Effect of botulinum toxin injection on speech outcomes among patients with synkinetic facial nerve palsy: An assessment of speech intelligibility and quality of life.

[BACKGROUND] Facial nerve palsy (FNP) considerably impairs functional outcomes and quality of life. For patients with synkinetic FNP, physiotherapy and botulinum toxin A (BTX) are commonly used to reduce hyperkinesis and improve facial expression. This study assessed the effect of BTX administration on oral competence in patients with FNP.

[METHODS] Patients referred for BTX for management of their synkinetic FNP were recruited from the Sydney Facial Nerve Service. BTX was administered by a single surgeon. Their oral competence was measured using clinician and patient-rated outcome measures before and 4 weeks after BTX administration. This included a consonant analysis of a recorded reading sample, a subjective intelligibility rating by the clinician and patient, as well as 3 validated patient-reported questionnaires: the Speech Handicap Index (SHI), the Facial Disability Index (FDI), and the Oral Competence Questionnaire (OCQ).

[RESULTS] Twenty participants were recruited for analysis. Patients were administered an average of 31.5 u of BTX on the ipsilateral side, and 9.25 u on the contralateral side. This resulted in statistically significant improvements in the percentage of correct consonants (p < 0.001), particularly post-alveolar/alveolar fricative sounds (s, z, and sh; p < 0.001). This corresponded with significantly better speech-related quality of life (SHI p = 0.003). There was no significant change in the OCQ or FDI scores.

[CONCLUSIONS] BTX administration for patients with synkinetic FNP showed improved speech-related quality of life and speech intelligibility.