• International Journal of Control, Automation, and Systems
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• v.5 no.3
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• pp.337-342
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• 2007

This paper proposes a helmet-type whole-head brain stimulator system considering a realistic head geometry. For more accurate design and computer simulations, a realistic volume conductor model was adopted and the current evoked on human cerebral cortex was analyzed using the boundary element method (BEM). To obtain a more focalized evoked current around the target points, various coil configurations were tested and an average targeting error of about 10 mm was obtained.

• Physical Therapy Korea
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• v.10 no.3
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• pp.17-27
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• 2003

Repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability beyond the duration of the rTMS trains themselves. Depending on rTMS parameters, a lasting inhibition or facilitation of cortical excitability can be induced. Therefore, rTMS of high or low frequency over motor cortex may change certain aspects of motor learning performance and cortical activation. This study investigated the effect of high and low frequency subthreshold rTMS applied to the motor cortex on motor learning of sequential finger movements and brain activation using functional MRI (fMRI). Three healthy right-handed subjects (mean age 23.3) were enrolled. All subjects were trained with sequences of seven-digit rapid sequential finger movements, 30 minutes per day for 5 consecutive days using their left hand. 10 Hz (high frequency) and 1 Hz (low frequency) trains of rTMS with 80% of resting motor threshold and sham stimulation were applied for each subject during the period of motor learning. rTMS was delivered on the scalp over the right primary motor cortex using a figure-eight shaped coil and a Rapid(R) stimulator with two Booster Modules (Magstim Co. Ltd, UK). Functional MRI (fMRI) was performed on a 3T ISOL Forte scanner before and after training in all subjects (35 slices per one brain volume TR/TE = 3000/30 ms, Flip angle $60^{\circ}$, FOV 220 mm, $64{\times}64$ matrix, slice thickness 4 mm). Response time (RT) and target scores (TS) of sequential finger movements were monitored during the training period and fMRl scanning. All subjects showed decreased RT and increased TS which reflecting learning effects over the training session. The subject who received high frequency rTMS showed better performance in TS and RT than those of the subjects with low frequency or sham stimulation of rTMS. In fMRI, the subject who received high frequency rTMS showed increased activation of primary motor cortex, premotor, and medial cerebellar areas after the motor sequence learning after the training, but the subject with low frequency rTMS showed decreased activation in above areas. High frequency subthreshold rTMS on the motor cortex may facilitate the excitability of motor cortex and improve the performance of motor sequence learning in normal subject.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.657-665
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• 2019

In this study, we conducted a study on the transcranial magnetic electrode, a method for the study of dementia and muscle pain, a neurodegenerative disease caused by an aging society, which is becoming a problem worldwide. In particular, transcranial magnetic electrodes have been studied to improve their ability to be deteriorated by dementia symptoms such as speech, cognitive ability, and memory by outputting magnetism deep into the brain using coils on the head epidermis. In this study, simulation was performed using Maxwell 3D program for the design of coil, the core of transcranial magnetic electrode. As a result of the simulation comparison between the coil designed by the previous research and the coil through the research and development, the output was found to be superior to the conventional designed coil. The graphs of the coil outputs of B-Field and H-Field are found to be symmetrical, but the symmetry between each coil is pseudo-symmetrical and not accurate. Based on these results, an experiment was conducted to confirm whether the output of the head epidermis through both coils is possible. In the magnitude field of the reverse-coil 2-coil analysis, the maximum output was 3.3920e + 004 H [A_per_meter], and the vector field showed the strongest magnetic field around 35 to 165 degrees. It was confirmed that the magnetic output canceled due to the magnetic output. In the case of the forward 2-coil, a maximum of 3.2348e + 004H [A_per_meter] similar to the reverse coil was observed, but in the case of the vector field, the magnetic output regarding the forward output and the head skin output was confirmed. However, when the height change in the output coil, the magnetic output was reduced.

