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Biomedical subjects

H A Jenkins

Publications and source records attributed to H A Jenkins.

At least 55 records · Page 3Linked to original sources
PubMed1989

Sudden sensorineural hearing loss as a presentation of multiple sclerosis.

While auditory involvement in multiple sclerosis is not infrequent, sensorineural hearing loss as the initial manifestation of this disease is rare. Auditory brain-stem evoked responses, speech audiometry, acoustic reflexes, and electronystagmography yield significant objective information concerning brain-stem involvement. Magnetic resonance imaging objectively documents white matter demyelinization. The acute onset of the retrocochlear type of auditory dysfunction without other evidence of central nervous system involvement can be an early manifestation of this disease. Two patients with multiple sclerosis had sudden sensorineural hearing loss, with one patient experiencing this as the sole initial complaint.

Acute Disease↗
PubMed1989

Management of petrous apex lesions.

Advancements in imaging pose new diagnostic and therapeutic dilemmas as smaller lesions in the relatively inaccessible regions of the petrous apex and clivus are identified. Differentiation of true pathology from artifact and anatomic variants is critical in management of these lesions. We describe our experience with five patients diagnosed with petrous apex lesions: three, cholesteatomas; one, cholesterol granuloma; and one, false-positive. Soft-tissue obliteration of the temporal bone defect with postoperative follow-up using high-resolution computed tomographic scanning and magnetic resonance imaging is proposed as an alternative to exteriorization.

Adolescent↗
PubMed1989

Psychological profile of patients with Menière's disease.

Forty-eight patients with Menière's disease underwent psychological assessment with the Minnesota Multiphasic Personality Inventory and Diagnostic Inventory of Personality and Symptoms. Using the presence or absence of recurrent vertigo or chronic dysequilibrium as the differentiating feature, the results of two groups were compared. A clinical diagnosis of depression (axis I) was evident in 80% of the patients with active vestibular symptoms examined by the Minnesota Multiphasic Personality Inventory and 70% by the Diagnostic Inventory of Personality and Symptoms compared with 32% (Minnesota Multiphasic Personality Inventory) and 39% (Diagnostic Inventory of Personality and Symptoms) in the inactive group. The data support the addition of depression to the clinical picture of active Menière's disease.

Adult↗
PubMed1989

Ultrastructural evidence of repair and neuronal survival after labyrinthectomy in the squirrel monkey.

Although the vestibular and cochlear branches of the VIIIth cranial nerve originate embryologically from the same primordia, results of the present investigation confirm previous findings indicating that the vestibular branch may be more plastic with respect to recovery after surgical insult than the cochlear division. In this report we show ultrastructural details of changes undergone by the vestibular nerve after surgery. Dendrites peripheral to the vestibular nerve ganglion (VNG) were severed by surgically removing the vestibular end organs; the squirrel monkeys were then allowed to recuperate, and tested for their vestibulospinal and vestibulo-oculomotor functions behaviorally. However, behavior deficits resulting from the injury are reported separately. The vestibular nerves excised from the internal acoustic meatus and the temporal bones were examined histologically for changes of VNG and fibers from day 1 to 1,247 days after labyrinthectomy. Light- and electron-microscopic examinations indicated that some perikarya and some fibers of the VNG remained in the ganglionic matrix for up to 1,247 days, the longest period studied, after the operation. Fibers extended toward the remodeled inner ear space in the absence of appropriate sensory cell targets. The surviving neurons and fibers exhibited various degrees of wallerian-like degeneration at first, but many of them retained ultracellular organelles and integrity even after 1,247 days. Since vestibular perikarya are bipolar, the unsevered fibers that project to the brainstem could retain functional synaptic connections, a possibility that is now under investigation. Schwann cells in the ganglionic matrix may also have contributed to vestibular neuron survival by providing the proper nourishment. Morphometric measurements determined that neurons remaining in the ganglion had significantly smaller cross-sectional areas than normal neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Predictors of functional success in telescopic spectacle use by low vision patients.

Telescopic spectacles can theoretically improve function of low vision patients by enlarging retinal images. However, unintended head movement may produce sufficient instability of enlarged retinal images to negate the visual benefit. We investigated this phenomenon as a cause of failure in 38 low vision patients who had previously attempted use of telescopic spectacles. Patients underwent evaluation of the vestibulo-ocular reflex, visual-vestibulo-ocular reflex, head stability in the pitch and yaw axes, and sensitivity of magnified visual acuity to head motion. Although it was impossible to distinguish successful from unsuccessful telescopic spectacle users by means of clinical or historical data, multiple logistic regression analysis was used to derive a useful predictive function based on measurements of sensitivity of magnified vision to head motion, and head instability in the pitch axis. Predictive performance was found to be superior to conventional clinical judgement. These findings support the hypothesis that retinal image stability is important to functional vision, and suggest that head-stabilizing strategies may improve function with telescopic spectacles in certain low vision patients.

