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Left Prefrontal tDCS during Learning Does Not Enhance Subsequent Verbal Episodic Memory in Young Adults: Results from Two Double-Blind and Sham-Controlled Experiments. Brain Sci 2023; 13:brainsci13020241. [PMID: 36831783 PMCID: PMC9954521 DOI: 10.3390/brainsci13020241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/21/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
Recent studies suggest that transcranial direct current stimulation (tDCS) applied over the prefrontal cortex (PFaC) may enhance episodic memory ability. As such, there is ongoing interest in the therapeutic potential of this technique in age-related memory decline. At the same time, the findings are not yet conclusive regarding the magnitude of this effect, and assumptions regarding underlying brain mechanisms of stimulation-induced changes in behaviour are yet to be tested in detail. Here, we evaluated the effect of tDCS over left PFC on verbal episodic memory in young adults. Two separate randomized, double-blind, sham-controlled experiments were carried out using (1) incidental learning followed by a recognition test and (2) intentional learning followed by a free recall. In both studies, participants performed a learning task with active or sham tDCS during the encoding period, followed by retrieval tasks on the same day and the next day. The results suggest that, contrary to expectations, active tDCS did not enhance memory performance relative to sham tDCS. Possible reasons behind the lack of enhancement effects are discussed, including the possibility that memory enhancement effects of tDCS may be smaller than first thought. Scientific practices that could improve estimation accuracy in the field are also discussed.
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Vimolratana O, Lackmy-Vallee A, Aneksan B, Hiengkaew V, Klomjai W. Non-linear dose response effect of cathodal transcranial direct current stimulation on muscle strength in young healthy adults: a randomized controlled study. BMC Sports Sci Med Rehabil 2023; 15:10. [PMID: 36717894 PMCID: PMC9887803 DOI: 10.1186/s13102-023-00621-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 01/25/2023] [Indexed: 01/31/2023]
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is a technique that modulates brain excitability in humans. Increasing the stimulation intensity or duration within certain limits could enhance tDCS efficacy with a polarity-dependent effect; anodal stimulation increases cortical excitability, whereas cathodal stimulation decreases excitability. However, recent studies have reported a non-linear effect of cathodal tDCS on neuronal excitability in humans, and there is no conclusive result regarding the effect of cathodal tDCS on muscle performance. METHODS Our study aimed to investigate the immediate effects of different intensities (i.e., 1, 1.5, and 2 mA and sham tDCS) of cathodal tDCS on muscle strength in healthy participants. All participants [mean age 23.17 (3.90) years] were recruited and randomly allocated into four groups (1, 1.5, and 2 mA cathodal tDCS and sham tDCS). Muscle strength in bilateral upper and lower extremities was measured before and immediately after tDCS using a handheld dynamometer. RESULTS Our results showed that cathodal tDCS at 1 and 1.5 mA reduced muscle strength bilaterally in upper and lower extremity muscles, whereas stimulation at 2 mA tended to increase muscle strength on the dominant limb. CONCLUSION These findings support the non-linear effects of cathodal tDCS on muscle strength, which should be considered for the clinical use of tDCS in motor rehabilitation. TRIAL REGISTRATION NCT04672122, date of first registration 17/12/2020.
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Affiliation(s)
- Oranich Vimolratana
- grid.10223.320000 0004 1937 0490Neuro Electrical Stimulation Laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, 999 Phutthamonthon 4 Road, Nakhon Pathom, 73170 Thailand ,grid.10223.320000 0004 1937 0490Faculty of Physical Therapy, Mahidol University, 999 Phutthamonthon 4 Road, Nakhon Pathom, 73170 Thailand
| | - Alexandra Lackmy-Vallee
- grid.462844.80000 0001 2308 1657Laboratoire d’Imagerie Biomédicale, LIB, CNRS, INSERM, Sorbonne Université, 75005 Paris, France
| | - Benchaporn Aneksan
- grid.10223.320000 0004 1937 0490Neuro Electrical Stimulation Laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, 999 Phutthamonthon 4 Road, Nakhon Pathom, 73170 Thailand ,grid.10223.320000 0004 1937 0490Faculty of Physical Therapy, Mahidol University, 999 Phutthamonthon 4 Road, Nakhon Pathom, 73170 Thailand
| | - Vimonwan Hiengkaew
- grid.10223.320000 0004 1937 0490Faculty of Physical Therapy, Mahidol University, 999 Phutthamonthon 4 Road, Nakhon Pathom, 73170 Thailand
| | - Wanalee Klomjai
- grid.10223.320000 0004 1937 0490Neuro Electrical Stimulation Laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, 999 Phutthamonthon 4 Road, Nakhon Pathom, 73170 Thailand ,grid.10223.320000 0004 1937 0490Faculty of Physical Therapy, Mahidol University, 999 Phutthamonthon 4 Road, Nakhon Pathom, 73170 Thailand
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The interaction between metaplastic neuromodulation and fatigue in multiple sclerosis. J Neurol Sci 2023; 444:120521. [PMID: 36528976 DOI: 10.1016/j.jns.2022.120521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND OBJECTIVE Neuromuscular fatigue contributes to decrements in quality of life in Multiple Sclerosis (MS), yet available treatments demonstrate limited efficacy. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique which presents promise in managing fatigue, possibly related to its capacity to modulate corticospinal excitability. There is evidence for capitalising on metaplasticity using tDCS for improving outcomes. However, this remains to be explored with fatigue in people with MS (pwMS). We investigated cathodal tDCS (ctDCS) priming on anodal tDCS (atDCS)-induced corticospinal excitability and fatigue modulation in pwMS. METHODS 15 pwMS and 15 healthy controls completed fatiguing exercise whilst receiving either ctDCS or sham (stDCS) primed atDCS to the motor cortex. We assessed change in contraction force and motor evoked potential (MEP) amplitude across time to represent changes in fatigue and corticospinal excitability. RESULTS AND CONCLUSION ctDCS primed atDCS induced MEP elevation in healthy participants but not in pwMS, possibly indicating impaired metaplasticity in pwMS. No tDCS-mediated change in the magnitude of fatigue was observed, implying that development of fatigue may not rely on changes in corticospinal excitability. SIGNIFICANCE These findings expand understanding of tDCS effects in pwMS, highlighting differences that may be relevant in the disease pathophysiology.
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Xiong HY, Cao YQ, Du SH, Yang QH, He SY, Wang XQ. Effects of High-Definition Transcranial Direct Current Stimulation Targeting the Anterior Cingulate Cortex on the Pain Thresholds: A Randomized Controlled Trial. PAIN MEDICINE 2023; 24:89-98. [PMID: 36066447 DOI: 10.1093/pm/pnac135] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/24/2022] [Accepted: 07/30/2022] [Indexed: 02/06/2023]
Abstract
BACKGROUND The majority of existing clinical studies used active transcranial direct current stimulation (tDCS) over superficial areas of the pain neuromatrix to regulate pain, with conflicting results. Few studies have investigated the effect of tDCS on pain thresholds by focusing on targets in deep parts of the pain neuromatrix. METHODS This study applied a single session of high-definition tDCS (HD-tDCS) targeting the anterior cingulate cortex (ACC) and used a parallel and sham-controlled design to compare the antinociceptive effects in healthy individuals by assessing changes in pain thresholds. Sixty-six female individuals (mean age, 20.5 ± 2.4 years) were randomly allocated into the anodal, cathodal, or sham HD-tDCS groups. The primary outcome of the study was pain thresholds (pressure pain threshold, heat pain threshold, and cold pain threshold), which were evaluated before and after stimulation through the use of quantitative sensory tests. RESULTS Only cathodal HD-tDCS targeting the ACC significantly increased heat pain threshold (P < 0.05) and pressure pain threshold (P < 0.01) in healthy individuals compared with sham stimulation. Neither anodal nor cathodal HD-tDCS showed significant analgesic effects on cold pain threshold. Furthermore, no statistically significant difference was found in pain thresholds between anodal and sham HD-tDCS (P > 0.38). Independent of HD-tDCS protocols, the positive and negative affective schedule scores were decreased immediately after stimulation compared with baseline. CONCLUSIONS The present study has found that cathodal HD-tDCS targeting the ACC provided a strong antinociceptive effect (increase in pain threshold), demonstrating a positive biological effect of HD-tDCS.
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Affiliation(s)
- Huan-Yu Xiong
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Yin-Quan Cao
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Shu-Hao Du
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Qi-Hao Yang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Si-Yi He
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Xue-Qiang Wang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China.,Department of Rehabilitation Medicine, Shanghai Shangti Orthopaedic Hospital, Shanghai, China
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Friehs MA, Stegemann MJ, Merz S, Geißler C, Meyerhoff HS, Frings C. The influence of tDCS on perceived bouncing/streaming. Exp Brain Res 2023; 241:59-66. [PMID: 36357591 PMCID: PMC9870834 DOI: 10.1007/s00221-022-06505-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/03/2022] [Indexed: 11/12/2022]
Abstract
Processing ambiguous situations is a constant challenge in everyday life and sensory input from different modalities needs to be integrated to form a coherent mental representation on the environment. The bouncing/streaming illusion can be studied to provide insights into the ambiguous perception and processing of multi-modal environments. In short, the likelihood of reporting bouncing rather than streaming impressions increases when a sound coincides with the moment of overlap between two moving disks. Neuroimaging studies revealed that the right posterior parietal cortex is crucial in cross-modal integration and is active during the bouncing/streaming illusion. Consequently, in the present study, we used transcranial direct current stimulation to stimulate this brain area. In the active stimulation conditions, a 9 cm2 electrode was positioned over the P4-EEG position and the 35 cm2 reference positioned over the left upper arm. The stimulation lasted 15 min. Each participant did the bouncing/streaming task three times: before, during and after anodal or sham stimulation. In a sample of N = 60 healthy, young adults, we found no influence of anodal tDCS. Bayesian analysis showed strong evidence against tDCS effects. There are two possible explanations for the finding that anodal tDCS over perceptual areas did not modulate multimodal integration. First, upregulation of multimodal integration is not possible using tDCS over the PPC as the integration process already functions at maximum capacity. Second, prefrontal decision-making areas may have overruled any modulated input from the PPC as it may not have matched their decision-making criterion and compensated for the modulation.
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Affiliation(s)
- Maximilian A. Friehs
- Lise-Meitner Research Group Cognition and Plasticity, Max-Planck-Institute for Human Cognitive and Brain Science, Leipzig, Germany ,School of Psychology, University College Dublin, Dublin, Ireland
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Hsu G, Shereen AD, Cohen LG, Parra LC. Robust enhancement of motor sequence learning with 4 mA transcranial electric stimulation. Brain Stimul 2023; 16:56-67. [PMID: 36574814 PMCID: PMC10171179 DOI: 10.1016/j.brs.2022.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Motor learning experiments with transcranial direct current stimulation (tDCS) at 2 mA have produced mixed results. We hypothesize that tDCS boosts motor learning provided sufficiently high field intensity on the motor cortex. METHODS In a single-blinded design, 108 healthy participants received either anodal (N = 36) or cathodal (N = 36) tDCS at 4 mA total, or no stimulation (N = 36) while they practiced a 12-min sequence learning task. Anodal stimulation was delivered across four electrode pairs (1 mA each), with anodes above the right parietal lobe and cathodes above the right frontal lobe. Cathodal stimulation, with reversed polarities, served as an active control for sensation, while the no-stimulation condition established baseline performance. fMRI-localized targets on the primary motor cortex in 10 subjects were used in current flow models to optimize electrode placement for maximal field intensity. A single electrode montage was then selected for all participants. RESULTS We found a significant difference in performance with anodal vs. cathodal stimulation (Cohen's d = 0.71) and vs. no stimulation (d = 0.56). This effect persisted for at least 1 h, and subsequent learning for a new sequence and the opposite hand also improved. Sensation ratings were comparable in the active groups and did not exceed moderate levels. Current flow models suggest the new electrode montage can achieve stronger motor cortex polarization than alternative montages. CONCLUSION The present paradigm shows a medium to large effect size and is well-tolerated. It may serve as a go-to experiment for future studies on motor learning and tDCS.
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Affiliation(s)
- Gavin Hsu
- Department of Biomedical Engineering, The City College of New York, The City University of New York, New York, NY, USA.
| | - A Duke Shereen
- Advanced Science Research Center at the Graduate Center of the City University of New York, USA
| | - Leonardo G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Lucas C Parra
- Department of Biomedical Engineering, The City College of New York, The City University of New York, New York, NY, USA
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Yuasa A, Uehara S, Ushizawa K, Toyama T, Gomez-Tames J, Hirata A, Otaka Y. Effects of cerebellar transcranial direct current stimulation on upper limb motor function after stroke: study protocol for the pilot of a randomized controlled trial. Pilot Feasibility Stud 2022; 8:259. [PMCID: PMC9748387 DOI: 10.1186/s40814-022-01223-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/01/2022] [Indexed: 12/15/2022] Open
Abstract
Abstract
Background
Transcranial direct current stimulation (tDCS) is a technique that can noninvasively modulate neural states in a targeted brain region. As cerebellar activity levels are associated with upper limb motor improvement after stroke, the cerebellum is a plausible target of tDCS. However, the effect of tDCS remains unclear. Here, we designed a pilot study to assess: (1) the feasibility of a study that aims to examine the effects of cerebellar tDCS combined with an intensive rehabilitation approach based on the concept of constraint-induced movement therapy (CIMT) and (2) the preliminary outcome of the combined approach on upper limb motor function in patients with stroke in the chronic stage.
