The discovery gives hope to patients who suffer from conditions such as Bell's palsy.

BBC: Facial palsy patients helped by mouth massage

Bell's palsy is the most common cause and although most make a good recovery, some are left with muscle weakness.

BBC: Facial palsy patients helped by mouth massage

Kefu's rugby future was in doubt earlier this week after he took a banned substance prednisone to treat viral disorder Bell's Palsy.

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