according to brain stem auditory evoked potentials].

Twenty patients with severe craniocerebral injury, hemorrhagic and ischemic strokes, and tumor of the brain were examined. The generated acoustic stem response (GASR) was studied in all of them. At the time of examination all the patients were in a state of coma. Considerable deviations of the GASR from the norm were disclosed. The method makes it possible to determine the level of the brain stem lesion and to lateralize the predominant damage to the stem.

Adult↗
PubMed1988

[Auditory evoked potentials of the brain stem in brain death].

Brainstem auditory evoked responses were recorded in a neurosurgical intensive care unit in 38 patients who had all the clinical criteria for brain death. Of the brain-dead patients, 65.8% never showed a response. 3.42% showed a type I wave, which was unilateral in 26.3% and bilateral in the other 7.9%. Types II to VII waves were never seen. An increase in latency of type I waves (2.25 +/- 0.24 ms) was noted. The interest and the limits of this non invasive electrophysiologic technique for the diagnosis of brain death are discussed.

Adolescent↗
PubMed1984

Absent auditory brain stem response: peripheral hearing loss or brain stem dysfunction?

Interpretation of auditory brain stem response (ABR) findings can be problematic in cases where waves III and V are absent. Such findings can be attributed to profound hearing loss, brain stem neuropathology, or both. Over a 3-year period, 48 patients with no known brain stem damage and on whom audiologic data were available were found to have no response by ABR or absent waves III and V. Severe to profound hearing loss was documented in 38 cases, audiometric data were equivocal in 3 cases, and 7 patients showed pure tone sensitivity ranging from normal hearing to moderate impairment. Thus 15% had better hearing sensitivity than might have been expected from their ABR findings. Each of these patients also exhibited abnormal acoustic reflex findings. We report the electrophysiological (ABR, MLR, acoustic reflex), medical (history, neurological, EEG, CT scan) and behavioral (audiometric, speech and language, learning disabilities, psychological) data which characterize this group of patients.

Acoustic Impedance Tests↗
PubMed1992

[Clinical aspects and pathogenesis of infarction of the brain stem].

Clinical and hemodynamic studies were carried out in 75 patients with stem brain infarction in the acute period, including repeated infarctions. The total rupture of the autoregulatory mechanisms of the brain blood flow was discovered, leading to the development of different phenomena of "brain steal" determining the clinical course of stem brain infarction. In the given pathology, the acute period is characterized by the development of the vicious circle of hemodynamic disorders, which is coupled with pathological dissociation in coagulation hemostasis. The progression of the hemodynamic changes requires pathogenetic correction of central and cerebral circulation.

Acute Disease↗
PubMed1988

[The relative importance of the brain stem acoustic evoked potential (BAEP) in patients with brain stem tumors].

The brain stem acoustic evoked potential is a non-invasive procedure at the disposal of neurological diagnostics that permits to obtain information about the functional condition of the brain stem. As regards the question of the topodiagnostic possibilities of this examination method in patients with brain stem tumours the BAEP parameters were compared with the clinical symptoms existing at the time of the examination as well as with computer tomographic findings. There is a good agreement of the severity of the clinical symptoms and the distinction of the BAEP changes. In case of unilateral BAEP changes or BAEP changes with a pronounced accentuation on one side indications with respect to the lateral localisation of the brain stem tumour in connection with the clinical findings can be derived. An exact topodiagnosis of brain stem tumours is exclusively possible by the correlation of clinical symptoms, results of picture-yielding examination methods and BAEP examination.

Adolescent↗
PubMed1980

Brain stem auditory evoked response and brain stem compression.

For the study of brain stem auditory evoked response (BAER) changes due to acutely expanding mass lesions, posterior fossa balloon catheters were inflated slowly in anesthetized cats while supratentorial and infratentorial intracranial pressure and vital signs were monitored. Reliable changes in BAER occurred before the Cushing response and were reversible by balloon deflation. Because BAER changes precede the agonal changes of the Cushing response, serial BAER recording in patients with known or suspected posterior fossa masses may be useful in the management of these lesions.

Animals↗
PubMed1978

Compound impulse response for the brain stem derived through combinations of cochlear and brain stem recordings.

To overcome some of the problems involved in the application of brain stem evoked responses (BSER) in otoneurological diagnosis an approach is developed which combines cochlear and brain stem recordings. The activity of the cochlea and brain stem generators, as seen from the far-field recording electrode, is considered to be the output from a single system. The impulse response of this system can be derived through deconvolution of the brain stem evoked responses, BSER, with the compound action potential, AP, followed by appropriate filtering. This method is used on the recordings from 15 subjects with various degrees of cochlear hearing loss. The results show that the compound impulse response, CIR, for the brain stem consists of five recognizable peaks. From the individual subjects this response pattern is largely independent of intensity. By plotting the amplitude and latency of the individual peaks for all 15 subjects a set of normative data is retrieved. The variation in the data is small, probably because interfeerence from the periphery is eliminated and the separation of activity from the different brain stem generators is improved.

Audiometry↗
PubMed2005

Experiences of families when a relative is diagnosed brain stem dead: understanding of death, observation of brain stem death testing and attitudes to organ donation.

