Positional nystagmus of benign paroxysmal type (BPPN) due to cerebellar vermis lesions. Pseudo-BPPN.
Positioning nystagmus accompanied by severe vertigo has been reported in patients with partial lesions of the inner ear, especially otolith lesions. Typically, this type of nystagmus shows a latent period and subsequent fatiguability. We concur with this finding and have constantly emphasized the significance of this phenomenon in clinical diagnosis. Since we started using CT-scanning, this type of nystagmus has been noted in 47 patients, all of whom had cerebellar vermis lesions. Attention should be focused on this association; if such a combination were seen in only 1 or 2 patients, it could simply be attributed to coincidence. But its occurrence in as many as 47 patients indicates a causal role of cerebellar vermis lesions. Its mechanism may be explained by incomplete inhibition of the vestibulo-oculomotor system including the cerebellar flocculonodular lobe or vestibulo-cerebellum.
Sakata
E
E
Neurotological Clinic, Saitama Medical School, Japan.
Ohtsu
K
K
Itoh
Y
Y
D002526:Cerebellar Diseases / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000209:etiology* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed; D014717:Vertigo / Q000209:etiology / Q000503:physiopathology