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Otieno LA, Semmler JG, Sidhu SK. Single joint fatiguing exercise decreases long but not short-interval intracortical inhibition in older adults. Exp Brain Res 2020; 239:47-58. [PMID: 33098654 DOI: 10.1007/s00221-020-05958-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/13/2020] [Indexed: 12/18/2022]
Abstract
Ageing is accompanied by neuromuscular changes which may alter fatigue in older adults. These changes may include changes in corticospinal excitatory and inhibitory processes. Previous research has suggested that single joint fatiguing exercise decreases short-(SICI) and long-(LICI) interval intracortical inhibition in young adults. However, this is yet to be established in older adults. In 19 young (23 ± 4 years) and 18 older (69 ± 5 years) adults, SICI (2 ms interstimulus interval; ISI) and LICI (100 ms ISI) were measured in a resting first dorsal interosseous (FDI) muscle using transcranial magnetic stimulation (TMS) before and after a 15 min sustained submaximal contraction at 25% of their maximum EMG. Subsequent ten 2-min contractions held at 25% EMG were also performed to sustain fatigue for a total of 30 min, while SICI and LICI were taken immediately after each contraction. There was no change in SICI post-fatiguing exercise compared to baseline in both young and older adults (P = 0.4). Although there was no change in LICI post-fatiguing exercise in younger adults (P = 1.0), LICI was attenuated in older adults immediately post-fatiguing exercise and remained attenuated post-fatigue (PF)1 and PF2 (P < 0.05). Contrary to previous studies, the lack of change in SICI and LICI in young adults following a sustained submaximal EMG contraction suggests that GABA modulation may be dependent on the type of fatiguing task performed. The reduction in LICI in older adults post-fatiguing exercise suggests an age-related decrease in GABAB-mediated activity with sustained submaximal fatiguing exercise.
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Khedr EM, Elserogy Y, Fawzy M, Abdelrahman AA, Galal AM, Noaman MM. Effect of psychotropic drugs on cortical excitability of patients with major depressive disorders: A transcranial magnetic stimulation study. Psychiatry Res 2020; 291:113287. [PMID: 32763548 DOI: 10.1016/j.psychres.2020.113287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 11/24/2022]
Abstract
Transcranial magnetic stimulation (TMS) can be used to evaluate the effects of pharmacological interventions. The aim of this study was to assess the impact of the selective serotonin reuptake inhibitor, sertraline, and the atypical antipsychotic drugs quetiapine and olanzapine, on cortical excitability in unmedicated patients with major depressive disorder (MDD). The study included 45 medication-free MDD patients diagnosed according to DSM V. They were divided randomly into three groups who received a single oral dose of one of the three drugs sertraline (50 mg), quetiapine (100 mg) and olanzapine (10 mg). Psychological evaluation was conducted using the Mini-Mental State Examination (MMSE) and Beck Depression Inventory Scale (BDI). Resting and active motor thresholds (rMT and aMT) together with contralateral and ipsilateral cortical silent periods (cSP, and iSP) were measured for each participant before and at the time of maximum concentration of drug intake. There was significant increase in excitability of motor cortex after sertraline without changes in GABAB neurotransmission. Quetiapine and olanzapine potentiated inhibitory GABAB neurotransmission (prolongation of cSP); olanzapine additionally prolonged the iSP. Thus TMS can differentiate between the impact of different psychotropic drugs on excitatory and inhibitory transmission in motor cortex.
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Nardone R, Sebastianelli L, Versace V, Brigo F, Golaszewski S, Pucks-Faes E, Saltuari L, Trinka E. Contribution of transcranial magnetic stimulation in restless legs syndrome: pathophysiological insights and therapeutical approaches. Sleep Med 2020; 71:124-134. [PMID: 32088150 DOI: 10.1016/j.sleep.2019.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 01/06/2023]
Abstract
Transcranial magnetic stimulation (TMS) may offer a reliable means to characterize significant pathophysiologic and neurochemical aspects of restless legs syndrome (RLS). Namely, TMS has revealed specific patterns of changes in cortical excitability and plasticity, in particular dysfunctional inhibitory mechanisms and sensorimotor integration, which are thought to be part of the pathophysiological mechanisms of RLS rather than reflect a non-specific consequence of sleep architecture alteration. If delivered repetitively, TMS is able to transiently modulate the neural activity of the stimulated and connected areas. Some studies have begun to therapeutically use repetitive TMS (rTMS) to improve sensory and motor disturbances in RLS. High-frequency rTMS applied over the primary motor cortex or the supplementary motor cortex, as well as low-frequency rTMS over the primary somatosensory cortex, seem to have transient beneficial effects. However, further studies with larger patient samples, repeated sessions, an optimized rTMS setup, and clinical follow-up are needed in order to corroborate preliminary results. Thus, we performed a systematic search of all the studies that have used TMS and rTMS techniques in patients with RLS.
