Question
What does the bascule maneuver involve, and in which BPPV variants is it applied in clinical practice?
Answer
The bascule represents a novel strategy for the management of the atypical forms of posterior semicircular canal (PSC) BPPV. In fact, although typical PSC-BPPV is effectively treated in most patients using standard repositioning maneuvers, atypical variants—characterized by otoconia lodging in uncommon or stenotic portions of the canal and producing unusual positional nystagmus—are often resistant to physical therapy, and their optimal management remains controversial. These atypical forms include PSC cupulolithiasis, apogeotropic PSC-BPPV, sitting-up vertigo, and PSC canalith jam. Anterior semicircular canal (ASC) BPPV represents another uncommon and frequently refractory variant. In such conditions, impulsive maneuvers may offer therapeutic benefit. To address these challenging presentations, we developed a customized impulsive technique—the “bascule maneuver”—performed along the plane of the affected canal (left anterior–right posterior [LARP] or right anterior–left posterior [RALP]). The maneuver is intended either to directly resolve these atypical variants or to convert them into typical forms, thereby facilitating localization of otoconia in diagnostically uncertain cases. After positioning the patient first in the initial diagnostic position (45° face-up toward the affected side) and subsequently in the second Semont position (45° face-down toward the healthy side), the procedure consists of continuous, repeated lateral bascule movements. The patient is briskly tilted side-to-side in a pendular manner along the roll plane (up to 10 repetitions per session), while maintaining a constant head orientation along the LARP or RALP plane, until a change or attenuation of positional nystagmus is observed. A significant cohort with atypical PSC-BPPV or ASC-BPPV were prospectively treated using the bascule maneuver. This novel therapeutic strategy proved to be effective in 84% of cases achieving either a direct resolution of BPPV or a conversion to a typical BPPV variant (mainly typical PSC-BPPV and lateral semicircular canal BPPV), either during the same session or at subsequent follow-up, allowing the identification of the original otolith location (i.e. more on the utricular than on the canal side) in most cases of cupulolithiasis and sitting-up vertigo. The majority of the remaining patients without clinical improvement was found to have a coexisting ipsilesional inner ear disorder (e.g., vestibular migraine, Ménière’s disease, or prior sudden hearing loss), suggesting a buoyancy-related mechanism that may mimic atypical PSC-BPPV. Based on these preliminary findings, the bascule maneuver appears to be a promising therapeutic option for the management of atypical PSC-BPPV.
