Advances in acupuncture treatment for tinnitus

Tinnitus represents a significant challenge in modern medicine, affecting more than 740 million people globally with a prevalence of 14.4% in adults. This review article examines advances in the treatment of tinnitus through acupuncture, an ancient therapy from Traditional Chinese Medicine that has gained scientific recognition for its clinical benefits. Tinnitus manifests as an abnormal perception of sound in the absence of external acoustic stimuli, causing a significant impact on patients' quality of life, mental health, and well-being. The condition can be classified as subjective (perceived only by the patient) or objective (also audible to the examiner), with different pathophysiological mechanisms involved.

The COVID-19 pandemic intensified the prevalence of the problem, with 24.3% to 40% of patients reporting worsening symptoms and 10% developing new-onset tinnitus after infection. The pathophysiology of tinnitus involves complex alterations in central and peripheral auditory pathways, including imbalance between neural excitation and inhibition, maladaptive neuroplastic changes, and neural hyperactivity across multiple brain regions. These mechanisms result in reorganization of functional brain networks, affecting not only auditory areas but also limbic and non-auditory cortical regions. Acupuncture demonstrates efficacy across multiple technical modalities.

Traditional manual acupuncture shows significant improvement in tinnitus disability and severity scores. Electroacupuncture produces results superior to simple manual acupuncture, while auricular acupuncture offers good long-term efficacy, especially in older patients. Needle retention time also influences outcomes, with studies indicating greater efficacy at 20 and 60 minutes of retention. The mechanisms of action of acupuncture in the treatment of tinnitus involve multiple neurobiological pathways.

Regulation of cortical hemodynamic activity is a central mechanism, with acupuncture modulating cerebral blood flow in hyperactive auditory regions. Patients with tinnitus show a compensatory increase in cortical excitability and cerebral blood flow, and acupuncture appears to normalize these parameters through promotion of neuroplasticity in injured cortical areas. Rebalancing of the nervous system represents another important mechanism. Acupuncture modulates neural plasticity through stimulation of sensory receptors, transmitting nerve impulses that rebalance the neurophysiological system.

Treatment suppresses abnormal excitation in the auditory cortex and regulates autonomic balance between sympathetic and parasympathetic systems, which is crucial in modulating tinnitus symptoms. Regulation of functional connectivity between brain regions constitutes a third relevant mechanism. Tinnitus involves dysfunctions across multiple central pathways with alterations in functional connectivity, including expansion and increased activity in auditory and non-auditory regions. Acupuncture demonstrates the ability to modulate this aberrant connectivity, particularly between the amygdala and superior frontal gyrus, regulating neuronal activity and improving symptoms and associated emotional features.

Modulation of the inflammatory response also contributes to therapeutic effects. Patients with tinnitus show elevations in inflammatory markers such as TNF-α, interleukin-1β, and vascular adhesion molecules. Acupuncture appears to exert anti-inflammatory effects, reducing these mediators and protecting vascular endothelial cells against oxidative stress. For objective tinnitus, although less studied, evidence suggests that acupuncture may be effective by treating underlying causative conditions, such as temporomandibular disorders, myoclonus, and vascular alterations.

The review identifies several limitations in current research, including small sample sizes, variable methodological quality, and a lack of standardization in treatment protocols. Future studies should expand sample size, include more types of tinnitus, increase experimental research in animal models, and more thoroughly explore therapeutic mechanisms. The clinical implications are promising, suggesting that acupuncture offers a safe, cost-effective, and effective therapeutic alternative for patients with tinnitus, particularly given the limited conventional options available.