Tinnitus can be caused by a variety of different conditions, including age-related hearing loss, circulatory system problems and build-up of earwax.
The study, published in JAMA Otolaryngology-Head & Neck Surgery, assesses the use of repetitive transcranial magnetic stimulation (rTMS), delivered with a coil to the patient's scalp.
"We do not believe that rTMS should be viewed as a replacement for effective tinnitus management strategies that are available now," write the authors. "Instead, rTMS could augment existing tinnitus therapies and provide a viable option for patients who do not respond favorably to other treatments."
Tinnitus is the perception of noise or ringing in the ears without a source. The problem affects around 1 in 5 people and is a symptom of underlying conditions such as age-related hearing loss and ear injuries.
Current forms of treatment for tinnitus include noise suppression, medications to alleviate the symptom's severity and targeting underlying health conditions that may be behind the problem.
Of those who experience chronic tinnitus, around 20% report that their problem is "clinically significant," negatively affecting their quality of life. Due to its disruptive characteristics, many scientists have researched potential new forms of treatment for tinnitus for decades.
Previous studies have indicated that people with tinnitus have increased activity in the auditory cortex region of the brain compared with people unaffected by the symptom. Low-frequency rTMS is known to reduce brain activity in targeted regions and, as a result, has been proposed as a potential method of treatment for tinnitus.
To test this hypothesis, Robert L. Folmer - of the Portland Veterans Affairs Medical Center and Oregon Health & Science University, Portland - and colleagues randomly assigned 70 patients with tinnitus to receive either active or placebo rTMS.
Treatment shows potential as future therapy for chronic tinnitus
The treatment was administered in the form of 2,000 pulses per session over the duration of 10 consecutive work days. The researchers conducted follow-up assessments after 1, 2, 4, 13 and 26 weeks from the final rTMS treatment session, with tinnitus severity measured using the Tinnitus Functional Index (TFI).
Patients receiving active rTMS experienced a 31% reduction in their tinnitus at the 26th week after treatment compared with their tinnitus at the start of the study. In comparison, patients receiving placebo rTMS as a whole only experienced a 7% reduction.
A total of 56% of participants in the active rTMS group (18 out of 32) responded to the treatment, in comparison with 22% of the placebo group (7 out of 32).
The authors believe that their findings are promising although limited by the small size of the study. They intend to expand the trial to address further questions such as whether the improvements to tinnitus last for 12 months or longer, what number of rTMS sessions are optimal and what factors influence whether the treatment is effective or not.
Also of interest is whether reducing the intensity of the placebo rTMS will reduce the number of patients who respond to the treatment. The researchers state that as seven patients receiving placebo treatment experienced improvement in their tinnitus, it is possible the treatment was not a completely inert placebo.
"If rTMS continues to demonstrate efficacy as a treatment for tinnitus, future investigations should include multisite clinical trials," suggest the authors. "If these larger clinical trials replicate efficacy of rTMS that has been demonstrated in the present study, then steps should be taken to implement the procedure as a clinical treatment for chronic tinnitus."
Somewhat surprisingly, a study published last year found that women who consume more caffeine are less likely to have tinnitus.