Methods
This pilot study has a double-blind randomized controlled design. Twenty-four chronic stroke patients with mild to moderate levels of upper limb motor impairment will be randomly assigned to an active or sham tDCS group. The participants will receive 20 min of active or sham tDCS to the contralesional cerebellum at the commencement of 4 h of daily intensive training, repeatedly for 5 days per week for 2 weeks. The primary outcomes are recruitment, enrollment, protocol adherence, and retention rates and measures to evaluate the feasibility of the study. The secondary outcome is upper limb motor function which will be evaluated using the Action Research Arm Test, Fugl-Meyer Assessment, for the upper extremity and the Motor Activity Log. Additionally, neurophysiological and neuroanatomical assessments of the cerebellum will be performed using transcranial magnetic stimulation and magnetic resonance imaging. These assessments will be conducted before, at the middle, and after the 2-week intervention, and finally, 1 month after the intervention. Any adverse events that occur during the study will be recorded.
Discussion
Cerebellar tDCS combined with intensive upper limb training may increase the gains of motor improvement when compared to the sham condition. The present study should provide valuable evidence regarding the feasibility of the design and the efficacy of cerebellar tDCS for upper limb motor function in patients with stroke before a future large trial is conducted.
Trial registration
This study has been registered at the Japan Registry of Clinical Trials (jRCTs042200078). Registered 17 December 2020
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Shen QR, Hu MT, Feng W, Li KP, Wang W. Narrative Review of Noninvasive Brain Stimulation in Stroke Rehabilitation. Med Sci Monit 2022; 28:e938298. [PMID: 36457205 PMCID: PMC9724451 DOI: 10.12659/msm.938298] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 11/03/2022] [Indexed: 09/02/2023] Open
Abstract
Stroke is a disease with a high incidence and disability rate, resulting in changes in neural network and corticoid-subcortical excitability and various functional disabilities. The aim of the present study was to discuss the current status of research and limitations and potential direction in the application of noninvasive brain stimulation (NIBS) on post-stroke patients. This literature review focused on clinical studies and reviews. Literature retrieval was conducted in PubMed, Cochrane, Scopus, and CNKI, using the following keywords: Repeated transcranial magnetic stimulation, Transcranial direct current stimulation, Transcranial alternating current stimulation, Transcranial alternating current stimulation, Transcranial focused ultrasound, Noninvasive vagus nerve stimulation, Stroke, and Rehabilitation. We selected 200 relevant publications from 1985 to 2022. An overview of recent research on the use of NIBS on post-stroke patients, including its mechanism, therapeutic parameters, effects, and safety, is presented. It was found that NIBS has positive therapeutic effects on dysfunctions of motor, sensory, cognitive, speech, swallowing, and depression after stroke, but standardized stimulus programs are still lacking. The literature suggests that rTMS and tDCS are more beneficial to post-stroke patients, while tFUS and tVNS are currently less studied for post-stroke rehabilitation, but are also potential interventions.
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Affiliation(s)
- Qian-ru Shen
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, PR China
| | - Meng-ting Hu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, PR China
| | - Wei Feng
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, PR China
| | - Kun-Peng Li
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, PR China
| | - Wu Wang
- Department of Rehabilitation Therapy, The Second Rehabilitation Hospital of Shanghai, Shanghai, PR China
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Amann M, Sidhu SK, McNeil CJ, Gandevia SC. Critical considerations of the contribution of the corticomotoneuronal pathway to central fatigue. J Physiol 2022; 600:5203-5214. [PMID: 36326193 PMCID: PMC9772161 DOI: 10.1113/jp282564] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Neural drive originating in higher brain areas reaches exercising limb muscles through the corticospinal-motoneuronal pathway, which links the motor cortex and spinal motoneurones. The properties of this pathway have frequently been observed to change during fatiguing exercise in ways that could influence the development of central fatigue (i.e. the progressive reduction in voluntary muscle activation). However, based on differences in motor cortical and motoneuronal excitability between exercise modalities (e.g. single-joint vs. locomotor exercise), there is no characteristic response that allows for a categorical conclusion about the effect of these changes on functional impairments and performance limitations. Despite the lack of uniformity in findings during fatigue, there is strong evidence for marked 'inhibition' of motoneurones as a direct result of voluntary drive. Endogenous forms of neuromodulation, such as via serotonin released from neurones, can directly affect motoneuronal output and central fatigue. Exogenous forms of neuromodulation, such as brain stimulation, may achieve a similar effect, although the evidence is weak. Non-invasive transcranial direct current stimulation can cause transient or long-lasting changes in cortical excitability; however, variable results across studies cast doubt on its claimed capacity to enhance performance. Furthermore, with these studies, it is difficult to establish a cause-and-effect relationship between brain responsiveness and exercise performance. This review briefly summarizes changes in the corticomotoneuronal pathway during various types of exercise, and considers the relevance of these changes for the development of central fatigue, as well as the potential of non-invasive brain stimulation to enhance motor cortical excitability, motoneuronal output and, ultimately, exercise performance.
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Affiliation(s)
- Markus Amann
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Simranjit K. Sidhu
- School of Biomedicine, The University of Adelaide, South Australia, Australia
| | - Chris J McNeil
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Simon C Gandevia
- Neuroscience Research Australia and University of New South Wales, Sydney, Australia
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Muccio M, Walton Masters L, Pilloni G, He P, Krupp L, Datta A, Bikson M, Charvet L, Ge Y. Cerebral metabolic rate of oxygen (CMRO 2) changes measured with simultaneous tDCS-MRI in healthy adults. Brain Res 2022; 1796:148097. [PMID: 36150457 PMCID: PMC10335216 DOI: 10.1016/j.brainres.2022.148097] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/06/2022] [Accepted: 09/16/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is a safe and well-tolerated noninvasive technique used for cortical excitability modulation. tDCS has been extensively investigated for its clinical applications; however further understanding of its underlying in-vivo physiological mechanisms remains a fundamental focus of current research. OBJECTIVES We investigated the simultaneous effects of tDCS on cerebral blood flow (CBF), venous blood oxygenation (Yv) and cerebral metabolic rate of oxygen (CMRO2) using simultaneous MRI in healthy adults to provide a reference frame for its neurobiological mechanisms. METHODS Twenty-three healthy participants (age = 35.6 ± 15.0 years old, 10 males) completed a simultaneous tDCS-MRI session in a 3 T scanner fitted with a 64-channels head coil. A MR-compatible tDCS device was used to acquire CBF, Yv and CMRO2 at three time points: pre-, during- and post- 15 minutes of 2.0 mA tDCS on left anodal dorsolateral prefrontal cortex. RESULTS During tDCS, CBF significantly increased (57.10 ± 8.33 mL/100g/min) from baseline (53.67 ± 7.75 mL/100g/min; p < 0.0001) and remained elevated in post-tDCS (56.79 ± 8.70 mL/100g/min). Venous blood oxygenation levels measured in pre-tDCS (60.71 ± 4.12 %) did not significantly change across the three timepoints. The resulting CMRO2 significantly increased by 5.9 % during-tDCS (175.68 ± 30.78 µmol/100g/min) compared to pre-tDCS (165.84 ± 25.32 µmol/100g/min; p = 0.0015), maintaining increased levels in post-tDCS (176.86 ± 28.58 µmol/100g/min). CONCLUSIONS tDCS has immediate effects on neuronal excitability, as measured by increased cerebral blood supply and oxygen consumption supporting increased neuronal firing. These findings provide a standard range of CBF and CMRO2 changes due to tDCS in healthy adults that may be incorporated in clinical studies to evaluate its therapeutic potential.
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Affiliation(s)
- Marco Muccio
- Department of Radiology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Lillian Walton Masters
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Giuseppina Pilloni
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Peidong He
- Department of Radiology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Lauren Krupp
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Abhishek Datta
- Research and Development, Soterix Medical, Inc, Woodbridge, NJ, United States
| | - Marom Bikson
- Department of Biomedical Engineering, City College of New York, New York City, NY, United States
| | - Leigh Charvet
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Yulin Ge
- Department of Radiology, NYU Grossman School of Medicine, New York City, NY, United States.
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Yasaroglu S, Liepert J. Transcranial direct current stimulation in stroke - Motor excitability and motor function. Clin Neurophysiol 2022; 144:16-22. [PMID: 36208617 DOI: 10.1016/j.clinph.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/28/2022] [Accepted: 09/08/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To characterize motor excitability changes and changes of motor performance induced by a single anodal and cathodal transcranial direct current stimulation (tDCS) session in stroke patients. METHODS Twenty subacute stroke patients participated. Motor performance was tested with the Box and Block Test [BBT]. Motor cortex excitability (short interval intracortical inhibition [SICI], intracortical facilitation [ICF], long interval intracortical inhibition [LICI]) was examined by paired pulse transcranial magnetic stimulation before and after a single tDCS session (20 minutes, 1,0 mA). On two different occasions, patients received anodal and cathodal tDCS over the affected hemisphere. TMS recordings were taken from both hands consecutively. RESULTS Anodal tDCS significantly reduced SICI without changing ICF or LICI. Cathodal tDCS did not change motor excitability. Both types of tDCS did not alter motor performance. Even prior to anodal tDCS, SICI in the affected hemisphere was lower than in the unaffected hemisphere and was correlated with BBT changes after anodal tDCS. CONCLUSIONS Anodal, but not cathodal tDCS specifically modulated intracortical inhibitory circuits, leading to a disinhibition. SIGNIFICANCE The results amplify our knowledge on excitability modulations of tDCS in stroke patients.
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Ehrhardt SE, Ballard T, Wards Y, Mattingley JB, Dux PE, Filmer HL. tDCS augments decision-making efficiency in an intensity dependent manner: A training study. Neuropsychologia 2022; 176:108397. [DOI: 10.1016/j.neuropsychologia.2022.108397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/15/2022]
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Maudrich T, Ragert P, Perrey S, Kenville R. Single-session anodal transcranial direct current stimulation to enhance sport-specific performance in athletes: A systematic review and meta-analysis. Brain Stimul 2022; 15:1517-1529. [PMID: 36442774 DOI: 10.1016/j.brs.2022.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/13/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) has emerged as a promising and feasible method to improve motor performance in healthy and clinical populations. However, the potential of tDCS to enhance sport-specific motor performance in athletes remains elusive. OBJECTIVE We aimed at analyzing the acute effects of a single anodal tDCS session on sport-specific motor performance changes in athletes compared to sham. METHODS A systematic review and meta-analysis was conducted in the electronic databases PubMed, Web of Science, and SPORTDiscus. The meta-analysis was performed using an inverse variance method and a random-effects model. Additionally, two subgroup analyses were conducted (1) depending on the stimulated brain areas (primary motor cortex (M1), temporal cortex (TC), prefrontal cortex (PFC), cerebellum (CB)), and (2) studies clustered in subgroups according to different sports performance domains (endurance, strength, visuomotor skill). RESULTS A total number of 19 studies enrolling a sample size of 258 athletes were deemed eligible for inclusion. Across all included studies, a significant moderate standardized mean difference (SMD) favoring anodal tDCS to enhance sport-specific motor performance could be observed. Subgroup analysis depending on cortical target areas of tDCS indicated a significant moderate SMD in favor of anodal tDCS compared to sham for M1 stimulation. CONCLUSION A single anodal tDCS session can lead to performance enhancement in athletes in sport-specific motor tasks. Although no definitive conclusions can be drawn regarding the modes of action as a function of performance domain or stimulation site, these results imply intriguing possibilities concerning sports performance enhancement through anodal M1 stimulation.