• Journal of Yeungnam Medical Science
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• v.11 no.2
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• pp.248-261
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• 1994

This study was undertaken to evaluate the clinical usefulness of magnetic motor evoked potential (MEP) in the diagnosis of stroke and predicting the motor improvement following stroke. The cortical, cervical and lumbar stimulations were performed in the case of 24 healthy controls and 24 ischemic stroke patients. The central motor conduction time (CMCT) was represented by the difference of latency to a target muscle between after transcranial stimulation and after cervical or lumbar stimulation. There was no case showing no response in controls. But in 11 out of 24 ischemic patients, we could not get cortical MEP. Mean CMCT of abductor pollicis brevis muscle was not significantly different in controls and stroke patients in whom MEPs were recorded. There were significant differences between mean CMCT of normal controls and that of stroke patients showing MEPs in AH Muscle. MEP Results from testing the stroke patients were correlated with site of lesion, degree of motor weakness and motor improvement after 1 to 2 months. These results suggest that magnetic MEP is easy and useful in electrophysiological test of central motor pathway and is useful indicator for representing the motor weakness and predicting the motor outcome in acute ischemic stroke patients.

• Annals of Clinical Neurophysiology
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• v.4 no.1
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• pp.81-84
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• 2002

Tetanus is a disorder known to interfere with inhibitory modulation of the motor system in humans. In this report, we describe the characteristic neurophysiological findings in a 52-year-old patient with generalized tetanus. The cutaneous silent period was absent and the silent period evoked in distal upper limb muscles by transcranial magnetic stimulation was shortened. These findings can be interpreted as evidence of impaired inhibitory mechanisms at multiple levels of the nervous system.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.1
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• pp.9-15
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• 2007

Purpose: Repetitive transcranial magnetic stimulation (rTMS) has recently been clinically applied in the treatment of drug resistant depressed patients. There are mixed findings about the efficacy of rTMS on depression. Furthermore, the influence of rTMS on the physiology of the brain is not clear. We prospectively evaluated changes of regional cerebral blood flow (rCBF) between pre- and post-rTMS treatment in patients with drug resistant depression. Materials and Methods: Twelve patients with drug-resistant depression (7 male, 5 female; age range: $19{\sim}52$ years; mean age: $29.3{\pm}9.3$ years) were given rTMS on right prefrontal lobe with low frequency (1 Hz) and on left prefrontal lobe with high frequency (20 Hz), with 20-minute-duration each day for 3 weeks. Tc-99m ECD brain perfusion SPECT was obtained before and after rTMS treatment. The changes of cerebral perfusion were analyzed using statistical parametric mapping (SPM; t=3.14, uncorrected p<0.01, voxel=100). Results: Following areas showed significant increase in rCBF after 3 weeks rTMS treatment: the cingulate gyrus, fusiform gyrus of right temporal lobe, precuneus, and left lateral globus pallidus. Significant decrement was noted in: the precental and middle frontal gyrus of right frontal lobe, and fusiform gyrus of left occipital lobe. Conclusion: Low-frequency rTMS on the right prefrontal cortex and high-frequency rTMS on the left prefrontal cortex for 3 weeks as an add-on regimen have increased and decreased rCBF in the specific brain regions in drug-resistant depressed patients. Further analyses correlating clinical characteristics and treatment paradigm with functional imaging data may be helpful in clarifying the pathophysiology of drug-resistant depressed patients.

• Physical Therapy Korea
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• v.8 no.4
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• pp.91-99
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• 2001

뇌 손상 후 급성기에 기능의 자발적인 회복이 일어나지만 환자들은 환측의 상지를 잘 사용하지 못하게 된다. 그 결과 원하는 움직임을 억제하는 상황을 발생시키는데 이것을 학습 무사용 증후군(learned nonu se syndrome)이라 한다. 이러한 학습 무사용 증후군을 치료하기 위해 억제-유도 치료(constraint-induced therapy)가 고안되었다. 억제-유도 치료는 연속되는 몇 주간에 걸쳐 매일 많은 시간 동안 건측의 상지를 묶어두고 환측 상지를 사용하게 하여 기능을 반복 학습하게 함으로써 기능을 증진시키는 방법이다. 이미 여러 연구자들이 경두개 자기자극(transcranial magnetic stimulation), 움직임 관련 피질전위(movement-related cortical potential), 기능적 자기공명 영상기법(functional magnetic resonance imaging) 등을 통하여 억제-유도 치료 후 운동피질영역에서의 재조직화를 보고함으로써 기능 증진과 관련된 회복 기전을 뒷받침하고 있다. 억제-유도 치료의 영역은 확대되어 뇌졸중, 척수손상, 고관절 치환술 후로 하지에서의 기능증진을 위하여 연구가 진행되고 있으며 특히 뇌졸중 후 실어증 환자에서 새로운 방법으로 제시되고 있다. 따라서, 억제-유도 치료는 신경학적인 손상 후 움직임의 재활에 있어서 치료-유도를 통한 중추신경계의 회복에 효과적으로 작용할 수 있다.

