Robert A. Dobie

A review of randomized clinical trials in tinnitus

Objectives: Review reports of randomized clinical trials (RCTs) in tinnitus to identify well‐established treatments, promising developments, and opportunities for improvement in this area of clinical research.

Depression and tinnitus

Most patients with tinnitus are neither depressed nor seriously bothered by their tinnitus. Patients who complain bitterly of tinnitus, however, are often found to have a MDD. Treatment with tricyclic antidepressant drugs helps these patients, especially those who complain of insomnia. Other types of drugs and psychotherapy may also be helpful.

Disabling tinnitus. Association with affective disorder.

Forty consecutive patients with disabling tinnitus were interviewed using a structured psychiatric interview and were asked to complete the Hopkins Symptom Checklist (SCL-90), the Chronic Illness Problem Inventory, and the Revised Ways of Coping Checklist. They were compared to a control group of 14 patients attending the same otolaryngologic clinic with a complaint of hearing loss. The tinnitus patients had a significantly greater lifetime prevalence of major depression (78% vs 21%) than controls and a significantly higher prevalence of current major depression (60% vs 7%). The currently depressed tinnitus patients had significantly higher scores on all subscales of the SCL-90 compared to the nondepressed tinnitus group and to the controls. The number of psychological problems as measured by the Chronic Illness Problem Inventory was significantly greater in the tinnitus group than in controls. This difference in psychosocial disability was due to the high psychologic and social impairment in the depressed tinnitus group, as there were no significant differences in psychosocial problems between the nondepressed tinnitus group and the controls. These results demonstrate that tinnitus disability is strongly associated with major depression and suggest that treatment of the concurrent affective illness may reduce disability due to tinnitus.

A New Standardized Format for Reporting Hearing Outcome in Clinical Trials

The lack of an adequate standardized method for reporting level of hearing function in clinical trials has hampered the ability of investigators to draw comparisons across studies. Variability in data reported and presentation format inhibits meta-analysis and makes it impossible to accumulate the large patient cohorts needed for statistically significant inference. Recognizing its importance to the field and after a widely inclusive discussion, the Hearing Committee of the American Academy of Otolaryngology–Head and Neck Surgery endorsed a new minimal standard for reporting hearing results in clinical trials, consisting of a scattergram relating average pure-tone threshold to word recognition score. Investigators remain free to publish their hearing data in any format they believe is interesting and informative, as long as they include the minimal data set to facilitate interstudy comparability.

CHRONIC TINNITUS: ASSOCIATION WITH PSYCHIATRIC DIAGNOSES

Twenty-one consecutive patients with severe tinnitus were interviewed using a structured psychiatric interview (the National Institute of Mental Health Diagnostic Interview Schedule) and were asked to complete the Hopkins Symptom Checklist (SCL-90) and the Chronic Illness Problem Inventory. They were compared to a control group of 14 patients attending an otolaryngological clinic with a complaint of hearing loss. The tinnitus patients had a significantly greater lifetime prevalence of major depression (62% vs 21%) than controls and a significantly higher prevalence of current major depression (48% vs 7%). The currently depressed tinnitus patients had significantly higher scores on all subscales of the SCL-90, except the phobia and paranoid subscales, compared to the non-depressed tinnitus group and on all scales compared to the controls. The number of psychosocial problems and thus the resulting disability experienced was significantly greater in the tinnitus group compared to controls and in the currently depressed tinnitus patients when compared to non-depressed tinnitus patients. In view of our results treatment should aim at not only alleviation of tinnitus, but also the frequently co-existing major depression.

A comparison of t test, F test, and coherence methods of detecting steady‐state auditory‐evoked potentials, distortion‐product otoacoustic emissions, or other sinusoids

Sinusoids in background noise can conveniently be detected using unsegmented power spectra, comparing power at the signal frequency to average power at several neighbor frequencies. In this case, the F test is preferable to t tests based on rms or dB values, because of the skewed distributions of rms and dB when signal-to-noise ratio (SNR) = 0. F-test performance improves as the number of frequencies increases, to about 15, but can be degraded if the background noise is not white, with a slope exceeding about 10 dB for the range of frequencies sampled. Segment analysis, using magnitude-squared coherence (MSC) or related statistics, has equivalent statistical power; MSC and F each yield unbiased SNR estimates that have identical distributions when SNR = 0. Selection of F or MSC for detection of sinusoids will usually be a matter of convenience.