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Affiliation(s)
- Tom Maudrich
- Department of Movement Neuroscience, Faculty of Sport Science, Leipzig University, Leipzig, Germany; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Patrick Ragert
- Department of Movement Neuroscience, Faculty of Sport Science, Leipzig University, Leipzig, Germany; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Stéphane Perrey
- EuroMov Digital Health in Motion, Univ Montpellier, IMT Mines Ales, Montpellier, France
| | - Rouven Kenville
- Department of Movement Neuroscience, Faculty of Sport Science, Leipzig University, Leipzig, Germany; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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Attention neuroenhancement through tDCS or neurofeedback: a randomized, single-blind, controlled trial. Sci Rep 2022; 12:17613. [PMID: 36266396 PMCID: PMC9584934 DOI: 10.1038/s41598-022-22245-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 10/12/2022] [Indexed: 01/13/2023] Open
Abstract
Neurofeedback and transcranial Direct Current Stimulation (tDCS) are promising techniques for neuroenhancement of attentional performance. As far as we know no study compared both techniques on attentional performance in healthy participants. We compared tDCS and neurofeedback in a randomized, single-blind, controlled experiment assessing both behavioral (accuracy and time reaction) and electrophysiological (N1, P1, and P3 components) data of participants responding to the Attention Network Task (ANT). Eighty volunteers volunteered for this study. We adopted standard protocols for both techniques, i.e., a Sensorimotor Rhythm (SMR) protocol for neurofeedback and the right DLPFC anodal stimulation for tDCS, applied over nine sessions (two weeks). We did not find significant differences between treatment groups on ANT, neither at the behavioral nor at the electrophysiological levels. However, we found that participants from both neuromodulation groups, irrespective of if active or sham, reported attentional improvements in response to the treatment on a subjective scale. Our study adds another null result to the neuromodulation literature, showing that neurofeedback and tDCS effects are more complex than previously suggested and associated with placebo effect. More studies in neuroenhancement literature are necessary to fully comprehend neuromodulation mechanisms.
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Qi S, Liang Z, Wei Z, Liu Y, Wang X. Effects of transcranial direct current stimulation on motor skills learning in healthy adults through the activation of different brain regions: A systematic review. Front Hum Neurosci 2022; 16:1021375. [PMID: 36277051 PMCID: PMC9582610 DOI: 10.3389/fnhum.2022.1021375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Objective This systematic review aims to analyze existing literature of the effects of transcranial direct current stimulation (tDCS) on motor skills learning of healthy adults and discuss the underlying neurophysiological mechanism that influences motor skills learning. Methods This systematic review has followed the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses. The PubMed, EBSCO, and Web of Science databases were systematically searched for relevant studies that were published from database inception to May 2022. Studies were included based on the Participants, Intervention, Comparison, Outcomes, and Setting inclusion strategy. The risk of bias was evaluated by using the Review manager 5.4 tool. The quality of each study was assessed with the Physiotherapy Evidence Database (PEDro) scale. Results The electronic search produced 142 studies. Only 11 studies were included after filtering. These studies performed well in terms of distribution, blinding availability and selective reporting. They reported that tDCS significantly improved motor skills learning. The main outcomes measure were the improvement of the motor sequence tasks and specific motor skills. Nine studies showed that tDCS interventions reduced reaction time to complete motor sequence tasks in healthy adults and two studies showed that tDCS interventions improved golf putting task performance. Conclusion The included studies showed that tDCS can help healthy adults to improve the motor skills learning by activating different brain regions, such as the primary motor cortex, left dorsolateral prefrontal cortex and right cerebellum. However, the number of included studies was limited, and the sample sizes were small. Therefore, more studies are urgently needed to validate the results of current studies and further explore the underlying neurophysiological mechanisms of tDCS in the future.
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Nejati V, Heyrani R, Nitsche M. Attention bias modification through transcranial direct current stimulation (tDCS): A review. Neurophysiol Clin 2022; 52:341-353. [DOI: 10.1016/j.neucli.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/09/2022] [Accepted: 09/10/2022] [Indexed: 11/07/2022] Open
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Moscaleski LA, Fonseca A, Brito R, Morya E, Morgans R, Moreira A, Okano AH. Does high-definition transcranial direct current stimulation change brain electrical activity in professional female basketball players during free-throw shooting? FRONTIERS IN NEUROERGONOMICS 2022; 3:932542. [PMID: 38235466 PMCID: PMC10790899 DOI: 10.3389/fnrgo.2022.932542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/04/2022] [Indexed: 01/19/2024]
Abstract
Differentiated brain activation in high-performance athletes supports neuronal mechanisms relevant to sports performance. Preparation for the motor action involves cortical and sub-cortical regions that can be non-invasively modulated by electrical current stimulation. This study aimed to investigate the effect of high-definition transcranial direct current stimulation (HD-tDCS) on electrical brain activity in professional female basketball players during free-throw shooting. Successful free-throw shooting (n = 2,361) from seven professional female basketball players was analyzed during two experimental conditions (HD-tDCS cathodic and sham) separated by 72 h. Three spectral bio-markers, Power Ratio Index (PRI), Delta Alpha Ratio (DAR), and Theta Beta Ratio (TBR) were measured (electroencephalography [EEG] Brain Products). Multi-channel HD-tDCS was applied for 20 min, considering current location and intensity for cathodic stimulation: FCC1h, AFF5h, AFF1h (-0.5 mA each), and FCC5h (ground). The within EEG analyses (pre and post HD-tDCS) of frontal channels (Fp1, Fp2, F3, F4, FC1, FC3) for 1 second epoch pre-shooting, showed increases in PRI (p < 0.001) and DAR (p < 0.001) for HD-tDCS cathodic condition, and in TBR for both conditions (cathodic, p = 0.01; sham, p = 0.002). Sub-group analysis divided the sample into less (n = 3; LSG) and more (n = 4; MSG) stable free-throw-shooting performers and revealed that increases in pre to post HD-tDCS in PRI only occurred for the LSG. These results suggest that the effect of HD-tDCS may induce changes in slow frontal frequency brain activities and that this alteration seems to be greater for players demonstrating a less stable free-throw shooting performance.
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Affiliation(s)
- Luciane Aparecida Moscaleski
- Center of Mathematics, Computation, and Cognition, Federal University of ABC (UFABC), São Bernardo do Campo, Brazil
| | - André Fonseca
- Center of Mathematics, Computation, and Cognition, Federal University of ABC (UFABC), São Bernardo do Campo, Brazil
| | - Rodrigo Brito
- Neuroscience Applied Laboratory, Federal University of Pernambuco, Recife, Brazil
| | - Edgard Morya
- Edmond and Lily Safra International Institute of Neuroscience, Santos Dumont Institute, Macaíba, RN, Brazil
| | - Ryland Morgans
- Department of Sports Medicine and Medical Rehabilitation, Sechenov First State Medical University, Moscow, Russia
| | - Alexandre Moreira
- Department of Sport, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Alexandre Hideki Okano
- Center of Mathematics, Computation, and Cognition, Federal University of ABC (UFABC), São Bernardo do Campo, Brazil
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Kunaratnam N, Saumer TM, Kuan G, Holmes Z, Swarbrick D, Kiss A, Mochizuki G, Chen JL. Transcranial direct current stimulation leads to faster acquisition of motor skills, but effects are not maintained at retention. PLoS One 2022; 17:e0269851. [PMID: 36099260 PMCID: PMC9469971 DOI: 10.1371/journal.pone.0269851] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/29/2022] [Indexed: 11/28/2022] Open
Abstract
Practice is required to improve one’s shooting technique in basketball or to play a musical instrument well. Learning these motor skills may be further enhanced by transcranial direct current stimulation (tDCS). We aimed to investigate whether tDCS leads to faster attainment of a motor skill, and to confirm prior work showing it improves skill acquisition and retention performance. Fifty-two participants were tested; half received tDCS with the anode on primary motor cortex and cathode on the contralateral forehead while concurrently practicing a sequential visuomotor isometric pinch force task on Day 1, while the other half received sham tDCS during practice. On Day 2, retention of the skill was tested. Results from a Kaplan-Meier survival analysis showed that participants in the anodal group attained a pre-defined target level of skill faster than participants in the sham group (χ2 = 9.117, p = 0.003). Results from a nonparametric rank-based regression analysis showed that the rate of improvement was greater in the anodal versus sham group during skill acquisition (F(1,249) = 5.90, p = 0.016), but there was no main effect of group or time. There was no main effect of group or time, or group by time interaction when comparing performance at the end of acquisition to retention. These findings suggest anodal tDCS improves performance more quickly during skill acquisition but does not have additional benefits on motor learning after a period of rest.
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Affiliation(s)
- Nirsan Kunaratnam
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Tyler M. Saumer
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Giovanna Kuan
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Zacharie Holmes
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Dana Swarbrick
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Alex Kiss
- Evaluative Clinical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - George Mochizuki
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Joyce L. Chen
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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No robust online effects of transcranial direct current stimulation on corticospinal excitability. Brain Stimul 2022; 15:1254-1268. [PMID: 36084908 DOI: 10.1016/j.brs.2022.08.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/05/2022] [Accepted: 08/31/2022] [Indexed: 11/22/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) has been used for over twenty years to modulate cortical (particularly motor corticospinal) excitability both during (online) and outlasting (offline) the stimulation, with the former effects associated to the latter. However, tDCS effects are highly variable, partially because stimulation intensity is commonly not adjusted individually (in contrast to transcranial magnetic stimulation, TMS). In Experiment 1, we therefore explored an empirical approach of personalizing tDCS intensity for the primary motor cortex (M1) based on dose-response curves (DRCs), individually relating tDCS Intensity (in steps from 0.3 to 2.0 mA) and Polarity (anodal, cathodal) to the online modulation of concurrent TMS motor evoked potentials (MEP), assessing DRC reliability across two separate days. No robust DRCs could be observed, neither at the individual nor at the group level, with the only robust effect being a (paradoxical) MEP facilitation during cathodal tDCS at 2.0 mA, but no modulation at traditional intensities of or near 1 mA. In Experiment 2, we therefore attempted to replicate the classical bidirectional online MEP modulation during 1 mA tDCS that had been reported by several of the early seminal tDCS papers. We either closely recreated stimulation parameters and temporal protocol of these original studies (Experiment 2A) or slightly modernized them according to current standards (Experiment 2B). In neither experiment did we observed any significant online MEP modulation. We conclude that an empirical titration of individually effective tDCS intensities may not be feasible as online tDCS effects do not appear to be sufficiently robust.
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Kashyap R, Bhattacharjee S, Bharath RD, Venkatasubramanian G, Udupa K, Bashir S, Oishi K, Desmond JE, Chen SHA, Guan C. Variation of cerebrospinal fluid in specific regions regulates focality in transcranial direct current stimulation. Front Hum Neurosci 2022; 16:952602. [PMID: 36118967 PMCID: PMC9479459 DOI: 10.3389/fnhum.2022.952602] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundConventionally, transcranial direct current stimulation (tDCS) aims to focalize the current reaching the target region-of-interest (ROI). The focality can be quantified by the dose-target-determination-index (DTDI). Despite having a uniform tDCS setup, some individuals receive focal stimulation (high DTDI) while others show reduced focality (“non-focal”). The volume of cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) underlying each ROI govern the tDCS current distribution inside the brain, thereby regulating focality.AimTo determine the regional volume parameters that differentiate the focal and non-focal groups.MethodsT1-weighted images of the brain from 300 age-sex matched adults were divided into three equal groups- (a) Young (20 ≤ × < 40 years), (b) Middle (40 ≤ × < 60 years), and (c) Older (60 ≤ × < 80 years). For each group, inter and intra-hemispheric montages with electrodes at (1) F3 and right supraorbital region (F3-RSO), and (2) CP5 and Cz (CP5-Cz) were simulated, targeting the left- Dorsolateral Prefrontal Cortex (DLPFC) and -Inferior Parietal Lobule (IPL), respectively. Both montages were simulated for two current doses (1 and 2 mA). For each individual head simulated for a tDCS configuration (montage and dose), the current density at each region-of-interest (ROI) and their DTDI were calculated. The individuals were categorized into two groups- (1) Focal (DTDI ≥ 0.75), and (2) Non-focal (DTDI < 0.75). The regional volume of CSF, GM, and WM of all the ROIs was determined. For each tDCS configuration and ROI, three 3-way analysis of variance was performed considering- (i) GM, (ii) WM, and (iii) CSF as the dependent variable (DV). The age group, sex, and focality group were the between-subject factors. For a given ROI, if any of the 3 DV’s showed a significant main effect or interaction involving the focality group, then that ROI was classified as a “focal ROI.”ResultsRegional CSF was the principal determinant of focality. For interhemispheric F3-RSO montage, interaction effect (p < 0.05) of age and focality was observed at Left Caudate Nucleus, with the focal group exhibiting higher CSF volume. The CSF volume of focal ROI correlated positively (r ∼ 0.16, p < 0.05) with the current density at the target ROI (DLPFC). For intrahemispheric CP5-Cz montage, a significant (p < 0.05) main effect was observed at the left pre- and post-central gyrus, with the focal group showing lower CSF volume. The CSF volume correlated negatively (r ∼ –0.16, p < 0.05) with current density at left IPL. The results were consistent for both current doses.ConclusionThe CSF channels the flow of tDCS current between electrodes with focal ROIs acting like reservoirs of current. The position of focal ROI in the channel determines the stimulation intensity at the target ROI. For focal stimulation in interhemispheric F3-RSO, the proximity of focal ROI reserves the current density at the target ROI (DLPFC). In contrast, for intrahemispheric montage (CP5-Cz), the far-end location of focal ROI reduces the current density at the target (IPL).
