Tremor is an involuntary and repetitive swinging movement of limb, which can be regarded as a periodic disturbance in tremor suppression system based on functional electrical stimulation (FES). Therefore, using repetitive controller to adjust the level and timing of FES applied to the corresponding muscles, so as to generate the muscle torque opposite to the tremor motion, is a feasible means of tremor suppression. At present, most repetitive control systems based on FES assume that tremor is a fixed single frequency signal, but in fact, tremor may be a multi-frequency signal and the tremor frequency also varies with time. In this paper, the tremor data of intention tremor patients are analyzed from the perspective of frequency, and an adaptive repetitive controller with internal model switching is proposed to suppress tremor signals with different frequencies. Simulation and experimental results show that the proposed adaptive repetitive controller based on parallel multiple internal models and series high-order internal model switching can suppress tremor by up to 84.98% on average, which is a significant improvement compared to the traditional single internal model repetitive controller and filter based feedback controller. Therefore, the adaptive repetitive control method based on FES proposed in this paper can effectively address the issue of wrist intention tremor in patients, and can offer valuable technical support for the rehabilitation of patients with subsequent motor dysfunction.
Humans ; Wrist ; Tremor/therapy* ; Movement ; Computer Simulation ; Electric Stimulation

Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel and minimally invasive technology. Since the US Food and Drug Administration approved unilateral ventral intermediate nucleus-MRgFUS for medication-refractory essential tremor in 2016, studies on new indications, such as Parkinson's disease (PD), psychiatric diseases, and brain tumors, have been on the rise, and MRgFUS has become a promising method to treat such neurological diseases. Currently, as the second most common degenerative disease, PD is a research hotspot in the field of MRgFUS. The actions of MRgFUS on the brain range from thermoablation, blood-brain barrier (BBB) opening, to neuromodulation. Intensity is a key determinant of ultrasound actions. Generally, high intensity can be used to precisely thermoablate brain targets, whereas low intensity can be used as molecular therapies to modulate neuronal activity and open the BBB in conjunction with injected microbubbles. Here, we aimed to summarize advances in the application of MRgFUS for the treatment of PD, with a focus on thermal ablation, BBB opening, and neuromodulation, in the hope of informing clinicians of current applications.
Humans ; Parkinson Disease/therapy* ; Brain ; Blood-Brain Barrier ; Essential Tremor/surgery* ; Brain Neoplasms ; Magnetic Resonance Imaging/methods* ; Magnetic Resonance Spectroscopy

Acupuncture Points ; Acupuncture Therapy ; Essential Tremor ; therapy ; Humans ; Male ; Young Adult

OBJECTIVE: In this study, there was an investigation as to whether there is a functional difference in essential tremor (ET), according to responses to beta-blockers, by evaluating regional changes in cerebral glucose metabolism. MATERIALS AND METHODS: Seventeen male patients with ET were recruited and categorized into two groups: 8 that responded to medical therapy (group A); and 9 that did not respond to medical therapy (group B). Eleven age-sex matched healthy control male subjects were also included in this study. All subjects underwent F-18 fluorodeoxyglucose (FDG)-PET, and evaluated for their severity of tremor symptoms, which were measured as a score on the Fahn-Tolosa-Marin tremor rating scale (FTM). The FDG-PET images were analyzed using a statistical parametric mapping program. RESULTS: The mean FTM score 6 months after the initiation of propranolol therapy was significantly lower in group A (18.13 > 8.13), compared with group B (14.67 = 14.67). The glucose metabolism in group A in the left basal ganglia was seen to be decreased, compared with group B. The ET showed a more significantly decreased glucose metabolism in both the fronto-temporo-occipital lobes, precuneus of right parietal lobe, and both cerebellums compared with the healthy controls. CONCLUSION: Essential tremor is caused by electrophysiological disturbances within the cortical-cerebellar networks and degenerative process of the cerebellum. Furthermore, ET may have different pathophysiologies in terms of the origin of disease according to the response to first-line therapy.
Adrenergic beta-Antagonists/*pharmacology/therapeutic use ; Aged ; Brain/*drug effects/metabolism/radiography ; Brain Mapping ; Essential Tremor/*diagnosis/drug therapy/radiography ; Fluorodeoxyglucose F18/*chemistry ; Glucose/*metabolism ; Humans ; Male ; Middle Aged ; *Positron-Emission Tomography ; Propranolol/pharmacology/therapeutic use ; Radiopharmaceuticals/*chemistry

