Tongue Asymmetry and Muscle Shortening During Speech in Partial Glossectomy Patients and Controls

Abstract

Tumors of the tongue are routinely removed by partial glossectomy surgery. This study examines the extent of anatomical asymmetries caused by the glossectomy surgery and its effects on the tongue’s resting position and motor symmetry. Magnetic resonance imaging (MRI) data of ten control subjects and ten glossectomy patients were obtained. 3D tongue volumes were extracted from high-resolution MRI data using Matlab. Using cine- and tagged-MRI data, shortening of the genioglossus, transverse, and verticalis muscles were calculated during a speech task involving /∫/ and /l/. Anatomical asymmetries were observed in the control subjects, although they were generally small and less than in glossectomy patients. Glossectomy patients aimed to distribute their tongue volume evenly in the oral cavity, irrespective of anatomical asymmetry, by posturing their tongue towards the resected side. Glossectomy patients shortened more muscles when executing the speech task. Muscle shortening asymmetry was observed in both control and patient groups.