Articles: alpha-rhythm.
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Randomized Controlled Trial Multicenter Study
In pursuit of a sensitive EEG functional connectivity outcome measure for clinical trials in Alzheimer's disease.
In clinical trials in Alzheimer's Disease (AD), an improvement of impaired functional connectivity (FC) could provide biological support for the potential efficacy of the drug. Electroencephalography (EEG) analysis of the SAPHIR-trial showed a treatment induced improvement of global relative theta power but not of FC measured by the phase lag index (PLI). We compared the PLI with the amplitude envelope correlation with leakage correction (AEC-c), a presumably more sensitive FC measure. ⋯ AEC-c may be a robust and sensitive FC measure for detecting treatment effects.
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Randomized Controlled Trial
Targeting reduced neural oscillations in patients with schizophrenia by transcranial alternating current stimulation.
Transcranial alternating current stimulation (tACS) modulates endogenous neural oscillations in healthy human participants by the application of a low-amplitude electrical current with a periodic stimulation waveform. Yet, it is unclear if tACS can modulate and restore neural oscillations that are reduced in patients with psychiatric illnesses such as schizophrenia. Here, we asked if tACS modulates network oscillations in schizophrenia. ⋯ In addition, 10Hz-tACS enhanced the 40Hz auditory steady-state response (ASSR), which is reduced in patients with schizophrenia. Importantly, clinical improvement of auditory hallucinations correlated with enhancement of alpha oscillations and the 40Hz-ASSR. Together, our findings suggest that tACS has potential as a network-level approach to modulate reduced neural oscillations related to clinical symptoms in patients with schizophrenia.
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Int J Psychophysiol · Nov 2016
Randomized Controlled TrialExpectation of nocebo hyperalgesia affects EEG alpha-activity.
Changes in EEG activity have been related to clinical and experimental pain. Expectation of a negative outcome can lead to pain enhancement (nocebo hyperalgesia) and can alter the response to therapeutic interventions. The present study characterizes EEG alteration related to pain facilitation by nocebo. ⋯ Five-minute EEG was recorded under: resting state, tonic innocuous heat and tonic noxious heat before and after the application of a sham inert cream to the non-dominant volar forearm combined with cognitive manipulation. The intensity and unpleasantness of heat-induced pain increased after cognitive manipulation in the nocebo group compared to control and was associated with enhanced low alpha (8-10Hz) activity. However, changes in alpha activity were predicted by catastrophizing but not by pain intensity or unpleasantness, which suggest that low alpha power might reflect brain activity related to negative cognitive-affective responses to pain.
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Randomized Controlled Trial
Static Magnetic Field Stimulation over the Visual Cortex Increases Alpha Oscillations and Slows Visual Search in Humans.
Transcranial static magnetic field stimulation (tSMS) was recently introduced as a promising tool to modulate human cerebral excitability in a noninvasive and portable way. However, a demonstration that static magnetic fields can influence human brain activity and behavior is currently lacking, despite evidence that static magnetic fields interfere with neuronal function in animals. ⋯ The typical relationship between prestimulus alpha power over posterior cortical areas and reaction time (RT) to targets during tSMS is altered such that tSMS-dependent increases in alpha power are associated with longer RTs for difficult, but not easy, target detection trials. Our results directly demonstrate that a powerful magnet placed on the scalp modulates normal brain activity and induces behavioral changes in humans.
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Int J Psychophysiol · Jul 2014
Randomized Controlled TrialTracking EEG changes in response to alpha and beta binaural beats.
A binaural beat can be produced by presenting two tones of a differing frequency, one to each ear. Such auditory stimulation has been suggested to influence behaviour and cognition via the process of cortical entrainment. However, research so far has only shown the frequency following responses in the traditional EEG frequency ranges of delta, theta and gamma. ⋯ EEG was recorded from the left and right temporal regions during pre-exposure baselines, stimulus exposure epochs and post-exposure baselines. Analysis of changes in broad-band and narrow-band amplitudes, and frequency showed no effect of binaural beat frequency eliciting a frequency following effect in the EEG. Possible mediating factors are discussed and a number of recommendations are made regarding future studies, exploring entrainment effects from a binaural beat presentation.