Effects of acupuncture on the outcome of tinnitus: An overview of systematic reviews

Tinnitus, the scientific term for ringing in the ears, is a problem that affects millions of people around the world. It is the perception of sounds such as buzzing, whistling, or humming in the absence of any external auditory stimulus. Studies indicate that approximately 10% of the world's population experiences some degree of tinnitus, with more than 120 million people suffering from severe symptoms. This condition can have significant impacts on patients' quality of life, interfering with sleep, concentration, and emotional well-being.

Currently, there is no definitive cure for primary tinnitus, and no medication has been approved specifically for its treatment by the main regulatory agencies worldwide.

Given this therapeutic gap, several alternative treatments have been explored, including acupuncture. This ancient practice of traditional Chinese medicine has demonstrated potential in the treatment of various conditions, and some studies suggest that it may affect cochlear blood flow and auditory nuclei, possibly explaining its beneficial effects on tinnitus. However, the results of research on acupuncture for tinnitus have been inconsistent, creating uncertainty for both patients and health professionals about its actual efficacy.

To clarify this question, Chinese researchers conducted a comprehensive study that systematically analyzed all scientific reviews previously published on acupuncture for the treatment of tinnitus. This research, published in November 2022, represents a special type of study called an "overview of systematic reviews," which examines multiple scientific reviews to provide a broader perspective on a given topic. The authors searched eight scientific databases, both Chinese and international, collecting information from inception through March 2022. They found 14 systematic reviews that met the established quality criteria, totaling analyses of hundreds of individual clinical studies.

To ensure the reliability of the results, the researchers rigorously evaluated the methodological quality, quality of reporting, and quality of evidence of each included review, using internationally recognized tools. They also calculated the degree of overlap between studies to identify possible duplications that could bias the results.

The main findings revealed a mixed but predominantly positive picture. Of the 14 reviews analyzed, 11 studies (approximately 79%) reported that acupuncture was effective in the treatment of tinnitus, while only three studies failed to reach definitive conclusions about its efficacy. Interestingly, all reviews published in Chinese showed positive results, while three of the five studies published in English presented inconclusive results. This difference may be related to the different populations studied, acupuncture techniques used, and evaluation criteria employed.

Analyses showed that acupuncture demonstrated superiority over conventional pharmacological treatments in several studies. Some research also demonstrated that the combination of acupuncture with medications was more effective than the use of medications alone. Electroacupuncture, a variation that uses electrical stimulation through the needles, also showed promising results compared with both traditional acupuncture and other conventional treatments.

For patients suffering from tinnitus, these results offer cautious hope. Acupuncture emerges as a potentially beneficial therapeutic option, especially considering its noninvasive nature and the relatively favorable safety profile reported in the studies. For health professionals, this evidence suggests that acupuncture may be considered as part of an integrated approach to managing tinnitus, particularly for patients who do not respond adequately to conventional treatments or who prefer non-pharmacological alternatives.

However, it is essential to interpret these results with caution due to important limitations identified in the study. The methodological quality assessment revealed that only one of the 14 reviews had moderate quality, while all others were classified as having very low quality. Common problems included failures in the registration of research protocols, incomplete search strategies, and inadequate statistical analyses. As for the quality of evidence, no outcome was classified as high quality, with the majority being of low or very low quality.

These limitations reflect challenges inherent to research in acupuncture, such as the difficulty in creating truly blinded control groups (since it is impossible to completely "mask" the application of needles) and the variability in techniques and protocols used. In addition, tinnitus is a complex condition with multifactorial causes, and its evaluation largely depends on subjective measures reported by patients themselves, which can introduce bias into the results.

The researchers conclude that, although acupuncture appears to be a positive and effective treatment for tinnitus, the low methodological quality and quality of evidence of the included studies prevent definitive conclusions. This situation highlights the urgent need for higher-quality research in the field. Future investigations should include large-scale, multicenter, randomized controlled clinical trials, with rigorous methodologies, adequate sample sizes, and appropriate control groups. It would also be valuable to standardize acupuncture protocols, including point selection, frequency, and duration of treatments, as well as to develop more objective measures to assess tinnitus improvement.

Only through more robust research will it be possible to definitively establish the role of acupuncture in the therapeutic arsenal against tinnitus and offer patients evidence-based guidance.