title: Recovery of Impaired Somatosensory Evoked Fields After Improvement of Tongue Sensory Deficits With Neurosurgical Reconstruction.
abstract: Somatosensory evoked fields (SEFs) induced by tongue stimulation can be useful as an objective parameter to assess sensory disturbances in the tongue. However, whether tongue SEFs can be useful as a clinical, objective follow-up assessment method of tongue sensation after oral surgery is unknown. We describe 2 cases in which tongue SEFs were successfully used in clinical assessment. Two patients with unilateral tongue sensory deficits caused by lingual nerve injury during lower third molar extraction were recruited. Both patients underwent surgery to repair the damaged nerve, and all tongue sensory evaluations were performed once before and once after surgery. SEFs were recorded by stimulating the affected and unaffected sides of the tongue separately, and cortical activity was evaluated over the contralateral hemisphere. The unilaterality of the deficit also was assessed. In both patients, stimulation of the unaffected side evoked reproducible cortical responses before and after surgery. Both patients also recovered some sensation after surgery, given that presurgery stimulation of the affected side failed to evoke cortical activity whereas postsurgery stimulation evoked cortical activity on both sides. Sensation was initially highly lateralized in both patients but was restored to approximately normal in the postsurgery evaluation. Finally, both patients rated their subjective tongue sensations on the affected side over 50% better after the surgical intervention. These cases indicate that tongue SEFs may have a clinical use as an objective parameter for assessing the course of tongue sensory recovery.
authors: Assistant Professor, Department of Oral Physiology, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan, and Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Electronic address: maezawa@den.hokudai.ac.jp.
authors: Hitoshi
authors: H
authors: Maezawa
authors: Lecture, Department of Oral and Maxillofacial Surgery, School of Medicine, Wakayama Medical University, Wakayama, Japan.
authors: Itaru
authors: I
authors: Tojyo
authors: Department Chief, Department of Oral and Maxillofacial Surgery, National Hospital Organization, Kyoto Medical Center, Kyoto, Japan.
authors: Kazuya
authors: K
authors: Yoshida
authors: Professor, Department of Oral and Maxillofacial Surgery, School of Medicine, Wakayama Medical University, Wakayama, Japan.
authors: Shigeyuki
authors: S
authors: Fujita
mesh_terms: D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D019635:Neurosurgical Procedures; D020127:Recovery of Function / Q000502:physiology*; D012678:Sensation Disorders / Q000503:physiopathology* / Q000601:surgery*; D012684:Sensory Thresholds; D014059:Tongue / Q000294:innervation* / Q000601:surgery*; D055815:Young Adult