Brain stem death may be a difficult concept for relatives to understand. Our ITU practice follows published recommendations that the use of explanatory leaflets showing CT scans and observing brain stem death testing in some cases may help relatives to understand that death has occurred. Using this strategy, we interviewed 27 relatives 12 months after bereavement following certification by brain stem testing, investigating their understanding of brain stem death, subsequent attitudes to organ donation, grief reactions and attitudes of those who had observed the tests. Most relatives understood that the brain stem death tests indicated that survival was not possible, although three relatives had not fully understood this and valued the opportunity to discuss it again. Only five relatives observed the tests, all were pleased that they had done so as this had confirmed their understanding that death had occurred; however, these relatives had more evidence of psychological distress. No relatives who agreed to organ donation regretted this but three who did not allow donation subsequently expressed regret. Several relatives thought that observing the tests would have helped them to understand that death had occurred, making easier the decision to allow organ donation.

Adult↗
PubMed1990

[Pathologic findings in auditory brain stem evoked potentials in 10 children with brain stem tumors].

The authors examined brain stem acoustic evoked potentials (BAEP) in 10 children aged 2-14 years with tumours in the posterior cranial fossa infiltrating the cerebellum and brain stem. The tumours were diagnosed by computed tomography and in eight patients confirmed on operation. For stimulation a monaural click was used. The authors assessed the latency of waves, intervals between and investigated the presence of waves and evaluated their amplitudes. They compared the results with normal values. In abnormal findings the latency of components was delayed, the components were generated in a rostral manner from the site of the lesion in all children. In four patients with severe affections of the brain stem the investigated components were lacking. In nine patients the BAEP evoked by monaural stimulation helped to asses the lateralization of the lesion. In eight patients a bilateral abnormality of the V wave was recorded. The most sensitive indicator for assessment of the site of the lesion was assessment of the interval between two consecutive waves.

Adolescent↗
PubMed1985

Brain-stem auditory evoked potentials in children with brain-stem or cerebellar dysfunction.

Brain-stem auditory evoked potentials (BAEPs) were recorded in 23 children who had signs of brain-stem or cerebellar dysfunction. In patients with brain-stem gliomas, BAEPs were abnormal in all except one, in whom involvement of the brain-stem auditory pathway was limited to the midbrain tectum. The BAEPs were normal in neuronal ceroid lipofuscinosis, but abnormal bilaterally in inheritable leukoencephalopathies. All patients with Leigh's encephalopathy had BAEP abnormalities; in two, abnormalities occurred before the appearance of lesions on computed tomographic scan. Patients with Friedreich's ataxia and giant axonal dystrophy had abnormal BAEPs, but the test was normal in a child with similar neurologic findings with vitamin E deficiency. Patients with diffuse metabolic encephalopathies had variable findings. Thus, BAEP abnormalities are nonspecific for various disease processes but are frequently seen in neoplastic and neurodegenerative diseases, with primary white matter or extensive brain-stem involvement.

Adolescent↗
PubMed1991

Changes in brain stem blood flow under various grades of brain stem ischemia.

This report describes a study of brain stem blood flow (BBF) change under various grades of brain stem ischemia in a new experimental rat model. The main damage was caused by occlusion of the median and paramedian perforating arteries of the basilar artery. In this model, hyperperfusion was generally observed in cases of mild or moderate ischemia within 1 hr after recirculation and lasted for approximately 1 hr. During hyperperfusion, BBF increased to over 60 ml/100 g brain/min and was significantly greater than basal values (p less than 0.01). The fact that hyperperfusion was unobserved in some cases might be due to the degree of damage to the medulla oblongata. Hypoperfusion or lack of reflow phenomena was also followed by severe ischemia with remarkable hypotension. It is fairly clear from our results that the pattern of postischemic hyperperfusion is responsible for decreased oxygen availability in the brain stem and dysfunction of autoregulation. Acetazolamide reactivity was disturbed and had an inverse response during hyperperfusion. Such phenomena can be explained by paralytically dilated vessels due to ischemia. If BBF falls below a critical level, as we have seen, postischemic hyperperfusion may be induced with dysfunction of autoregulation and inverse acetazolamide reactivity due to vasoparalysis in the brain stem.

Acetazolamide↗
PubMed1988

Selective unilateral absence or attenuation of wave V of brain-stem auditory evoked potentials with intrinsic brain-stem lesions.

The contribution of ipsilateral and contralateral auditory brain-stem structures to the generation of wave V of brain-stem auditory evoked potentials is a controversial subject. We describe two cases with an intrinsic brain-stem lesion that involved the lateral lemniscus unilaterally in the middle and upper pons. The focal nature of the auditory structures was confirmed by detailed neuropathologic data in one case and by magnetic resonance scans in the other one. In both cases, brain-stem auditory evoked potentials revealed the unilateral absence (case 1) or marked attenuation (case 2) of wave V on stimulation of the ear contralateral to the intrinsic pontine lesion. Findings in both cases strongly suggest that wave V is predominantly generated by pontine structures contralateral to the stimulated ear and that the integrity of the contralateral lateral lemniscus is essential.

Adult↗