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Biomedical subjects

A W Morrison

Publications and source records attributed to A W Morrison.

At least 37 records · Page 2Linked to original sources
PubMed1983

Significance of tomography in Meniere's disease: visualization and morphology of the vestibular aqueduct.

The revival of endolymphatic sac surgery has led to many investigations in Meniere's disease, including lateral tomography of the vestibular aqueduct. Contrary to recent literature, we found no difference in the presence and morphology of the vestibular aqueduct when assessed radiologically in a group of Meniere's patients and a control group. Our assessment of this information in regard to etiology and treatment of Meniere's disease is presented.

Humans↗
PubMed1983

Significance of tomography in Meniere's disease: periaqueductal pneumatization.

The revival of endolymphatic sac surgery has led to many investigations in Meniere's disease, including lateral tomography of the periaqueductal pneumatization. We radiologically assessed a series of Meniere's patients and a control group, and found hypocellularity to be more common in Meniere's disease as the literature has stated. However, we found this finding bilaterally in patients with unilateral disease. Our assessment of this information in regard to the etiology and treatment of Meniere's disease is presented.

Humans↗
PubMed1983

Electrocochleography and the glycerol dehydration test: a case study.

The electrocochleographic changes which occurred during glycerol dehydration in an ear affected by endolymphatic hydrops due to Menière's disease are discussed. This single case study is reported because the recordings were large and stable, and because they clearly showed the electrocochleographic abnormality associated with endolymphatic hydrops; namely, a large summating potential (SP) in relation to the action potential (AP). After dehydration a dramatic improvement occurred in both the pure tone and speech audiogram. The electrocochleogram showed a decrease in the SP amplitude and little change in the AP amplitude so that the SP/AP waveform became almost normal. The significance of these findings is discussed.

Adult↗
PubMed1983

Cochleostomy or endolymphatic sac surgery for advanced Meniere's disease.

The operation of cochleostomy is described. The surgical technique is vital for the true assessment of results. If the cochlear duct is punctured, the risk to hearing is unacceptably high. If only the osseous spiral lamina is punctured, the results are acceptable in the short term, though the rationale cannot be explained. In the management of difficult patients with more advanced Meniere's disease, some variant of cochleostomy should probably be included in the therapeutic options. The results of endolymphatic sac surgery are significantly better in a matched group of patients.

Cochlea↗
PubMed1983

Sac surgery on the only or better hearing ear.

In a neuro-otological practice, many patients are seen with bilateral Meniere's disease. Some of these poor prognostic cases start in childhood or adolescence. Of all the conservative operations, endolymphatic sac surgery alone should be considered for the only or better hearing ear. The risk of surgical anacusis is less than 2 per cent, a risk outweighed by the significant short and long term benefit for these difficult patients. Including patients who undergo revision surgery, control of vertigo is very acceptable, and hearing gain, especially in only hearing ears, is often essential for rehabilitation. The best results probably are obtained when surgery is performed early in the course of the disease.

Adult↗
PubMed1982

Electrophoretic separation and identification of perilymph proteins in cases of acoustic neuroma.

Previous studies of perilymph proteins have emphasised the difficulty of obtaining samples free of blood or serum proteins. The present investigation has established a method of polyacrylamide gel electrophoresis, which enables contaminated specimens to be readily identified and therefore discarded. Analysis of uncontaminated samples has confirmed the presence of an elevated perilymph protein in cases of acoustic neurinomata. Perilymph proteins have been separated and identified and although no characteristic pattern of proteins associated with acoustic neurinomata has emerged, further work should be undertaken to establish the site of origin of perilymph proteins and the pattern of abnormalities to be expected in pathological processes.

Electrophoresis, Polyacrylamide Gel↗
PubMed1981

Metabolic investigations in Menière's disease.

This paper presents the results of various metabolic investigations in patients with Menière's disease. It is a follow-up article on the preliminary findings of the study which was published in this Journal recently (Moffat et al., 1979). Fifty patients (29 male, and 21 female) with Menière's disease conforming to the criteria set out by the Committee of Hearing and Equilibration of the American Academy of Ophthalmology and Otolaryngology (1972) were involved. The incidence of abnormal metabolic states was no higher than that of a comparable group in the general population. One of the patients had a diabetic glucose tolerance test curve, four had lag curves. One patient had a high TSH level and was clinically myxoedematous. Three patients (two male, and one female) had primary hyperlipidaemia and one female patient had hyperlipidaemia secondary to myxoedema. There was no significant difference in response to intradermal pin prick skin tests compared with a controlled group.

Adolescent↗
PubMed1981

Perilymph total protein levels associated with cerebellopontine angle lesions.

The total protein levels in the perilymph of patients with acoustic neuromas, meningiomas, and Meniere's disease are contrasted. All specimens were obtained from the lateral semicircular canal during removal of the bony labyrinth. Any specimens with significant contamination by hemoglobin or serum proteins, as judged by the presence of hemoglobin/haptoglobin complexes, were discarded from this study. The findings of greatly increased perilymph protein levels in the tumor groups confirmed the reports of other workers. The levels in the Meniere's disease group compared favorably with the normal protein levels in perilymph. A very significant (p Less Than 0.05) difference between the acoustic neuroma group and the meningioma group is noted. This difference is probably tumor related, because in all cases of both groups, tumor entered and filled the internal auditory meatus.

Cerebellopontine Angle↗
PubMed1980

Clinical usefulness of electrocochleography in Meniere's disease: an analysis of dehydrating agents.

Both electrocochleography and glycerol dehydration have an important diagnostic and prognostic role in the management of patients with endolymphatic hydrops, whether idiopathic as in Meniere's disease or secondary to certain diseases of the otic capsule. Abnormal electrocochleographic responses in a "normal" ear can be used to predict when Meniere's disease will become bilateral. There is a significant correlation between the effects of glycerol and of endolymphatic sac surgery on the pars inferior, at least over the span of several years. The subject hearing gains, the objective improvements in electrocochleographic responses, and the objective evidence of diminished inner ear impedance, all following proven glycerol dehydration, indicate that even in fairly advanced Meniere's disease, but especially in the earlier stages, reversibility is possible. This is a tantalizing therapeutic challenge.

Action Potentials↗
PubMed1979

Metabolic investigations in Menière's disease. Preliminary findings.

The aetiology of Menière's disease is unknown but in recent years many theories have been advanced to explain the observed pathological changes. These include abnormal metabolic states, allergy and personality type. In an attempt to throw more light on this and to confirm or refute the earlier work we studied twenty-seven (fifteen male:twelve female) patients with Menière's disease who conformed to the criteria set out by the Committee of Hearing and Equilibration of the American Academy of Ophthalmology and Otolaryngology (Alford, 1972). In this series the incidence of abnormal metabolic states was no higher than that of a comparable group in the general population. There was no significant difference in response to pin prick skin tests compared with a control group. Klockhoff and Lindblom's (1966) glycerol dehydration test was applied to twenty-one patients. The response to this test was measured by changes in the osmolality of the serum, the pure tone threshold of hearing and the maximum speech discrimination score. Continuous transtympanic electrocochleographic recordings during glycerol dehydration were carried out and in 10 patients there was a definite decrease in the negative summating potential. An electrophysiological explanation for this has been put forward and the possible use of this measurement in the diagnosis and management of Menière's disease has been discussed. The intercorrelation between these measures and their predictive value will become apparent in the future.

Action Potentials↗