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Carment L, Dupin L, Guedj L, Térémetz M, Cuenca M, Krebs MO, Amado I, Maier MA, Lindberg PG. Neural noise and cortical inhibition in schizophrenia. Brain Stimul 2020; 13:1298-1304. [PMID: 32585356 DOI: 10.1016/j.brs.2020.06.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 05/25/2020] [Accepted: 06/14/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Neural information processing is subject to noise and this leads to variability in neural firing and behavior. Schizophrenia has been associated with both more variable motor control and impaired cortical inhibition, which is crucial for excitatory/inhibitory balance in neural commands. HYPOTHESIS In this study, we hypothesized that impaired intracortical inhibition in motor cortex would contribute to task-related motor noise in schizophrenia. METHODS We measured variability of force and of electromyographic (EMG) activity in upper limb and hand muscles during a visuomotor grip force-tracking paradigm in patients with schizophrenia (N = 25), in unaffected siblings (N = 17) and in healthy control participants (N = 25). Task-dependent primary motor cortex (M1) excitability and inhibition were assessed using transcranial magnetic stimulation (TMS). RESULTS During force maintenance patients with schizophrenia showed increased variability in force and EMG, despite similar mean force and EMG magnitudes. Compared to healthy controls, patients with schizophrenia also showed increased M1 excitability and reduced cortical inhibition during grip-force tracking. EMG variability and force variability correlated negatively to cortical inhibition in patients with schizophrenia. EMG variability also correlated positively to negative symptoms. Siblings had similar variability and cortical inhibition compared to controls. Increased EMG and force variability indicate enhanced motor noise in schizophrenia, which relates to reduced motor cortex inhibition. CONCLUSION The findings suggest that excessive motor noise in schizophrenia may arise from an imbalance of M1 excitation/inhibition of GABAergic origin. Thus, higher motor noise may provide a useful marker of impaired cortical inhibition in schizophrenia.
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Khedr EM, Ahmed OG, Sayed HM, Abo-Elfetoh N, Ali AM, Gomaa AM. Electrophysiological differences in cortical excitability in different forms of dementia: A transcranial magnetic stimulation and laboratory biomarkers study. Neurophysiol Clin 2020; 50:185-193. [PMID: 32591186 DOI: 10.1016/j.neucli.2020.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/17/2020] [Accepted: 05/17/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The aim of the present study was to identify neurophysiologic markers to differentiate between Alzheimer dementia (AD), Vascular dementia (VaD), and Parkinson's disease dementia (PDD), and to examine their relationship to levels of transforming growth factor β1 (TGFβ1). METHODS The study included 15 patients with each type of dementia (AD, VaD, PDD) and 25 control subjects. Dementia patients were diagnosed according to the DiagnosticandStatisticalManualofMentalDisorders4thedition-revised(DSM-IV-R). Modified Mini Mental State Examination (MMMSE), motor cortex excitability including resting and active motor thresholds (rMT, aMT), input-output (I/O) curve, contralateral and ipsilateral silent periods (cSP, iSP), short-interval intracortical inhibition (SICI) at 1,2 and 4ms, and serum levels of TGFβ1 were examined. RESULTS There were no significant differences between groups with regards to age, sex, education or socioeconomic level. There was significant neuronal hyperexcitability in the form of reduced rMT and aMT and a shallower I/O curve in all three groups of dementia compared with the control group. The durations of cSP and iSP were longer in AD and PDD groups compared with the control group, whereas there were no significant differences in VaD. SICI was less effective in the three dementia groups than in the control group at intervals of 4ms. Serum levels of TGFβ1 were significantly elevated in all dementia groups in comparison with the control group. There was a significant negative correlation between serum level of TGFβ1 and cSP, iSP, and SICI across all patients and a significant negative correlation between serum level of TGFβ1 and iSP duration in AD. CONCLUSION Although motor thresholds were reduced in all patients, measures of SICI, cSP and iSP could distinguish between dementia groups. Serum level of TGFβ1 negatively correlated with iSP specifically in the AD group. This suggests that levels of TGFβ1 may relate to GABAergic dysfunction in dementia.
