Definition of Idiopathic Tremor Tremor is a rhythmic and unconscious reciprocal muscle activity anywhere in the body and is one of the most common and widespread movement disorders. Overview Idiopathic tremor is a disorder characterized by postural and motor tremor, and is one of the most common disorders in which tremor is the clinical manifestation, with a prevalence of about 1%, no gender differences, a “bimodal” onset in adolescence or early adulthood, and a family history of tremor in more than 50%-70% of patients. Most patients have mild symptoms. Clinical manifestations Generally speaking, tremor is a single symptom, the frequency of tremor is 4-12HZ, the tremor is postural or action, and it is not obvious when it is relaxing, the tremor of the upper limbs is common, followed by the head, the lower limbs, and the voice, the tremor is often firstly seen in the unilateral upper limbs, and then it will soon be involved in the opposite side of the upper limbs, the symptom is slow progressing, and the tremor is intermittent at the beginning, and is only seen when it is emotionally tense, and it can be persistent after that. The symptoms progress slowly, starting intermittently, only in times of emotional stress, and then persisting. Symptoms are intermittent at first, only seen during emotional stress, and may persist later. Symptoms are aggravated during emotional stress or stress, and the tremor amplitude increases. Symptoms are reduced or disappear after sleep, mainly affecting the fine movements of the dominant hand, and symptoms are reduced after moderate alcohol intake, with no Parkinsonian manifestations, such as rigidity and slowness of movement. Diagnosis The diagnosis is mainly based on family history and clinical manifestations, with no specific laboratory tests and negative CT/MRI of the head. The primary diagnostic criteria are postural or locomotor tremor of the hands or forearms, simple head tremor without torsion, and no neurologic signs other than cogwheeling. Secondary diagnostic criteria are a long history of the disease (>3 years). Family history, reduced symptoms with alcohol consumption, exclusion criteria, unilateral resting tremor, rigidity, bradykinesia, sudden onset of tremor Differential Diagnosis Parkinson’s disease (unilateral onset, resting tremor, bradykinesia, tonicity) Cerebellar tremor (ataxia, speech disorders, MRI) Dystonic tremor (abnormally asymmetric contraction of muscles) Diseases of the internal system (hyperthyroidism, hepatic encephalopathy, etc.) Psychogenic tremor (small amplitude, high frequency) Pharmacologic and surgical treatment of idiopathic tremor Most patients have mild symptoms that do not require treatment; initial onset can be treated with medication or moderate alcohol consumption depending on the occasion. When symptoms persist, regular medication is needed, propranolol, pramipexole; surgery may be considered if medication is not effective. Medication β-adrenergic receptor blockers: propranolol, more significant improvement in upper limb tremor (50%-60%), 5-10mg/dose, 3 times/day to start, gradually increasing the dosage, can be up to 320mg/d. Side effects: bradycardia, hypotension, weakness, nausea, vomiting, etc. Contraindications: cardiac insufficiency, Second or third degree AV block, asthma or other bronchospasm disorders, if unable to tolerate propranolol try other similar medications such as alopecia Aromatizole Paromidone likewise improves upper extremity tremor significantly (50%-70%), start at 62.5mg/day and gradually increase dosage up to 250mg/dose, 3x/d Side effects: heavier response to the first dose, but can be gradually tolerate nausea, vomiting, ataxia, vertigo. Propranolol and pramipexole have similar efficacy and may be more effective in combination. Second-line drugs: topiramate, gabapentin, benzodiazepines. Surgery Stereotactic thalamic disruption, started in 1950, accurately localized to the ventral intermediate nucleus of the thalamus, thermocoagulation disruption, the effect is obvious, the shortcomings are irreversible surgical complications. Deep Brain Stimulation (DBS) of the VIM, with a 90% effectiveness rate, was started in 1990, when electrodes were implanted into the ventral intermediary nucleus (VIM) of the thalamus through stereotactic surgery, and electrical impulses were delivered to the VIM to modulate the electrical activity of the neural circuits to ameliorate the symptoms, which was similar to the disruption procedure, but it was reversible, adjustable, and safer, and it has been reported in the literature to be effective in 90% of the patients. Deep Brain Electrical Stimulation The equipment used for deep brain electrical stimulation, also known as a pacemaker in clinical practice, consists of three parts – the first part is the electrode implanted in the brain, which is implanted in the nucleus accumbens through stereotactic surgery, and the other end of the electrode is led out to the outside of the skull; the second part is the pulse generator located in the chest, which is designed to send electrical pulses; the third part connects the two; the third part connects the two, which is designed to send electrical pulses. The extracranial part of the electrode and the extension lead are buried under the patient’s skin. Surgical Procedure of Deep Brain Stimulation: 1) Installation of the base ring of the stereotactic head frame in the preoperative preparation room; 2) CT or MRI scanning to obtain images; 3) Surgical planning and calculation of the target coordinates; 4) Incision of the frontal scalp and drilling of the bone holes under local anesthesia; 5) Microelectrode recordings to confirm the target position; 6) Intraoperative stimulation test; 7) Implantation of the Deep Brain Stimulation and immobilization; 8) Implantation of the thoracic pulse generator and extension leads. Implantation of thoracic pulse generator and extension leads. Stereotactic VIM electrode implantation requires accurate, specialized stereotactic equipment for CT or MRI visualization of the localization frame, MRI-guided target identification, intraoperative electrophysiological target characteristic signals, and intraoperative electrical stimulation for temporary treatment. Postoperative electrical stimulation therapy: After 20-30 days of rest, electrical stimulation should be turned on after the surgery. Continuous electrical stimulation is needed to control the symptoms, and some patients choose to turn off the electrical stimulation after going to sleep in order to save electricity, and the parameters of the electrical stimulation can be adjusted according to the patient’s symptomatic changes, and VIM electrical stimulation can be effective in the treatment of idiopathic tremor in the long term. Conclusion Idiopathic tremor is one of the most common dyskinesia disorders, usually with minor symptoms, but also causing impaired motor function. Propranolol and pramipexole are first-line drugs for the treatment of idiopathic tremor, but the overall effectiveness of drug therapy is 50%. For medically refractory idiopathic tremor, deep brain electrical stimulation of the VIM nucleus of the thalamus should be considered, with an effectiveness rate of 90%.