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Affiliation(s)
- Rajan Kashyap
- Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, India
- School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore
- *Correspondence: Rajan Kashyap,
| | - Sagarika Bhattacharjee
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
- Psychology, School of Social Sciences (SSS), Nanyang Technological University, Singapore, Singapore
| | - Rose Dawn Bharath
- Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, India
| | - Ganesan Venkatasubramanian
- InSTAR Program, Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, India
| | - Kaviraja Udupa
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Shahid Bashir
- Neuroscience Center, King Fahad Specialist Hospital Dammam, Dammam, Saudi Arabia
| | - Kenichi Oishi
- The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - John E. Desmond
- The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - S. H. Annabel Chen
- Psychology, School of Social Sciences (SSS), Nanyang Technological University, Singapore, Singapore
- Centre for Research and Development in Learning (CRADLE), Nanyang Technological University, Singapore, Singapore
- Lee Kong Chian School of Medicine (LKC Medicine), Nanyang Technological University, Singapore, Singapore
- National Institute of Education, Nanyang Technological University, Singapore, Singapore
| | - Cuntai Guan
- School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore
- Cuntai Guan,
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Palimeris S, Ansari Y, Remaud A, Tremblay F, Corriveau H, Boudrias MH, Milot MH. Effect of a tailored upper extremity strength training intervention combined with direct current stimulation in chronic stroke survivors: A Randomized Controlled Trial. FRONTIERS IN REHABILITATION SCIENCES 2022; 3:978257. [PMID: 36189037 PMCID: PMC9397935 DOI: 10.3389/fresc.2022.978257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 07/14/2022] [Indexed: 11/25/2022]
Abstract
Strengthening exercises are recommended for managing persisting upper limb (UL) weakness following a stroke. Yet, strengthening exercises often lead to variable gains because of their generic nature. For this randomized controlled trial (RCT), we aimed to determine whether tailoring strengthening exercises using a biomarker of corticospinal integrity, as reflected in the amplitude of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS), could optimize training effects in the affected UL. A secondary aim was to determine whether applying anodal transcranial direct current stimulation (tDCS) could enhance exercise-induced training effects. For this multisite RCT, 90 adults at the chronic stage after stroke (>6 months) were recruited. Before training, participants underwent TMS to detect the presence of MEPs in the affected hand. The MEP amplitude was used to stratify participants into three training groups: (1) low-intensity, MEP <50 μV, (2) moderate-intensity, 50 μV < MEP < 120 μV, and (3) high-intensity, MEP>120 μV. Each group trained at a specific intensity based on the one-repetition maximum (1 RM): low-intensity, 35–50% 1RM; moderate-intensity, 50–65% 1RM; high-intensity, 70–85% 1RM. The strength training targeted the affected UL and was delivered 3X/week for four consecutive weeks. In each training group, participants were randomly assigned to receive either real or sham anodal tDCS (2 mA, 20 min) over the primary motor area of the affected hemisphere. Pre-/post-intervention, participants underwent a clinical evaluation of their UL to evaluate motor impairments (Fugl-Meyer Assessment), manual dexterity (Box and Blocks test) and grip strength. Post-intervention, all groups exhibited similar gains in terms of reduced impairments, improved dexterity, and grip strength, which was confirmed by multivariate and univariate analyses. However, no effect of interaction was found for tDCS or training group, indicating that tDCS had no significant impact on outcomes post-intervention. Collectively, these results indicate that adjusting training intensity based on the size of MEPs in the affected extremity provides a useful approach to optimize responses to strengthening exercises in chronic stroke survivors. Also, the lack of add-on effects of tDCS applied to the lesioned hemisphere on exercise-induced improvements in the affected UL raises questions about the relevance of combining such interventions in stroke.
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Affiliation(s)
- Stephania Palimeris
- Faculty of Medicine and Health Sciences, School of Physical and Occupational Therapy, McGill University, Montréal, QC, Canada
- BRAIN Lab, Jewish Rehabilitation Hospital, Laval, QC, Canada
- Montreal Center for Interdisciplinary Research in Rehabilitation (CRIR) and CISSS-Laval, Montréal, QC, Canada
| | | | | | - François Tremblay
- Bruyère Research Institute, Ottawa, ON, Canada
- Faculty of Health Sciences, School of Rehabilitation Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Hélène Corriveau
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, École de réadaptation, Sherbrooke, QC, Canada
- Centre de recherche sur le vieillissement, CIUSSS de l'Estrie-CHUS, Sherbrooke, QC, Canada
| | - Marie Hélène Boudrias
- Faculty of Medicine and Health Sciences, School of Physical and Occupational Therapy, McGill University, Montréal, QC, Canada
- BRAIN Lab, Jewish Rehabilitation Hospital, Laval, QC, Canada
- Montreal Center for Interdisciplinary Research in Rehabilitation (CRIR) and CISSS-Laval, Montréal, QC, Canada
| | - Marie Hélène Milot
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, École de réadaptation, Sherbrooke, QC, Canada
- Centre de recherche sur le vieillissement, CIUSSS de l'Estrie-CHUS, Sherbrooke, QC, Canada
- *Correspondence: Marie Hélène Milot
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Ester T, Kullmann S. Neurobiological regulation of eating behavior: Evidence based on non-invasive brain stimulation. Rev Endocr Metab Disord 2022; 23:753-772. [PMID: 34862944 PMCID: PMC9307556 DOI: 10.1007/s11154-021-09697-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/15/2021] [Indexed: 12/28/2022]
Abstract
The prefrontal cortex is appreciated as a key neurobiological player in human eating behavior. A special focus is herein dedicated to the dorsolateral prefrontal cortex (DLPFC), which is critically involved in executive function such as cognitive control over eating. Persons with obesity display hypoactivity in this brain area, which is linked to overconsumption and food craving. Contrary to that, higher activity in the DLPFC is associated with successful weight-loss and weight-maintenance. Transcranial direct current stimulation (tDCS) is a non-invasive neurostimulation tool used to enhance self-control and inhibitory control. The number of studies using tDCS to influence eating behavior rapidly increased in the last years. However, the effectiveness of tDCS is still unclear, as studies show mixed results and individual differences were shown to be an important factor in the effectiveness of non-invasive brain stimulation. Here, we describe the current state of research of human studies using tDCS to influence food intake, food craving, subjective feeling of hunger and body weight. Excitatory stimulation of the right DLPFC seems most promising to reduce food cravings to highly palatable food, while other studies provide evidence that stimulating the left DLPFC shows promising effects on weight loss and weight maintenance, especially in multisession approaches. Overall, the reported findings are heterogeneous pointing to large interindividual differences in tDCS responsiveness.
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Affiliation(s)
- Theresa Ester
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.
- German Center of Diabetes Research (DZD), Tübingen, Germany.
| | - Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.
- German Center of Diabetes Research (DZD), Tübingen, Germany.
- Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Ebehard Karls University Tübingen, Tübingen, Germany.
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Hong KS, Khan MNA, Ghafoor U. Non-invasive transcranial electrical brain stimulation guided by functional near-infrared spectroscopy for targeted neuromodulation: A review. J Neural Eng 2022; 19. [PMID: 35905708 DOI: 10.1088/1741-2552/ac857d] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/29/2022] [Indexed: 11/12/2022]
Abstract
One of the primary goals in cognitive neuroscience is to understand the neural mechanisms on which cognition is based. Researchers are trying to find how cognitive mechanisms are related to oscillations generated due to brain activity. The research focused on this topic has been considerably aided by developing non-invasive brain stimulation techniques. The dynamics of brain networks and the resultant behavior can be affected by non-invasive brain stimulation techniques, which make their use a focus of interest in many experiments and clinical fields. One essential non-invasive brain stimulation technique is transcranial electrical stimulation (tES), subdivided into transcranial direct and alternating current stimulation. tES has recently become more well-known because of the effective results achieved in treating chronic conditions. In addition, there has been exceptional progress in the interpretation and feasibility of tES techniques. Summarizing the beneficial effects of tES, this article provides an updated depiction of what has been accomplished to date, brief history, and the open questions that need to be addressed in the future. An essential issue in the field of tES is stimulation duration. This review briefly covers the stimulation durations that have been utilized in the field while monitoring the brain using functional-near infrared spectroscopy-based brain imaging.
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Affiliation(s)
- Keum-Shik Hong
- Department of Cogno-mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumgeong-gu, Busan, Busan, 609735, Korea (the Republic of)
| | - M N Afzal Khan
- Pusan National University, Department of Mechanical Engineering, Busan, 46241, Korea (the Republic of)
| | - Usman Ghafoor
- School of Mechanical Engineering, Pusan National University College of Engineering, room 204, Busan, 46241, Korea (the Republic of)
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Kricheldorff J, Göke K, Kiebs M, Kasten FH, Herrmann CS, Witt K, Hurlemann R. Evidence of Neuroplastic Changes after Transcranial Magnetic, Electric, and Deep Brain Stimulation. Brain Sci 2022; 12:929. [PMID: 35884734 PMCID: PMC9313265 DOI: 10.3390/brainsci12070929] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 02/04/2023] Open
Abstract
Electric and magnetic stimulation of the human brain can be used to excite or inhibit neurons. Numerous methods have been designed over the years for this purpose with various advantages and disadvantages that are the topic of this review. Deep brain stimulation (DBS) is the most direct and focal application of electric impulses to brain tissue. Electrodes are placed in the brain in order to modulate neural activity and to correct parameters of pathological oscillation in brain circuits such as their amplitude or frequency. Transcranial magnetic stimulation (TMS) is a non-invasive alternative with the stimulator generating a magnetic field in a coil over the scalp that induces an electric field in the brain which, in turn, interacts with ongoing brain activity. Depending upon stimulation parameters, excitation and inhibition can be achieved. Transcranial electric stimulation (tES) applies electric fields to the scalp that spread along the skull in order to reach the brain, thus, limiting current strength to avoid skin sensations and cranial muscle pain. Therefore, tES can only modulate brain activity and is considered subthreshold, i.e., it does not directly elicit neuronal action potentials. In this review, we collect hints for neuroplastic changes such as modulation of behavior, the electric activity of the brain, or the evolution of clinical signs and symptoms in response to stimulation. Possible mechanisms are discussed, and future paradigms are suggested.
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Affiliation(s)
- Julius Kricheldorff
- Department of Neurology, School of Medicine and Health Sciences, Carl von Ossietzky University, 26129 Oldenburg, Germany; (J.K.); (K.W.)
| | - Katharina Göke
- Division of Medical Psychology, Department of Psychiatry and Psychotherapy, University Hospital Bonn, 53127 Bonn, Germany; (K.G.); (M.K.)
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 3G8, Canada
| | - Maximilian Kiebs
- Division of Medical Psychology, Department of Psychiatry and Psychotherapy, University Hospital Bonn, 53127 Bonn, Germany; (K.G.); (M.K.)
| | - Florian H. Kasten
- Experimental Psychology Lab, Carl von Ossietzky University, 26129 Oldenburg, Germany; (F.H.K.); (C.S.H.)
| | - Christoph S. Herrmann
- Experimental Psychology Lab, Carl von Ossietzky University, 26129 Oldenburg, Germany; (F.H.K.); (C.S.H.)
- Research Center Neurosensory Sciences, Carl von Ossietzky University, 26129 Oldenburg, Germany
| | - Karsten Witt
- Department of Neurology, School of Medicine and Health Sciences, Carl von Ossietzky University, 26129 Oldenburg, Germany; (J.K.); (K.W.)
- Research Center Neurosensory Sciences, Carl von Ossietzky University, 26129 Oldenburg, Germany
| | - Rene Hurlemann
- Division of Medical Psychology, Department of Psychiatry and Psychotherapy, University Hospital Bonn, 53127 Bonn, Germany; (K.G.); (M.K.)
- Research Center Neurosensory Sciences, Carl von Ossietzky University, 26129 Oldenburg, Germany
- Department of Psychiatry and Psychotherapy, Carl von Ossietzky University, 26129 Oldenburg, Germany
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75
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Zandonai T, Bertucco M, Graziani N, Montani V, Cesari P. Transcranial Direct Current Stimulation (tDCS) modulates motor execution in a limb reaching task. Eur J Neurosci 2022; 56:4445-4454. [PMID: 35790041 DOI: 10.1111/ejn.15756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/10/2022] [Accepted: 06/30/2022] [Indexed: 11/30/2022]
Abstract
The majority of human activities show a trade-off between movement speed and accuracy. Here we tested 16 participants in a quick pointing action after 20 minutes (2mA) of transcranial Direct Current Stimulation (tDCS) delivered at the Supplementary Motor Area (SMA) in a single-blind crossover design study for testing the feedforward components in the control of action. tDCS stimuli were delivered in three randomized sessions of stimulations as anodal, cathodal and sham as a control. The task performed Pre and Post tDCS stimulation, was to point as fast and as precise as possible with the big toe to targets having different sizes (2 and 8 cm; Width) and positioned at different Distances (20 and 60 cm; Distance). An optoelectronic motion capture system was used to collect the kinematics of movement. Result indicates that individuals after receiving anodal stimulation decreased their movement time and increased their movement speed while the opposite happened after receiving a cathodal stimulation. The scarcity of studies in this area invites us to plan a research that aims at the trade-off especially in the clinical settings.
