Oral incompetence: changes in speech intelligibility following facial nerve paralysis

Background: Speech may be compromised following facial nerve paralysis (FNP), depending on the cause of the paralysis. This can result in lower quality of life and a reduced capacity to return to vocational roles. Despite its prevalence, it is incompletely understood and rarely described. This study prospectively evaluated the impact of FNP on speech intelligibility. Methods: This observational study recruited patients who were diagnosed with FNP and who reported oral incompetence from the Sydney Facial Nerve Service. Their speech was analysed using patient reported outcome measures (Speech Handicap Index) and perceived intelligibility (Speech Pathologist, community member control participants, participant self-rating, and dictation software). Results: Forty participants with FNP and 40 controls were recruited. Participants with FNP rated their intelligibility to be significantly worse than other raters (p <0.001). Consonant analysis demonstrated bilabial, fricatives and labiodental phonemes to be most commonly affected following FNP. Conclusion: Oral competence is compromised after FNP which can lead to a poorer perception of their intelligibility and reduced speech related quality of life.