[Brain stem auditory evoked potentials in brain stem dysfunction].
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Animals↗
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[Differentiation of brain stem anesthesia from high spinal anesthesia using auditory brain stem response].
A 67-year old woman having intractable chronic postherpetic neuralgia at the neck to forearm for two years was treated with subarachnoid block. Initially, bolus of 1% lidocaine 8 ml, with methylprednisolone acetate 20 mg was injected intrathecally at 6th cervical intervertebral space. The auditory brain stem response (ABR) during high spinal block with intact consciousness was not depressed in its wave height. ABR recorded showed prolongation of latency of 3 and 5 waves and prolongation of 1-3 phase to phase interval without prolongation of 3-5 phase to phase interval. Intrathecal nerve block was then performed with 1% lidocaine 15 ml and methylprednisolone acetate 20 mg, because she complained awareness and shocking sensation with controlled respiration during the first block. She assured that she felt nothing during the second block. The ABR recorded during the second block showed near complete suppression in its height of all waves and prolongation of all wave latencies. During recovery period, 1-3 and 3-5 phase to phase interval prolongation was recorded. One can differentiate brain stem anesthesia from other state that induces unconsciousness after block which is capable of inducing accidental brain stem anesthesia. These two blocks improved activity of daily living of the patient and severity of her pain decreased to 1/5 to 1/10.
Aged↗
The movement of the brain stem and vessels around the brain stem in children with hydrocephalus and the Arnold Chiari deformity.
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Arnold-Chiari Malformation↗
Auditory brain stem responses evoked by lateralized clicks: is lateralization extracted in the human brain stem?
The dependence of binaurally evoked auditory brain stem responses and the binaural difference potential on simultaneously presented interaural time and level differences is investigated in order to assess the representation of stimulus lateralization in the brain stem. Auditory brain stem responses to binaural click stimuli with all combinations of three interaural time and three interaural level differences were recorded from 12 subjects and 4 channels. The latency of Jewett wave V is shortest for zero interaural time difference and longest for the trading stimuli. The amplitude of wave V is largest for centrally perceived stimuli, i.e., the diotic and trading stimuli, and smallest for the most laterally perceived stimuli. The latency of the most prominent peak of the binaural difference potential DN1 mainly depends on the interaural time difference. The amplitude of the components of the binaural difference potential, DP1-DN1, depends similarly on stimulus conditions as wave V amplitude in the case of the binaural stimuli: smallest amplitudes are found for the most lateral stimuli and largest amplitudes for central stimuli. The results demonstrate that interaural level and time differences are not processed independently. This supports the hypothesis that directional information in humans is already extracted and represented at the level of the brain stem.
Acoustic Stimulation↗
Neuropathological findings in 9 cases of listeria monocytogenes brain stem encephalitis.
Brain stem encephalitis is a particular manifestation of infection with the bacterium Listeria monocytogenes. Here, we present the neuropathological findings in 9 such cases. In the brain stem, the inflammatory infiltrates were located predominantly within nuclei and tracts of cranial nerves innervating the oropharynx. These findings support the hypothesis that the food-borne bacterium Listeria monocytogenes invades the brain stem along cranial nerves.
Adolescent↗
Current management of brain stem gliomas.
Brain stem gliomas constitute 10-20% of central nervous system tumors in children. Management of these tumors remains controversial. In general, the prognosis for long-term survival is poor, but brain stem gliomas represent a heterogeneous population of tumors, some of which have a better prognosis than others. Improvements in diagnostic imaging techniques, particularly the availability of magnetic resonance imaging, provide the means to differentiate among these populations. Advances in radiation therapy may provide the means to improve survival. In this article we review the reported series and the present state of the art for the diagnosis and management of children with brain stem gliomas.
Adrenal Cortex Hormones↗
Acute intracranial hypertension and auditory brain-stem responses. Part 3: The effects of posterior fossa mass lesions on brain-stem function.
The auditory brain-stem responses (BER's), infratentorial intracranial pressure (ICP), systemic blood pressure (BP), and heart rate were recorded before, during and after expansion of an infratentorial epidural mass in anesthetized cats. Two types of BER's to increasing posterior fossa pressure were noted. In Type 1, there was predominantly suppression of the electrical activity of the auditory nuclei of the upper brain stem (Waves V and IV) and upward transtentorial herniation of the midbrain. In Type 2, the neural activity of the lower brain-stem nuclei (Waves III and II) was affected as well as that of the upper brain stem. There was upward and foraminal impaction of the brain stem and cerebellum which was confirmed by the postmortem brain sections. The change in the amplitudes of BER Waves V and III proved useful in detecting upward transtentorial herniation of the midbrain and foraminal herniation of the cerebellum in acute expanding lesions of the posterior fossa. Medullary paralysis was also detected by observing Wave III.