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Affiliation(s)
- Thomas Zandonai
- Department of Pharmacology, Paediatrics and Organic Chemistry, Miguel Hernández University of Elche Alicante, Spain.,Neuropharmacology on Pain and Functional Diversity (NED), Institute of Health and Biomedical Research of Alicante (ISABIAL Foundation), Alicante, Spain
| | - Matteo Bertucco
- Department of Neurosciences, Biomedicine and Movement Sciences. University of Verona, Verona, Italy
| | - Nadia Graziani
- Department of Neurosciences, Biomedicine and Movement Sciences. University of Verona, Verona, Italy
| | - Veronica Montani
- Department of Neurosciences, Biomedicine and Movement Sciences. University of Verona, Verona, Italy
| | - Paola Cesari
- Department of Neurosciences, Biomedicine and Movement Sciences. University of Verona, Verona, Italy
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76
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No effects of prefrontal multichannel tACS at individual alpha frequency on phonological decisions. Clin Neurophysiol 2022; 142:96-108. [DOI: 10.1016/j.clinph.2022.07.494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 05/23/2022] [Accepted: 07/17/2022] [Indexed: 11/23/2022]
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77
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Blinding efficacy and adverse events following repeated transcranial alternating current, direct current, and random noise stimulation. Cortex 2022; 154:77-88. [PMID: 35759817 DOI: 10.1016/j.cortex.2022.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 04/10/2022] [Accepted: 05/03/2022] [Indexed: 11/22/2022]
Abstract
As transcranial electrical stimulation (tES) protocols advance, assumptions underlying the technique need to be retested to ensure they still hold. Whilst the safety of stimulation has been demonstrated mainly for a small number of sessions, and small sample size, adverse events (AEs) following multiple sessions remain largely untested. Similarly, whilst blinding procedures are typically assumed to be effective, the effect of multiple stimulation sessions on the efficacy of blinding procedures also remains under question. This is especially relevant in multisite projects where small unintentional variations in protocol could lead to inter-site difference. We report AE and blinding data from 1,019 participants who received up to 11 semi-consecutive sessions of active or sham transcranial alternating current stimulation (tACS), direct current stimulation (tDCS), and random noise stimulation (tRNS), at 4 sites in the UK and US. We found that AEs were often best predicted by factors other than tES, such as testing site or session number. Results from the blinding analysis suggested that blinding was less effective for tDCS and tACS than tRNS. The occurrence of AEs did not appear to be linked to tES despite the use of smaller electrodes or repeated delivery. However, blinding efficacy was impacted in tES conditions with higher cutaneous sensation, highlighting a need for alternative stimulation blinding protocols. This may be increasingly necessary in studies wishing to deliver stimulation with higher intensities.
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78
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Short periods of bipolar anodal TDCS induce no instantaneous dose-dependent increase in cerebral blood flow in the targeted human motor cortex. Sci Rep 2022; 12:9580. [PMID: 35688875 PMCID: PMC9187751 DOI: 10.1038/s41598-022-13091-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/20/2022] [Indexed: 12/03/2022] Open
Abstract
Anodal transcranial direct current stimulation (aTDCS) of primary motor hand area (M1-HAND) can enhance corticomotor excitability, but it is still unknown which current intensity produces the strongest effect on intrinsic neural firing rates and synaptic activity. Magnetic resonance imaging (MRI) combined with pseudo-continuous Arterial Spin Labeling (pcASL MRI) can map regional cortical blood flow (rCBF). The measured rCBF signal is sensitive to regional changes in neuronal activity due to neurovascular coupling. Therefore, concurrent TDCS and pcASL MRI may reveal the relationship between current intensity and TDCS-induced changes in overall firing rates and synaptic activity in the cortical target. Here we employed pcASL MRI to map acute rCBF changes during short-duration aTDCS of left M1-HAND. Using the rCBF response as a proxy for regional neuronal activity, we investigated if short-duration aTDCS produces an instantaneous dose-dependent rCBF increase in the targeted M1-HAND that may be useful for individual dosing. Nine healthy right-handed participants received 30 s of aTDCS at 0.5, 1.0, 1.5, and 2.0 mA with the anode placed over left M1-HAND and cathode over the right supraorbital region. Concurrent pcASL MRI at 3 T probed TDCS-related rCBF changes in the targeted M1-HAND. Movement-induced rCBF changes were also assessed. Apart from a subtle increase in rCBF at 0.5 mA, short-duration aTDCS did not modulate rCBF in the M1-HAND relative to no-stimulation periods. None of the participants showed a dose-dependent increase in rCBF during aTDCS, even after accounting for individual differences in TDCS-induced electrical field strength. In contrast, finger movements led to robust activation of left M1-HAND before and after aTDCS. Short-duration bipolar aTDCS does not produce consistant instantaneous dose-dependent rCBF increases in the targeted M1-HAND at conventional intensity ranges. Therefore, the regional hemodynamic response profile to short-duration aTDCS may not be suited to inform individual dosing of TDCS intensity.
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79
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Aneksan B, Sawatdipan M, Bovonsunthonchai S, Tretriluxana J, Vachalathiti R, Auvichayapat P, Pheungphrarattanatrai A, Piriyaprasarth P, Klomjai W. Five-Session Dual-Transcranial Direct Current Stimulation With Task-Specific Training Does Not Improve Gait and Lower Limb Performance Over Training Alone in Subacute Stroke: A Pilot Randomized Controlled Trial. Neuromodulation 2022; 25:558-568. [PMID: 35667771 DOI: 10.1111/ner.13526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/15/2021] [Accepted: 07/28/2021] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine the effect of five-session dual-transcranial direct current stimulation (dual-tDCS) combined with task-specific training on gait and lower limb motor performance in individuals with subacute stroke. MATERIALS AND METHODS Twenty-five participants who had a stroke in the subacute phase with mild motor impairment were recruited, randomized, and allocated into two groups. The active group (n = 13) received dual-tDCS with anodal over the lesioned hemisphere M1 and cathodal over the nonlesioned hemisphere, at 2 mA for 20 min before training for five consecutive days, while the sham group (n = 12) received sham mode before training. Gait speed as a primary outcome, temporospatial gait variables, lower-limb functional tasks (sit-to-stand and walking mobility), and muscle strength as secondary outcomes were collected at preintervention and postintervention (day 5), one-week follow-up, and one-month follow-up. RESULTS The primary outcome and most of the secondary outcomes were improved in both groups, with no significant difference between the two groups, and most of the results indicated small to moderate effect sizes of active tDCS compared to sham tDCS. CONCLUSION The combined intervention showed no benefit over training alone in improving gait variables and lower-limb performance. However, some performances were saturated at some point, as moderate to high function participants were recruited in the present study. Future studies should consider recruiting participants with more varied motor impairment levels and may need to determine the optimal stimulation protocols and parameters to improve gait and lower-limb performance.
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Affiliation(s)
- Benchaporn Aneksan
- Neuro Electrical Stimulation laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, Salaya, Nakhon Pathom, Thailand; Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, Thailand
| | - Montawan Sawatdipan
- Neuro Electrical Stimulation laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, Salaya, Nakhon Pathom, Thailand; Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, Thailand
| | - Sunee Bovonsunthonchai
- Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, Thailand
| | - Jarugool Tretriluxana
- Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, Thailand
| | - Roongtiwa Vachalathiti
- Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, Thailand
| | - Paradee Auvichayapat
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | | | - Pagamas Piriyaprasarth
- Neuro Electrical Stimulation laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, Salaya, Nakhon Pathom, Thailand; Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, Thailand
| | - Wanalee Klomjai
- Neuro Electrical Stimulation laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, Salaya, Nakhon Pathom, Thailand; Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, Thailand.
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80
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Klomjai W, Siripornpanich V, Aneksan B, Vimolratana O, Permpoonputtana K, Tretriluxana J, Thichanpiang P. Effects of cathodal transcranial direct current stimulation on inhibitory and attention control in children and adolescents with attention-deficit hyperactivity disorder: A pilot randomized sham-controlled crossover study. J Psychiatr Res 2022; 150:130-141. [PMID: 35367657 DOI: 10.1016/j.jpsychires.2022.02.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 02/10/2022] [Accepted: 02/28/2022] [Indexed: 02/07/2023]
Abstract
The pathophysiological of attention-deficit hyperactivity disorder (ADHD) includes hypoactivation of the dorso-lateral prefrontal cortex (DLPFC). Most studies have used anodal (excitatory) transcranial direct current stimulation (tDCS) to improve ADHD symptoms, however, a meta-analysis showed limited effect on improving inhibition, and no evidence of attention improvement. We thus present a pilot protocol for investigating the effect of other montage i.e. cathodal (inhibitory) tDCS on neurophysiological and behavioral measures in ADHD. Eleven participants underwent active (1.5 mA, 20 min) and sham cathodal tDCS over the left DLPFC for 5 consecutive days at a 1-month interval. Quantitative electroencephalography was recorded in a resting state with the eyes opened and closed during visual go/no-go and auditory continuous performance tasks at baseline, after five sessions, and at 1-week and 1-month follow-ups. Correct responses and omission errors were recorded. After five active sessions, alpha power increased in the right frontal area when the eyes were opened, and delta power in the left frontal area and omission errors decreased during go/no-go tasks, with no differences at follow-ups. The results revealed improvements in inhibitory control, but not for attention. No aftereffects were observed in either outcomes. However, the changes found in both hemispheres would probably support the hypothesis that cathodal stimulation over the left DLPFC may increase the activity of the right DLPFC via transcallosal inhibition. Results of this pilot trial would help to design and implement a full-scale randomized control trials for further ADHD research. This study was registered on ClinicalTrials.gov (NCT03955692).
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Affiliation(s)
- Wanalee Klomjai
- Neuro Electrical Stimulation Laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, Salaya, Nakhon Pathom, 73170, Thailand; Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Vorasith Siripornpanich
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Benchaporn Aneksan
- Neuro Electrical Stimulation Laboratory (NeuE), Faculty of Physical Therapy, Mahidol University, Salaya, Nakhon Pathom, 73170, Thailand; Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Oranich Vimolratana
- Department of Physical Therapy, School of Integrative Medicine, Mae Fah Luang University, Chiang Rai, 57100, Thailand
| | - Kannika Permpoonputtana
- National Institute for Child and Family Development, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Jarugool Tretriluxana
- Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand; Motor Control and Neural Plasticity Laboratory, Faculty of Physical Therapy, Mahidol University, Salaya, Nakhon Pathom, 73170, Thailand
| | - Peeradech Thichanpiang
- Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand; Division of Occupational Therapy, Faculty of Physical Therapy Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom, 73170, Thailand.
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81
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Olgiati E, Malhotra PA. Using non-invasive transcranial direct current stimulation for neglect and associated attentional deficits following stroke. Neuropsychol Rehabil 2022; 32:732-763. [PMID: 32892712 DOI: 10.1080/09602011.2020.1805335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Neglect is a disabling neuropsychological syndrome that is frequently observed following right-hemispheric stroke. Affected individuals often present with multiple attentional deficits, ranging from reduced orienting towards contralesional space to a generalized impairment in maintaining attention over time. Although a degree of spontaneous recovery occurs in most patients, in some individuals this condition can be treatment-resistant with prominent ongoing non-spatial deficits. Further, there is a large inter-individual variability in response to different therapeutic approaches. Given its potential to alter neuronal excitability and affect neuroplasticity, non-invasive brain stimulation is a promising tool that could potentially be utilized to facilitate recovery. However, there are many outstanding questions regarding its implementation in this heterogeneous patient group. Here we provide a critical overview of the available evidence on the use of non-invasive electrical brain stimulation, focussing on transcranial direct current stimulation (tDCS), to improve neglect and associated attentional deficits after right-hemispheric stroke. At present, there is insufficient robust evidence supporting the clinical use of tDCS to alleviate symptoms of neglect. Future research would benefit from careful study design, enhanced precision of electrical montages, multi-modal approaches exploring predictors of response, tailored dose-control applications and increased efforts to evaluate standalone tDCS versus its incorporation into combination therapy.
