Therapeutic maneuvers in the treatment of paroxysmal positional vertigo: can they indicate a central genesis?

Typical Paroxysmal Positional Nystagmus (PPNy) is a highly specific clinical finding that indicates the existence of a specific peripheral lesion: Paroxysmal Positional Vertigo (PPV). However, besides this typical nystagmus of high topodiagnostic significance, atypical PPNy's are also frequently found. Such atypical findings can lead one to suspect a central vestibular system pathology and often require additional diagnostic testing. Of 1805 patients with complaints of vertigo, 305 proved affected by PPV. The present study evaluated how patients affected by the posterior semicircular canal PPV (278/305, 91.2%) responded to canalith repositioning maneuvers. In 246 patients (88.5%) the Semont maneuver was performed as simplified by Toupet, while the remaining 32 subjects (11.5%) were treated with the Epley maneuver as modified by Herdman. The Semont maneuver provides the relief of symptoms in 96% of patients while the Epley maneuver resolved 78% of cases. The patients that did not respond to the maneuvers, even after several attempts, were subsequently treated using "habituation"-based rehabilitation techniques (the Brandt-Daroff technique and Vestibular Habituation Training). The presence of atypical PPNy was found in 57 subjects. Of these, the liberatory maneuver always resolved the PPV. In the present study, the choice to perform a neuroradiological study was based on the lack of response to physical therapy, whether performed with liberatory maneuvers or with habituation techniques. In 2 of the 3 cases of PPV which remained unchanged despite treatment, imaging revealed a severe expansive CNS pathology. In these patients the dizziness complaints disappeared after neurosurgery: this fact appears to confirm the central origin of these PPNy cases. These data clearly indicate that the results of PPV treatment must be carefully evaluated. In cases of PPV of the PSC, when either typical or atypical PPNy persists one month after diagnosis, with no appreciable period of remission, neuroradiological tests should be performed in order to rule out any CNS pathology.