PMC5315360_01
Nystagmus on diagnostic tests for benign paroxysmal positional vertigo (BPPV) following laparoscopic cholecystectomy. On the right Dix-Hallpike test at initial evaluation, when the patient in upright sitting position with the head turning 45 degrees to the left (a) is moved to head hanging position (b), a vertical upbeating nystagmus with counterclockwise torsional component toward the dependent ear is induced, indicating a diagnosis of right posterior canal BPPV. On the roll test at re-evaluation 1 day after the Epley maneuver for the treatment of right posterior canal BPPV, a geotropic horizontal nystagmus toward the right is provoked when rolling the patient to the right (c) from the neutral position (d), and a weaker geotropic horizontal nystagmus toward the left is induced when rolling the patient to the left (e), suggesting the occurrence of right horizontal canal BPPV due to canal conversion. Arrows depict the directions of nystagmus.
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PMC5315360_01_10.1177_2050313X17692938-fig1.jpg
fig1-2050313X17692938
On the right Dix-Hallpike test, brief vertigo and vertical upbeating nystagmus with counterclockwise torsional component toward the dependent ear were induced (Figure 1(a) and (b)). This time the Dix-Hallpike test was negative, indicating the posterior canal BPPV was resolved, but the roll test showed a geotropic direction-changing horizontal nystagmus (Figure 1(c)-(e)), with more intense nystagmus when patient's head turned to the right than to the left.
PMC5315360_02