Adult↗
PubMed1989

Adaptation to telescopic spectacles: vestibulo-ocular reflex plasticity.

The vestibulo-ocular reflex (VOR) is a mechanism for the production of rapid compensatory eye movements during head movements. To investigate the adaptation of this reflex to spectacle magnifiers, the effect on the VOR of a brief period of wearing telescopic spectacles during head rotation was studied in normal subjects. VOR gain, as measured in darkness, was defined to be the ratio of compensatory slow phase eye velocity to head velocity. Initial VOR gain as measured for vertical axis sinusoidal head rotation at 0.1 Hz, amplitude 60 degrees/sec, was about 0.7. After 15 min adaptation by sinusoidal rotation during the viewing of a remote video display through X2, X4, or X6 binocular telescopic spectacles, 47-70% of subjects exhibited significant VOR gain increases of 7-46%. These increases were measured with occlusion of the unmagnified visual field peripheral to the telescopes during adaptation. There was considerable interindividual variability in adaptation to telescopic spectacles. Telescopic spectacle power had little or no effect on the amount of VOR change after adaptation, although all telescope powers produced a greater VOR gain change than did adaptation without telescopes. Testing of VOR gain at multiple frequencies indicated that adaptation to telescopic spectacles by rotation at a single sinusoidal frequency induces VOR gain changes across a broad spectrum of frequencies of head rotation. When the unmagnified peripheral visual field was unobstructed during adaptation, VOR gain increases were significantly less than when the unmagnified peripheral visual field was occluded, and were similar to those observed during adaptation without the wearing of telescopic spectacles at all. VOR gain adaptation was associated with amerlioration of symptoms of oscillopsia and motion discomfort initially experienced by about 20% of subjects wearing telescopic spectacles.

Adaptation, Physiological↗
PubMed1988

Surgical dimensions of the facial recess in adults and children.

The facial recess approach permits surgical access to the round window area. This route is used in patients who are undergoing cochlear implantation. To evaluate the feasibility of this procedure in children as compared with adults, serial sections of temporal bones were used to measure the surgical dimensions of the facial recess. No statistically significant differences in the dimensions of the facial recess or the extended facial recess approaches were found between children and adults. The relationship of the facial and chorda tympani nerves to the annular plane exhibited no change with postnatal growth. These structures translate posteriorly and laterally toward the annular plane as they descend within the temporal bone. Therefore, the facial recess approach represents no greater hazard in a child than in an adult.

Adult↗
PubMed1988

Dynamic visual acuity with telescopic spectacles: improvement with adaptation.

Telescopic spectacles are used as aids for the visually impaired in order to increase effective visual acuity. Because ocular stabilization reflexes are not fully compensatory when telescopic spectacles are worn, head motion would be expected to produce retinal image motion which could decrease visual acuity. Using 1.0 Hz sinusoids of vertical axis head rotation, we investigated the effect of head velocity and telescopic spectacle magnification on binocular dynamic visual acuity (DVA), the acuity during head motion, in 34 normally sighted subjects. The visual field peripheral to the telescopes was masked. Up to a head velocity amplitude of 30 degrees/sec, DVA was insensitive to head velocity for X2 telescopic spectacles. For X4 and, to a greater degree, X6 telescopic spectacles, DVA decreased progressively as head velocity increased. DVA measurements were repeated after a 15 min adaptation period, during which a distant video monitor was viewed using telescopic spectacles. For X4 telescopic spectacles, DVA increased significantly after adaptation. With an unobstructed peripheral visual field, initial DVA with X4 telescopic spectacles was equal to adapted DVA with peripheral vision occluded, but adaptation produced no further improvement in DVA with the peripheral field unobstructed. These data indicate that the visual acuity obtained with telescopic spectacles is substantially reduced under conditions where head motion occurs, potentially reducing the functional value of these devices in low vision rehabilitation. The adverse effect of head motion on DVA may be reduced by adaptation.

Adaptation, Physiological↗
PubMed1987

Migraine and sudden sensorineural hearing loss.

A 62-year-old woman developed recurrent episodes of sudden sensorineural hearing loss, occurring with migraine headaches. This is an unusual complication of migraine, which probably arises from a reversible vasoconstriction of the cochlear blood vessels. Pathogenesis of migraine and its variants are reviewed herein, along with the rationale of the modalities in its treatment. In this case, the patient's hearing improved after administration of ergot alkaloids, carbon dioxide/oxygen inhalations, and stellate ganglion blocks; it is not known whether this improvement represented therapeutic effect or spontaneous recovery.

Female↗
PubMed1987

Volumetric analysis of the tympanic isthmus in human temporal bones.

A volumetric study on the tympanic isthmus and its relationship to temporal bone pneumatization was conducted in 110 serially sectioned temporal bones with and without middle ear pathology. With a microcomputer and digitizing tablet, the area of the tympanic isthmus and the degree of pneumatization in sample sections were calculated. Nonpathologic temporal bones showed a significant correlation between the volume of the tympanic isthmus and the degree of pneumatization. The narrowest area of the tympanic isthmus and the degree of pneumatization were also highly correlated. The result indicated a definite inhibition of pneumatization due to chronic middle ear infection when compared with nonpathologic temporal bones.