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Affiliation(s)
- Elena Olgiati
- Department of Brain Sciences, Imperial College London, London, UK.,Imperial College Healthcare NHS Trust, London, UK
| | - Paresh A Malhotra
- Department of Brain Sciences, Imperial College London, London, UK.,Imperial College Healthcare NHS Trust, London, UK.,UK Dementia Research Institute, Care Research & Technology Centre, Imperial College London and University of Surrey, London, UK
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82
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Caulfield KA, Indahlastari A, Nissim NR, Lopez JW, Fleischmann HH, Woods AJ, George MS. Electric Field Strength From Prefrontal Transcranial Direct Current Stimulation Determines Degree of Working Memory Response: A Potential Application of Reverse-Calculation Modeling? Neuromodulation 2022; 25:578-587. [PMID: 35670064 DOI: 10.1111/ner.13342] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/24/2020] [Accepted: 11/30/2020] [Indexed: 12/26/2022]
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) for working memory is an enticing treatment, but there is mixed evidence to date. OBJECTIVES We tested the effects of electric field strength from uniform 2 mA dosing on working memory change from prestimulation to poststimulation. Second, we statistically evaluated a reverse-calculation method of individualizing tDCS dose and its effect on normalizing electric field at the cortex. MATERIALS AND METHODS We performed electric field modeling on a data set of 28 healthy older adults (15 women, mean age = 73.7, SD = 7.3) who received ten sessions of active 2 mA tDCS (N = 14) or sham tDCS (N = 14) applied over bilateral dorsolateral prefrontal cortices (DLPFC) in a triple-blind design. We evaluated the relationship between electric field strength and working memory change on an N-back task in conditions of above-median, high electric field from active 2 mA (N = 7), below-median, low electric field from active 2 mA (N = 7), and sham (N = 14) at regions of interest (ROI) at the left and right DLPFC. We then determined the individualized reverse-calculation dose to produce the group average electric field and measured the electric field variance between uniform 2 mA doses vs individualized reverse-calculation doses at the same ROIs. RESULTS Working memory improvements from pre- to post-tDCS were significant for the above-median electric field from active 2 mA condition at the left DLPFC (mixed ANOVA, p = 0.013). Furthermore, reverse-calculation modeling significantly reduced electric field variance at both ROIs (Levene's test; p < 0.001). CONCLUSIONS Higher electric fields at the left DLPFC from uniform 2 mA doses appear to drive working memory improvements from tDCS. Individualized doses from reverse-calculation modeling significantly reduce electric field variance at the cortex. Taken together, using reverse-calculation modeling to produce the same, high electric fields at the cortex across participants may produce more effective future tDCS treatments for working memory.
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Affiliation(s)
- Kevin A Caulfield
- Brain Stimulation Laboratory, Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA.
| | - Aprinda Indahlastari
- Center for Cognitive Aging and Memory Clinical Translational Research, McKnight Brain Institute, Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Nicole R Nissim
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - James W Lopez
- Brain Stimulation Laboratory, Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA
| | - Holly H Fleischmann
- Brain Stimulation Laboratory, Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA
| | - Adam J Woods
- Center for Cognitive Aging and Memory Clinical Translational Research, McKnight Brain Institute, Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Mark S George
- Brain Stimulation Laboratory, Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA; Ralph H. Johnson VA Medical Center, Charleston, SC, USA
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83
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Huang Y, Zhang Y, Zhang Y, Mai X. Effects of Transcranial Direct Current Stimulation Over the Left Primary Motor Cortex on Verbal Intelligence. Front Hum Neurosci 2022; 16:888590. [PMID: 35693542 PMCID: PMC9177941 DOI: 10.3389/fnhum.2022.888590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
Previous studies have shown that changes in gray matter density and volume in the left primary motor cortex are significantly associated with changes in individuals’ verbal intelligence quotient (VIQ), but not with their performance intelligence quotient (PIQ). In the present study, we examined the effects of transcranial direct current stimulation (tDCS) over the left primary motor cortex on performance in intelligence tests. We chose four subtests (two each for VIQ and PIQ) of the Wechsler Adult Intelligence Scale-Chinese Revised version and randomized participants into anodal, cathodal, and sham groups. We found that anodal stimulation significantly improved performance in verbal intelligence subtests compared to cathodal and sham stimulation, while performance intelligence subtest scores did not change in any stimulation condition. These findings suggest that the excitation level of the left primary motor cortex has a unique effect on verbal intelligence.
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Affiliation(s)
- Yifan Huang
- Department of Psychology, Renmin University of China, Beijing, China
| | - Yinling Zhang
- Department of Psychology, Renmin University of China, Beijing, China
| | - Yizhe Zhang
- Psychological Counseling Center, Shanghai University, Shanghai, China
| | - Xiaoqin Mai
- Department of Psychology, Renmin University of China, Beijing, China
- *Correspondence: Xiaoqin Mai,
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84
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Anodal Transcranial Direct Current Stimulation (atDCS) of the Primary Motor Cortex (M1) Facilitates Nonconscious Error Correction of Negative Phase Shifts. Neural Plast 2022; 2022:9419154. [PMID: 35662740 PMCID: PMC9159881 DOI: 10.1155/2022/9419154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/14/2022] [Accepted: 04/25/2022] [Indexed: 11/17/2022] Open
Abstract
Accurate motor timing requires the temporally precise coupling between sensory input and motor output including the adjustment of movements with respect to changes in the environment. Such error correction has been related to a cerebello-thalamo-cortical network. At least partially distinct networks for the correction of perceived (i.e., conscious) as compared to nonperceived (i.e., nonconscious) errors have been suggested. While the cerebellum, the premotor, and the prefrontal cortex seem to be involved in conscious error correction, the network subserving nonconscious error correction is less clear. The present study is aimed at investigating the functional contribution of the primary motor cortex (M1) for both types of error correction in the temporal domain. To this end, anodal transcranial direct current stimulation (atDCS) was applied to the left M1 in a group of 18 healthy young volunteers during a resting period of 10 minutes. Sensorimotor synchronization as well as error correction of the right index finger was tested immediately prior to and after atDCS. Sham stimulation served as control condition. To induce error correction, nonconscious and conscious temporal step-changes were interspersed in a sequence of an isochronous auditory pacing signal in either direction (i.e., negative or positive) yielding either shorter or longer intervals. Prior to atDCS, faster error correction in conscious as compared to nonconscious trials was observed replicating previous findings. atDCS facilitated nonconscious error correction, but only in trials with negative step-changes yielding shorter intervals. In contrast to this, neither tapping speed nor synchronization performance with respect to the isochronous pacing signal was significantly modulated by atDCS. The data suggest M1 as part of a network distinctively contributing to the correction of nonconscious negative step-changes going beyond sensorimotor synchronization.
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85
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Ostrowski J, Svaldi J, Schroeder PA. More focal, less heterogeneous? Multi-level meta-analysis of cathodal high-definition transcranial direct current stimulation effects on language and cognition. J Neural Transm (Vienna) 2022; 129:861-878. [PMID: 35585206 PMCID: PMC9217872 DOI: 10.1007/s00702-022-02507-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/26/2022] [Indexed: 11/17/2022]
Abstract
High-definition transcranial direct current stimulation (HD-tDCS) is a relatively focal, novel non-invasive brain stimulation method with the potential to investigate the causal contributions of specific cortical brain regions to language and cognition. Studies with HD-tDCS typically employ a 4 × 1 electrode design with a single central target electrode surrounded by four return electrodes, among which return current intensity is evenly distributed. With cathodal HD-tDCS, neural excitability in the target region is assumed to be reduced, which offers interesting perspectives for neuropsychological research and interventions. This multi-level meta-analysis compiles published studies using cathodal HD-tDCS in 4 × 1 configuration to modulate cognition and behavior. Regarding HD-tDCS, 77 effect sizes were gathered from 11 eligible reports. We extended this database with 52 effect sizes from 11 comparable reports using conventional tDCS with cathodal polarity. We observed no significant overall effect and no moderation by within-study and between-study variables in HD. In the extended analysis, results suggested a non-linear moderation of cathodal tDCS effects by intensity, driven by negative effect sizes at 1.5 mA. However, studies varied tremendously in task parameters, outcomes, and even technical parameters. Interestingly, within-study heterogeneity exceeded between-study heterogeneity in the present sample, and moderators hardly reduced the residual heterogeneity. Across domains and configurations, both positive and negative effect sizes are possible. We discuss the findings in relation to conventional cathodal tDCS and the framework of polarity specificity. Fundamental aspects of cathodal HD-tDCS are still to be addressed in future research.
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Affiliation(s)
- Jan Ostrowski
- Department of Psychology, University of Tübingen, Tübingen, Germany.,Department of Systems Neuroscience, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Jennifer Svaldi
- Department of Psychology, University of Tübingen, Tübingen, Germany
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86
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Ghodratitoostani I, Gonzatto OA, Vaziri Z, Delbem ACB, Makkiabadi B, Datta A, Thomas C, Hyppolito MA, Santos ACD, Louzada F, Leite JP. Dose-Response Transcranial Electrical Stimulation Study Design: A Well-Controlled Adaptive Seamless Bayesian Method to Illuminate Negative Valence Role in Tinnitus Perception. Front Hum Neurosci 2022; 16:811550. [PMID: 35677206 PMCID: PMC9169505 DOI: 10.3389/fnhum.2022.811550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/23/2022] [Indexed: 11/30/2022] Open
Abstract
The use of transcranial Electrical Stimulation (tES) in the modulation of cognitive brain functions to improve neuropsychiatric conditions has extensively increased over the decades. tES techniques have also raised new challenges associated with study design, stimulation protocol, functional specificity, and dose-response relationship. In this paper, we addressed challenges through the emerging methodology to investigate the dose-response relationship of High Definition-transcranial Direct Current Stimulation (HD tDCS), identifying the role of negative valence in tinnitus perception. In light of the neurofunctional testable framework and tES application, hypotheses were formulated to measure clinical and surrogate endpoints. We posited that conscious pairing adequately pleasant stimuli with tinnitus perception results in correction of the loudness misperception and would be reinforced by concurrent active HD-tDCS on the left Dorsolateral Prefrontal Cortex (dlPFC). The dose-response relationship between HD-tDCS specificity and the loudness perception is also modeled. We conducted a double-blind, randomized crossover pilot study with six recruited tinnitus patients. Accrued data was utilized to design a well-controlled adaptive seamless Bayesian dose-response study. The sample size (n = 47, for 90% power and 95% confidence) and optimum interims were anticipated for adaptive decision-making about efficacy, safety, and single session dose parameters. Furthermore, preliminary pilot study results were sufficient to show a significant difference (90% power, 99% confidence) within the longitudinally detected self-report tinnitus loudness between before and under positive emotion induction. This study demonstrated a research methodology used to improve emotion regulation in tinnitus patients. In the projected method, positive emotion induction is essential for promoting functional targeting under HD-tDCS anatomical specificity to indicate the efficacy and facilitate the dose-finding process. The continuous updating of prior knowledge about efficacy and dose during the exploratory stage adapts the anticipated dose-response model. Consequently, the effective dose range to make superiority neuromodulation in correcting loudness misperception of tinnitus will be redefined. Highly effective dose adapts the study to a standard randomized trial and transforms it into the confirmatory stage in which active HD-tDCS protocol is compared with a sham trial (placebo-like). Establishing the HD-tDCS intervention protocols relying on this novel method provides reliable evidence for regulatory agencies to approve or reject the efficacy and safety. Furthermore, this paper supports a technical report for designing multimodality data-driven complementary investigations in emotion regulation, including EEG-driven neuro markers, Stroop-driven attention biases, and neuroimaging-driven brain network dynamics.
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Affiliation(s)
- Iman Ghodratitoostani
- Neurocognitive Engineering Laboratory, Center for Engineering Applied to Health, Institute of Mathematics and Computer Science, University of São Paulo, São Carlos, Brazil
- *Correspondence: Iman Ghodratitoostani
| | - Oilson A. Gonzatto
- Institute of Mathematics and Computer Science, University of São Paulo, São Carlos, Brazil
| | - Zahra Vaziri
- Department of Neuroscience and Behavior, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirao Preto, Brazil
| | - Alexandre C. B. Delbem
- Neurocognitive Engineering Laboratory, Center for Engineering Applied to Health, Institute of Mathematics and Computer Science, University of São Paulo, São Carlos, Brazil
| | - Bahador Makkiabadi
- Research Center for Biomedical Technologies and Robotics, Institute for Advanced Medical Technologies, Tehran, Iran
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | - Miguel A. Hyppolito
- Department of Ophthalmology, Otorhinolaryngology, Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil
| | - Antonio C. D. Santos
- Department of Neuroscience and Behavior, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirao Preto, Brazil
| | - Francisco Louzada
- Institute of Mathematics and Computer Science, University of São Paulo, São Carlos, Brazil
| | - João Pereira Leite
- Department of Neuroscience and Behavior, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirao Preto, Brazil
- João Pereira Leite
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87
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Ehsani F, Ahmadi M, Masoudian N, Jaberzadeh S. Priming of postural training with cerebellar anodal transcranial direct current stimulation for its effects on postural balance and fear of falling in patients with multiple sclerosis: A randomized, double-blind, sham-controlled study. J Clin Neurosci 2022; 99:294-301. [DOI: 10.1016/j.jocn.2022.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 02/14/2022] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
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88
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Fava de Lima F, Silva CR, Kohn AF. Transcutaneous spinal direct current stimulation (tsDCS) does not affect postural sway of young and healthy subjects during quiet upright standing. PLoS One 2022; 17:e0267718. [PMID: 35482798 PMCID: PMC9049532 DOI: 10.1371/journal.pone.0267718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/13/2022] [Indexed: 12/02/2022] Open
Abstract
Transcutaneous spinal direct current stimulation (tsDCS) is an effective non-invasive spinal cord electrical stimulation technique to induce neuromodulation of local and distal neural circuits of the central nervous system (CNS). Applied to the spinal cord lumbosacral region, tsDCS changes electrophysiological responses of the motor, proprioceptive and nociceptive pathways, alters the performance of some lower limb motor tasks and can even modulate the behavior of supramedullary neuronal networks. In this study an experimental protocol was conducted to verify if tsDCS (5 mA, 20 minutes) of two different polarizations, applied over the lumbosacral region (tenth thoracic vertebrae (T10)), can induce changes in postural sway oscillations of young healthy individuals during quiet standing. A novel initialization of the electrical stimulation was developed to improve subject blinding to the different stimulus conditions including the sham trials. Measures of postural sway, both global and structural, were computed before, during and following the DC stimulation period. The results indicated that, for the adopted conditions, tsDCS did not induce statistically significant changes in postural sway of young healthy individuals during quiet standing.
