Agus G, Puxeddu R, Demontis G P, Puxeddu P
Department of Surgery, University of Cagliari, Italy.
Acta Otolaryngol Suppl. 1995;520 Pt 1:143-7. doi: 10.3109/00016489509125213.
An atypical paroxysmal positioning nystagmus (PPNy), "reversed" in its directional components, is a rare finding in patients suffering from benign paroxysmal positioning vertigo (BPPV). It poses problems of pathophysiogenetic interpretation, differential diagnosis with a CNS lesion and therapeutic strategy. Such a finding was observed in 7 patients (out of a total of 450 BPPV) and took on the typical PPNy pattern after repeated diagnostic manoeuvres. These aspects are incompatible with the "heavy cupula" mechanism (cupulolithiasis) and are better explained by the presence of "free endolymph aggregates" (canalolithiasis) within the posterior semicircular canal (p.s.c). Moreover, canalolithiasis would also permit a more convincing interpretation of all the clinical findings observed in typical p.s.c.-BPPV.
一种非典型的阵发性位置性眼球震颤（PPNy），其方向成分“反转”，在患有良性阵发性位置性眩晕（BPPV）的患者中是一种罕见的发现。它带来了病理生理机制解释、与中枢神经系统病变的鉴别诊断以及治疗策略等问题。在450例BPPV患者中有7例观察到了这样的发现，经过反复的诊断操作后呈现出典型的PPNy模式。这些情况与“重嵴帽”机制（嵴帽结石症）不相符，而后半规管（p.s.c）内存在“游离内淋巴聚集体”（管结石症）能更好地解释这些情况。此外，管结石症也能更有说服力地解释在典型的后半规管BPPV中观察到的所有临床发现。
