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Electrical Brain Stimulation to Treat Neurological Disorders
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
DC brain polarization is not “stimulation” in the same sense as the stimulation of the brain and nerves with conventional electrical techniques at much higher electric fields. It does not appear to cause nerve cell firing on its own and does not produce discrete effects such as the muscle twitches associated with classical stimulation. It is also important to distinguish it from electroconvulsive therapy, which is used to treat mental illnesses such as major depression by passing pulses of approximately 1 Amp and fields of 1000 Volt/m into the brain in order to provoke an epileptic seizure. One of the first clinical applications of tDCS was for treatment of hemiparesis (motor paralysis) following stroke. Currently, tDCS is being studied for the treatment of a number of conditions including stroke, migraine,10 and major depression.
Medical device implants for neuromodulation
Published in Ze Zhang, Mahmoud Rouabhia, Simon E. Moulton, Conductive Polymers, 2018
Electrical stimulation methods are invasive when they are implanted in the brain or body, and noninvasive when they are placed on the exterior of the brain or body. DBS is an example of an invasive method, in that a surgically implanted, battery-operated medical device delivers electrical stimulation to the targeted area. Examples of noninvasive neuromodulation are transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). In TMS, pulses of electric current are delivered to a coil placed on the patient’s head to generate an electric field in the brain via electromagnetic induction. tDCS, on the other hand, influences the resting membrane potential of neurons to modulate their spontaneous firing rates. Two or more electrodes are positioned over the scalp and a weak direct current flows through the skull into the cerebral cortex. The current enters the brain through an anode, exits through a cathode, and depolarizes or hyperpolarizes neurons in the targeted region, depending on the polarity. Although there have been reports of therapeutic benefits for neurological and psychiatric disorders using noninvasive approaches (Fitzgerald and Daskalakis 2011; Fregni et al. 2006), the efficacy of the methods has not been established, and in some cases, the approaches are controversial (Horvath et al. 2014).
Introduction to Noninvasive Therapies
Published in Robert B. Northrop, Non-Invasive Instrumentation and Measurement in Medical Diagnosis, 2017
We have seen in the previous section how certain brain volumes can be noninvasively stimulated by time-varying, transcranial magnetic fields that cause the creation of electric fields and circulating currents in the underlying, nonhomogeneous volume conductor formed by cortical neurons. In this section, we will describe the NI stimulation of brain tissues by DC applied through electrodes directly attached to the scalp. tDCS is used for safe neurostimulation therapy for the treatment of depression, obsessive–compulsive disorder, migraine, insomnia, and chronic pain (e.g., caused by fibromyalgia) (Mendonca et al. 2011, Mueller 2015). A typical tDCS therapy consists of five 20 min sessions over five consecutive days, Monday through Friday. Sometimes a second series of five sessions may be necessary (Mueller 2015). tDCS affects brain activity: measured with FMRI or PET, it has been found that cortical neurons under the DC (+) anode have their activity raised by ∼20%–40% when the current density under the anode exceeds 40 μA/cm2. At the (−) cathode, at the same current density, brain function is reduced by 10%–30% (Siever 2013).
Towards Human Objective Real-Time Trust of Autonomy Measures for Combat Aviation
Published in The International Journal of Aerospace Psychology, 2023
Patrick Highland, Thomas Schnell, Katharine Woodruff, Gianna Avdic-McIntire
There are many other measures of trust that are not suited for operationally relevant live-flight. For MWL-based trust measures not used, Functional Near Infrared Spectroscopy (fNIRS) showed promise as an objective workload measure. However, as of 2016, the technology was still too intrusive to fit under a typical military flight helmet (McKendrick et al., 2016). Other objective measures of MWL are also not suitable in the live-flight environment for a variety of reasons and are summarized in the work of Mehta and Parasuraman (2013). For a MWL measure technique to be suitable, it would have to be characterized as, “Portability/mobility – High.” The only other technique that fit that criteria was transcranial Direct Current Stimulation (tDCS). tDCS involves stimulating regions of the brain with low-level direct current to affect a change. Recent research has shown that the same tDCS application to different subjects can produce performance improvements in some and performance decrements in others. Research has not been conducted into how to tailor tDCS to individual outcomes. As a result, the use of tDCS in team-based military applications (such as WVRAC) was not recommended by researchers in 2019 (Davis & Smith, 2019).
Acute effects of transcranial direct current stimulation on cycling and running performance. A systematic review and meta-analysis
Published in European Journal of Sport Science, 2022
Fernando Shyamali Kaushalya, Salvador Romero-Arenas, Amador García-Ramos, David Colomer-Poveda, Gonzalo Marquez
tDCS is a neuromodulatory technique that transiently modulate the neuron resting membrane potential and consequently increase (anodal) or decrease (cathodal) the excitability of the targeted brain area by applying a very low direct current from electrodes placed on the scalp. It has been suggested that the potential mechanism underlining the ergogenic effect of anodal-tDCS on endurance motor performance could be related to improved cortical excitability within the primary motor cortex which in turn lead to decreases in supraspinal fatigue and rating of perceived exertion. Our meta-analysis demonstrated that applying anodal-tDCS as a supportive tool in athletes’ performance enhancement can increase time to exhaustion performance during cycling and running exercise task. These findings are extremely related to sports performance, as time to exhaustion is one of the most important factors to define the final effort of many sports such as cycling, running, soccer, basketball, among others. Therefore, tDCS can be considered as a supportive training tool that allowing to enhance training effectiveness athletes and coaches.
The electric brain: do-it-yourself healthcare with transcranial direct current stimulation
Published in Journal of Responsible Innovation, 2018
In 2012, Loo et al. conducted a study on 64 participants with depression in which they used tDCS on the subjects for the purposes of alleviating their depressive symptoms. The researchers applied anodal stimulation to the left dorsolateral prefrontal cortex and cathodal stimulation to the lateral aspect of the contralateral orbit. This stimulation was applied at a voltage of 2 mA for 20 min. The control group for the study had the same arrangement of electrodes, but the applied stimulation was at a voltage of 1 mA for 30 s to give the subject the sensation of stimulation. Both groups were treated every weekday for 3 weeks (15 treatments in total). Although the effects were not seen early on, after 6 weeks the stimulated group had statistically significant (P < .05) improvements in mood when compared to the control group. The researchers found tDCS to be more effective than antidepressants for this group of people. This research suggests that tDCS had the potential to help those who suffer from depression.