Meniere's disease is difficult to treat because its etiology is still unknown and pathophysiology is not fully understood. Clinical laboratory studies indicate that the inner ear changes in Meniere's disease may be caused by a dysfunction of the endolymphatic sac. Surgery was performed on the patients with intractable Meniere's disease, who had progressive sensorineural hearing loss, vertigo and unsteadiness against oral medication. Postural stability after operation was evaluated chronologically with a force platform is to measure the change of the center point of foot pressure on the platform surface. The signal from the force platform fed into a signal processor (San-eisokki 7T-17) was analyzed with an 8-directional vectrogram after sampling and eliminating the noise.
Thirty six patients were compared with 31 controls. The vectrogram was useful for observing the 8-directional sway. Postural stability was abnormal in 25 out of 36 cases (69%) before the operation,13 of 22 cases (59%) at 1-3 months, in 4 out of 16 cases (25%) at 4-6 months and in 1 out of 10 cases (10%) at 7-12 months after endolymphatic sac operation.
From our obervation, postural control was well compensated in 75% of the operated patients 4-6 months following operation. The results of postural stability after operation were in agreement with the results of the general questionnaire.
The 8-directional vectrogram proved useful for evaluating the postural stability in postoperative patients with Meniere's disease.
