Essential tremor is the most prevalent movement disorder in neurologic practice, affecting between 4% and 5% of the world population over age 40, with incidence that progressively increases with aging. Despite its first-line pharmacologic options — propranolol and primidone —, a substantial fraction of patients experiences inadequate response (up to 50% do not respond satisfactorily), limiting adverse effects (bradycardia, hypotension, fatigue with propranolol; sedation and ataxia with primidone), or clinical contraindications that preclude prolonged use. For these patients, therapeutic alternatives are scarce: botulinum toxin offers partial benefit, deep brain stimulation is reserved for severe cases, and no new pharmacologic class has been approved for essential tremor in recent decades.
A network meta-analysis published on March 21, 2026 in Healthcare (MDPI, vol. 14, no. 6, art. 803), by Shi Qingping and colleagues from the Heilongjiang University of Chinese Medicine, offers for the first time a direct comparison among multiple acupuncture modalities for essential tremor. Using the Surface Under the Cumulative Ranking (SUCRA) method, the review ranks the efficacy and safety of each modality — and the results position scalp acupuncture as the intervention with the highest probability of being the most effective.
NETWORK META-ANALYSIS — ESSENTIAL TREMOR
Network meta-analysis design
The network meta-analysis is an extension of the conventional meta-analysis that allows simultaneous comparison of multiple interventions — even those that have never been directly compared in head-to-head clinical trials. For essential tremor, where multiple acupuncture modalities exist (conventional, electroacupuncture, scalp acupuncture, auriculotherapy, thread embedding) and therapeutic combinations, this method is particularly valuable, as it allows ranking all options in a single integrated analysis.
The authors searched 8 electronic databases from inception through October 2025, including 20 randomized clinical trials with 1,067 patients. The evaluated modalities included: conventional (manual) acupuncture, electroacupuncture, scalp acupuncture, auriculotherapy, thread embedding, and various combinations of these techniques with propranolol. The SUCRA (Surface Under the Cumulative Ranking) method was used to rank each intervention by probability of being the most effective — a score from 0% to 100% where higher values indicate greater probability of superiority.
Hierarchy of modalities by SUCRA
The results of the SUCRA analysis reveal a consistent and clinically informative pattern. For overall efficacy rate — the most relevant outcome for clinical practice —, scalp acupuncture led the ranking with a SUCRA of 81.5%, indicating the highest probability of being the most effective intervention among all the evaluated modalities. For reduction of the tremor score by the Fahn-Tolosa-Marin instrument — a more specific measure of tremor severity —, conventional (manual) acupuncture obtained the highest SUCRA, of 76.6%.
All 9 acupuncture modalities analyzed produced significant improvement in the efficacy rate compared with the control group, confirming that the therapeutic effect of acupuncture in essential tremor is not dependent on a single technique. However, the ranking allows optimization of selection: scalp acupuncture to maximize the probability of overall response, and conventional acupuncture to prioritize objective reduction on the tremor scale.
SUCRA RANKINGS BY OUTCOME
Why does scalp acupuncture lead?
Scalp acupuncture uses needles inserted in zones of the scalp topographically correlated with motor and sensory áreas of the cerebral córtex. Its neurophysiologic basis is especially plausible for essential tremor: the cerebellar-thalamic-cortical circuit, whose dysfunction is at the genesis of essential tremor, is accessible by descending cortical modulation pathways that scalp acupuncture activates directly. Functional neuroimaging studies demonstrate that stimulation of the motor zones of the scalp modifies connectivity in this network, reducing the pathologic 4–12 Hz oscillation that characterizes the tremor.
The proposed mechanism involves regulation of GABAergic activity in the thalamus, possibly rebalancing the inhibition that maintains motor circuits in a state of involuntary oscillation. Scalp acupuncture, by directly stimulating the cortical motor representation, produces "top-down" modulation that differs from the predominantly peripheral mechanism of conventional acupuncture — and that may explain its superiority in the global response rate for a centrally originating condition such as essential tremor.
Safety profile
A notable finding of the meta-analysis is the safety profile of acupuncture interventions. Adverse-event analysis demonstrated that acupuncture modalities presented significantly lower incidence of adverse events compared with controls (RR = 0.13; 95% CI: 0.07–0.25; p < 0.00001) — that is, an 87% reduction in incidence of adverse events. This datum is particularly relevant for essential tremor, a chronic condition that requires long-duration treatment, where the safety profile is determinant for therapeutic adherence.
Frequently Asked Questions
Scalp acupuncture is a technique that uses needles inserted in specific zones of the scalp, correlated with functional áreas of the cerebral córtex (motor, sensory, visual, etc.). Differently from conventional acupuncture — which stimulates points distributed throughout the body along meridians —, scalp acupuncture acts by direct cortical modulation, being particularly indicated for neurologic conditions such as essential tremor, stroke sequelae, and movement disorders. The needles are inserted subcutaneously into the scalp and manipulated with rapid rotation.
The decision to replace should be individualized by the physician. The data of this meta-analysis suggest that acupuncture modalities are effective and safe, with all 9 modalities surpassing control. However, the combination acupuncture + propranolol presented the best safety profile, suggesting that the integrative approach (acupuncture + reduced-dose pharmacotherapy) may be superior to complete replacement. Patients with contraindication to propranolol (asthma, bradycardia, AV block) are natural candidates for acupuncture as monotherapy.
The meta-analysis does not specify a single protocol, given that the 20 RCTs used varied protocols. Based on the included studies and clinical practice, protocols of 8 to 12 weeks with 2 to 3 weekly sessions are the most frequent. Response in essential tremor tends to be more gradual than in painful conditions, given that it involves reorganization of central motor circuits — assessment of response should be made at the end of the complete cycle, not after few sessions.
No. Although both are movement disorders that present with tremor, they are distinct conditions in pathophysiology, presentation, and treatment. Essential tremor is typically postural and kinetic (appears when maintaining a position or during movement), bilateral and symmetric, without associated rigidity or bradykinesia. Parkinson’s disease presents resting tremor, generally asymmetric, accompanied by rigidity, bradykinesia, and postural instability. Correct differential diagnosis is fundamental, as the therapeutic approaches — including acupuncture protocols — are distinct for each condition.
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Healthcare (MDPI)(em inglês)Founded in 1989 by physicians trained at the University of São Paulo (USP) and specialized in China, CEIMEC is a Brazilian national reference in the teaching and practice of medical acupuncture. With more than 3,000 physicians trained over 35 years, it collaborates with HC-FMUSP and is recognized by the Brazilian Medical College of Acupuncture (CMBA/AMB).
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