Transcranial Direct Current Stimulation (tDCS) for major depression - Interim analysis of cloud supervised technical data from the DepressionDC trial.

BACKGROUND: Transcranial direct current stimulation (tDCS) of prefrontal cortex regions has been reported to exert antidepressant effects, though large scale multicenter trials in major depressive disorder (MDD) supporting this notion are still lacking. Application of tDCS in multicenter settings, however, requires measurement, storage and evaluation of technical parameters of tDCS sessions not only for safety reasons but also for quality control. To address this issue, we conducted an interim analysis of supervised technical data across study centers in order to monitor technical quality of tDCS in an ongoing multicenter RCT in MDD (DepressionDC trial). METHODS: Technical data of 818 active tDCS sessions were recorded, stored in a data cloud, and analysed without violating study blinding. Impedance, voltage and current were monitored continuously with one data point recorded every second of stimulation. RESULTS: Variability of impedance was considerable (1,42 kΩ, to 8,23 kΩ), inter-individually and even more intra-individually, but did not significantly differ between the study centre in Munich and all other sites. CONCLUSION: Measurement, centralized data storage via data cloud and remote supervision of technical parameters of tDCS are feasible and proposed for future RCTs on therapeutic tDCS in multiple settings.

[Improving SNR (signal to noise ratio) in multichannel EEG recording]. / Verbesserung des SNR bei mehrkanaligen EEG-Ableitungen.

The main problem in measurements of the focal VEP (Visual Evoked Potential) is its weak SNR (Signal-to-Noise Ratio). The most common method for enhancement of the SNR is the stimulus synchronized averaging. For study of single responses other ways in SNR improvement are needed. In this contribution a new method based on space-time selective measurement is introduced, which can be interpreted as beaming a signal source. Since the anatomical structures of sources generating the focal VEP are known in general and if the electrode positions are of sufficient density over the visual cortex, a source beamer can be realized by controlling the channels' delays.

Low thyroxine levels in female psychiatric inpatients with riboflavin deficiency: implications for folate-dependent methylation.

Intermediates in the folate-dependent methylation pathways may play a role in the etiology and treatment of such mental disorders as major depression. These pathways include a step dependent on a riboflavin (B2)-derived coenzyme, flavin adenine dinucleotide (FAD), which is reportedly sensitive to thyroid status and to phenothiazine and tricyclic drug exposure. In a sample of 52 male and female acute psychiatric inpatients, 17% (n = 9) showed B2 deficiency (i.e., insufficient FAD activity) on a functional red blood cell enzyme assay, but only one B2-deficient individual showed deficiency in another B-complex vitamin (folate). All patients with B2 deficiency were women, who were also significantly younger than the rest of the sample. The B2-deficient women had significantly lower thyroxine levels, even when controlling for sex and covarying for age. B2-deficient patients exhibited a nonsignificant trend toward more unipolar depression (44% vs 14%), but not toward bipolar or schizophrenic disorders. As in a previous study, drug exposure did not show a relationship to riboflavin deficiency in this sample. The findings suggest that B2 (FAD) activity may serve as a sensitive marker of thyroxine status in certain female psychiatric inpatients and that B2 deficiency may play an etiological role in defects of the methylation pathways in a subset of mentally ill individuals.

Contrast media-induced oliguric renal failure.

Seven patients had acute oliguric renal failure after intravenous urography (2), celiac arteriography (2), or cardiac angiography (3). Diatrizoate meglumine was the contrast media used in all of the cases. These patients had an average age of 63 years and six were 55 years of age or older. Diabetes mellitus, negative fluid balance before the procedure, underlying renal insufficiency, and hypertension were common, being present in three, four, five, and six of the patients respectively . Anuria or oliguria occurred within 24 hours of the procedure and persisted from 36 to 96 hours (72 hours average). The serum creatinine level rose significantly in all of the patients and reached a peak in two to seven days after the procedure. In six patients, recovery was complete by two to three weeks. The seventh patient experienced only partial recovery. These cases taken together with a mounting number of recent reports suggest that contrast media-induced oliguric renal failure is more common than generally believed. Diabetes mellitus, older age, and underlying renal insufficiency seem to be important predisposing factors.

Prolonged hemolysis from overheated dialysate.

A patient with chronic renal failure exposed to overheated dialysate (50 degrees C) for 20 minutes developed evidence of delayed and protracted hemolysis, which continued for several days. By contrast, in the only previously reported similar case, sudden gross hemolysis followed by cardiac arrest occurred. It is emphasized that the rapidity and severity of hemolysis due to thermal injury to erythrocytes are dependent upon the duration of exposure and the height of temperature to which extracorporeal blood is exposed. Methods of preventing such incidents and therapeutic approaches are outlined.