Does cross-innervation occur after facial palsy?

When the unaffected facial nerve was stimulated in 30 patients with facial palsy, evoked action potentials could be recorded from the contralateral (paralysed) perioral muscles. Similarly, in four normal subjects responses were evoked contralateral to the stimulated facial nerve. The latency of these responses in the patients remained unchanged over several months, and they were conducted at a rate compatible with conduction along muscle fibres. The contralateral responses are suggested to be due to conduction along muscle fibres crossing the midline rather than to cross-innervation.