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.


CONCLUSIONS
In healthy older persons, cTBS-induced motor plasticity was reduced in the COMT Val/Val group as compared with the (158)Met carrier group.
Department of Physical Medicine and Rehabilitation, Hallym University College of Medicine, Chooncheon, Korea.
Nam Jae
NJ
Lee
Hallym Institute of Translational Genomics & Bioinformatics, Hallym University Sacred Heart Hospital, Anyang, Korea.
Hyun Jung
HJ
Ahn
Department of Physical Medicine and Rehabilitation, Hallym University College of Medicine, Chooncheon, Korea.
Kwang-Ik
KI
Jung
Department of Physical Medicine and Rehabilitation, Hallym University College of Medicine, Chooncheon, Korea.
Suk Hoon
SH
Ohn
ILSONG Institute of Life Science, Hallym University, Anyang, Korea.
Jeonghoon
J
Hong
Hallym Institute of Translational Genomics & Bioinformatics, Hallym University Sacred Heart Hospital, Anyang, Korea. ; ILSONG Institute of Life Science, Hallym University, Anyang, Korea. ; Department of Neurology, Hallym University Sacred Heart Hospital, Anyang, Korea.
Yun Joong
YJ
Kim
Department of Physical Medicine and Rehabilitation, Hallym University College of Medicine, Chooncheon, Korea. ; Hallym Institute of Translational Genomics & Bioinformatics, Hallym University Sacred Heart Hospital, Anyang, Korea.
Woo-Kyoung
WK
Yoo
Catechol-O-methyltransferase; Genetic polymorphism; Motor cortex; Neuronal plasticity; Transcranial Magnetic Stimulation