Committee on Hearing and Equilibrium Guidelines For The Diagnosis And Evaluation Of Therapy In Meniere's Disease*
* Adopted by the Board of Directors of the American Academy of Otolaryngology-Head and Neck Surgery, March 12, 1994
Reproduced, with permission, from Committee on Hearing and Equilibrium, Committee on Hearing and Equilibrium guidelines for the diagnosis and evaluation of therapy in Meniere's disease, Otolaryngology-Head and Neck Surgery, 113:181-185 with permission from Mosby-Year Book, Inc. This copyrighted material may only be used personally and may not be distributed further. All rights reserved.
Copyright 1995 by the American Academy of Otolaryngology-Head and Neck Surgery Foundation, Inc.
Members of the Committee on Hearing and Equilibrium: Edwin M. Monsell, MD, PhD, Chairman; Thomas A. Balkany, MD; George A. Gates, MD; Robert A. Goldenberg, MD; William A. Meyerhoff, MD, PhD, and John W. House, MD, Consultant.
In 1972 and 1985 the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery published recommended guidelines for reporting the results of treatment of Meniere's disease. These reports have proved very beneficial to efforts to understand this disorder and its treatment. With advancing knowledge it has become evident that the reporting guidelines could be refined further.
In undertaking this review, the Committee established several guiding principles. We wished to establish a distinction between the recording of results and the analysis and interpretation of results. Insofar as is possible, we wanted to retain and integrate the methods recommended in the 1972 and 1985 reports. We wanted guidelines to be "upwardly compatible" in the sense of computer software, so that existing data could not only be conserved but analyzed in new ways. Reporting methods should be clearly stated, straightforward to apply, as simple as possible, and usable in a wide range of settings, from multicenter university studies to reviews of personal experience by individual private practitioners. Specialized test equipment should not be required. Methods should facilitate statistical evaluation and comparison of results among studies. The guidelines should encourage reports to reflect disease severity in a meaningful manner.
DEFINITION OF MENIERE'S DISEASE
For reporting purposes Meniere's disease is a clinical disorder defined as the idiopathic syndrome of endolymphatic hydrops. A disease is a pathophysiologic state. The underlying pathophysiologic state in Meniere's disease is endolymphatic hydrops, which can only be demonstrated with certainty after death by histopathologic study of the temporal bones. For clinical purposes (treatment and reporting), the presence of endolymphatic hydrops can be inferred during life by the presence of the following as further defined below: recurrent, spontaneous episodic vertigo; hearing loss; aural fullness; and tinnitus. Either tinnitus or aural fullness (or both) must be present on the affected side to make the diagnosis for reporting purposes under these guidelines.
VERTIGO
Vertigo is the sensation of motion when no motion is occurring relative to earth's gravity. Conversely, motion intolerance is a feeling of dysequilibrium, spatial disorientation, or malaise during active or passive movement. The definitive spell of Meniere's disease is spontaneous rotational vertigo lasting at least 20 minutes (commonly several hours), is often prostrating, and is accompanied by nausea and commonly by vomiting or retching. Consciousness is not lost. During the definitive episode, horizontal rotatory nystagmus is always present. This type of vertigo is termed episodic vertigo of the Meniere type. Although vertiginous episodes of variable duration and character may occur in patients with Meniere's disease, at least two definitive episodes of 20 minutes or longer must occur to permit the diagnosis of definite Meniere's disease.
HEARING LOSS
It is a common clinical observation that patients with aural fullness or tinnitus may perceive that they have a loss of hearing when pure-tone sensitivity and word recognition (speech discrimination) are normal. Consequently, sensorineural hearing loss must be documented audiometrically in the treated ear on at least one occasion to permit the diagnosis of Meniere's disease. Hearing loss in Meniere's disease is usually easy to identify but is difficult to define precisely. Diagnostic hearing loss may take any of the following forms:
1. The average (arithmetic mean) of hearing thresholds at 0.25, 0.5, and 1 kHz is 15 dB or more higher that the average of 1, 2, and 3 kHz.
2. In unilateral cases, the average of threshold values at 0.5, 1, 2, and 3 kHz is 20 dB or more poorer in the ear in question than on the opposite side.
3. In bilateral cases, the average of threshold values at 0.5, 1, 2, and 3 kHz is greater than 25 dB in the studied ear.
4. In the judgment of the investigator, the patient's hearing loss meets reasonable audiometric criteria for hearing loss characteristic of Meniere's disease. The rationale for using this criterion should be stated and justified for each case.
