CDP–SOT HIMP Meniere’s disease Menière’s disease PCGD Porpoise SHIMP TBI VHIT VOR gain activities-specific balance confidence anticonvulsant drugs apogeotropic benign paroxysmal positional vertigo bilateral vestibular disease (BVD) bilateral vestibular dysfunction bilateral vestibulopathy bithermal caloric paresis caloric test caloric tests cervical cervicogenic chemical labyrinthectomy cochleovestibular nerve compensatory saccades covert saccades cupulolithiasis dexamethasone disability