Quantitative electroencephalography (qEEG) showed that Alzheimer's disease (AD) is characterized by increased theta power, decreased alpha and beta power, and decreased coherence in the alpha and theta band in posterior regions. These abnormalities are thought to be associated with functional disconnections among cortical areas, death of cortical neurons, axonal pathology, and cholinergic deficits. Since transcranial Direct Current Stimulation (tDCS) over the temporo-parietal area is thought to have beneficial effects in patients with AD, in this study we aimed to investigate whether tDCS benefits are related to tDCS-induced changes in cortical activity, as represented by qEEG. A weak anodal current (1.5 mA, 15 min) was delivered bilaterally over the temporal-parietal lobe to seven subjects with probable AD (Mini-Mental State Examination, MMSE score >20). EEG (21 electrodes, 10-20 international system) was recorded for 5 min with eyes closed before (baseline, t0) and 30 min after anodal and cathodal tDCS ended (t1). At the same time points, patients performed a Word Recognition Task (WRT) to assess working memory functions. The spectral power and the inter- and intra-hemispheric EEG coherence in different frequency bands (e.g., low frequencies, including delta and theta; high frequencies, including alpha and beta) were calculated for each subject at t0 and t1. tDCS-induced changes in EEG neurophysiological markers were correlated with the performance of patients at the WRT. At baseline, qEEG features in AD patients confirmed that the decreased high frequency power was correlated with lower MMSE. After anodal tDCS, we observed an increase in the high-frequency power in the temporo-parietal area and an increase in the temporo-parieto-occipital coherence that correlated with the improvement at the WRT. In addition, cathodal tDCS produced a non-specific effect of decreased theta power all over the scalp that was not correlated with the clinical observation at the WRT. Our findings disclosed that tDCS induces significant modulations in the cortical EEG activity in AD patients. The abnormal pattern of EEG activity observed in AD during memory processing is partially reversed by applying anodal tDCS, suggesting that anodal tDCS benefits in AD patients during working memory tasks are supported by the modulation of cortical activity.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4814712 | PMC |
http://dx.doi.org/10.3389/fnins.2016.00134 | DOI Listing |
J Affect Disord
January 2025
School of Medicine and Health, Department of Diagnostic and Interventional Neuroradiology, Technical University of Munich, Munich, Germany; School of Medicine and Health, TUM-NIC Neuroimaging Center, Technical University of Munich, Munich, Germany.
Aim: This study investigates the effects of transcranial direct current stimulation (tDCS) on brain network connectivity in individuals with obsessive-compulsive disorder (OCD).
Methods: In a randomized, double-blind, sham-controlled experimental design anodal tDCS (vs. sham) was applied in a total of 43 right-handed patients with OCD, targeting the right pre-supplementary motor area (pre-SMA).
Neuroimage
January 2025
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA; College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA; Department of Pharmacology & Neuroscience, Creighton University, Omaha, NE, USA. Electronic address:
Noninvasive brain stimulation of the primary motor cortex has been shown to alter therapeutic outcomes in stroke and other neurological conditions, but the precise mechanisms remain poorly understood. Determining the impact of such neurostimulation on the neural processing supporting motor control is a critical step toward further harnessing its therapeutic potential in multiple neurological conditions affecting the motor system. Herein, we leverage the excellent spatio-temporal precision of magnetoencephalographic (MEG) imaging to identify the spectral, spatial, and temporal effects of high-definition transcranial direct current stimulation (HD-tDCS) on the neural responses supporting motor control.
View Article and Find Full Text PDFClin Neurol Neurosurg
January 2025
Department of Neurocience and Mental Health, Botucatu Medical School (UNESP), Botucatu, São Paulo, Brazil.
Introduction: Our primary clinical trial indicated that anodal stimulation of the right posterior parietal region associated with specific and perceptual task training was superior to placebo in reducing stroke-induced hemispatial neglect (HN) immediately after the treatment protocol. However, our primary study did not investigate whether this benefit was maintained in the long term after stroke. Therefore, this study aimed to evaluate the long-term effects of the protocol applied in the ELETRON trial on outcomes associated with HN, functionality, and mortality.
View Article and Find Full Text PDFCerebellum
January 2025
Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, USA.
The cerebellum is involved in non-motor processing, supported by topographically distinct cerebellar activations and closed-loop circuits between the cerebellum and the cortex. Disruptions to cerebellar function may negatively impact prefrontal function and processing. Cerebellar resources may be important for offloading cortical processing, providing crucial scaffolding for normative performance and function.
View Article and Find Full Text PDFEur Child Adolesc Psychiatry
January 2025
Department of Psychiatry, Neurology, Psychotherapy and Psychosomatics in Childhood and Adolescence, Rostock University Medical Center, Gehlsheimer Straße 20, 18147, Rostock, Germany.
Transcranial direct current stimulation (tDCS) remains experimental for many psychiatric disorders in adults. Particularly in childhood, there is limited research on the evidence for the efficacy and mechanisms of action of tDCS on the developing brain. The objective of this review is to identify published experimental studies to examine the efficacy and mechanisms of tDCS in children with psychiatric or developmental disorders in early (prepubertal) childhood (aged under 10 years).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!