Although hearing usually fluctuates early in Meniere's disease, fluctuation is not universally present and is not essential to the diagnosis, provided that hearing loss is documented at some time, as above. The determination of hearing change should be based on the four-tone average (arithmetic mean) of thresholds at 0.5, 1, 2, and 3 kHz. A change of 10 dB or more or a change in word recognition score (speech discrimination) of 15 percentage points or more is considered clinically significant. In case the pure-tone average and word recognition scores change in opposite directions, the pure-tone average will determine the overall nature of the change for reporting purposes. We have adopted the four-tone average of 0.5, 1, 2, and 3 kHz because this average takes into account the importance of high frequencies in normal hearing. This particular four-tone average is consistent with the 1985 version of the guidelines and the Academy's formula for calculation of hearing handicap.
TINNITUS AND AURAL FULLNESS
We reaffirm the Committee statement of 1985 that tinnitus and aural fullness are difficult to quantify independent of results for hearing and for control of vertigo. Investigators are, of course, free to created and validate scales for tinnitus, fullness, and other measures.
OTHER DIAGNOSTIC CONSIDERATIONS
It is important to state what Meniere's disease is not. Episodic vertigo without hearing loss, tinnitus, or aural fullness constitutes a syndrome known as vestibular neuritis of the recurrent type or recurrent vestibulopathy.3 A single episode of vertigo lasting several days followed by gradual recovery of equilibrium, even with persistent hearing loss, tinnitus, and aural fullness, is more consistent with classic vestibular neuritis than Meniere's disease.4 Bilateral sensorineural hearing loss that progresses in a stepwise fashion over weeks to months and that responds to immunosuppressive medications is more likely a primary autoimmune or allergic disorder or immune-mediated vasculitis, such as otosyphillis. Even it episodic vertigo of the Meniere type is present, the diagnosis of Meniere's disease should not be applied to such cases. If there is bilateral hearing loss with a pure-tone average worse than 70 dB or word recognition worse than 50%, the diagnosis of Meniere's disease should be questioned.
The syndrome of endolymphatic hydrops may be caused by disorders other than Meniere's disease. 5 Posttraumatic endolymphatic hydrops may occur after head trauma or surgery. Postinfectious (delayed) endolymphatic hydrops may follow a mumps infection. Although hearing loss occurs at the time of infection, episodic vertigo vertigo may not begin until months or years later. Endolymphatic hydrops, whether idiopathic or not, may be nonprogressive or asymptomatic, in which case vertigo would not develop and the diagnosis of Meniere's disease would not be made.
Otosyphilis is a a disorder that includes episodic vertigo of the Meniere type, hearing loss, and interstitial keratitis. Histopathologic findings include endolymphatic hydrops and vasculitis.5 Classic Cogan's syndrome includes episodic vertigo of the Meniere type, hearing loss, and interstitial keratitis, but without syphilis.5 Variant Cogan's syndrome includes episodic vertigo of the Meniere type, hearing loss, uveitis, or other ocular inflammation, and no serologic evidence of syphilis. All the specific cases of the syndrome of endolymphatic hydrops discussed above must be excluded to establish the diagnosis of an idiopathic disorder. These may be excluded by the clinical history, physical examination, serologic testing for syphilis, and ophthalmologic consultation, if indicated.
Results from patients with conditions other than Meniere's disease may be included in reports of treatment results in Meniere's disease, but such data should be reported and analyzed in separate categories. The diagnosis of Meniere's disease must be established independently for each ear in order for a case to be considered bilateral Meniere's disease.
DIAGNOSTIC SCALE
We have devised a diagnostic scale based on clinical criteria (Table 1). In developing this scale, we have borrowed concepts used in the diagnosis of multiple sclerosis.6 Only patients in the definite or certain categories should be reported as having Meniere's disease. We have included the designations "possible Meniere's disease" and :probable Meniere's disease," because they may constitute important groups to study. It would be desirable to have a treatment that would prevent progression to successive stages and further loss of hearing.
