PMC10196188_01
(A) PTA on admission: total SSNHL in both ears: 112 dB on the right and 115 on the left. (B) PTA after 3-month follow-up: severe hearing loss in both ears: 67 dB on the right and 73 on the left. (C) The electrocochleogram showed the binaural SP/AP ratio in the normal range at 90 dBnHL, with the left ear SP/AP ratio of 0.33 and the right ear SP/AP ratio of 0.25. PTA, pure-tone average; SSNHL, sudden sensorineural hearing loss; dB, decibel; SP, summating potential; AP, action potential; dBnHL, decibel normal hearing level; R, right; L, left.
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F1
PTA showed a total SSNHL of 112 dB in the right ear and 115 dB in the left ear (Figure 1A), and no infarct foci were found on the head MRI. The electrocochleogram showed the binaural SP/AP ratio in the normal range at 90 dBnHL, with the left ear SP/AP ratio of 0.33 and the right ear SP/AP ratio of 0.25 (Figure 1C). Tone Audiogram showed that SSNHL persisted; however, there was a clear improvement, with PTA average of 67 dB on the right and 73 dB on the left (Figure 1B). The speech audiometry showed 55 dB with 100% speech discrimination on the right and 60 dB with 100% speech discrimination on the left.
(A, B) 3rd day, diffusion-weighted MRI showed hyperintense foci at the bilateral cerebellum; (C, D) 10 days later, diffusion-weighted MRI showed new hyperintense foci at the bilateral MCP; (E, F) brain and neck CTA revealed occlusion of the bilateral VA V3 segment, proximal V4 segment and bilateral AICA, severe stenosis of the distal left VA V4 segment. MRI, magnetic resonance imaging; MCP, middle cerebellar peduncle; CTA, computed tomography angiography; VA, vertebral artery; AICA, anterior inferior cerebellar artery.
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F2
Reexamination of the brain MRI demonstrated an acute infarction in the bilateral cerebellum (Figures 2A, B). A brain MRI revealed a new acute infarction extending to the bilateral MCP (Figures 2C, D). Brain and neck CTA showed occlusion of the bilateral vertebral artery (VA) V3 segment, proximal V4 segment, and bilateral AICA as well as severe stenosis of the distal left VA V4 segment (Figures 2E, F).
Time course of the disease. Diagram illustrating time course of disease in our patient. PTA, pure-tone average; R, right; L, left; MRI, magnetic resonance imaging; MCP, middle cerebellar peduncle.
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F3
A time-course diagram of disease progression is shown in Figure 3.