Direction-changing positional nystagmus is generally thought to be of central origin. Reversal of initial positional nystagmus during maintaining the head position in patients with benign paroxysmal positional vertigo (BPPV) is quite unusual and could be a sign of peripheral pathology. Vestibular reflex adaptation. simultaneous co-existence of canalolithiasis and cupulolithiasis in th... https://steedaes.shop/product-category/timing-chains/