Written by Joyce Smith, BS. Compared to previous studies, this study suggests that bimodal neuromodulation, using higher-frequency tones with synchronized or shorter delayed tongue stimulation, delivers a more sustained therapeutic benefit for tinnitus.
Tinnitus is a phantom auditory perception of ringing in the ears and, while bothersome for up to 30% of our adult population, the symptoms can become incapacitating for 6% of the referenced population, thus making it a major health issue today 1,2. To date there are no clinical treatments for tinnitus 3; however, research on animals and pilot human studies have shown that bimodal neuromodulation, when combining sound and electrical somatosensory stimulation 4 (including tongue stimulation) 5, can benefit sufferers by promoting brain placidity and improving tinnitus.
To better study bimodal neuromodulation in humans, a randomized, double-blinded, exploratory study 6 enrolled 326 adults with chronic subjective tinnitus. The study’s main objective was to establish further safety and efficacy data based on a previous pilot study in humans 7 in which paired sound and electrical tongue stimulation provided significant improvements in tinnitus symptoms. To that end, participants were randomized into three treatment arms (1:1:1) with three different stimulation settings to explore which stimulation parameters contributed to the therapeutic effects. Treatment was self-administered by participants at home using the device for a recommended 60 min/day with a minimum compliance criterion of 36 hours over the full treatment period.
The tinnitus treatment device consisted of wireless (Bluetooth) headphones that deliver sequences of audio tones layered with wideband noise to both ears, combined with electrical stimulation pulses delivered to 32 electrodes embedded in a small non-invasive device placed on the tip of the tongue. Each participant received training in the use of a handheld device that controlled the timing, intensity, and delivery of the stimuli. Before the first time use, researchers had the device configured to the patient’s hearing profile and optimized to the patient’s sensitivity level for tongue stimulation. Participants were instructed to use the device for 60 minutes daily for 12 weeks.
Of the 326 enrolled participants, 83.7% used the device at or above the minimum compliance level of 36 hours over the 12-week treatment period. Upon treatment completion, participants returned their device and were assessed at three visits over the following 12-month period. Overall, participants achieved a statistically significant reduction in tinnitus symptom severity at the end of treatment based on two commonly used outcome measures, the Tinnitus Handicap Inventory (Cohen’s d effect size: −0.87 to −0.92 across treatment arms; P < 0.001) and the Tinnitus Functional Index (−0.77 to −0.87; P < 0.001). After 12 weeks of treatment (more than 81% of participants) and at 12 months after treatment, more than 77% out of approximately 151 participants experienced an improvement in tinnitus symptoms while the remaining approximately 20% of participants experienced no change. There was also a trend towards greater improvement for those who had more severe symptoms at baseline. Exit surveys revealed that 67% of participants (n=272) felt they had benefited from using the device while 77.8% (n=270) said they would recommend the treatment to other people with tinnitus. These positive responders also exhibited a greater reduction in tinnitus symptoms compared to those who responded “no”. Hopefully, these encouraging long-term results will lead to additional clinical trials that will further validate the merits of bimodal neuromodulation as an effective treatment device for tinnitus.
Source: Brendan Conlon et al. Bimodalneuromodulation combining sound and tongue stimulation reduces tinnitus symptoms in a large randomized clinical study, Science Translational Medicine (2020). DOI: 10.1126/scitranslmed.abb2830
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Posted December 1, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Heller AJ. Classification and epidemiology of tinnitus. Otolaryngologic clinics of North America. 2003;36(2):239-248.
- McCormack A, Edmondson-Jones M, Somerset S, Hall D. A systematic review of the reporting of tinnitus prevalence and severity. Hearing research. 2016;337:70-79.
- Cima RFF, Mazurek B, Haider H, et al. A multidisciplinary European guideline for tinnitus: diagnostics, assessment, and treatment. Hno. 2019;67(Suppl 1):10-42.
- Marks KL, Martel DT, Wu C, et al. Auditory-somatosensory bimodal stimulation desynchronizes brain circuitry to reduce tinnitus in guinea pigs and humans. Sci Transl Med. 2018;10(422).
- Markovitz CD, Smith BT, Gloeckner CD, Lim HH. Investigating a new neuromodulation treatment for brain disorders using synchronized activation of multimodal pathways. Sci Rep. 2015;5:9462.
- Conlon B, Langguth B, Hamilton C, et al. Bimodal neuromodulation combining sound and tongue stimulation reduces tinnitus symptoms in a large randomized clinical study. Sci Transl Med. 2020;12(564).
