Tinnitus has been a part of my life for so long I can’t remember not having it. While it doesn’t seem to bother me the way it does others, it can be very annoying, especially when I’m in a very quiet environment, camping for instance. So it would be incredible if a breakthrough in tinnitus treatment were to come along.
Background. Perception of sound in the absence of an external auditory source is called tinnitus, which may negatively affect quality of life. Anodal transcranial direct current stimulation tDCS of the left temporoparietal area LTA was explored for tinnitus relief. Objective. This pilot study examined tDCS dose current intensity and duration and response effects for tinnitus suppression. Methods. Twenty-five participants with chronic tinnitus and a mean age of 54 years took part. Anodal tDCS of LTA was carried out. Current intensity 1 mA and 2 mA and duration 10 minutes, 15 minutes, and 20 minutes were varied and their impact on tinnitus measured. Results. tDCS was well tolerated. Fifty-six percent of participants 14 experienced transient suppression of tinnitus, and 44% of participants 11 experienced long-term improvement of symptoms overnight—less annoyance, more relaxed, and better sleep. There was an interaction between duration and intensity of the stimulus on the change in rated loudness of tinnitus, F2, 48 = 4.355, P = .018, and clinical global improvement score, F2, 48 = 3.193, P = .050, after stimulation. Conclusions. Current intensity of 2 mA for 20 minutes was the more effective stimulus parameter for anodal tDCS of LTA. tDCS can be a potential clinical tool for reduction of tinnitus, although longer term trials are needed.
Again, this study begs the question: If 2 mA was more effective than 1 mA, why not 3?
P.S. Thanks you know who you are!
Results: Auditory verbal hallucinations were robustly reduced by tDCS relative to sham stimulation, with a mean diminution of 31% SD=14; d=1.58, 95% CI=0.76–2.40. The beneficial effect on hallucinations lasted for up to 3 months. The authors also observed an amelioration with tDCS of other symptoms as measured by the Positive and Negative Syndrome Scale d=0.98, 95% CI=0.22–1.73, especially for the negative and positive dimensions. No effect was observed on the dimensions of disorganization or grandiosity/excitement.
Conclusions: Although this study is limited by the small sample size, the results show promise for treating refractory auditory verbal hallucinations and other selected manifestations of schizophrenia.
Our results indicate that only anodal stimulation of the left prefrontal cortex, but not cathodal stimulation of left DLPFC or anodal stimulation of M1, increases the accuracy of the task performance when compared to sham stimulation of the same area. This accuracy enhancement during active stimulation cannot be accounted for by slowed responses, as response times were not changed by stimulation. Our results indicate that left prefrontal anodal stimulation leads to an enhancement of working memory performance. Furthermore, this effect depends on the stimulation polarity and is specific to the site of stimulation. This result may be helpful to develop future interventions aiming at clinical benefits.
The aim of this study was to assess the differences in the effects induced by tDCS applied to frontal and temporo-parietal areas on phonemic and semantic fluency functional networks in patients with PD.
Sixteen patients were randomized to receive tDCS to left dorsolateral prefrontal cortex (DLPFC) and left temporo-parietal cortex (TPC) in a counterbalanced order. Immediately following stimulation, patients underwent a verbal fluency paradigm inside a fMRI scanner. Changes induced by tDCS in activation and deactivation task-related pattern networks were studied using free-model independent component analyses (ICA).
Functional connectivity in verbal fluency and deactivation task-related networks was significantly more enhanced by tDCS to DLPFC than to TPC. In addition, DLPFC tDCS increased performance on the phonemic fluency task, after adjusting for baseline phonemic performance.
These findings provide evidence that tDCS to specific brain regions induces changes in large scale functional networks that underlay behavioural effects, and suggest that tDCS might be useful to enhance phonemic fluency in PD.
General scientific summary Local electric field distributions generated by transcranial direct current stimulation (tDCS) with an extracephalic reference electrode were evaluated to address the safety issues of extracephalic tDCS. We compared the maximum current density and electric field intensity values generated by six different electrode montages. Our simulation results demonstrated that the electric fields in the brainstem generated by the extracephalic reference were comparable to, or even less than, those generated by the cephalic reference, suggesting that the use of extracephalic reference does not lead to unwanted modulation of brainstem autonomic centers.