Animals↗
Brain stem auditory evoked potentials in determining site of lesion of brain stem gliomas in children.
Brain stem auditory evoked potential (BAEP) test results are reported on seven children (2 1/2-13 years) with brain stem neoplasms. In each case, the BAEP test results clearly indicated the site of lesion as determined by computerized tomography and observation during surgery. Seven criteria for the assessment of BAEP test results are also presented: 1. Peak latency, 2. Intra-peak latency, 3. Inter-peak latency, 4. Response stability, 5. Amplitude, 6. Waveshape, and 7. Peak presence. Six children had positive indications on at least four of the seven criteria described, while one child had two positive indications. However, dramatic abnormality on any single criterion warrants serious investigation.
Adolescent↗
The auditory brain stem response interaural latency difference (ILD) in patients with brain stem lesions.
The ABR interaural latency difference (ILD) from 15 patients with brain stem lesions was compared to the ILDs from patients with VIIIth nerve tumors, cochlear pathology, and a normal control group. All patients in the study had to meet the criteria of bilaterally symmetrical hearing for pure-tone thresholds in order to offset the effect of hearing loss on the ILD. Although the ILDs for the brain stem lesion group were larger than for the cochlear or normal groups, they were significantly smaller than for the VIIIth nerve tumor group. It appears that the ILD is not as sensitive a measure for detecting brain stem involvement as VIIIth nerve tumors.
Adult↗
Acute intracranial hypertension and auditory brain-stem responses. Part 1: Changes in the aduitory brain-stem and somatosensory evoked responses in intracranial hypertension in cats.
Changes in auditory brain-stem responses (BER's) and somatosensory evoked responses (SER's) were investigated to correlate mass volume, intracranial pressure, and neurological dysfunction in mass-induced intracranial hypertension in cats. As the intracranial pressure was raised by expansion of a supratentorial balloon, the late components of the SER's were suppressed first, followed by the early components of the SER's, then Wave V and Wave IV of the BER's, in that order. This suggests that the nonspecific reticular projections are most vulnerable to compression ischemia, and the specific somatosensory pathways are the next most vulnerable. Neural activity of the auditory pathways in the upper brain stem was also gradually suppressed, but less so than that of the somatosensory pathways. After complete transtentorial herniation, in spite of immediate mass evacuation, the function of the somatosensory pathways was greatly impaired, often irreversibly. The neural activity of the auditory pathways in the upper brain stem revealed progressive recovery during a 3-hour period. The measurements of BER Wave V is thought to be useful in predicting transtentorial herniation.
Animals↗
[Immunohistochemical research on brain stem injury: expression of heat shock protein 70 in rat brain after traumatic brain stem injury].
The aim of this study was to determine the expression of heat shock protein 70 (HSP70) as molecular chaperones, following traumatic brain stem injury(TBSI). The expression of HSP70 was detected in respective brain regions of rats 1 h, 3 h, 6 h, 12 h, 24 h after brain stem stabbing wound. Numerous HSP70 immunoreactivity positive blood vessel endothelioid and glia cells were found in cerebral, cerebellar cortex and hippocampus after 1 h, with H.E stain unchanged. In the area near the focal of brain stem injury, HSP70 immunoreactivity positive neurons increased significantly after 1 h of injury, reaching the highest level after 3 h, much higher than in other areas. HSP70 immunoreactivity positive cells still existed after 24 h of injury. It was suggested that TBSI cause the defectiveness of protein structure in brain, and induce HSP70 proteolysis of denature protein including misfolding or aggregate. TBSI can be diagnosed regionally by the increasing of HSP70 immunoreactivity positive neurons in the focal of brain stems.
Animals↗
Frequency-specific maturation of the eighth nerve and brain-stem auditory pathway: evidence from derived auditory brain-stem responses (ABRs).
Previous studies of human auditory development using frequency-specific auditory brain-stem responses (ABRs) have reported that maturation for both peak and interpeak latencies occurs earlier for responses generated by low-frequency stimuli. In two of these studies, low-frequency ABRs presumed to originate from apical locations in the cochlea were likely dominated by activity from higher frequency regions closer to the base. In the present study, the high-pass noise-masking technique was used to generate derived ABRs that represent activity from isolated place specific regions along the basilar membrane. Analysis of auditory brain-stem maturation based on I-V interpeak latency differences with adult means revealed a frequency-specific pattern of development. Developmental changes occurred faster and mature function was attained earlier for ABRs from the mid-center-frequency (CF) derived conditions than from either the highest or lowest CF derived conditions. The differential maturation of mid-CF derived ABRs may reflect the delayed effects of the pattern of development that occurs in the cochlea.
