Reduction of Continuous Theta Burst Stimulation-Induced Motor Plasticity in Healthy Elderly With COMT Val158Met Polymorphism

OBJECTIVE: To delineate whether cortical plasticity induced by continuous theta burst stimulation (cTBS) differed according to catechol-O-methyltransferase (COMT) gene polymorphism in healthy older adults. METHODS: Eighteen healthy older volunteers (mean age 73.78+/-5.04; 12 females and 6 males) were recruited. Volunteers randomly assigned in either a sham-first or real cTBS first group participated in two separate TMS visits with at least a 2-day wash-out period. Genotyping was carried out at baseline by a separate researcher who was blinded. cTBS was delivered in a hot spot over M1 at an active motor threshold of 80%. Motor evoked potentials (MEPs) were obtained at 120% of the resting motor threshold before and after sham/cTBS. RESULTS: The relative MEP to baseline was significantly decreased 0 and 10 minutes post-stimulation and increased 40 minutes post-stimulation, as compared with the sham condition. Immediately after cTBS, the Val/Val group had a significantly reduced relative MEP value, as compared with the MET carrier group. CONCLUSION: In healthy older persons, cTBS-induced motor plasticity was reduced in the COMT Val/Val group as compared with the 158Met carrier group.

Videofluoroscopy-Guided Balloon Dilatation for the Opening Dysfunction of Upper Esophageal Sphincter by Postoperative Vagus Nerve Injury: A Report on Two Cases

Dysphagia secondary to peripheral cranial nerve injury originates from weak and uncoordinated contraction-relaxation of cricopharyngeal muscle. We report on two patients who suffered vagus nerve injury during surgery and showed sudden dysphagia by opening dysfunction of upper esophageal sphincter (UES). Videofluoroscopy-guided balloon dilatation of UES was performed. We confirmed an early improvement of the opening dysfunctions of UES, although other neurologic symptoms persisted. While we did not have a proper comparison of cases, the videofluoroscopy-guided balloon dilatation of UES is thought to be helpful for the early recovery of dysphagia caused by postoperative vagus nerve injury.