Different bimodal neuromodulation settings reduce tinnitus symptoms in a large randomized trial.

More than 10% of the population suffers from tinnitus, which is a phantom auditory condition that is coded within the brain. A new neuromodulation approach to treat tinnitus has emerged that combines sound with electrical stimulation of somatosensory pathways, supported by multiple animal studies demonstrating that bimodal stimulation can elicit extensive neural plasticity within the auditory brain. More recently, in a large-scale clinical trial, bimodal neuromodulation combining sound and tongue stimulation drove significant reductions in tinnitus symptom severity during the first 6 weeks of treatment, followed by diminishing improvements during the second 6 weeks of treatment. The primary objective of the large-scale randomized and double-blinded study presented in this paper was to determine if background wideband noise as used in the previous clinical trial was necessary for bimodal treatment efficacy. An additional objective was to determine if adjusting the parameter settings after 6 weeks of treatment could overcome treatment habituation effects observed in the previous study. The primary endpoint at 6-weeks involved within-arm and between-arm comparisons for two treatment arms with different bimodal neuromodulation settings based on two widely used and validated outcome instruments, Tinnitus Handicap Inventory and Tinnitus Functional Index. Both treatment arms exhibited a statistically significant reduction in tinnitus symptoms during the first 6-weeks, which was further reduced significantly during the second 6-weeks by changing the parameter settings (Cohen's d effect size for full treatment period per arm and outcome measure ranged from - 0.7 to - 1.4). There were no significant differences between arms, in which tongue stimulation combined with only pure tones and without background wideband noise was sufficient to reduce tinnitus symptoms. These therapeutic effects were sustained up to 12 months after the treatment ended. The study included two additional exploratory arms, including one arm that presented only sound stimuli during the first 6 weeks of treatment and bimodal stimulation in the second 6 weeks of treatment. This arm revealed the criticality of combining tongue stimulation with sound for treatment efficacy. Overall, there were no treatment-related serious adverse events and a high compliance rate (83.8%) with 70.3% of participants indicating benefit. The discovery that adjusting stimulation parameters overcomes previously observed treatment habituation can be used to drive greater therapeutic effects and opens up new opportunities for optimizing stimuli and enhancing clinical outcomes for tinnitus patients with bimodal neuromodulation.

A randomised, double-blind, placebo-controlled parallel trial of closed-loop infraslow brain training in food addiction.

The posterior cingulate cortex (PCC) is involved in food craving in obese food addicted individuals. This randomised, double-blind, placebo-controlled parallel study explored the potential therapeutic effects of infraslow neurofeedback (ISF-NF) on food craving targeting the PCC in obese women with symptoms of food addiction. Participants received six sessions of either ISF-NF (n = 11) or placebo (n = 10) over a three-week period. There were no reported adverse effects. Electrophysiologically, there were significant increases in infraslow activity (p = 0.0002) and infraslow/beta nesting (p < 0.001) in the PCC in the ISF-NF group (mean r = 0.004 ± 0.002) compared to placebo (mean r = 0.02 ± 0.002) two days after the last intervention. Also, there was a significant decrease in different dimensions of state food craving compared to baseline and to placebo. Findings suggest that source localized IFS-NF results in electrophysiological changes and may be associated with reduced food craving. This trial is registered at www.anzctr.org.au , identifier, ACTRN12617000601336. This study was funded by the Otago Medical Research Grant: CT375.

High definition transcranial pink noise stimulation of anterior cingulate cortex on food craving: An explorative study.

Dysfunctional neural activity in the cortical reward system network has been implicated in food addiction. This is the first study exploring the potential therapeutic effects of high definition transcranial pink noise stimulation (HD-tPNS) targeted at the anterior cingulate cortex (ACC) on craving and brain activity in women with obesity who showed features of food addiction (Yale Food Addiction Scale score of ≥3). Sixteen eligible females participated in a randomized, double-blind, parallel group study. Participants received six 20-minute sessions of either 1 mA (n = 8) or sham (n = 8) stimulation with HD-tPNS over two weeks. Anode was placed above the ACC (Fz) with 4 cathodes (F7, T3, F8, and T4). Food craving was assessed using the Food Cravings Questionnaire State (FCQ-S) and brain activity was measured using electroencephalogram (EEG). Assessments were at baseline, and two days, four weeks, and six weeks after stimulation. A 22% decrease (mean decrease of -1.11, 95% CI -2.09, -0.14) was observed on the 5-point 'intense desire to eat' subscale two days after stimulation in the HD-tPNS group compared to sham. Furthermore, whole brain analysis showed a significant decrease in beta 1 activity in the ACC in the stimulation group compared to sham (threshold 0.38, p = 0.04). These preliminary findings suggest HD-tPNS of the ACC transiently inhibits the desire to eat and, thus, warrants further examination as a potential tool in combating food craving.