TABLE ONE
DIAGNOSIS OF MENIERE'S DISEASE
Possible Meniere's disease
Episodic vertigo of the Meniere's type without documented hearing loss, or sensorineural hearing loss, fluctuating or fixed, with dysequilibrium but without definitive episodes. Other causes excluded
Probable Meniere's disease
One definitive episode of vertigo. Audiometrically documented hearing loss on at least one occasion. Tinnitus or aural fullness in the treated ear. Other causes excluded
Definite Meniere's disease
Two or more definitive spontaneous episodes of vertigo 20 minutes or longer. Audiometrically documented hearing loss on at least one occasion. Tinnitus or aural fullness in the treated ear. Other cases excluded.
Certain Meniere's disease
Definite Meniere's disease, plus histopathologic confirmation.
STAGING
Although the Committee considered a composite system of staging that would incorporate hearing, vestibular symptoms, and other features, such systems were believed to be too subjective and ambiguous. Individual patients might fit into more than one category or into no category. Two investigators might assign the same patients to different categories. Because hearing is the most readily measured variable and the variable most related to the natural history of Meniere's disease, we devised a staging system based solely on hearing (Table 2). We do not intend to imply that all patients will progress through a series of stages in sequence. Staging should only be applied retrospectively but should be used to characterize the patient's status just before treatment. Once a stage has been established for a given patient and a given course of treatment, the stage of disease for that patient does not change for reporting purposes even if hearing does change after treatment.
TABLE TWO
STAGING OF DEFINITE AND CERTAIN MENIERE'S DISEASE
Stage 1 is < or =" 25">
Stage 2 is a 26-40 four tone average
Stage 3 is a 41-70 four tone average
Stage 4 is a >70 four tone average
FUNCTIONAL IMPAIRMENT AND DISABILITY
To patients, vertigo is the most important symptom of Meniere's disease; however, the measurement of vertigo is difficult because of its subjective nature. Counting the frequency of episodes gives a reasonable indication of the severity of vertigo in Meniere's disease. It does not take into account the possibility that a few severe attacks may be worse for a patient than frequent mild attacks, but it serves as a useful index that may change with the natural history of the disease or to treatment.
To help assess the effects of episodic vertigo on daily activities, a six-point functional level scale is introduced that we believe better reflects how Meniere's disease affects a patient's activities than the disability scale of the 1985 guidelines (Table 3). It is suggested that clinicians review the choices of disability level with each patient and allow the patient to make the final selection.
TABLE THREE
FUNCTIONAL LEVEL SCALE
Regarding my current state of overall function, not just during attacks (check the ONE that best applies):
1. My dizziness has no effect on my activities at all.
2. When I am dizzy I have to stop what I am doing for a while, but it soon passes and I can resume activities. I continue to work, drive, and engage in any activity I choose without restriction. I have not changed any plans or activities to accommodate my dizziness.
3. When I am dizzy, I have to stop what I am doing for a while, but it does pass and I can resume activities. I continue to work, drive, and engage in most activities I choose, but I have had to change some plans and make some allowance for my dizziness.
4. I am able to work, drive, travel, take care of a family, or engage in most essential activities, but I must exert a great deal of effort to do so. I must constantly make adjustments in my activities and budge my energies. I am barely making it.
5. I am unable to work, drive, or take care of a family. I am unable to do most of the active things that I used to. Even essential activities must be limited. I am disabled.
6. I have been disabled for 1 year or longer and/or I receive compensation (money) because of my dizziness or balance problem.
The raw data of the functional level scale should be reported for each patient at each time interval recorded (baseline, 2 years, etc.). The treatment outcome regarding disability should also be expressed as improved, unchanged, or worse for each patient.
REPORTING RESULTS OF TREATMENT
To make comparisons among studies and to facilitate meta-analysis, the Committee believes that the frequency of definitive attacks for the period 6 months before treatment should be compared with the interval occurring between 18 and 24 months after treatment (Table 5).7 In this manner, the two intervals are of the same duration, and the elapsed time after treatment is standardized. Hearing comparisons should be made with the worst audiogram of each of the two 6-month intervals. Except to note the necessity to treat with another modality, for example, neurectomy after surgery of the endolymphatic sac, characterization of treatment response for an individual patient should not be made until the patient has been observed for 24 months after treatment.
