Complex nystagmus in traumatic benign paroxysmal positional vertigo: A case study on the critical value of knowing semicircular canal excitation and inhibition patterns

A 73-year-old female presented to the emergency department with chief complaint of dizziness after sustaining a fall one month prior to dizziness onset. Although careful examination of eye movement patterns during positional testing was attempted at varying stages of her inpatient admission, her complex nystagmus patterns as a result of traumatic benign paroxysmal vertigo were difficult to manage. In particular, the nystagmus pattern from this case suggests the BPPV was variable and affecting either 1) left posterior semicircular canal (pSCC) exclusively 2) left pSCC and right anterior semicircular canal, 3) left and right pSCC canal. This case illustrates the importance of two critical details; positional testing should include observing nystagmus with fixation removed and an experienced clinician should be involved as early as possible.