ABSTRACT
The authors report their experience utilizing a recently described rapid rate, binaural click and 1000-Hz tone burst modification of the brain stem auditory evoked potentials (BAEP), modified (MBP), in 27 symptomatic patients with non-brain stem compressive space-taking cerebral lesions (22), hydrocephalus (4), and pseudotumor cerebri (1). Many presented with clinical signs suggestive of increased intracranial pressure (ICP) and focal neurological deficits. The cerebral lesions, mostly large tumors with edema, had very substantial radiological signs of mass effect. Fourteen patients were also studied following surgical decompression. A number of significant changes in the wave V and Vn latency/intensity and less so amplitude/intensity function was found in the 27 patients, compared to normal volunteers, as well as those studied pre- and postoperatively. Similar MBP changes had been noted in normal volunteers placed in a dependent head position. Possible mechanisms to explain these findings are discussed. The MBP methodology shows promise and further development could make neuro-intensive care unit monitoring practical.
Subject(s)
Brain Neoplasms/diagnosis , Brain Neoplasms/physiopathology , Critical Care/methods , Evoked Potentials, Auditory, Brain Stem/physiology , Monitoring, Physiologic/instrumentation , Adult , Auditory Pathways/physiopathology , Brain Edema/diagnosis , Brain Edema/physiopathology , Evoked Potentials, Somatosensory/physiology , Female , Humans , Hydrocephalus/diagnosis , Hydrocephalus/physiopathology , Intracranial Pressure/physiology , Male , Middle Aged , Monitoring, Physiologic/methods , Pilot Projects , Pseudotumor Cerebri/diagnosis , Pseudotumor Cerebri/physiopathology , Reaction Time/physiologyABSTRACT
The authors review the brainstem auditory evoked potential (BAEP), and present studies on 40 healthy subjects. In addition to the conventional click evoked BAEP, three modified BAEP examinations were performed. The modified BAEP tests include a 1,000 Hz tone-burst BAEP, and more rapid rate binaural click and 1,000 Hz tone-burst BAEPs-each of the last two studies performed at four diminishing moderate intensities. In addition to the usual parameters, the authors examined the Wave V to Vn interpeak latency, and stimulus intensity versus Wave V latency and amplitude functions in the rapid rate binaural studies. Studies were also repeated on healthy subjects in a dependant head position in an attempt to increase intracranial pressure. Discussion centers on the BAEP, its current utility in medicine, unique neurophysiology, and literature support that the above modifications could increase the practicality of the test in patients at risk with intracranial lesions and perhaps improve the feasibility for real-time continuous or frequent monitoring in the future.
Subject(s)
Diagnosis, Computer-Assisted/methods , Electroencephalography/methods , Evoked Potentials, Auditory, Brain Stem/physiology , Reaction Time/physiology , Adult , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Young AdultABSTRACT
We report an unusual case of bilateral inflammatory aural polyps in a patient with Samter's triad. This 52-year-old patient had a history of chronic rhinosinusitis with sinonasal polyps, asthma, and aspirin sensitivity, with progressive right-sided hearing loss, otorrhea, and aural fullness. She was found to have bilateral aural polyps, with the larger obstructing lesion on the right. A computed tomography supported these findings and revealed bilateral opacification of the middle ear cleft and mastoid air cells. An initial right tympanomastoidectomy was performed with the specimen histologically resembling a typical sinonasal polyp. We speculate that this patient's middle ear polyposis is secondary to the inflammatory changes of Samter's triad. This has not been described previously in the literature.
