Revisiting BPPV: Incidence and Behavior of Atypical Variants.

Objectives: Typical BPPV forms are widespread and easily diagnosed disorders. However, some forms of labyrinthine lithiasis can differ from the typical BPPV paradigm, showing their own signs and symptoms and resulting in variable therapeutic responses. The aim of this retrospective study is to describe the incidence of the so-called atypical forms compared to the more common BPPV, describing their clinical behavior. Methods: This retrospective study analyzed clinical and instrumental data of 139 patients evaluated over a 12-month period at a referral center. Patients were divided into two groups. The first group (Group A) included patients with so-called "typical" and unilateral labyrintholithiasis, while the second group (Group B) included patients with so-called "atypical" forms. Results: Based on clinical characteristics, 82 patients were assigned to group A while 57 (51.01%) to group B. In group A, resolution of the clinical picture required fewer sessions and a smaller number of therapeutic maneuvers than in group B (p < 0.001). Furthermore, in group A, resolution of symptoms was observed immediately after one of the therapeutic maneuvers performed in 74.07% of cases, while in group B, resolution of the clinical picture was observed during one of the follow-up visits in 39.66% of cases (p < 0.001). Conclusions: Although considered rare, "atypical" forms have an increased prevalence in tertiary centers. The location of the canaliths within the labyrinth can be hypothesized based on the pattern of nystagmus, which serves as a guide for treatment.