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Affiliation(s)
- Felipe Fava de Lima
- Biomedical Engineering Laboratory, Escola Politécnica, University of São Paulo, São Paulo, Brazil
- * E-mail:
| | - Cristiano Rocha Silva
- Biomedical Engineering Laboratory, Escola Politécnica, University of São Paulo, São Paulo, Brazil
| | - Andre Fabio Kohn
- Biomedical Engineering Laboratory, Escola Politécnica, University of São Paulo, São Paulo, Brazil
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89
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Directionality of the injected current targeting the P20/N20 source determines the efficacy of 140 Hz transcranial alternating current stimulation (tACS)-induced aftereffects in the somatosensory cortex. PLoS One 2022; 17:e0266107. [PMID: 35324989 PMCID: PMC8947130 DOI: 10.1371/journal.pone.0266107] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 03/14/2022] [Indexed: 11/19/2022] Open
Abstract
Interindividual anatomical differences in the human cortex can lead to suboptimal current directions and may result in response variability of transcranial electrical stimulation methods. These differences in brain anatomy require individualized electrode stimulation montages to induce an optimal current density in the targeted area of each individual subject. We aimed to explore the possible modulatory effects of 140 Hz transcranial alternating current stimulation (tACS) on the somatosensory cortex using personalized multi-electrode stimulation montages. In two randomized experiments using either tactile finger or median nerve stimulation, we measured by evoked potentials the plasticity aftereffects and oscillatory power changes after 140 Hz tACS at 1.0 mA as compared to sham stimulation (n = 17, male = 9). We found a decrease in the power of oscillatory mu-rhythms during and immediately after tactile discrimination tasks, indicating an engagement of the somatosensory system during stimulus encoding. On a group level both the oscillatory power and the evoked potential amplitudes were not modulated by tACS neither after tactile finger stimulation nor after median nerve stimulation as compared to sham stimulation. On an individual level we could however demonstrate that lower angular difference (i.e., differences between the injected current vector in the target region and the source orientation vector) is associated with significantly higher changes in both P20/N20 and N30/P30 source activities. Our findings suggest that the higher the directionality of the injected current correlates to the dipole orientation the greater the tACS-induced aftereffects are.
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90
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Schroeder PA, Seewald A, Svaldi J. Spotlight on the Left Frontal Cortex: No Evidence for Response Inhibition from Cathodal High-Definition tDCS over Left IFG or Left DLPFC. J Cogn Neurosci 2022; 34:1090-1102. [PMID: 35303094 DOI: 10.1162/jocn_a_01849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Inhibitory control functions draw on a fronto-basal network with central cortical hubs at the right inferior frontal gyrus (IFG) and the pre-SMA. However, few neuropsychological studies investigated the role of brain regions in the left frontal cortex and some previous evidence from bilateral studies remained inconclusive. This study presents a systematic investigation with high-definition transcranial direct current stimulation (HD tDCS) in a focal 4 × 1 configuration, which was used to target the left IFG or the left dorsolateral prefrontal cortex (DLPFC) with 1-mA active or sham cathodal HD tDCS. Healthy participants were randomized into three groups. We analyzed performance in an adaptive stop-signal task to quantify inhibitory control before (baseline), during cathodal HD tDCS (on-line), and after cathodal HD tDCS (off-line) to either left IFG, left DLPFC, or sham. Results from 67 participants and Bayesian analyses indicated moderate evidence against an effect of cathodal tDCS (left DLPFC and left IFG compared with sham) regardless of timing, that is, on-line or off-line cathodal HD tDCS. The study results are examined in view of previous neuropsychological and neurostimulation studies with bilateral and unilateral cathodal tDCS in healthy and patient samples. Theoretically, our results are compatible with a right-lateralization of response inhibition functions and suggest a negligible role of the left frontal hemisphere in healthy participants, but more stimulation parameters can be still explored in the left hemisphere. In line with previous studies, right inferior frontal gyrus seems a more promising target to investigate or alleviate response inhibition with tDCS.
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Affiliation(s)
| | - Anna Seewald
- University of Tübingen, Germany.,University of Marburg, Germany
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91
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Muffel T, Shih PC, Kalloch B, Nikulin V, Villringer A, Sehm B. Differential effects of anodal and dual tDCS on sensorimotor functions in chronic hemiparetic stroke patients. Brain Stimul 2022; 15:509-522. [DOI: 10.1016/j.brs.2022.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/14/2022] [Accepted: 02/21/2022] [Indexed: 11/24/2022] Open
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Gu J, Li D, Li Z, Guo Y, Qian F, Wang Y, Tang L. The Effect and Mechanism of Transcranial Direct Current Stimulation on Episodic Memory in Patients With Mild Cognitive Impairment. Front Neurosci 2022; 16:811403. [PMID: 35250453 PMCID: PMC8891804 DOI: 10.3389/fnins.2022.811403] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE This study aimed to investigate the efficacy of transcranial direct current stimulation (tDCS) on episodic memory in patients with mild cognitive impairment (MCI) and analyze the neural mechanism of tDCS therapy from the perspective of neuroelectrophysiological parameters. METHODS Forty MCI patients were recruited and randomly divided into a sham group (n = 20) and a tDCS group (n = 20). Patients in the tDCS group were treated with a tDCS instrument for 20 min, once a day, for 5 days. Patients in the sham group were treated with sham stimulus. Montreal Cognitive Assessment Scale (MoCA), Wechsler Memory Scale (WMS), and event-related potential (ERP) (amplitude and latency of P300 wave) were comparatively assessed between the two groups at pre-treatment, 5 days and 4 weeks post-treatment points. RESULTS The two groups showed no significant difference in any of the assessed parameters at pre-treatment (P > 0.05). At 5 days post-treatment, memory quotient (MQ) score in the tDCS group significantly increased (P < 0.05), scores of picture memory, visual regeneration, logical memory, memory span, visual regeneration-delay, and logical memory-delay were significantly increased compared to pre-treatment (P < 0.01). The P300 amplitude significantly increased, and its latency significantly shortened (P < 0.01). Four weeks post-treatment, the scores of MQ and visual regeneration-delay in the tDCS group increased, compared to pre-treatment (P < 0.05); picture memory, visual regeneration, logical memory, memory span, and logical memory-delay improved (P < 0.01); the P300 amplitude increased, and its latency shortened (P < 0.01). At 5 days and 4 weeks post-treatment points, the tDCS group, compared with the sham group (P < 0.01), exhibited greater scores of MQ, picture memory, visual regeneration, logical memory, memory span, visual regeneration-delay, and logical memory-delay, increased P300 amplitude, and shortened P300 latency. Similarly, the tDCS group showed higher MQ scores at 5 days post-treatment (P < 0.05) and 4 weeks post-treatment (P < 0.01). Before treatment and after 5 days of treatment, P300 amplitude and latency difference were positively correlated with MQ difference (P < 0.05). CONCLUSION tDCS improved episodic memory in MCI patients, and the effect lasted for 4 weeks. Changes in ERP (P300) suggested that tDCS could promote changes in brain function.
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Affiliation(s)
- Jun Gu
- Department of Mental Rehabilitation, Wuxi Mental Health Center, Wuxi, China
| | - Da Li
- Department of Mental Rehabilitation, Wuxi Mental Health Center, Wuxi, China
| | - Zhaohui Li
- Department of Neurorehabilitation, Wuxi Tongren Rehabilitation Hospital, Wuxi, China
| | - Yuan Guo
- Psychometric Laboratory, Wuxi Mental Health Center, Wuxi, China
| | - Fuqiang Qian
- Medical Administration Department, Wuxi Mental Health Center, Wuxi, China
| | - Ying Wang
- Department of Psychiatry, Wuxi Mental Health Center, Wuxi, China
| | - Li Tang
- Department of Psychiatry, Wuxi Mental Health Center, Wuxi, China
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93
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Agadagba SK, Eldaly ABM, Chan LLH. Transcorneal Electrical Stimulation Induces Long-Lasting Enhancement of Brain Functional and Directional Connectivity in Retinal Degeneration Mice. Front Cell Neurosci 2022; 16:785199. [PMID: 35197826 PMCID: PMC8860236 DOI: 10.3389/fncel.2022.785199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/14/2022] [Indexed: 12/21/2022] Open
Abstract
To investigate neuromodulation of functional and directional connectivity features in both visual and non-visual brain cortices after short-term and long-term retinal electrical stimulation in retinal degeneration mice. We performed spontaneous electrocorticography (ECoG) in retinal degeneration (rd) mice following prolonged transcorneal electrical stimulation (pTES) at varying currents (400, 500 and 600 μA) and different time points (transient or day 1 post-stimulation, 1-week post-stimulation and 2-weeks post-stimulation). We also set up a sham control group of rd mice which did not receive any electrical stimulation. Subsequently we analyzed alterations in cross-frequency coupling (CFC), coherence and directional connectivity of the primary visual cortex and the prefrontal cortex. It was observed that the sham control group did not display any significant changes in brain connectivity across all stages of electrical stimulation. For the stimulated groups, we observed that transient electrical stimulation of the retina did not significantly alter brain coherence and connectivity. However, for 1-week post-stimulation, we identified enhanced increase in theta-gamma CFC. Meanwhile, enhanced coherence and directional connectivity appeared predominantly in theta, alpha and beta oscillations. These alterations occurred in both visual and non-visual brain regions and were dependent on the current amplitude of stimulation. Interestingly, 2-weeks post-stimulation demonstrated long-lasting enhancement in network coherence and connectivity patterns at the level of cross-oscillatory interaction, functional connectivity and directional inter-regional communication between the primary visual cortex and prefrontal cortex. Application of electrical stimulation to the retina evidently neuromodulates brain coherence and connectivity of visual and non-visual cortices in retinal degeneration mice and the observed alterations are largely maintained. pTES holds strong possibility of modulating higher cortical functions including pathways of cognition, awareness, emotion and memory.
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Affiliation(s)
- Stephen K. Agadagba
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Abdelrahman B. M. Eldaly
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- Electrical Engineering Department, Faculty of Engineering, Minia University, Minia, Egypt
| | - Leanne Lai Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- *Correspondence: Leanne Lai Hang Chan,
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94
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Kan RL, Xu GX, Shu KT, Lai FH, Kranz G, Kranz GS. Effects of non-invasive brain stimulation in multiple sclerosis: systematic review and meta-analysis. Ther Adv Chronic Dis 2022; 13:20406223211069198. [PMID: 35126965 PMCID: PMC8814979 DOI: 10.1177/20406223211069198] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 12/07/2021] [Indexed: 12/29/2022] Open
Abstract
Objective: The objective of this meta-analysis was to summarize evidence on the therapeutic effects of non-invasive brain stimulation (NIBS) on core symptoms of multiple sclerosis (MS). Specifically, findings from studies deploying transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) protocols were summarized in this review. Methods: We systematically searched articles published in four databases, until 31 May 2021, which compared the effects of active tDCS or rTMS with sham intervention in MS patients. We used a random-effects model for this meta-analysis. Meta-regression and subgroup meta-analysis were used to examine the effects of stimulation dose and different stimulation protocols, respectively. Results: Twenty-five randomized controlled trials (RCTs) were included in this review, consisting of 19 tDCS and 6 rTMS studies. tDCS led to a significant and immediate reduction of fatigue with a large effect size (Hedges’s g = −0.870, 95% confidence intervals (CI) = [−1.225 to −0.458], number needed to treat (NNT) = 2). Particularly, a subgroup analysis showed that applying tDCS over the left DLPFC and bilateral S1 led to fatigue reductions compared to sham stimulation. Furthermore, tDCS had favorable effects on fatigue in MS patients with low physical disability but not those with high physical disability, and additionally improved cognitive function. Finally, whereas rTMS was observed to reduce muscle spasticity, these NIBS protocols showed no further effect on MS-associated pain and mood symptoms. Conclusion: tDCS in MS alleviates fatigue and improves cognitive function whereas rTMS reduces muscle spasticity. More high-quality studies are needed to substantiate the therapeutic effects of different NIBS protocols in MS.