Aged↗
PubMed1987

Intradiploic epidermoid cyst of the sphenoid wing.

Epidermoids are blastomatous malformations of abnormal epithelial proliferation. Intradiploic epidermoids are very rare lesions that may occur in all flat bones of the calvarium and in the paranasal sinuses, maxilla, temporal bone, and sphenoid bone. This article describes the unique case of an intradiploic epidermoid tumor located in the greater sphenoid wing. Theories of pathogenesis, clinical behavior, diagnosis, and treatment of diploic epidermoids are reviewed.

Adult↗
PubMed1987

Intracranial and intratemporal facial neuroma.

Primary tumors of the facial nerve are relatively rare and have a variety of presenting symptoms. This article reviews 248 cases of facial neuroma in the world's literature and adds seven cases that were managed at the Baylor College of Medicine. Facial weakness was most common symptom, with facial spasm or tics, hearing loss, and masses in the external auditory canal also being frequently seen. At surgery, the tympanic, vertical, and labyrinthine segments were the most commonly involved areas. On the basis of this review, general principles have been drawn up to help the clinician in diagnosis and management of this (at times) difficult problem.

Adult↗
PubMed1987

Traumatic intratemporal facial nerve injury: management rationale for preservation of function.

A retrospective review of 29 cases of intratemporal facial nerve injuries included 18 temporal bone fractures, 7 gunshot wounds, and 4 iatrogenic complications. Surgical exploration confirmed involvement of the fallopian canal in the perigeniculate region in 14 longitudinal and 3 transverse or mixed fractures of the petrous pyramid. Gunshot and iatrogenic injuries usually occurred within the tympanic and vertical segments of the facial canal and at the stylomastoid foramen. When hearing is salvageable, the middle fossa approach provides the best access to the perigeniculate region of the facial nerve. In the presence of severe sensorineural hearing loss, the transmastoid-translabyrinthine approach is the most appropriate for total facial nerve exploration. Grade I to III results can be anticipated in timely decompression of lesions caused by edema or intraneural hemorrhage. Undetectable at the time of surgery, stretch and compression injuries with disruption of the endoneural tubules often lead to suboptimal results. Moderate-to-severe dysfunction (Grade IV), with slight weakness and synkinesis, is the outcome to be expected from the use of interpositional grafts.

Facial Nerve↗
PubMed1987

Vestibulo-ocular reflex during magnified vision: adaptation to reduce visual-vestibular conflict.

This report describes the short-term effect of 2.2X telescopic spectacles on the vestibulo-ocular reflex (VOR) in seven volunteers. VOR gain was initially measured in darkness and light during passive sinusoidal rotations. Subjects were then rotated in light for 15 min while wearing telescopic spectacles. Dynamic visual acuity (DVA), vision during head rotation, was measured with telescopic spectacles. Initial VOR gain in darkness was 0.74 +/- 0.10 (mean +/- S.D.); VOR gain with unmagnified vision was 1.07 +/- 0.04. Initial VOR gain with magnified vision was 1.37 +/- 0.53. DVA was poorer than static acuity in three of four subjects. After adaptation, VOR gain in darkness increased to 0.83 +/- 0.12, with six of seven subjects exhibiting a gain increase of 7-23% (p less than 0.05 for 5). Adapted VOR gain with magnified vision was 1.54 +/- 0.25. Adapted performance was more consistent and oscillopsia was reduced. Adapted DVA improved 30-100% in four subjects. These changes indicate VOR adaptation to telescopic spectacles decreases visual-vestibular conflict.

Adaptation, Physiological↗
PubMed1986

Facial paralysis as the initial presentation of an internal carotid artery aneurysm.

Aneurysms of the intrapetrous internal carotid artery are rarely encountered and can present difficult diagnostic problems. A review of the literature revealed 34 cases, and we now add a 35th. Presenting symptoms and signs are dependent on the direction of expansion of the aneurysm, with neurologic dysfunction typical of medial expansion, whereas lateral erosion often suggests a glomus tumor.

Adolescent↗
PubMed1986

Hereditary congenital cholesteatoma. A variant of branchio-oto dysplasia.

A mother and daughter both presented at age 5 years with the triad of right-sided congenital cholesteatoma, right preauricular pits, and bilateral sensorineural hearing loss. Twenty-six years apart, both were treated with middle ear exploration and removal of a cholesteatoma that filled the sinus tympani, facial recess, and middle ear. The sensorineural hearing losses were nonprogressive, and the preauricular pits were asymptomatic. These two cases may represent a unique variant of branchio-oto dysplasia. The mechanism of formation of these anomalies and the possible modes of inheritance are conjectural. This triad, however, supports genetic predisposition rather than aberrant epithelial rests during morphogenesis as a possible cause in congenital cholesteatoma.

Adult↗