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Neuronavigation based 10 sessions of repetitive transcranial magnetic stimulation therapy in chronic migraine: an exploratory study. Neurol Sci 2020; 42:131-139. [PMID: 32556749 DOI: 10.1007/s10072-020-04505-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 05/30/2020] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Chronic migraine is a disease of altered cortical excitability. Repetitive transcranial magnetic stimulation provides a novel non-invasive method to target the nociceptive circuits in the cortex. Motor cortex is one such potential target. In this study, we targeted the left motor cortex using fMRI-guided neuronavigation. MATERIALS AND METHODS Twenty right-handed patients were randomized into real and sham rTMS group. Baseline subjective pain assessments were done using visual analog scale (VAS) and questionnaires: State-Trait Anxiety Inventory, Becks Depression Inventory, and Migraine Disability Assessment (MIDAS) questionnaire. Objectively, pain was assessed by means of thermal pain thresholds using quantitative sensory testing. For corticomotor excitability parameters, resting motor thresholds and motor-evoked potentials were mapped. For rTMS total, 600 pulses in 10 trains at 10 Hz with an intertrain interval of 60 s were delivered in each session. Ten such sessions were given 5 days per week over 2 consecutive weeks. The duration of each session was 10 min. Real rTMS was administered at 70% of Resting MT. All the tests were repeated post-intervention and after 1 month of follow-up. There are no studies reporting the use of fMRI-based TMS for targeting the motor cortex in CM patients. RESULTS We observed a significant reduction in the mean VAS rating, headache frequency, and MIDAS questionnaire in real rTMS group which was maintained after 1 month of follow-up. CONCLUSION Ten sessions of fMRI-based rTMS over the left motor cortex may provide long-term pain relief in CM, but further studies are warranted to confirm our preliminary findings.
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Intraoperative neurophysiological monitoring during scoliosis surgery in patients with Duchenne muscular dystrophy. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2020; 29:2029-2035. [PMID: 32440770 DOI: 10.1007/s00586-020-06458-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 05/10/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE Little is known about the reliability and value of intraoperative neurophysiological monitoring (IONM) in patients with Duchenne muscular dystrophy (DMD) undergoing scoliosis correction surgery. The aim of this study was to investigate the feasibility of IONM and the cortical excitability in these patients. METHODS Fifteen patients with DMD and scoliosis and 15 patients with adolescent idiopathic scoliosis (AIS) underwent scoliosis correction surgery with the use of IONM. IONM consisted of transcranial electrical stimulation motor evoked potential (Tc-MEP) and somatosensory evoked potential (SSEP) monitoring. The highest Tc-MEP amplitudes were collected to test the feasibility. Preoperative compound muscle action potentials (CMAPs) and transcranial magnetic stimulation (TMS)-MEPs were recorded to test the cortical excitability. SSEPs were scored as elicitable or not elicitable. RESULTS Tc-MEP amplitudes were significantly lower in the DMD group for both the gastrocnemius and tibialis anterior muscles. However, the abductor hallucis muscle had similar amplitudes in both the DMD as the AIS group. TMS/CMAP and Tc-MEP/CMAP ratios were similar in the DMD and AIS group (P = 0.126 and P = 0.792 respectively). CONCLUSIONS Tc-MEP and SSEP monitoring is feasible, particularly when Tc-MEPs are recorded from the abductor hallucis muscle in patients with DMD. Similar TMS/CMAP and Tc-MEP/CMAP ratios show that there were no differences observed in cortical excitability between the groups. IONM seems a feasible and valuable neurophysiological tool to signal possible surgically induced damage to the spinal cord during scoliosis correction surgery in patients with DMD.
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Lanza G. Repetitive TMS for sleep disorders: are we ready? Sleep Med 2020. [PMID: 32386885 DOI: 10.1016/j.sleep.2020.03.001.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Krishnan C. Effect of paired-pulse stimulus parameters on the two phases of short interval intracortical inhibition in the quadriceps muscle group. Restor Neurol Neurosci 2020; 37:363-374. [PMID: 31306142 DOI: 10.3233/rnn-180894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Short interval intracortical inhibition (SICI) is commonly used to assess inhibition in the motor cortex and is known to be affected by the paired-pulse stimulus parameters (i.e., interstimulus interval [ISI], conditioning stimulus intensity [CSI] and test stimulus intensity [TSI]) used during testing. While the effects of stimulus parameters are well-studied in the upper-extremity, evidence in the lower-extremity is lacking. OBJECTIVE To comprehensively examine the effects of alterations in paired-pulse stimulus parameters on the two phases of SICI in the quadriceps muscle group. METHODS Seventeen adults (8 males, 9 females) volunteered to participate in this study. SICI was examined over a range of CSIs (70-90% active motor threshold [AMT]), TSIs (100-140% AMT), and ISIs (1.0-3.0 ms) using both EMG and torque responses elicited by transcranial magnetic stimulation (TMS). RESULTS The results indicated that SICI at 1.0 ms ISI was best revealed with a CSI of 70% and TSI ≥110% AMT, whereas SICI at 2.5 ms ISI was best revealed with a CSI of 80-90% and a TSI of ≥130% AMT. Unlike upper-extremity muscles, evaluating SICI with a CSI of 70% AMT and an ISI of 1.0 ms produced the greatest inhibition for all TSIs. In general, inhibitory effects were contaminated by facilitatory effects when using a TSI of 100% AMT. CONCLUSIONS The amount of inhibition was dependent on the stimulation parameters used during testing. A CSI of 70% AMT, ISI of 1.0 ms, and TSI of ≥110% AMT appear to be optimal for measuring SICI in the quadriceps muscle; however, other parameters can be used if careful consideration is given to the described interaction between the parameters.
