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Biomedical subjects

E L Applebaum

Publications and source records attributed to E L Applebaum.

83 records · Page 5Linked to original sources
PubMedDate not supplied

Value of special auditory tests in the latero-medial inferior pontine syndrome.

Results from a special battery of auditory tests are used to document, for the first time, recovery from a total unilateral hearing loss occurring as part of a latero-medial inferior pontine syndrome. Although sensitivity for pure tones and speech was regained within two months of onset, definite retrocochlear signs persisted for nine months. The tests which best demonstrated the lingering retrocochlear abnormality were binaural masking level difference procedures for 500 Hz pure tones and speech and examination of the amplitude of the acoustic reflex over a ten second time period. The relative sensitivity of other speech and pure tone tasks in detecting the retrocochlear problem is detailed.

Animals↗
PubMedDate not supplied

Auditory and vestibular system findings in patients with vascular loops in the internal auditory canal.

Many anatomic studies have shown that a loop of the anterior inferior cerebellar artery is frequently found in the cerebellopontine angle and internal auditory canal. The concept of vascular cross-compression has been extended to the eighth cranial nerve, and patients with symptoms of hearing loss, tinnitus, and vertigo have been treated surgically by separating the vascular loop from the nerve. Previous reports have emphasized vascular anatomy, surgical approaches, and treatment results. Our study provides details of audiometric and vestibular system test results in a series of ten patients with prominent vascular loops in the internal auditory canal diagnosed by computerized tomography after subarachnoid space air injection (pneumo-CT). All patients had a unilateral (or asymmetric) hearing loss on the side of the lesion, and no vascular loops were detected on the contralateral sides. Hearing losses ranged from mild to profound. Audiometric findings were generally of a cochlear type, and most patients had excellent speech discrimination. Spontaneous nystagmus was detected in all patients during neurotologic testing, and half of the patients had normal caloric test results. The variability of audiometric and vestibular system test results is probably a reflection of anatomic variations of the vascular loop and its branches. Auditory and vestibular symptoms may be due to a complex interaction between the eighth cranial nerve and the vascular loop, in which the loop compresses the nerve and the nerve compromises circulation to the inner ear. Although symptoms from vascular loops and eighth nerve tumors are similar, the findings of a cochlear type of hearing loss, excellent speech discrimination, and normal caloric test results should raise the suspicion of a vascular loop.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

An endoscopic method of tympanic membrane fluorescein angiography.

Fluorescein angiography is a recently developed method of studying the tympanic membrane's dynamic vasculature. Our preliminary studies using an ophthalmic fundus camera and aural speculum did not always permit visualization of the entire tympanic membrane, and the electronic flash unit used in our initial studies did not cycle fast enough to visualize effectively the rapid arterial phase of blood flow. In this report, we describe an endoscopic method of tympanic membrane fluorescein angiography that uses a continuous xenon light source. A representative angiogram from a normal subject is described. The mallear artery apparently is the major blood supply to the posterior half of the tympanic membrane, which is consistently better perfused than the anterior half. Branches from the annular ring of blood vessels supply the anterior half of the tympanic membrane. Preliminary studies of two temporalis fascia tympanoplasty patients indicate that the graft becomes revascularized 2 to 4 weeks after surgery and that posterior grafts may revascularize earlier than anterior grafts.

Adult↗
PubMedDate not supplied

Treatment of spastic dysphonia without nerve section.

Spastic dysphonia is a disorder characterized by strained, constricted phonation with excessively adducted vocal cords. Despite initial success with recurrent laryngeal nerve section, the search for other treatment continues. Our clinical study involved inserting a needle electrode percutaneously into the region of the recurrent laryngeal nerve in five patients with spastic dysphonia. Electrical stimulation resulted in dramatic improvement in three patients and minimal improvement in two. Our experimental study was designed to create an animal model for an implantable nerve stimulator to be used on a long-term basis. A Medtronic spinal cord stimulation system was implanted into a dog, and a cuff electrode was positioned around the recurrent laryngeal nerve. Vocal cord position could be altered by varying the stimulus frequency. Long-term stimulation of the recurrent laryngeal nerve was relatively safe and effective. Eventually, we plan to implant nerve stimulators into spastic dysphonia patients who respond well to percutaneous stimulation.

Adult↗
PubMedDate not supplied

Mechanisms of pneumothorax following tracheal intubation.

To investigate the mechanism by which pneumothorax may occur as a complication of tracheal intubation, we submitted four cats to tracheotomy and three to tracheal intubation. To simulate the dissection of air along fascial planes following tracheotomy, we placed catheters in either the pretracheal or subcutaneous plane and applied positive pressure to the catheters. The cats undergoing tracheal intubation were ventilated with excessive positive pressure. Computed tomography was used to document the progression of pneumothorax. High positive pressures during mechanical ventilation led to pneumothorax and pneumomediastinum, and the mechanism was primarily the dissection of air along the perivascular sheaths of the pulmonary arteries, presumably due to rupture of perivascular alveoli. Dissection of air along the pretracheal fascia following tracheotomy produced pneumomediastinum but not pneumothorax. This suggests that pneumothorax occurring clinically is more likely a complication of assisted ventilation than a complication of tracheotomy surgery.

Animals↗
PubMedDate not supplied

Otologic complications following temporomandibular joint arthroscopy.

The recent application of arthroscopic surgical techniques to the temporomandibular joint (TMJ) has facilitated the diagnosis and treatment of TMJ disorders. However, as TMJ arthroscopy is performed more frequently, new complications are being recognized. We report three patients who developed severe otologic complications following TMJ arthroscopy. Two sustained complete or severe sensorineural hearing loss and severe vertigo from trauma to the ipsilateral ear. The third patient had complete facial paralysis from trauma to the facial nerve in the middle ear and a conductive hearing loss from incus dislocation. Complete hearing loss and facial paralysis from trauma to the main trunk of the facial nerve have not been reported previously as complications of TMJ arthroscopy.

Adult↗
PubMedDate not supplied

Radiation-induced carcinoma of the temporal bone.

A case of a patient in whom carcinoma of the right temporal bone developed 39 years after a series of injections of radium chloride is presented. Carcinomas of the temporal bone and paranasal sinuses are a complication of radium administered therapeutically or ingested accidentally by watch dial painters.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Otosclerotic involvement of the cochlea: a histologic and audiologic study.

This study sought correlations between sensorineural hearing loss and otosclerotic endosteal involvement in 29 temporal bones examined histologically. The sensorineural hearing loss of the affected parts of the cochlea was determined by the last antemortum bone conduction audiogram available. There were eight temporal bones with only stapes footplate involvement, six with one discrete focus of otosclerotic endosteal involvement, and 15 with two or more foci of endosteal involvement. Analysis of audiometric data showed that the group of bones with two or more foci of endosteal involvement had a similar incidence of 45 dB sensorineural loss (9 of 15 or 60%) as did the group with no endosteal involvement (5 of 8 or 62%). The group with two or more foci had a greater incidence of 60 dB or greater sensorineural loss (46%) compared with the groups with none (12%) or one focus (16%) involved. Correlation between hearing loss and involvement of cochlear endosteum was poor. Correlation existed in only 2 of 15 ears with two or more foci involving the cochlear endosteum. There was no correlation in the other groups. It appears that cochlear endosteal involvement alone may not be sufficient explanation for the sensorineural hearing loss found with otosclerosis, except in the most severely involved ears.

Adult↗