Commentary: Post-traumatic benign paroxysmal positional vertigo: mechanisms, clinical phenotypes, and a structured clinical pathway for management

Kong and Seo (1) reviewed the literature on post-traumatic benign paroxysmal positional vertigo (BPPV).One of their conclusions is that modest biomechanical insults to the head may cause BPPV.We found, in acute-prospective studies, in patients (n = >150) with acute moderate-to-severe traumatic brain injury (TBI) [Mayo clinic classification for TBI (2)] a BPPV prevalence of up to 60%, with BPPV being more likely the greater the forces acting upon the skull (3, 4).These findings were recently reproduced (5).On this background, the presence of BPPV could indicate the severity of the TBI to be categorized as at least moderate.As BPPV is relatively rare before the sixth decade, the presence of BPPV especially in the young might therefore serve as marker of TBI severity (6).Kong and Seo also discuss the fact that BPPV may be overlooked or misdiagnosed in acute trauma settings.In fact, a considerable amount (c.30%) of patients with acute TBI do not report vestibular symptoms or imbalance (7, 8) due to "vestibular agnosia" (VA).Vestibular agnosia manifests as an attenuated or absent perception of self-motion and is linked to imbalance, a condition we have reported on for the first time in TBI in an acute, prospective study (8).The authors state that post-traumatic BPPV may differ from idiopathic BPPV in clinically meaningful ways, with which we agree, however, this difference is not considered in their proposed algorithm for treating BPPV.The algorithm is problematic since there are no controlled studies assessing the barriers to diagnosing and treating BPPV acutely (training, clinical costs, staff cognitive biases) nor data indicating when to treat and whom to treat since many patients show recurrence despite repeated BPPV particle repositioning [Calzolari et al. (8) report 40% recurrence at 6-months despite treatment at 0 and 6-months].The authors also fail to acknowledge the lack of robust controlled data on the