| 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) |
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| 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) |
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| 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) |
| 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) |
| audiometry, evoked response | A form of electrophysiologic audiometry in which an analog computer is included in the circuit to average out ongoing or spontaneous brain wave activity. A characteristic pattern of response to a sound stimulus may then become evident. Evoked response audiometry is known also as electric response audiometry. (12 Dec 1998) |
| evoked response audiometry | A type of electrophysiologic audiometry in which electrical potentials of neural impulses from the cochlear nerve and various levels in the brain in response to acoustic stimulation are used to localise the site of a lesion causing a hearing loss. (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) |
| audiometry | The measurement of hearing. (12 Dec 1998) |
| audiometry, pure-tone | Measurement of hearing based on the use of pure tones of various frequencies and intensities as auditory stimuli. (12 Dec 1998) |
| audiometry, speech | Measurement of the ability to hear speech under various conditions of intensity and noise interference using sound-field as well as earphones and bone oscillators. (12 Dec 1998) |
| automatic audiometry | An audiometric technique using an automatic audiometer, which enables the patient to track his own hearing thresholds by controlling the intensity of the signal being presented to him, while the audiometer sweeps through the audible frequency range. (05 Mar 2000) |
| Bekesy audiometry | Automatic audiometry utilizing the Bekesy audiometer; the patient makes two threshold tracings, one in which the tone is rapidly turned on and off (interrupted tone) and one in which the tone is presented steadily (continuous tone); results may be suggestive of middle-ear, cochlear, or eighth nerve lesions. (05 Mar 2000) |
| cortical audiometry | Measurement of the potentials that arise in the auditory system above the level of the brainstem. (05 Mar 2000) |