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Summers RLS, Chen M, MacKinnon CD, Kimberley TJ. Evidence for normal intracortical inhibitory recruitment properties in cervical dystonia. Clin Neurophysiol 2020; 131:1272-1279. [PMID: 32304844 DOI: 10.1016/j.clinph.2020.03.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/17/2020] [Accepted: 03/22/2020] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Dystonia is associated with reduced intracortical inhibition as measured by the cortical silent period (cSP); however, this may be due to abnormal cSP threshold or input-output properties. This study evaluated cSP recruitment properties in people with cervical dystonia (CD). METHODS Bilateral electromyographic recordings were collected in the upper trapezius muscle in response to transcranial magnetic stimulation of the left and right primary motor cortex in a group with CD (n = 19) and controls (n = 21). cSP threshold, cSP input-output properties at stimulation intensities from 1 to 1.4x the cSP threshold, ipsilateral silent period duration (iSP) and timing and magnitude of the contralateral and ipsilateral motor evoked potential (MEP) were assessed. RESULTS The cSP threshold, input-output properties, and contralateral MEP magnitude were not significantly different between groups (all p > 0.07). Hemispheric symmetry was present in the control group while the CD group had reduced iSP (p < 0.01) and a trend for reduced ipsilateral MEP response (p = 0.053) in the left hemisphere. CONCLUSIONS Recruitment properties of intracortical inhibition are similar between control and CD groups. Transcallosal inhibition is asymmetric between hemispheres in people with CD. SIGNIFICANCE Evidence of normal intracortical inhibition recruitment properties challenge the commonly held view that cortical inhibition is reduced in dystonia.
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Huang HW, Tsai JJ, Su PF, Mau YL, Wu YJ, Wang WC, Lin CCK. Cortical Excitability by Transcranial Magnetic Stimulation as Biomarkers for Seizure Controllability in Temporal Lobe Epilepsy. Neuromodulation 2020; 23:399-406. [PMID: 31840383 DOI: 10.1111/ner.13093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 11/08/2019] [Accepted: 11/25/2019] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To investigate whether indicators of cortical excitability are good biomarkers of seizure controllability in temporal lobe epilepsy (TLE). MATERIALS AND METHODS Three groups of subjects were recruited: those with poorly controlled (PC) TLE (N = 41), well-controlled (WC) TLE (N = 71), and healthy controls (N = 44). Short- and long-latency recovery curves were obtained by paired-pulse transcranial magnetic stimulation. Linear mixed effect models were used to study the effects of group, interstimulus interval (ISI), and antiepileptic drugs on long-interval intracortical inhibition (LICI) and short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). RESULTS The mixed effect model that did not incorporate antiepileptic drugs showed that group and ISI were significant factors for LICI and SICI/ICF. LICI in the healthy control group was greater than in the two epilepsy groups, and the difference was significant at ISIs of 50, 150, and 200 msec. In contrast, SICI/ICF in the PC group was greater than in the healthy control and WC groups, and the difference was significant at an ISI of 15 msec. However, due to large variance, it was difficult to identify a cutoff value with both good sensitivity and good specificity. Incorporating the information of antiepileptic drugs to the mixed effect model did not change the overall results. CONCLUSIONS Although LICI and SICI/ICF parameters were significantly different at the group level, they may not be suitable biomarkers for the controllability of TLE at the subject level.
