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Biomedical subjects

J A Vernon

Publications and source records attributed to J A Vernon.

At least 19 recordsLinked to original sources

Clinical trial to compare tinnitus masking and tinnitus retraining therapy.

CONCLUSION: Both tinnitus masking (TM) and tinnitus retraining therapy (TRT) can be effective therapies for amelioration of tinnitus. TM may be more effective for patients in the short term, but with continued treatment TRT may produce the greatest effects. OBJECTIVES: Although TM and TRT have been used for many years, research has not documented definitively the efficacy of these methods. The present study was a controlled clinical trial to prospectively evaluate the clinical efficacy of these two methods for US military veterans with severe tinnitus. SUBJECTS AND METHODS: Over 800 veterans were screened to ensure that enrolled patients had tinnitus of sufficient severity to justify 18 months of individualized treatment. Qualifying patients (n=123) were placed quasi-randomly (alternating placement) into treatment with either TM or TRT. Treatment was administered at 0, 3, 6, 12, and 18 months. Outcomes of treatment were evaluated primarily using three self-administered tinnitus questionnaires (Tinnitus Handicap Inventory, Tinnitus Handicap Questionnaire, Tinnitus Severity Index). RESULTS: Findings are presented from the three written questionnaires with respect to three categories of patients: describing tinnitus as a 'moderate,' 'big,' and 'very big' problem at baseline. Based on effect sizes, both groups showed considerable improvement overall. In general, TM effects remained fairly constant over time while TRT effects improved incrementally. For the patients with a 'moderate' and 'big' problem, TM provided the greatest benefit at 3 and 6 months; benefit to these TRT patients was slightly greater at 12 months, and much greater at 18 months. For patients with a 'very big' problem, TM provided the greatest benefit at 3 months. For these latter patients, results were about the same between groups at 6 months, and improvement for TRT was much greater at 12 months, with further gains at 18 months.

Acoustic Stimulation↗

Masking of tinnitus through a cochlear implant.

The relief of tinnitus has been effected in a cochlear-implant patient by presenting masking sounds to the microphone of the implant. Oddly enough, the presence of the masking sound improved the clarity of speech and music.

Acoustic Stimulation↗

Characteristics of tinnitus induced by head injury.

OBJECTIVE: To determine if the characteristics of tinnitus produced by head trauma are specific and exclusive when compared with other origins of tinnitus. DESIGN: Retrospective study using clinic test results and data from the Tinnitus Data Registry compiled from questionnaires, interviews, and testing. Tinnitus produced by head injury was compared with tinnitus of mixed origins, including no known origin. SETTING: A tinnitus referral clinic where all patients must see an otologist or an ear, nose, and throat physician prior to attending the clinic. PATIENTS: All patients had severe to moderately severe constant tinnitus and presented with tinnitus as the primary symptom. RESULTS: No exclusive characteristics were found to describe head injury-induced tinnitus. The tinnitus for the group with head injury was statistically significantly (P = .004) louder and occurred with greater incidence of continuing pain in the ears. The group with head injury also had more episodes of dizziness and a more severe form of tinnitus. However, no marked difference was noted in pitch of tinnitus, complexity (number of sounds) of tinnitus, or the minimum masking level. CONCLUSIONS: This retrospective study found that tinnitus induced by head injury was significantly (P = .004) louder than tinnitus induced from other causes but, interestingly, did not require higher levels of masking. The patients with head injury-induced tinnitus more frequently (P = .0003) displayed residual inhibition although the duration of residual inhibition was not different from that of the comparison group. Other symptoms associated with the tinnitus onset were more frequently mentioned by the group with head trauma-induced tinnitus, except for the condition of pressure sensation in the ears. Using a severity questionnaire, the group with head trauma-induced tinnitus rated their tinnitus as being more severe than did the comparison group. However, such things as pitch of the tinnitus, masking level, acceptance of wearable maskers, general hearing level, and complexity of the tinnitus did not distinguish the two groups.

Craniocerebral Trauma↗

Measuring tinnitus parameters: loudness, pitch, and maskability.

Improved procedures have been developed for obtaining hearing thresholds, loudness matches, pitch matches, and masking curves of tinnitus. Computer programs enable all of these measures to be obtained in a single session. These measures have been obtained in tinnitus and nontinnitus subjects, with an external stimulus used to simulate tinnitus in nontinnitus subjects. These measures, obtained in repeated sessions, were used to determine the test-retest variability of each measure. The test-retest standard error of measurement, across-subjects, is reported, which enables changes in tinnitus to be determined. In nontinnitus subjects, the accuracy, as well as the reliability, is described.

Acoustic Stimulation↗

Pathophysiology of tinnitus: a special case--hyperacusis and a proposed treatment.

The occurrence of hyperacusis is rare. In our Tinnitus Clinic, where more than 4,000 patients have been seen, hyperacusis has been seen only four times. Treatment of hyperacusis has been a combination of protection from external sounds along with desensitization to sound. Desensitization has been produced by very low intensity masking which is gradually increased every two to four weeks. The process of desensitization requires a great deal of time.

Adult↗

Attempts to suppress tinnitus with transcutaneous electrical stimulation.

Various electrical stimuli were tested for their ability to suppress or relieve severe tinnitus. Stimulation was applied transdermally by electrodes placed on the preauricular and postauricular regions and on the two mastoids. Of the 50 patients tested, only 14 (28%) obtained relief that met the criterion of a reduction in the tinnitus by 40% or more. When relief was obtained, it usually extended for several hours into the poststimulation period. There was only one positive response (2%) in the placebo trial, which was administered to all patients. It was concluded that transdermal electrical stimulation such as that used in this research is not a practical therapeutic procedure for the relief of tinnitus.

Clinical Trials as Topic↗

Research in tinnitus. A report of progress.

As one reviews the contents of this presentation, one finds there are no dramatic "breakthroughs" and there are frequent examples of neutral or negative findings. One should not let this state of affairs discourage continued research. It is often the case that many mistrials are encountered when investigating an area where very little is known. We expect research on tinnitus to proceed at a slow pace, but under no circumstances should the research effort in tinnitus be curtailed.

Electric Stimulation Therapy↗

Tinnitus masking:unresolved problems.

With care to provide properly chosen masking sounds, masking can help in 60-80% of clinically significant tinnitus cases. There is no universal masker; instead, an individual evaluation of each patient's tinnitus must be performed in order to match the masking sounds to the patient's audiogram and the spectral characteristics of the tinnitus. Successful long-term masking can usually be achieved in patients for whom (1) hearing impairment is not excessive. (2) the tinnitus frequency, FT, can be reliably located, and (3) the tinnitus can be completely masked by a band of noise at or near FT at a low sensation level. Such patients often experience residual inhibition (temporary suppression of tinnitus upon cessation of masking) which may accumulate with sustained use of masking, in some cases becoming permanent. Long-term masking is difficult or impossible for patients whose hearing is so impaired they cannot hear the masker, or those for whom the masking sounds must be presented at unacceptably loud levels to obtain adequate coverage of the tinnitus. There is a great need for additional work to determine what factors influence the effectiveness of masking, in order to improve our ability to provide appropriate masking stimuli even for the difficult cases.

Humans↗

Electrical output of lizard ear: relation to hair-cell population.

Cochlear potentials measured in several species of lizard show a close correlation between maximum electrical output and number of hair cells, whereas there is no uniform relation to sensitivity. These results are interpreted as indicating structural differentiation and frequency discrimination in spatial terms in the more advanced lizard ears.

Animals↗