Fig. 2. Case report: masked bone conduction thresholds are shown for a series of audiograms performed on September 8 (A), October 19 (B), November 11 (C), and December 2 (D).

A, The initial baseline audiogram demonstrated high-frequency sensorineural hearing loss (SNHL) that is symmetric and bilateral (dashed box).

B, Six weeks later, the patient complained of left-sided hearing loss and the audiogram revealed left-sided mid-tone SNHL (dashed box).

C, Three weeks later, when the patient presented with contralateral SNHL, the audiogram showed resolution of left-sided mid-tone SNHL and new right-sided mid-tone SNHL (dashed box).

D, Three weeks later, when the patient again presented with left-sided symptoms, the audiogram showed resolution of right-sided mid-tone SNHL and new left-sided mid-tone SNHL (dashed box). Subsequent audiogram was similar to the initial evaluation; however, the fluctuation continued.