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Lee A, Kim H, Kim J, Choi DS, Jung JH, Lee J, Kim YH. Modulating Effects of Whole-body Vibration on Cortical Activity and Gait Function in Chronic Stroke Patients. BRAIN & NEUROREHABILITATION 2020; 13:e12. [PMID: 36744184 PMCID: PMC9879458 DOI: 10.12786/bn.2020.13.e12] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/28/2020] [Accepted: 03/05/2020] [Indexed: 11/08/2022] Open
Abstract
Whole-body vibration exercise (WBVe) can provide proper somatosensory stimulation and improve muscle strength in stroke patients. This study investigated the effects of WBVe on gait function and cortical activity in patients with chronic stroke. Thirty stroke patients were randomly assigned to either the WBVe or the control group. The WBVe group received the vibration in a half-squat position for 5 minutes at an intensity of 20 Hz. The control group kept the same posture but did not receive the vibration. Cortical activity was investigated using functional near-infrared spectroscopy (fNIRS). Gait function was assessed by a 10-m walk test (10MWT), a timed up and go (TUG) test, a Fugl-Meyer Assessment, and a Tinetti Performance-Oriented Mobility Assessment (TPOMA). In group analysis of the fNIRS data, oxygenated hemoglobin concentration was significantly increased in the ipsilesional supplementary motor area, bilateral sensorimotor cortex, and contralesional prefrontal cortex in the WBVe group compared to the control group (p < 0.05). Functional assessment demonstrated a significant interaction between time and group for the 10MWT and TUG test, suggesting that the WBVe group demonstrated meaningful improvement after intervention (p < 0.05). These results suggested that WBVe modulated the cerebral cortical activities and resulted in improvement of gait function in chronic stroke patients. Trial Registration ClinicalTrials.gov Identifier: NCT03375346.
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The present and the future of Transcranial Magnetic Stimulation in Restless Legs Syndrome. Sleep Med 2020. [PMID: 32151506 DOI: 10.1016/j.sleep.2020.02.002.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Khedr EM, Elserogy Y, Fawzy M, Elnoaman M, Galal AM. Global cortical hypoexcitability of the dominant hemisphere in major depressive disorder: A transcranial magnetic stimulation study. Neurophysiol Clin 2020; 50:175-183. [PMID: 32169427 DOI: 10.1016/j.neucli.2020.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 10/24/2022] Open
Abstract
BACKGROUND Accumulating evidence suggests that major depressive disorders (MDD) are associated with an imbalance of excitation-inhibition within the prefrontal cortex (PFC), generated by a deficit of inhibitory synaptic transmission onto glutamatergic principal neurons. Transcranial magnetic stimulation (TMS) protocols can be used to measure neuronal excitability and GABAergic inhibition and thus provide additional evidence to evaluate this theory. OBJECTIVE In the present study, TMS protocols were used to compare GABAergic function and cortical excitability of dominant hemisphere in unmedicated patients with MDD versus a control group of healthy individuals. METHODS The study included 43 MDD patients according to DSM-V and 20 age- and sex- matched healthy volunteers. Psychological evaluation was conducted using the Beck Depression Inventory (BDI). Resting and active motor thresholds (rMT and aMT) together with contralateral and ipsilateral cortical silent periods (cSP, and iSP) were measured for each participant. RESULTS rMT and aMT were higher in MDD patients compared with the control group, while cSP and iSP were significantly shorter in duration. There were significant positive correlations between the BDI score and rMT, aMT (P=0.001 and 0.002 respectively), and a negative correlation with cSP duration (P=0.001). CONCLUSION Global hypoexcitability of both pyramidal cortical neurons (elevated MTs) and GABAergic controls (shortened SPs) was evidenced within the left/dominant motor cortex in MDD. These results are consistent with previous reports of abnormal glutamate and GABA function in frontal cortex.
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Iglesias AH. Transcranial Magnetic Stimulation as Treatment in Multiple Neurologic Conditions. Curr Neurol Neurosci Rep 2020; 20:1. [PMID: 32020300 DOI: 10.1007/s11910-020-1021-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Transcranial magnetic stimulation (TMS) is a method of Non-Invasive Brain Stimulation that is based on electro-physical principles discovered by Michael Faraday. A TMS device is made of one or two copper coils, positioned superficially to a site of interest in the brain, to non-invasively produce a brief magnetic pulse to an estimated depth from the surface of the scalp with the following axonal depolarization. This axonal depolarization activates cortical and subcortical networks with multiple effects. There are different methods of TMS used, all with different mechanisms of action. TMS is well tolerated with very few side effects. RECENT FINDINGS TMS is now approved for major depression disorder and obsessive-compulsive disorder. There is significant data to consider approval of TMS for many neurological disorders. This is a review of the uses of TMS in diverse neurological conditions, including stroke and spasticity, migraine, and dementia. TMS is a device that utilizes non-invasive brain stimulation, and it has shown promising results with objective clinical and basic science data. Its ability to trigger neuronal plasticity and potentiating synaptic transmission gives it incredible therapeutic potential. There are diverse mechanisms of action, and this could be troublesome in elaborating clinical trials and standardization of therapy.
