Anterior SCC BPPV is diagnosed with the Dix-Hallpike test (same as posterior canal), however detecting the involved side may differ.  Often times, both testing positions reveal nystagmus which can lead to the false diagnosis of bilateral canal involvement.  This is because when a patient is placed in a position with full neck extension, there is potential for debris in either semicircular canal to move away from the cupula triggering nystagmus and symptoms.  Therefore, the clinician should consider the torsional component of nystagmus in addition to the dependent ear (Herdman, S. J. 2007).  



Traditionally, anterior canal involvement is thought to rarely occur due to the canals orientation in relation to the utricle and saccula.  However, recent evidence demonstrates that it may be a more common occurrence than previously believed (Jackson, Morgan, & Krueger, 2007).   

 

Jackson and colleagues 2007 reported that 21.2% of patient's examined in their study (n=260) demonstrated anterior canal BPPV.  Additionally, "Head trauma was statistically significantly more frequently identified as an etiologic event in these patients compared to other involvement (Jackson, Morgan, & Krueger, 2007)."