Amplitude-modulation following response (AMFR): Effects of modulation rate, carrier frequency, age, and state ☆

Scalp responses to continuous amplitude-modulated (AM) tones were recorded from adults and 1-month-old infants. The amplitude-modulation following (or envelope) response (AMFR) was quantified using magnitude-squared coherence. This measurement indicates the strength of the frequency-following response relative to background neural noise. The optimal modulation rate for generating the AMFR was determined by studying the effects of stimulus modulation rate on the response. Stimulus AM rate was varied between 10 and 80 Hz for continuous tonal stimuli of 500 Hz, and between 20 and 80 Hz for continuous tonal stimuli of 2000 Hz. Optimal modulation rate was defined as the AM rate that provided the highest coherence estimate. Adult AMFR coherence increased between 10 and 40 Hz (20-40 Hz for 2000 Hz), and decreased between 40 and 80 Hz in both carrier frequency conditions. Infant AMFR coherence, in contrast, monotonically increased between 10 and 80 H (20-80 Hz for 2000 Hz). Thus, within the frequency range examined, 40 Hz is optimal for generating the AMFR in adults, whereas 80 Hz is optimal in infants. Adults were tested while awake and infants were tested during periods of sleep. Given the observed age difference in effective modulation rate, we examined modulation rate effects in a group of adults in both awake and sedated states. As in sleeping infants, 80 Hz was optimal for generating AMFRs in the sedated adults.

The burdens of age-related and occupational noise-induced hearing loss in the United States.

Objectives: Aging and noise are generally considered the most common causes of adult hearing loss in developed countries. This study estimates the contributions of aging and occupational noise in the United States. Design: A model of hearing loss burden in American adults was constructed using data from the Census Bureau, from an international standard that predicts age-related and noise-induced hearing loss (ISO-1999), from the American Medical Association method of determining hearing impairment, and from sources estimating the distribution of occupational noise exposure in different age and sex groups. Results: Occupational noise exposure probably accounts for less than 10% of the burden of adult hearing loss in the United States; most of the rest is age-related. Most of the occupational noise burden is attributable to unprotected exposures above 95 dBA, and becomes apparent in middle age, when occupational noise exposure has ceased but age-related threshold shifts are added to prior noise-induced shifts, resulting in clinically significant impairment. Conclusions: In our current state of knowledge, noise-induced hearing loss is still the most important preventable cause of hearing loss in the United States. The burden of occupational noise-induced hearing loss could probably be reduced by stricter enforcement of existing regulations. Longer lifespans in developed countries and migration of manufacturing jobs to developing countries will continue to reduce the relative contribution of occupational hearing loss in countries like the United States. Preventive interventions for age-related hearing loss, even if only partially effective, could potentially reduce the burden of adult hearing loss more than elimination of occupational noise.

Occupational Noise-induced Hearing Loss: Acoem Task Force on Occupational Hearing Loss

Noise-induced hearing loss (NIHL) continues to be one of the most prevalent occupational conditions and occurs across a wide spectrum of industries. Occupational hearing loss is preventable through a hierarchy of controls, which prioritize the use of engineering controls over administrative controls and personal protective equipment. The occupational and environmental medicine (OEM) physician works with management, safety, industrial hygiene, engineering, and human resources to insure that all components of hearing loss prevention programs are in place.1 The OEM physician should emphasize to employers the critical importance of preventing hearing loss through controls and periodic performance audits rather than just conducting audiometric testing. Nevertheless, audiometric testing, besides documenting the permanent loss of hearing, can be of value in the identification of hearing loss at a time when early preventive intervention is possible. The American College of Occupational and Environmental Medicine (ACOEM) believes that OEM physicians should understand a worker’s noise exposure history and become proficient in the early detection and prevention of NIHL.

Patterns of Nutritional Deficiency in Head and Neck Cancer

A nutritional assessment battery consisting of anthropometric measurements, skin tests, laboratory assessment of visceral and somatic proteins, and a questionnaire was used to characterize the nutritional status of 50 consecutive new head and neck tumor patients. Forty percent of our patients had good nutrition, 20% fair, and 40% poor, with elements of both protein-calorie and protein malnutrition. There was, as expected, a positive relationship between tumor stage and nutritional impairment, but this fell short of statistical significance. There was a just significant tendency for patients with pharyngeal tumors to exhibit poorer scores than did those with oral or laryngeal tumors. Age, sex, smoking history, admitted alcohol consumption, and type of hospital (university, private multispecialty, or Veterans Administration) were not correlated with nutritional status. The best predictor of impaired nutritional status was the patients description of his recent diet: a normal diet predicted a good score (0–2), and a soft or liquid diet predicted a fair or poor score (3–5), with an overall accuracy of 72%.