Figure 1: Hyperexcitability of blink-reflex circuit in patients with Meige’s syndrome. Note: (A) The trigeminal nerve is the afferent nerve and the facial nerve is the efferent nerve in the blink-reflex circuit. (B) The brain stem trigeminal evoked potential (BTEP) waveform was induced by low-threshold stimulation (0.6 mA), which proved hyperexcitability of the afferent pathway in the blink-reflex circuit. (C) The abnormal enhanced waveforms recorded by facial electromyography (fEMG) demonstrated hyperexcitability of the afferent pathway of the blink-reflex circuit. (D) The blink reflex has two components, an early R1 and a late R2 response. The R1 response is usually present ipsilateral to the side being stimulated, whereas the R2 response is typically present bilaterally.