Biofield Devices
Len Wisneski in The Scientific Basis of Integrative Health, 2017
Transcranial direct current stimulation (tDCS) is an example of a noninvasive electrical stimulation technique, wherein electrodes are placed upon the scalp. The effects of tDCS are dependent on the placement of the electrodes, intensity (0.25–100 Hz; 0–250 μA), and duration of stimulation, and whether anodal (generally excitatory) or cathodal (generally inhibitory) stimulation is applied [221]. tDCS is considered to be neuromodulatory and has been found to increase cognitive performance in tests of attention, memory, problem solving, and other executive functions [222]. Current understanding of the mechanisms of tDCS is, broadly, that stimulation either promotes neuronal hyperpolarization (decreasing excitability) or depolarization (increasing excitability). Interestingly, the neuromodulatory effects of tDCS can endure beyond the period of stimulation and this phenomenon is a function of current strength and duration of stimulation [221].
Electrical Brain Stimulation to Treat Neurological Disorders
Bahman Zohuri, Patrick J. McDaniel in Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Transcranial Direct Current Stimulation (tDCS) is the application of weak electrical currents (1–2 milliamp) and induced electric fields in the brain of order 1 Volt/m to modulate the activity of neurons in the brain.7 Several generations of neurophysiological experiments have shown that neurons respond to static direct current (DC) electrical fields by altering their firing rates. Firing increases when the positive pole or electrode (anode) is located near the cell body or dendrites and decrease when the field is reversed.8 However, when the electrodes are placed on the scalp, the current density produced in the brain is exceedingly small, changing membrane potentials only by a fraction of a millivolt. Much of the current is shunted through the skin and within the brain, trough the cerebral fluid thus limiting the effect on neurons.8
Stimulant Use Disorder
James MacKillop, George A. Kenna, Lorenzo Leggio, Lara A. Ray in Integrating Psychological and Pharmacological Treatments for Addictive Disorders, 2017
Another potential approach to treating stimulant addiction is the use of noninvasive neuromodulation techniques such as repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS). RTMS uses a magnetic field that passes unimpeded through the skull and generates an electrical current in the brain via electromagnetic transduction, depolarizing the neurons in cortex underlying the coil. TDCS applies direct current stimulation to the scalp via an anode and cathode that are placed on the scalp, usually over the dorsolateral prefrontal cortex, right and left. A small amount of current passes through the skull, which then modulates brain activity by changing the resting membrane potential of neurons underlying the cathode and anode; synaptic activity at the neurons may also be changed [138]. In general, low-frequency rTMS is thought to inhibit neuronal activity, while high-frequency rTMS excites neuronal activity [139]. There are four small studies that tentatively suggest a role of rTMS in cocaine use disorder: high-frequency (10 Hz or 15 Hz) rTMS to the left [140, 141], right [142], or medial [143] prefrontal cortex reduces cocaine craving. However, low-frequency rTMS to the left dorsolateral prefrontal cortex was found to increase methamphetamine craving [144]. In two double-blind studies, tDCS (right anodal, left cathodal) to the dorsal lateral prefrontal cortex reduced stimulant craving [145, 146]. Given this trend in the research, high-frequency rTMS and tDCS may provide a useful technique in curbing stimulant use.
HD-tDCS as a neurorehabilitation technique for a case of post-anoxic leukoencephalopathy
Published in Neuropsychological Rehabilitation, 2022
Sarah Garcia, Benjamin M. Hampstead
tDCS uses a low intensity electrical current, delivered via scalp electrodes, to modulate the excitability of brain tissue under and between the electrodes (Bikson et al., 2004). “Traditional” tDCS passes the electricity between two relatively large pads (e.g., 25–35 cm2) – an anode that introduces the current and a cathode that collects it. The current study used High Definition (HD-)tDCS, which provides more focal stimulation delivery by surrounding a small centre electrode with multiple small electrodes of the opposite polarity. This centre electrode uses the full current strength (e.g., 2 mA) while the ring electrodes each use about ¼ of the current (e.g., ∼0.5 mA if 4 electrodes). The neurophysiological effects of HD-tDCS appear to exceed those of the pad-based approach (Kuo et al., 2013; Pelletier & Cicchetti, 2015).
Ethical and Legal Considerations of Alternative Neurotherapies
Published in AJOB Neuroscience, 2021
Ashwini Nagappan, Louiza Kalokairinou, Anna Wexler
Another form of brain stimulation, transcranial direct current stimulation (tDCS), is an experimental technique that provides low levels of electrical current to the brain. There are over 2,000 published studies in the scientific literature, claiming that tDCS may be effective for clinical indications, such as chronic pain and depression (Lefaucheur et al. 2017), as well as for cognitive enhancement indications such as improving memory and learning (Buch et al. 2017; Coffman, Clark, and Parasuraman 2014). However, scholars have criticized the proliferation of small sample-size studies, the absence of longitudinal research (see, e.g., Horvath, Forte, and Carter, 2015; Mancuso et al. 2016; Price and Hamilton, 2015), and have questioned whether electrical current is even reaching the brain (Vöröslakos et al. 2018). tDCS does not have FDA approval in the U.S., nor is it recommended by any professional organization for the treatment of any indication. In addition to tDCS, a variety of other transcranial electrical stimulation techniques are used by providers, such as cranial electrotherapy stimulation (CES), which is FDA-cleared for anxiety, depression and insomnia; a recent review, however, found that there was limited evidence to support its use for these indications (Shekelle et al. 2018).
Transcranial Direct Current Stimulation Reduces the Negative Impact of Mental Fatigue on Swimming Performance
Published in Journal of Motor Behavior, 2022
Elahe Nikooharf Salehi, Saeed Jaydari Fard, Shapour Jaberzadeh, Maryam Zoghi
TDCS is a noninvasive brain stimulation technique that uses a weak (1–2 mA) direct current for up to 20 min. It has been argued that anodal tDCS may increase cortical excitability, whereas cathodal tDCS may decrease cortical excitability (Nitsche et al., 2003). These applications can also modulate the function of deeper cortical structures, such as the ACC (Bellaïche et al., 2013), which is strongly activated during prolonged Stroop task (Lorist et al., 2005; Swick & Jovanovic, 2002). The potential positive effects of tDCS have been evaluated in a variety of neurological disorders (for a review, see (Flöel, 2014)). New research indicates that tDCS can improve a wide range of cognitive functions in healthy individuals (Santarnecchi et al., 2015). Particularly, it has been found that left DLPFC play a key role in motivational function, cognitive control and pacing strategies (MacDonald et al., 2000; Robertson & Marino, 2016). Since it has been suggested that the tDCS parameters e.g electrode montage, duration, intensity, etc are similar for improving attention and reducing mental fatigue, the mechanism may be the same for both (McKinley, 2018). The literature indicate that both anodal and cathodal tDCS over the left DLPFC can be used for improvement of attention, vigilance, accuracy and RT in healthy populations (McKinley et al., 2012; Nelson et al., 2014). Considering the fact that these cognitive abilities are significantly affected by fatigue, we may conclude that there is a clear potential for the use of tDCS for reduction of the negative impact of mental fatigue on athletes.
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