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 (158)Met carrier group.
['Lee|Nam Jae|NJ|', 'Ahn|Hyun Jung|HJ|', 'Jung|Kwang-Ik|KI|', 'Ohn|Suk Hoon|SH|', 'Hong|Jeonghoon|J|', 'Kim|Yun Joong|YJ|', 'Yoo|Woo-Kyoung|WK|']
Catechol-O-methyltransferase Genetic polymorphism Motor cortex Neuronal plasticity Transcranial Magnetic Stimulation