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Oguri M, Saito Y, Okanishi T, Matuura Y, Akiyama S, Ikeguchi T, Narita A, Hirooka Y, Maegaki Y. High-frequency component in flash visual evoked potentials in type 3 Gaucher disease. Brain Dev 2020; 42:19-27. [PMID: 31561936 DOI: 10.1016/j.braindev.2019.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/23/2019] [Accepted: 08/20/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To characterize the visual evoked potentials (VEP) in patients with type 3 Gaucher disease (GD) with or without progressive myoclonus epilepsy. METHODS Three young adults with progressive myoclonus epilepsy (type 3a GD) and two children without progressive myoclonus epilepsy (type 3b GD) were enrolled. Flash visual and somatosensory evoked potentials (F-VEP and SEP, respectively) were retrospectively reviewed in all patients under enzyme replacement therapy. Pattern reversal visual evoked potentials (PR-VEP) were recorded in the type 3a group. RESULT High-frequency components were provoked at early latencies on averaged F-VEP in all patients with type 3a and one patient with type 3b GD. Conversely, no activities were recorded in PR-VEP. The onset latency of the components began at 15.3-19.8 ms after flash stimulation. Four-five of the F-VEP examination the activities' duration overrode the N75 waveforms and were prolonged toward the P100 peak latency. The F-VEP amplitude did not differ between the type 3a and type 3b groups, while the SEP amplitude was higher in the type 3a than in the type 3b group. SIGNIFICANCE High-frequency components on F-VEP using bandpass filter at 10-200 Hz may help assess augmented excitability in the visual cortex of type 3 GD patients.
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Lepley AS, Ly MT, Grooms DR, Kinsella-Shaw JM, Lepley LK. Corticospinal tract structure and excitability in patients with anterior cruciate ligament reconstruction: A DTI and TMS study. NEUROIMAGE-CLINICAL 2019; 25:102157. [PMID: 31901791 PMCID: PMC6948362 DOI: 10.1016/j.nicl.2019.102157] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/03/2019] [Accepted: 12/26/2019] [Indexed: 01/23/2023]
Abstract
BACKGROUND Underlying neural factors contribute to poor outcomes following anterior cruciate ligament reconstruction (ACLR). Neurophysiological adaptations have been identified in corticospinal tract excitability, however limited evidence exists on neurostructural changes that may influence motor recovery in ACLR patients. OBJECTIVE To 1) quantify hemispheric differences in structural properties of the corticospinal tract in patients with a history of ACLR, and 2) assess the relationship between excitability and corticospinal tract structure. METHODS Ten participants with ACLR (age: 22.6 ± 1.9 yrs; height: 166.3 ± 7.5 cm; mass: 65.4 ± 12.6 kg, months from surgery: 70.0 ± 23.6) volunteered for this cross-sectional study. Corticospinal tract structure (volume; fractional anisotropy [FA]; axial diffusivity [AD]; radial diffusivity [RD]; mean diffusivity [MD]) was assessed using diffusion tensor imaging, and excitability was assessed using transcranial magnetic stimulation (motor evoked potentials normalized to maximal muscle response [MEP]) for each hemisphere. Hemispheric differences were evaluated using paired samples t-tests. Correlational analyses were conducted on structural and excitability outcomes. RESULTS The hemisphere of the ACLR injured limb (i.e. hemisphere contralateral to the ACLR injured limb) demonstrated lower volume, lower FA, higher MD, and smaller MEPs compared to the hemisphere of the non-injured limb, indicating disrupted white matter structure and a reduction in excitability of the corticospinal tract. Greater corticospinal tract excitability was associated with larger corticospinal tract volume. CONCLUSIONS ACLR patients demonstrated asymmetry in structural properties of the corticospinal tract that may influence the recovery of motor function following surgical reconstruction. More research is warranted to establish the influence of neurostructural measures on patient outcomes and response to treatment in ACLR populations.