• Annals of Clinical Neurophysiology
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• v.5 no.2
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• pp.187-191
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• 2003

Purpose: MEPs elicited by transmagnetic stimulations of the motor cortex are facilitated by voluntary muscle contraction. We evaluated the effects of the imagination of the movements on latencies of MEPs and reciprocal inhibition by using transmagnetic stimulations. Methods: Twenty two healthy volunteers(eight men and fourteen women) were studied. TMSs were delivered at rest and during imagining abducting or adducting right thumb. A stimulator with a round coil and a fixed intensity of 80% of maximum was used to evoke MEPs. MEPs were evoked by magnetic stimulations over the scalp and cervical spine(C7-T1), and central motor conduction times(CMCT) were calculated by subtracting the latency of compound muscle action potentials(CMAPs) obtained by stimulating over the cervical spine from that obtained by stimulating over the scalp. The motor evoked potentials were recorded from right abductor pollicis brevis muscle(APB) and adductor pollicis muscle(AP) simultaneously. Results: Imagination of abduction resulted in a shortened latency of the CMAPs in APB, and a prolonged latency in AP. Imagination of adduction resulted in a shortened latency in AP, and a prolonged latency in APB. But the imagination caused no significant change in the latency of CMAPs elicited by stimulation over cervical spine. Therefore, the changes of the CMCTs account for these latency changes with imagination of movement. With the imagination of abduction, there are significant reduction of the CMCT's in APB(10.8%) and prolongation in AP(5.8%). On the other hand, with the imagination of adduction, prolongation of the CMCT's in APB(7.3%) and reduction in AP(5.9%) were observed. Conclusion: These findings indicate that imagination of muscle contraction increases the excitability of the human corticospinal system. Reciprocal inhibition may be accountable for the prolonged latency in the antagonist muscle.

• Biomedical Science Letters
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• v.29 no.4
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• pp.263-273
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• 2023

This study aimed to investigate effect of scalp acupuncture (SA) and repetitive transcranial magnetic stimulation (rTMS) intervention on neuromotor function in photothrombotic cerebral infarction (PCI) rat model. Sixty male SD rats were used. PCI was induced on M1 cortex of right frontal lobe. SA was performed at the Qianding (GV21), Xuanli (GB6) acupoints of ipsilesional M1. Low-frequency rTMS was delivered to contralesional M1. All rats were randomly divided into 4 groups: group A, normal (n, 15); group B, PCI without any stimulation intervention (n, 15); group C, PCI with SA (n, 15); group D, PCI with rTMS (n, 15). Rota-rod test and Ladder rung walking test (LWT) were done weekly for 8 weeks after PCI. SA or rTMS was started from post-PCI 4^th day as protocol for 8 weeks. H/E stain and IHC were done. Western blot and qRT-PCR study were performed for MAP2 and BDNF from ipsilesional M1 peri-infarction tissue. Brain MRI study was conducted to quantify the volume of cerebral infarction. As a result, left forelimb and hindlimb function significantly improved more in group C and D than control group, with expressed more BDNF and MAP2. And brain MRI showed focal infarction of right M1 after PCI, and infarction volume progressively decreased in group C and D than group B from post-PCI 5^th to 8^th week. SA or rTMS was more effective than no intervention group on neuromotor function of PCI rat model. The functional recovery was associated with stimulation intervention-related neurogenesis.

• Physical Therapy Korea
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• v.17 no.2
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• pp.17-24
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• 2010

The aim of this study was to determine the effect of action observational physical training (AOPT) on manual dexterity and corticomotor facilitation in stroke patients. Ten hemiparetic patients participated in this study. Each subject was asked to participate the three conditions; base condition (Base), physical training (PT), AOPT. Participants were asked to observe the action in the video that a therapist moved the blocks during the AOPT conditions. Corticomotor facilitation was determined in three conditions by monitoring changes in the amplitude of motor-evoked potentials (MEPs) elicited in hand muscles by transcranial magnetic stimulation. MEP responses were measured from the first dorsal interosseous after participants attended to three conditions. For the manual dexterity, Box and Block test (BBT) was used. The results of present study were summarized as follows: MEPs amplitude significantly tended to be larger than PT and Base condition. The scores of BBT in the AOPT condition were also significantly larger than other conditions. In conclusion, this finding of present study indicates that physical training for observation of an action is beneficial for enhancing a dexterity of paretic arm in stroke patients.