An automatic control system was designed to suppress pathological tremor on wrist joint with two degrees of freedom (DoF) using functional electrical stimulation (FES). The tremor occurring in the wrist flexion-extension and adduction-abduction was expected to be suppressed. A musculoskeletal model of wrist joint was developed to serve as the control plant, which covered four main muscles (extensor carpi radialis longus, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris). A second-order mechanical impedance model was used to describe the wrist skeletal dynamics. The core work was to design the controller and a hybrid control strategy was proposed, which combined inverse model based on feed forward control and linear quadratic regulator (LQR) optimal control. Performance of the system was tested under different input conditions (step signal, sinusoidal signal, and real data of a patient)., The results indicated that the proposed hybrid controller could attenuate over 94% of the tremor amplitude on multi-DoF wrist joint.
Electric Stimulation ; Humans ; Muscle, Skeletal ; physiopathology ; Tremor ; prevention & control ; therapy ; Wrist ; Wrist Joint ; physiopathology

The common marmoset (Callithrix jacchus) is a small-bodied, popular New World monkey and is used widely in reproductive biology, neuroscience, and drug development, due to its comparative ease of handling, high reproductive efficiency, and its unique behavioral characters. In this review, we discuss the marmoset models in Parkinson's disease (PD), which is a neurological movement disorder primarily resulting from a degeneration of dopaminergic neurons with clinical features of tremor, rigidity, postural instability, and akinesia. The most common PD models involve the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6-hydroxydopamine to study the pathogenesis and to evaluate novel therapies. Following the systemic or local administration of these neurotoxins, the marmosets with very severe Parkinson's symptoms are recommended to be placed in an intensive care unit with artificial feeding to increase survival rate. All procedures with MPTP should be conducted in a special room with enclosed cages under negative-pressure by trained researchers with personal protection. Behavioral tests are conducted to provide an external measure of the brain pathology. Along with several biomarkers, including alpha-synuclein and DJ-1, non-invasive neuroimaging techniques such as positron emission tomography and magnetic resonance imaging are used to evaluate the functional changes associated with PD. With the recent growing interest in potential and novel therapies such as stem cell and gene therapy for PD in Korea, the marmoset can be considered as a suitable non-human primate model in PD research to bridge the gap between rodent studies and clinical applications.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine ; alpha-Synuclein ; Animals* ; Biomarkers ; Biology ; Brain Diseases ; Callithrix* ; Dopaminergic Neurons ; Genetic Therapy ; Humans ; Intensive Care Units ; Korea ; Magnetic Resonance Imaging ; Methods* ; Models, Animal ; Movement Disorders ; Neuroimaging ; Neurosciences ; Neurotoxins ; Nutritional Support ; Oxidopamine ; Parkinson Disease* ; Platyrrhini ; Positron-Emission Tomography ; Primates ; Rodentia ; Stem Cells ; Survival Rate ; Tremor

Acupuncture Points ; Acupuncture Therapy ; Adolescent ; Female ; Humans ; Tremor ; therapy

Acupuncture Points ; Acupuncture Therapy ; instrumentation ; methods ; Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; Tremor ; therapy

Adult ; Aged ; Combined Modality Therapy ; Electric Stimulation Therapy ; Electroacupuncture ; Essential Tremor ; therapy ; Female ; Humans ; Male ; Middle Aged

Deep Brain Stimulation ; methods ; Essential Tremor ; therapy ; Female ; Humans ; Middle Aged