TABLE FOUR
Summary of reporting guidelines
Complete control of spells is a Class A result
1 to 40 spells is a Class B result
41 to 80 spells is a Class C result
81 to 120 spells is a Class D result
More than 120 spells is a Class E result
Secondary treatment initiated due to disability from vertigo is a Class F result
The worse preoperative audiogram for 6 months before treatment should be compared with the worst postoperative audiogram between 18 and 24 months after treatment. If patients are routinely recalled at 24 months, both hearing and vertigo can be assessed then. For clinical studies it is desirable to use consistent follow-up intervals. An accuracy of the recording interval of plus or minus 1 month is reasonable.
Clinicians may find it useful to have a standard form or chart stamp to record the patient's status during office visits. The frequency of definitive episodes for the previous 6 months, the pure-tone average, the word recognition, and the functional level can each be recorded.
Investigators are encouraged to report results 4 years after treatment (frequency of definitive spells and worst audiogram 42 to 48 months after treatment. In addition, odd follow-up intervals greater than 2 years may be used. For example, investigators may wish to report their results at most recent follow-up. Prospective data collection is encouraged.
OPTIONS AND FUTURE DEVELOPMENTS
The guidelines described here are not meant to be exclusionary. Publication of extensive data in tabular form is recommended to facilitate meta-analyses (Table 5). In cases in which this is not feasible, authors and publishers may offer to make the raw data available on request. Assessments of chronic dysequilibrium, otolithic crises, central nervous system compensation, and the use of electrocochleography (EChoG) or otoacoustic emissions (OAE) may be valuable but are beyond the scope of these guidelines. The difficulty in recommending guidelines that require EChoG or OAE is that these tests are nor universally available or standardized. The validity of EChoG and OAE as serial measures in human subjects with Meniere's disease deserves further study. Caloric test results, especially after vestibular neurectomy and aminoglycoside treatment are encouraged. Caloric results might help assess the mechanisms of treatment efficacy and failure. Early posttreatment audiometric results (4 to 10 weeks) may provide indications of the amount of hearing loss attributable to possible deleterious effects of treatment. Kaplan-Meier actuarial analysis 8 may be helpful in describing the time course of recrudescence and the institution of secondary treatment. It is hoped that advances in clinical and laboratory research will advance our understanding of Meniere's disease. New ideas may make revision of these guidelines necessary.
TABLE FIVE
Example of standard data table of raw data
Subject Treatment Stage Age/sex Baseline 2 yr 4 yr
1 Q 3 45/M 1.2/45/80/4 0/40/85/1 0.5/55/70/1
2 R 2 56/F 4/27/96/4 0.2/10/100/2 0.8/45/80/5
3 Q 1 23/F 3/10/100/5 0/40/70/1 0/70/50/1
4 R 4 60/F 1/71/40/5 0.2/71/40/1 0/72/40/1
FV, Frequency of vertigo, definitive episodes per month for the previous 6 months; HT, hearing thresholds, pure-tone average in decibels; WR, word recognition (speech discrimination) in percent; FL, functional level (1-6); and Q and R, treatments under evaluation.
The Subcommittee on Equilibrium of the Committee on Hearing and Equilibrium originated the first draft of these guidelines, which were further developed by the full Committee on Hearing and Equilibrium.
References
1. Committee on Hearing and Equilibrium. Meniere's disease: criteria for diagnosis and evaluation of therapy for reporting. Trans Amer Acad Opth Otolaryngol 1972;76:1462-4.
2. Committee on Hearing and Equilibrium. Meniere's disease: criteria for diagnosis and evaluation of therapy for reporting. AAO-HNS Bulletin 1985;5(July):6-7.
3. Rutka, JA, Barber HO. Recurrent vestibulopathy: third review. J Otolaryngol 1986;15:105-7.
4. Schuknecht, HF, Kitamura, K. Second Louis H. Clef Lecture. Vestibular neuritis Ann Otol Rhinol Laryngol 1983; 106(suppl):1-19.
5. Schuknecht HF, Gulya AJ. Endolymphatic hydrops, an overview and classification. Ann Otol Rhinol Laryngol 1983; 106(suppl):1-20.
6. Rose AS, Elison, GW, Myers, LW, Tourtelotte, WW. Criteria for the clinical diagnosis of multiple sclerosis. Neurology 1976;26:20-2.
7. Pearson B, Brackmann DE. Committee on Hearing and Equilibrium guidelines for reporting treatment results in Meniere's disease. Otolaryngology Head Neck Surg 1985;93:579-81.
8. Monsell, EM, Wiet, RJ. Endolymphatic sac surgery: methods of study and results. Am J Otol 1988;9:396-402.
