Direct tongue neurotization: the effect on speech intelligibility in patients with Möbius syndrome

Möbius syndrome is a disorder characterized by developmental impairment of cranial nerve VII, VI, often XII, and other cranial nerves. Facial reanimation in such patients restores the ability of some motion and of limited emotional expression. In one-fourth of these patients, hypoglossal involvement results in severe speech impairment due to tongue atrophy and lack of voluntary mobility. Bilabial incompetence due to facial paralysis further deteriorates speech capability. Direct tongue neurotization has been used by the senior author (J.K.T) to improve tongue function and speech intelligibility in patients with Möbius syndrome. This study presents the senior author's experience with the technique as a component of multistage facial reanimation procedures.

Data collection was performed by retrospective review on six patients with Möbius syndrome who underwent direct tongue neurotization. In addition, each patient was videotaped for 30 minutes preoperatively and postoperatively according to a standardized protocol.

Four independent investigators scored speech intelligibility in each patient using a standardized grading system. The results showed considerable improvement in speech intelligibility and articulation. Higher improvement was noted in patients with partial bilateral hypoglossal involvement than in patients with complete unilateral involvement of the hypoglossal nerve, as well as in younger ages. No difference was noted between sexes.

To the authors' knowledge, this is the first study presenting the effect of direct tongue neurotization on speech intelligibility in patients with Möbius syndrome. Tongue neurotization has therefore an important role in restoring the ability of these patients to communicate and obtain the potential to develop normal social skills.