목적: The major typical types of benign paroxysmal positional vertigo (BPPV) include posterior canal canalolithiasis (PC-BPPV), horizontal canal canalolithiasis and cupulolithiasis (HC-BPPV), and anterior canal canalolithiasis (AC-BPPV). We defined atypical BPPV as cases where the clinical presentation does not align with the established criteria for typical subtypes or where symptoms and nystagmus persist despite repeated canalith repositioning therapy (CRT). We evaluated the clinical course and vitamin D levels in individuals diagnosed with atypical BPPV compared to those with typical BPPV. 방법:We investigated the clinical courses (number of previous BPPV diagnoses, the intensity of nystagmus at the initial visit, number of CRT treatment failures, the time to symptom resolution, and the persistence of untreated nystagmus in the patients). Vitamin D levels were measured at the time of the first visit for symptoms. 결과:Among a total of 55 patients, 30 were diagnosed with typical BPPV (mean age: 56.9 years, 21 females), while 25 were identified as having atypical BPPV (mean age: 56.9 years, 13 females). Atypical BPPV presented in various forms, including cases with heavy cupula or light cupula of HC (n=11), cupulolithiasis of PC-BPPV (n=7), apogeotropic PC-BPPV (n=1), symptoms and nystagmus unresolved after repeated CRT sessions with undefined positional nystagmus (n=6). The number of previous BPPV diagnoses was 1.72 in the atypical BPPV group and 1.36 in the typical BPPV group (p=0.310). The intensity of nystagmus observed on the initial visit tended to be lower in atypical BPPV compared to typical BPPV (atypical BPPV: right 4.4 deg/sec, left 4.5 deg/sec; typical BPPV: right 18.3 deg/sec, left 17.4 deg/sec). Vitamin D levels were significantly lower in the atypical BPPV group (19.17 ng/mL) compared to the typical BPPV group (32.70 ng/mL, p<0.001). The number of CRT failures showed significantly higher failure rates in the atypical BPPV group (2.84 vs. 0.14, p<0.001). The duration from symptom onset to resolution was significantly longer in the atypical BPPV group (30.07 days) compared to the typical BPPV group (5.83 days, p=0.018). Until the last observation point (more than five weeks after the first clinic visit), persistent nystagmus was observed in 11 cases (44.0%) in the atypical BPPV group, despite symptom resolution. 결론:Atypical BPPV is a refractory vestibular disorder with an unclear pathophysiological mechanism. In this study, we observed that atypical BPPV is associated with lower vitamin D levels, resistance to repeated repositioning maneuvers, and a prolonged disease duration.