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Kim JS, Kim DH, Kim HJ, Jung KJ, Hong J, Kim DY. Effect of Repetitive Transcranial Magnetic Stimulation in Post-stroke Patients with Severe Upper-Limb Motor Impairment. BRAIN & NEUROREHABILITATION 2019; 13:e3. [PMID: 36744269 PMCID: PMC9879525 DOI: 10.12786/bn.2020.13.e3] [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: 09/11/2019] [Revised: 10/04/2019] [Accepted: 10/06/2019] [Indexed: 11/08/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) has been known to improve the motor function through modulation of excitability in the cerebral cortex. However, most studies with rTMS were limited to post-stroke patients with mild to moderate motor impairments. The effect of rTMS on severe upper-limb motor impairment remains unclear. Therefore, this study investigated the effects of rTMS on the upper extremity function in post-stroke patients with severe upper-limb motor impairment. Subjects were divided into 3 groups, low-, high-frequency rTMS and control group were received stimulation 10 times for 2 weeks. The motor scale of Fugl-Meyer Assessment (FMA) and cortical excitability on the unaffected hemisphere were measured before and after performing 10 rTMS sessions. The motor scale of upper extremity FMA (UE-FMA) and shoulder component of the UE-FMA were significantly improved in both low- and high-frequency rTMS groups. However, no significant improvement was observed in the wrist and hand components. No significant differences were noted in low- and high-frequency rTMS groups. The amplitude of motor evoked potential on the unaffected hemisphere showed a significant decrease in the low- and high-frequency stimulation groups. rTMS may be helpful in improving upper extremity motor function even in post-stroke patients with severe upper-limb motor impairment.
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Magalhães SC, Queiroz de Paiva JP, Kaelin-Lang A, Sterr A, Eckeli AL, Winkler AM, Fernandes do Prado G, Amaro E, Conforto AB. Short-interval intracortical inhibition is decreased in restless legs syndrome across a range of severity. Sleep Med 2019; 62:34-42. [PMID: 31539846 DOI: 10.1016/j.sleep.2019.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/10/2019] [Accepted: 03/12/2019] [Indexed: 01/18/2023]
Abstract
BACKGROUND Decreased short-interval intracortical inhibition (SICI) to transcranial magnetic stimulation (TMS) of the primary motor cortex was described in subjects with restless legs syndrome/Willis-Ekbom disease (RLS/WED). It remained to be determined whether the magnitude of SICI decrease would be similar across levels of RLS/WED severity. Moreover, it was unknown whether, in addition to decreases in SICI, changes in cortical thickness or area could be detected in subjects with RLS/WED compared to controls. The objective of this study was to compare SICI, cortical thickness, and cortical area in subjects with idiopathic mild to moderate RLS/WED, severe to very severe RLS/WED, and controls. METHODS The severity of RLS/WED was assessed by the International Restless Legs Syndrome Severity Scale (IRLSS). SICI and 3T magnetic resonance imaging (MRI) data of subjects with RLS/WED and controls were compared. A receiver operating characteristic curve for SICI was designed for discrimination of participants with RLS/WED from controls. Cortical thickness and area were assessed by automated surface-based analysis. RESULTS SICI was significantly reduced in patients with mild to moderate and severe to very severe RLS/WED, compared to controls (one-way analysis of variance: F = 9.62, p < 0.001). Receiver operating characteristic curve analysis predicted RLS/WED when SICI was above 35% (area under the curve = 0.79, 95% CI 0.67-0.91, p < 0.001). Analyses of the whole brain and of regions of interest did not reveal differences in gray matter thickness or area between controls and subjects with RLS/WED. CONCLUSION SICI is an accurate cortical biomarker that can support the diagnosis of RLS/WED even in subjects with mild symptoms, but cortical thickness and area were not useful for discriminating subjects with this condition from controls.
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Higashihara M, Menon P, Geevasinga N, Van den Bos MAJ, Kiernan MC, Vucic S. Motor neuron disease with malignancy: Clinical and pathophysiological insights. Clin Neurophysiol 2019; 130:1557-1561. [PMID: 31301633 DOI: 10.1016/j.clinph.2019.05.026] [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: 12/12/2018] [Revised: 04/11/2019] [Accepted: 05/13/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE While some regard an association between motor neuron disease (MND) and malignancy as co-incidental, others have argued that it could represent a distinct clinical entity. The present study undertook in depth phenotyping along with assessment of cortical function to further explore disease pathophysiology in MND with malignancy (MND-M) patients. METHODS Clinical features along with assessment of peripheral and cortical function was undertaken in 13 MND-M and results were compared to sporadic and familial MND cohorts. RESULTS From a cohort 13 patients (10 males; aged 65.2 ± 2.0 years), 38.5% were diagnosed with a haematological malignancy. The lower motor neuron phenotype predominated in the in the MND-M patients (χ2 = 10.8, P < 0.01), with the upper motor neuron (UMN) score being significantly reduced in MND-M patients compared to sporadic and familial MND cohorts (χ2 = 6.84, P < 0.01). The neurological deficits did not respond to treatment of the underlying malignancy in the majority of MND-M (92%) patients, and as such there were no significant differences in survival between the cohorts. Despite a paucity of UMN signs, cortical hyperexcitability was evident in MND-M patients, as indicated by reduction in short interval intracortical inhibition (P < 0.01) and increase in motor evoked potential amplitude (P < 0.01), that were similar to findings in sporadic and familial MND cohorts. CONCLUSIONS The present study suggests that MND-M falls within the spectrum of MND. SIGNIFICANCE The concept of a co-incidental association between MND and malignancy is supported through the present study by the presence of cortical dysfunction, combined with clinical findings that can be explained within the spectrum of abnormality evident in classical MND phenotypes.
