Normal Values for Cervical Vestibular-Evoked Myogenic Potentials.

OBJECTIVES: To assess the variability of normal values for cervical vestibular-evoked myogenic potentials (cVEMP) testing and to provide guidance regarding which parameters should be reported for clinical practice. STUDY DESIGN: Forty-eight normal subjects with no history of hearing loss or vestibular symptoms underwent cVEMP testing. Measurement parameters were tabulated and compared to other sets of cVEMP normal values in the literature. The literature was reviewed to assess the clinical significance of abnormal cVEMP results. The distributions of threshold and symmetry ratios for normal subjects were compared to the distributions of 90 patients who underwent cVEMP testing. SETTING: Tertiary academic center. RESULTS: Upper limits of 42% symmetry ratio and the range of 65 to 95 dB HL for threshold were established for our center.The quartile coefficients of dispersion were much less than 1.0 for all cVEMP parameters in the literature, suggesting that the variability in normal ranges across the literature is small. The distributions for threshold and symmetry ratio were similar between normal and patient groups. There is a lack of information in the literature regarding the impairment of function resulting from various degrees of abnormality of VEMP results. CONCLUSIONS: Normal values for cVEMP parameters are statistically consistent in the literature. The clinical significance of abnormal values has not been validated. For clinical purposes, cVEMP "thresholds" should be reported. Reporting of other parameters is optional.

Clinical practice guideline: tinnitus executive summary.

The American Academy of Otolaryngology--Head and Neck Surgery Foundation (AAO-HNSF) has published a supplement to this issue featuring the new Clinical Practice Guideline: Tinnitus. To assist in implementing the guideline recommendations, this article summarizes the rationale, purpose, and key action statements. The 13 recommendations developed address the evaluation of patients with tinnitus, including selection and timing of diagnostic testing and specialty referral to identify potential underlying treatable pathology. It will then focus on the evaluation and treatment of patients with persistent primary tinnitus, with recommendations to guide the evaluation and measurement of the impact of tinnitus and to determine the most appropriate interventions to improve symptoms and quality of life for tinnitus sufferers.

Clinical practice guideline: tinnitus.

OBJECTIVE: Tinnitus is the perception of sound without an external source. More than 50 million people in the United States have reported experiencing tinnitus, resulting in an estimated prevalence of 10% to 15% in adults. Despite the high prevalence of tinnitus and its potential significant effect on quality of life, there are no evidence-based, multidisciplinary clinical practice guidelines to assist clinicians with management. The focus of this guideline is on tinnitus that is both bothersome and persistent (lasting 6 months or longer), which often negatively affects the patient's quality of life. The target audience for the guideline is any clinician, including nonphysicians, involved in managing patients with tinnitus. The target patient population is limited to adults (18 years and older) with primary tinnitus that is persistent and bothersome. PURPOSE: The purpose of this guideline is to provide evidence-based recommendations for clinicians managing patients with tinnitus. This guideline provides clinicians with a logical framework to improve patient care and mitigate the personal and social effects of persistent, bothersome tinnitus. It will discuss the evaluation of patients with tinnitus, including selection and timing of diagnostic testing and specialty referral to identify potential underlying treatable pathology. It will then focus on the evaluation and treatment of patients with persistent primary tinnitus, with recommendations to guide the evaluation and measurement of the effect of tinnitus and to determine the most appropriate interventions to improve symptoms and quality of life for tinnitus sufferers. ACTION STATEMENTS: The development group made a strong recommendation that clinicians distinguish patients with bothersome tinnitus from patients with nonbothersome tinnitus. The development group made a strong recommendation against obtaining imaging studies of the head and neck in patients with tinnitus, specifically to evaluate tinnitus that does not localize to 1 ear, is nonpulsatile, and is not associated with focal neurologic abnormalities or an asymmetric hearing loss. The panel made the following recommendations: Clinicians should (a) perform a targeted history and physical examination at the initial evaluation of a patient with presumed primary tinnitus to identify conditions that if promptly identified and managed may relieve tinnitus; (b) obtain a prompt, comprehensive audiologic examination in patients with tinnitus that is unilateral, persistent (≥ 6 months), or associated with hearing difficulties; (c) distinguish patients with bothersome tinnitus of recent onset from those with persistent symptoms (≥ 6 months) to prioritize intervention and facilitate discussions about natural history and follow-up care; (d) educate patients with persistent, bothersome tinnitus about management strategies; (e) recommend a hearing aid evaluation for patients who have persistent, bothersome tinnitus associated with documented hearing loss; and (f) recommend cognitive behavioral therapy to patients with persistent, bothersome tinnitus. The panel recommended against (a) antidepressants, anticonvulsants, anxiolytics, or intratympanic medications for the routine treatment of patients with persistent, bothersome tinnitus; (b) Ginkgo biloba, melatonin, zinc, or other dietary supplements for treating patients with persistent, bothersome tinnitus; and (c) transcranial magnetic stimulation for the routine treatment of patients with persistent, bothersome tinnitus. The development group provided the following options: Clinicians may (a) obtain an initial comprehensive audiologic examination in patients who present with tinnitus (regardless of laterality, duration, or perceived hearing status); and (b) recommend sound therapy to patients with persistent, bothersome tinnitus. The development group provided no recommendation regarding the effect of acupuncture in patients with persistent, bothersome tinnitus.

Addressing animal model issues in auditory research.

OBJECTIVE: To better understand the differences in auditory systems across species. METHODS: Auditory brainstem response (ABR) click thresholds were obtained from normal 3- to 6-week-old animals including 15 guinea pigs, 62 mice, and 6 rats. Pure-tone ABR thresholds were obtained in 7 guinea pigs, 6 mice, and 13 rats. Threshold variability was then considered a function of basilar membrane length, mean body weight, basal metabolic rate, and longevity as identified in the literature. RESULTS: Interspecies variability of auditory thresholds for normal-hearing animals is not explained by differences in mean body weight, metabolic rate, or longevity. Simple linear models appear to adequately describe threshold variability across the parameters studied. Click thresholds, with significant low-frequency content, suggest that mice have better hearing than rats or guinea pigs. CONCLUSION: In spite of wide variations in cochlear anatomy and metabolic factors, different species have evolved similar auditory thresholds across species in normal, young animals.