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Affiliation(s)
- Rebecca L.D. Kan
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, SAR, China
| | - Grace X.J. Xu
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, SAR, China
| | - Kate T. Shu
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, SAR, China
- Department of Rehabilitation, Third Military Medical University Southwest Hospital, Chongqing, China
| | - Frank H.Y. Lai
- Faculty of Health and Life Sciences, The Northumbria University Newcastle, Newcastle upon Tyne, UK
| | - Gottfried Kranz
- Neurological Rehabilitation Center Rosenhügel, Vienna, Austria
| | - Georg S. Kranz
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, SAR, 999077, China; Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria; The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China
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95
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Feasibility of Combining Transcranial Direct Current Stimulation and Active Fully Embodied Virtual Reality for Visual Height Intolerance: A Double-Blind Randomized Controlled Study. J Clin Med 2022; 11:jcm11020345. [PMID: 35054039 PMCID: PMC8779186 DOI: 10.3390/jcm11020345] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/02/2022] [Accepted: 01/05/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Transcranial Direct Current Stimulation (tDCS) and Virtual Reality Exposure Therapy (VRET) are individually increasingly used in psychiatric research. OBJECTIVE/HYPOTHESIS Our study aimed to investigate the feasibility of combining tDCS and wireless 360° full immersive active and embodied VRET to reduce height-induced anxiety. METHODS We carried out a pilot randomized, double-blind, controlled study associating VRET (two 20 min sessions with a 48 h interval, during which, participants had to cross a plank at rising heights in a building in construction) with online tDCS (targeting the ventromedial prefrontal cortex) in 28 participants. The primary outcomes were the sense of presence level and the tolerability. The secondary outcomes were the anxiety level (Subjective Unit of Discomfort) and the salivary cortisol concentration. RESULTS We confirmed the feasibility of the association between tDCS and fully embodied VRET associated with a good sense of presence without noticeable adverse effects. In both groups, a significant reduction in the fear of height was observed after two sessions, with only a small effect size of add-on tDCS (0.1) according to the SUD. The variations of cortisol concentration differed in the tDCS and sham groups. CONCLUSION Our study confirmed the feasibility of the association between wireless online tDCS and active, fully embodied VRET. The optimal tDCS paradigm remains to be determined in this context to increase effect size and then adequately power future clinical studies assessing synergies between both techniques.
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96
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Ghasemian-Shirvan E, Mosayebi-Samani M, Farnad L, Kuo MF, Meesen RL, Nitsche MA. Age-dependent non-linear neuroplastic effects of cathodal tDCS in the elderly population; a titration study. Brain Stimul 2022; 15:296-305. [DOI: 10.1016/j.brs.2022.01.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/27/2021] [Accepted: 01/16/2022] [Indexed: 11/16/2022] Open
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97
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Padrón I, García-Marco E, Moreno I, Birba A, Silvestri V, León I, Álvarez C, López J, de Vega M. Multisession Anodal tDCS on the Right Temporo-Parietal Junction Improves Mentalizing Processes in Adults with Autistic Traits. Brain Sci 2021; 12:brainsci12010030. [PMID: 35053774 PMCID: PMC8773564 DOI: 10.3390/brainsci12010030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/21/2021] [Accepted: 12/25/2021] [Indexed: 11/16/2022] Open
Abstract
Persons with autism spectrum disorder (ASD) have impaired mentalizing skills. In this study, a group of persons with ASD traits (high-AQ scores) initially received sham tDCS before completing a pre-test in two mentalizing tasks: false belief and self-other judgments. Over the next week, on four consecutive days, they received sessions of anodal electrical stimulation (a-tDCS) over the right temporo-parietal junction (rTPJ), a region frequently associated with the theory of mind. On the last day, after the stimulation session, they completed a new set of mentalizing tasks. A control group (with low-AQ scores) matched in age, education and intelligence received just sham stimulation and completed the same pre-test and post-test. The results showed that the high-AQ group improved their performance (faster responses), after a-tDCS, in the false belief and in the self-other judgments of mental features, whereas they did not change performance in the false photographs or the self-other judgments of physical features. These selective improvements cannot be attributed to increased familiarity with the tasks, because the performance of the low-AQ control group remained stable about one week later. Therefore, our study provides initial proof that tDCS could be used to improve mentalizing skills in persons with ASD traits.
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Affiliation(s)
- Iván Padrón
- Instituto Universitario de Neurociencia, Universidad de La Laguna, 38200 La Laguna, Spain; (I.P.); (E.G.-M.); (I.M.); (I.L.); (C.Á.); (J.L.)
| | - Enrique García-Marco
- Instituto Universitario de Neurociencia, Universidad de La Laguna, 38200 La Laguna, Spain; (I.P.); (E.G.-M.); (I.M.); (I.L.); (C.Á.); (J.L.)
- Facultad de Ciencias de la Salud, Universidad Europea de Canarias, 38300 La Orotava, Spain
- Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain
| | - Iván Moreno
- Instituto Universitario de Neurociencia, Universidad de La Laguna, 38200 La Laguna, Spain; (I.P.); (E.G.-M.); (I.M.); (I.L.); (C.Á.); (J.L.)
| | - Agustina Birba
- Cognitive Neuroscience Center (CNC), Universidad de San Andrés, Buenos Aires B1644BID, Argentina;
- National Scientific and Technical Research Council (CONICET), Buenos Aires C1033AAJ, Argentina
| | - Valentina Silvestri
- Department of Psychology, University of Milan-Bicocca, Piazza dell’Ateneo Nuovo 1, 20126 Milan, Italy;
| | - Inmaculada León
- Instituto Universitario de Neurociencia, Universidad de La Laguna, 38200 La Laguna, Spain; (I.P.); (E.G.-M.); (I.M.); (I.L.); (C.Á.); (J.L.)
| | - Carlos Álvarez
- Instituto Universitario de Neurociencia, Universidad de La Laguna, 38200 La Laguna, Spain; (I.P.); (E.G.-M.); (I.M.); (I.L.); (C.Á.); (J.L.)
| | - Joana López
- Instituto Universitario de Neurociencia, Universidad de La Laguna, 38200 La Laguna, Spain; (I.P.); (E.G.-M.); (I.M.); (I.L.); (C.Á.); (J.L.)
- Department of Psychology, Faculty of Health Sciences, University of Hull, Hull HU6 7RX, UK
| | - Manuel de Vega
- Instituto Universitario de Neurociencia, Universidad de La Laguna, 38200 La Laguna, Spain; (I.P.); (E.G.-M.); (I.M.); (I.L.); (C.Á.); (J.L.)
- Correspondence: ; Tel.: +34-630027293
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98
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Chinzara T, Buckingham G, Harris D. Transcranial direct current stimulation (tDCS) and sporting performance: A systematic review and meta-analysis of tDCS effects on physical endurance, muscular strength, and visuomotor skills. Eur J Neurosci 2021; 55:468-486. [PMID: 34904303 DOI: 10.1111/ejn.15540] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has been linked with a range of physiological and cognitive enhancements relevant to sporting performance. As a number of positive and null findings have been reported in the literature, the present meta-analysis sought to synthesise results across endurance, strength, and visuomotor skill domains to investigate if tDCS improves any aspect of sporting performance. Online database searches in August 2020 identified 43 full-text studies which examined the acute effects of tDCS compared to sham/control conditions on physical endurance, muscular strength, and visuomotor skills in healthy adults. Meta-analysis indicated a small overall effect favouring tDCS stimulation over sham/control (standardized mean difference (SMD)=0.25, CI95%[0.14;0.36]). Effects on strength (SMD=0.31, CI95%[0.10;0.51]) and visuomotor (SMD=0.29, CI95%[0.00;0.57]) tasks were larger than endurance performance (SMD=0.18, CI95%[0.00;0.37]). Meta-regressions indicated effect sizes were not related to stimulation parameters, but other factors such as genetics, gender, and experience may modulate tDCS effects. The results suggest tDCS has the potential to be used as an ergogenic aid in conjunction with a specified training regime.
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Affiliation(s)
- Trish Chinzara
- Department of Sport and Health Science, University of Exeter, UK.,Goldsmiths University of London, London, UK
| | - Gavin Buckingham
- Department of Sport and Health Science, University of Exeter, UK
| | - David Harris
- Department of Sport and Health Science, University of Exeter, UK
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Burden C, Leach RC, Sklenar AM, Urban Levy P, Frankenstein AN, Leshikar ED. Examining the influence of brain stimulation to the medial prefrontal cortex on the self-reference effect in memory. Brain Behav 2021; 11:e2368. [PMID: 34734486 PMCID: PMC8671799 DOI: 10.1002/brb3.2368] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/05/2021] [Accepted: 09/06/2021] [Indexed: 12/18/2022] Open
Abstract
Past work shows that processing information in relation to the self improves memory which is known as the self-reference effect in memory. Other work suggests that transcranial direct current stimulation (tDCS) can also improve memory. Given recent research on self-reference context memory effects (improved memory for contextual episodic details associated with self-referential processing), we were interested in examining the extent stimulation might increase the magnitude of the self-reference context memory effect. In this investigation, participants studied objects superimposed on different background scenes in either a self-reference or other-reference condition while receiving either active or sham stimulation to the dorsal medial prefrontal cortex (dmPFC), a cortical region known to support self-reference context memory effects. Participants then completed a memory test that assessed item memory (have you seen this object before?) and context memory (with which background scene was this object paired?). Results showed a self-reference context memory effect driven by enhanced memory for stimuli processed in the self-reference compared to the other-reference condition across all participants (regardless of stimulation condition). tDCS, however, had no effect on memory. Specifically, stimulation did not increase the magnitude of the self-reference context memory effect under active compared to sham stimulation. These results suggest that stimulation of the dmPFC at encoding may not add to the memory benefits induced by self-referential processing suggesting a boundary condition to tDCS effects on memory.
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Affiliation(s)
- Camill Burden
- University of Illinois at Chicago, Chicago, Illinois, USA
| | - Ryan C Leach
- University of Illinois at Chicago, Chicago, Illinois, USA
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Lee S, Smith PF, Lee WH, McKeown MJ. Frequency-Specific Effects of Galvanic Vestibular Stimulation on Response-Time Performance in Parkinson's Disease. Front Neurol 2021; 12:758122. [PMID: 34795633 PMCID: PMC8593161 DOI: 10.3389/fneur.2021.758122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/11/2021] [Indexed: 12/28/2022] Open
Abstract
Background: Galvanic vestibular stimulation (GVS) is being increasingly explored as a non-invasive brain stimulation technique to treat symptoms in Parkinson's disease (PD). To date, behavioral GVS effects in PD have been explored with only two stimulus types, direct current and random noise (RN). The interaction between GVS effects and anti-parkinsonian medication is unknown. In the present study, we designed multisine (ms) stimuli and investigated the effects of ms and RN GVS on motor response time. In comparison to the RN stimulus, the ms stimuli contained sinusoidal components only at a set of desired frequencies and the phases were optimized to improve participants' comfort. We hypothesized GVS motor effects were a function of stimulation frequency, and specifically, that band-limited ms-GVS would result in better motor performance than conventionally used broadband RN-GVS. Materials and Methods: Eighteen PD patients (PDMOFF/PDMON: off-/on-levodopa medication) and 20 healthy controls (HC) performed a simple reaction time task while receiving sub-threshold GVS. Each participant underwent nine stimulation conditions: off-stimulation, RN (4–200 Hz), ms-θ (4–8 Hz), ms-α (8–13 Hz), ms-β (13–30 Hz), ms-γ (30–50 Hz), ms-h1 (50–100 Hz), ms-h2 (100–150 Hz), and ms-h3 (150–200 Hz). Results: The ms-γ resulted in shorter response time (RPT) in both PDMOFF and HC groups compared with the RN. In addition, the RPT of the PDMOFF group decreased during the ms-β while the RPT of the HC group decreased during the ms-α, ms-h1, ms-h2, and ms-h3. There was considerable inter-subject variability in the optimum stimulus type, although the frequency range tended to fall within 8–100 Hz. Levodopa medication significantly reduced the baseline RPT of the PD patients. In contrast to the off-medication state, GVS did not significantly change RPT of the PD patients in the on-medication state. Conclusions: Using band-limited ms-GVS, we demonstrated that the GVS frequency for the best RPT varied considerably across participants and was >30 Hz for half of the PDMOFF patients. Moreover, dopaminergic medication was found to influence GVS effects in PD patients. Our results indicate the common “one-size-fits-all” RN approach is suboptimal for PD, and therefore personalized stimuli aiming to address this variability is warranted to improve GVS effects.
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Affiliation(s)
- Soojin Lee
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada.,Wellcome Centre for Integrative Neuroimaging, Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Won Hee Lee
- Department of Software Convergence, Kyung Hee University, Yongin, South Korea
| | - Martin J McKeown
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada.,Faculty of Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
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