| brainstem auditory evoked potentials | <investigation, physiology> A special neurologic test which measures the brainstem and brains nervous response to auditory stimulation. It is used to evaluate neurologic integrity and hearing in newborns. Can be used in the evaluation of stroke, acoustic neuroma, Meniere's disease and multiple sclerosis Acronym: BAEP (15 Nov 1997) |
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| evoked potentials, auditory, brainstem | Electrical waves in the cerebral cortex generated by brainstem structures in response to auditory click stimuli. These are found to be abnormal in many patients with cerebellopontine angle lesions, multiple sclerosis, or other demyelinating diseases. (12 Dec 1998) |
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| auditory evoked potentials | <investigation> A special neurologic test, known as brainstem auditory evoked potentials, which measures the brain and brainstem nervous response to auditory stimulation. A test used to evaluate neurologic integrity and hearing in newborns. Can be used in the evaluation of stroke, acoustic neuroma, Meniere's disease and multiple sclerosis (27 Sep 1997) |
| evoked potentials, auditory | The electric response evoked in the cerebral cortex by acoustic stimulation or stimulation of the auditory pathways. (12 Dec 1998) |
| brainstem evoked response audiometry | An electrophysiologic measure of auditory function utilizing responses produced by the auditory nerve and the brainstem to repetitive acoustic stimuli. (05 Mar 2000) |
| evoked potentials | <physiology> The use of electrodes to measure the electrical activity of nerves. May be used as a guide during surgical removal of tumours growing around important nerves. (16 Dec 1997) |
| evoked potentials, motor | The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and transcranial magnetic stimulation. It is often used for monitoring during neurosurgery. (12 Dec 1998) |
| evoked potentials, somatosensory | The electric response evoked in the cerebral cortex by stimulation of afferent pathways from peripheral nerves to cerebrum. (12 Dec 1998) |
| evoked potentials, visual | The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways. (12 Dec 1998) |
| auditory brainstem response audiometry | An electrophysiologic measure of auditory function utilizing responses produced by the auditory nerve and the brainstem to repetitive acoustic stimuli. (05 Mar 2000) |
| brainstem | <anatomy> The lowest part of the brain, which merges with the spinal cord. It consists of the medulla oblongata, midbrain and pons. Originally, the entire unpaired subdivision of the brain, composed of (in anterior sequence) the rhombencephalon, mesencephalon, and diecephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the term's connotation has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable. (05 Mar 2000) |
| brainstem glioma | <oncology, tumour> This primary brain tumour occurs in the pons or the medulla. They account for approximately 15% of brain tumours in children. Symptoms include double vision, facial weakness, vomiting and difficulty walking. Surgery is difficult due to location so radiation therapy and chemotherapy are used. Overall survival is 20 to 30%. (27 Sep 1997) |
| brainstem haemorrhage | Haemorrhage into the pons or mesencephalon, often secondary to brainstem distortion by transtentorial herniations due to rapidly expanding intracranial lesions. (05 Mar 2000) |
| reticular nuclei of the brainstem | The vaguely delineated cell groups composing the gray matter of the reticular formation of the rhombencephalon and mesencephalon. In general, large-celled territories occupy the medial two-thirds of the reticular formation: gigantocellular nucleus of medulla oblongata, nuclei tegmenti pontis caudalis and oralis. Smaller groups of reticular nuclei are found laterally and in paramedian locations; lateral nuclei receive sensory collaterals and project medially; paramedian reticular nuclei largely project to the cerebellum. See: reticular formation. (05 Mar 2000) |
| membrane potentials | Ratio of inside versus outside concentration of potassium, sodium, chloride and other ions in diffusible tissues or cells. Also called transmembrane and resting potentials, they are measured by recording electrophysiologic responses in voltage-dependent ionic channels of (e.g.) nerve, muscle and blood cells as well as artificial membranes. (12 Dec 1998) |
| cochlear microphonic potentials | The electric response of the cochlear hair cells to acoustic stimulation. (12 Dec 1998) |