This trial was a randomized, single-blinded, sham-controlled study, in which the patients were blinded to treatment assignment. First, all candidates underwent audiological testing of hearing thresholds, tympanometry and stapedius reflex tests. The patients who were selected for the study were interviewed to assess and evaluate their condition and then underwent a detailed physical examination that included a complete otorhinolaryngologic examination and a complete blood test. Then, the subjects were randomized to undergo true or sham ACP. Seven days before (baseline) and seven days after twelve acupuncture (ACP) sessions (up to six weeks), which were performed twice a week, all participants underwent 99mTc-ECD SPECT scanning and completed the Portuguese version of the Tinnitus Handicap Inventory (THI), the Visual Analogue Scale (VAS), Hamilton Anxiety Scale (HAS) and the Beck Depression Inventory (BDI). The purpose of this study was to integrate the neuroscience research findings with the clinical research on tinnitus. Thus, a randomized, single-blinded, placebo-controlled trial was implemented to investigate the effect of ACP as a treatment for tinnitus using ethylcysteine dimer single-photon emission computer tomography (99mTc-ECD SPECT).

Acupuncture (ACP) is frequently used to treat tinnitus, the condition defined as the perception of sound in the absence of an external auditory stimulus. However, no information is available regarding the consequences of ACP on the neural architecture and functionality of the brain in tinnitus patients. The aim of this study was to investigate changes in brain activity using ethylcysteine dimer single-photon emission computer tomography (99mTc-ECD SPECT) in patients with tinnitus and normal hearing who underwent ACP treatment. Methods and Findings: This was a randomized, single-blinded, sham-controlled study. The participants were adults (18-60 years old) with either normal hearing or chronic, idiopathic and continuous (+ 3 months) tinnitus. Fifty-seven (57) subjects were randomized to receive true (n=30) or sham (n=27) ACP, and 99mTc-ECD SPECT exams were performed seven days before (baseline) and seven days after twelve ACP sessions (up to six weeks), which were performed twice a week. Secondary outcomes included changes in the Tinnitus Handicap Inventory (THI), the Visual Analog Scale (VAS), the Hamilton Anxiety Scale (HAS) and the Beck Depression Inventory (BDI). Data regarding imaging outcomes were analyzed with Statistical Parametric Mapping (SPM8) software using a factorial design. For secondary outcomes, regression models were built considering two different analytical paradigms: intention-to-treat (ITT; where multiple imputations were conducted due to loss to follow-up) and complete cases. No significant differences in brain perfusion were observed between patients who underwent true versus sham ACP treatment. However, a significant improvement in THI scores at the end of true ACP treatment was observed for all domains (all p < 0.001), with the exception of the catastrophic field. For the other outcome measurements (VAS, BDI and HAS), no significant differences were observed between groups. The small sample size represents a potential limitation of this study. Conclusions: These findings suggest that ACP may improve the impact of tinnitus on daily life, although additional studies are needed to verify the consequences of ACP on the neural architecture and functionality of the brain in tinnitus patients.

Inclusion Criteria:

Patients who met all the following conditions were considered for inclusion:

• 18 to 60 years of age
• Existence of typical conditions of subjective and continuous tinnitus, either unilateral or bilateral, for more than three months
• Normal hearing sensitivity in the conventional audiometric range (up to 25 dB from 250 to 8000 Hz) bilaterally and normal immittance measures (type A curve) in both ears

Exclusion Criteria:

The exclusion criteria were as follows:

• Objective, acute or intermittent tinnitus
• History of Ménière's disease
• Tinnitus induced by cerebellopontine angle tumors, cardiovascular disease, or a serious medical or mental illness
• History of central nervous system disease
• Current pregnancy or breast-feeding
• Patients with a lack of willingness or availability to cooperate were also excluded.