Auditory Pathways↗
Brain stem cheiro-oral syndrome: neurological signs for brain stem lesions.
Cheiro-oral syndrome (COS) is characterized by a sensory disturbance in one hand and the ipsilateral oral corner. It is usually due to a lesion in the parietal cortex, thalamocortical projections or thalamus. Brain stem lesions may rarely produce COS. We present two COS patients with midbrain infarction and pontine hemorrhage, respectively. In our patients, unilateral oculomotor nerve palsy or medial longitudinal fasciculus syndrome concurred with sensory disturbances of cheiro-oral distribution. COS produced by cortical/thalamic lesion is not accompanied with such oculomotor signs. Thus, oculomotor deficits are decisive in differentiating brain stem from cortical or thalamic COS.
Aged↗
Multiple fraction-per-day radiotherapy for patients with brain stem tumors.
Brain stem tumors are among the most resistant brain tumors to therapy. The majority progress within 18 months of diagnosis and treatment. Multiple-fraction-per-day (MFD) radiotherapy would theoretically allow higher total doses of radiotherapy to be delivered in order to improve local tumor control without increasing neurotoxicity secondary to treatment. Seventeen patients with brain stem tumors were evaluated and treated at Duke University Medical Center (DUMC) from 1985 to 1991 with a MFD regimen. Six patients were accrued to Pediatric Oncology Group (POG) Protocol 8495 and were not included in this analysis, leaving eleven patients for review. Local fields were treated with fraction sizes of 110 or 117 cGy twice daily. There were 3 patients who received a total of 60.5-68.2 Gy and 8 who received 70.2-71.5 Gy. Initial and follow-up CT and/or MRI studies were available for review on all but one patient. All patients had progression of disease and have died. Median time to tumor progression was 5.8 months. Median overall survival was 11.2 months. There was no significant influence upon time to tumor progression or survival by total radiation dose received. Patients were classified by imaging group per the criteria of Stroink et al. based on review of their pre-treatment CT or MRI scans. One patient had no initial films available, 2 were in Group II (no contrast was given to separate A or B), 3 in IIA, 4 in IIB, and 1 in III. Autopsy in 3 patients failed to demonstrate histologic evidence of injury attributable to radiotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Alterations in brain-stem auditory responses induced by head down tilting in hypertensives with supine brain-stem disorders.
The influence of head down (HD) tilting on brain-stem auditory evoked responses (BAER) was studied in hypertensives with supine brain-stem disorders (occipital headache, vertigo, nausea, diplopia, blurred vision occurring after night recumbency), in hypertensives without such phenomena and in normotensives. In the latter two categories of subjects HD tilting had no effect on BAER. On the contrary, in hypertensives with supine brain-stem disorders the manoeuvre induced a constant prolongation of I-V and III-V intervals and a depression in the amplitude of wave V; the alterations of BAER produced by HD tilting reveal probably a dysfunction of the superior brain-stem area and might be due to the impaired cerebral venous draining subsequent to the manoeuvre. The study of BAER after HD tilting seems to be a proper means to attest the supine brain-stem disorders displayed by some hypertensives.
Brain Ischemia↗
Brain stem audiometry: status and clinical applications of click evoked brain stem responses.
Over the past 10 years, numerous reports on click evoked brain stem responses have appeared in both the general otolaryngologic and the audiologic literature. Equipment is now commercially available, is relatively simple to operate, and permits the routine recording of these potentials. The technique is especially useful in the objective establishment of hearing thresholds in the newborn and in adult subjects and appears to be more reliable than the cortical evoked response (AEP). Other uses and applications of the technique, as in the detection of brain stem lesions and acoustic tumors, in coma and brain death, are discussed.
Adult↗
Lateralization, impedance, auditory brain stem response and synthetic sentence audiometry in brain stem disorders.
Applied individually, the conventional audiometric tests are unsatisfactory in the diagnosis of retrocochlear disorders. An accurate identification of a retrocochlear lesion, however, is not always possible using a single test, and only an appropriate test battery provides the basis for correct prediction of a retrocochlear lesion. Because of this observation, lateralization tests, impedance studies, auditory brain stem responses and speech audiometry with synthetic sentences have been applied to patients affected with retrocochlear disorders (acute nucleoreticular vestibular syndrome, multiple sclerosis and focal lesions). Analysis of the results has demonstrated the value of the tests employed, but the various tests were not strongly correlated and are therefore complementary.
Acoustic Impedance Tests↗
Studies on brain stem. IX. Comparative anatomical study of brain stems of some species of bats.
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Animals↗