抄録
Lateral semicircular canal benign paroxysmal positional vertigo reveals atypically direction changing positional nystagmus (geotropic and apogeotropic). Furthermore, this condition used to be recognized as the clinical sign of posterior cranial fossa lesions, in particular, lesions of the brainstem and cerebellum. On the other hand, a good number of clinical reports indicate, nowadays, that such positional nystagmus is more likely to be caused by peripheral vestibular lesions and this has become widely well-known. For instance, geotropic direction changing positional nystagmus is caused by canalolithiasis and apogeotropic direction changing nystagmus is associated with cupulolithiasis. Some textbooks argue whether or not such positional nystagmus could represent central nervous system findings and signs, and this still remains controversial. We therefore tried to examine states of nystagmus based on a review of clinical papers and deliberate the clinical significance and diagnostic value of nystagmus. Base on the results of our literature research we were unable to determine whether or not nystagmus findings could suggest central nervous system lesions. We concluded that, notwithstanding direction changing positional nystagmus, the best approach would be to consider each situation again from the beginning, taking the patient's present history in greater detail and performing neurological and neuro-otological examinations on each patient, which could provide the most important information to doctors regarding dizzy patients.
