Abstract
Benign paroxysmal positional vertigo (BPPV) is peripheral vertigo caused by a change in position. The pathophysiology is tied to crystals of calcium carbonate, ectopically dislocated in the endolymph of semicircular canals.
Diagnosis is based on typical clinical history and findings on Dix-Hallpike positional test. Neither oculography nor electronystagmography (ENG) examinations are routinely performed.
We focused on assessing the participation of functional disturbances of the inner ear in this diagnosis. Out of 36 patients with positional vertigo, 33 had BPPV of the posterior canal.
Out of these, 19 had a secondary form and 14 had idiopathic BPPV. Hearing was impaired in 20 patients (66%) - all patients with otosclerosis, Menière's disease - but also 5 out of 10 patients with idiopathic BPPV.
ENG findings corresponding to hypo-function of the lateral canal ipsilateral to the BPPV were found in 5 patients, including 1 with idiopathic BPPV. ENG typical of central vestibulocerebellar lesion was found in 3 patients, all with recurrent positional vertigo of unknown etiology and with BPPV characteristics.
Impaired inner ear function is frequently found not only in secondary BPPV (17 out of 19 patients, 89 %) but also in the idiopathic form (6/14 patients - 43 %). In order to describe idiopathic BPPV with inner ear impairment of unknown etiology and undetectable during routine examination, we propose the term "cryptogenic BPPV".