Blink reflex excitability recovery curves in patients with dysfunctions after facial nerve palsy.

The blink reflex excitability recovery curves were studied in 12 patients with postparalytic facial dysfunctions (PPFD) and 12 healthy control subjects. The inhibitory effects of the conditioning stimuli on the ipsilateral R2 and contralateral R2 responses observed in control subjects were significantly less in patients with PPFD. The enhanced recovery of the R2 responses was similar on the affected side and unaffected side in the patients. These results indicate that patients with PPFD have an increased excitability of central interneurons which mediate the R2 pathway. It is suggested that not only changes in the peripheral facial nerve but also changes in the central nervous system may contribute to the onset of PPFD.