Postural instability in Meniere's disease

Dynamic posturography for staging of patients with Ménière's disease

Objective:

In recent years, techniques such as computerised dynamic posturography have facilitated objective evaluation of patients with balance disorders. In this study, we used computerised dynamic posturography for clinical staging of Ménière's disease.

Material and methods:

We applied a computerised dynamic posturography sensory organisation test to 53 patients with American Academy of Otolaryngology criteria of Ménière's disease. The following parameters were considered in data analysis: computerised dynamic posturography scores for testing the patient's centre of gravity with a mobile surface, immobile visual surroundings and eyes closed, scores for testing with a mobile surface, mobile visual surroundings and eyes open, and vestibular ratio. We used four hearing threshold stages (although we had no patients at stage four).

Results and discussion:

This study did not observe a statistically significant correlation between audiometric hearing thresholds and computerised dynamic posturography scores. Computerised dynamic posturography scores showed statistically significant variation with time elapsed since the last vertigo attack. Although our results showed an increasing trend in computerised dynamic posturography scores as Ménière's disease activity level decreased from recent post-attack (i.e. less than one week since last attack) through late post-attack (i.e. one week to 60 days since last attack) to inactive (i.e. more than 60 days since last attack), these differences were not statistically significant.

Meniere's disease

Meniere's disease (MD) is a disorder of the inner ear that causes vertigo attacks, fluctuating hearing loss, tinnitus and aural fullness. The aetiology of MD is multifactorial. A characteristic sign of MD is endolymphatic hydrops (EH), a disorder in which excessive endolymph accumulates in the inner ear and causes damage to the ganglion cells. In most patients, the clinical symptoms of MD present after considerable accumulation of endolymph has occurred. However, some patients develop symptoms in the early stages of EH. The reason for the variability in the symptomatology is unknown and the relationship between EH and the clinical symptoms of MD requires further study. The diagnosis of MD is based on clinical symptoms but can be complemented with functional inner ear tests, including audiometry, vestibular-evoked myogenic potential testing, caloric testing, electrocochleography or head impulse tests. MRI has been optimized to directly visualize EH in the cochlea, vestibule and semicircular canals, and its use is shifting from the research setting to the clinic. The management of MD is mainly aimed at the relief of acute attacks of vertigo and the prevention of recurrent attacks. Therapeutic options are based on empirical evidence and include the management of risk factors and a conservative approach as the first line of treatment. When medical treatment is unable to suppress vertigo attacks, intratympanic gentamicin therapy or endolymphatic sac decompression surgery is usually considered. This Primer covers the pathophysiology, symptomatology, diagnosis, management, quality of life and prevention of MD.

Factors Affecting Postural Instability in Ménière’s Disease

Objective

To assess the influence of factors that can affect the postural instability of Ménière’s disease (MD) patients.

Study Design

Case-control study.

Setting

Outpatient clinic in a university hospital.

Subjects and Methods

Fifty-four definite MD patients and 66 controls were included. Two-legged stance tasks were performed in 4 conditions: eyes open with and without foam rubber and eyes closed with and without foam rubber. We examined 6 variables: the velocity of movement of the center of pressure (COP), the envelopment area traced by the movement of the COP, Romberg’s ratio of velocity and area, and the foam ratios of velocity and area. For patients, stepwise multiple regression analyses were performed to explore the relationship between the 6 variables and the following independent variables: gender, age, the presence of abnormal caloric and/or cervical vestibular evoked myogenic potential (cVEMP) responses, the time elapsed since the last vertigo attack, and the disease duration.

Results

The presence of MD had a significantly positive relationship with all 6 of the variables ( P < .05). The presence of abnormal caloric and/or cVEMP responses had a significantly positive relationship with Romberg’s ratio of velocity ( P < .05) and area ( P < .01). The shorter time interval from last vertigo attack to measurement had a significantly positive relationship with the foam ratio of area ( P < .01).

Conclusion

MD patients show poor postural performance, which is affected by the existence of their peripheral vestibular function and the shorter time interval from last vertigo attack to measurement.

Disturbances in equilibrium function after major earthquake

Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events.