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Abstract
PURPOSE OF REVIEW Caffeine is the most widely consumed central nervous stimulant. For people with epilepsy, it is often unclear whether drinking coffee carries a risk of triggering seizures. RECENT FINDINGS The relationship between caffeine, seizures, epilepsy, and anti-seizure drugs is not fully understood. Clinical studies are scarce. In animal models, caffeine can increase seizure susceptibility but can also protect from seizures. Effects seem dose-dependent and are influenced by the duration of intake and the developmental stage at which caffeine exposure started. Caffeine reduces the efficacy of several anti-seizure medications, especially topiramate. It is unclear how these findings, mainly from animal studies, can be translated to the clinical condition. At present, there is no evidence to advise people with epilepsy against the use or overuse of caffeine. Until clinical studies suggest otherwise, caffeine intake should be considered as a factor in achieving and maintaining seizure control in epilepsy.
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Coppola G, Di Lorenzo C, Parisi V, Lisicki M, Serrao M, Pierelli F. Clinical neurophysiology of migraine with aura. J Headache Pain 2019; 20:42. [PMID: 31035929 PMCID: PMC6734510 DOI: 10.1186/s10194-019-0997-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/16/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND The purpose of this review is to provide a comprehensive overview of the findings of clinical electrophysiology studies aimed to investigate changes in information processing of migraine with aura patients. MAIN BODY Abnormalities in alpha rhythm power and symmetry, the presence of slowing, and increased information flow in a wide range of frequency bands often characterize the spontaneous EEG activity of MA. Higher grand-average cortical response amplitudes, an increased interhemispheric response asymmetry, and lack of amplitude habituation were less consistently demonstrated in response to any kind of sensory stimulation in MA patients. Studies with single-pulse and repetitive transcranial magnetic stimulation (TMS) have reported abnormal cortical responsivity manifesting as greater motor evoked potential (MEP) amplitude, lower threshold for phosphenes production, and paradoxical effects in response to both depressing or enhancing repetitive TMS methodologies. Studies of the trigeminal system in MA are sparse and the few available showed lack of blink reflex habituation and abnormal findings on SFEMG reflecting subclinical, probably inherited, dysfunctions of neuromuscular transmission. The limited studies that were able to investigate patients during the aura revealed suppression of evoked potentials, desynchronization in extrastriate areas and in the temporal lobe, and large variations in direct current potentials with magnetoelectroencephalography. Contrary to what has been observed in the most common forms of migraine, patients with familial hemiplegic migraine show greater habituation in response to visual and trigeminal stimuli, as well as a higher motor threshold and a lower MEP amplitude than healthy subjects. CONCLUSION Since most of the electrophysiological abnormalities mentioned above were more frequently present and had a greater amplitude in migraine with aura than in migraine without aura, neurophysiological techniques have been shown to be of great help in the search for the pathophysiological basis of migraine aura.
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Mattavelli G, Pisoni A, Romero Lauro LJ, Marino BF, Bonomi M, Rosanova M, Papagno C. TMS-EEG approach unveils brain mechanisms underlying conscious and unconscious face perception. Brain Stimul 2019; 12:1010-1019. [PMID: 30852122 DOI: 10.1016/j.brs.2019.02.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 02/22/2019] [Accepted: 02/23/2019] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Conscious perception of external stimuli has been related to recurrent activity in distributed cortical networks, although brain mechanisms controlling unconscious processing and stimuli access to conscious report need to be clarified. OBJECTIVE This study aims at investigating modulations in cortical excitability related to conscious perception and unconscious processing of face stimuli with different visibility levels. METHODS We used TMS-EEG over the right occipital face area (rOFA), or the right premotor cortex (rPMC) as control site, to measure cortical excitability during a backward masking paradigm with individually defined stimuli visibility. RESULTS Event related potentials showed significant differences for faces compared to houses, and detected faces compared to missed ones, 200 ms post target onset. TMS over rOFA, but not over rPMC, triggered a relative positivity starting 150 ms post target when faces with high visibility were consciously reported. Moreover, rOFA TMS evoked differential responses for high versus low visible faces in conscious and unconscious processing at 290-390 and 180-240 ms, respectively. CONCLUSION Results unveiled a causal link between rOFA excitability and late responses related to access to conscious perception, suggesting a critical role of recurrent activity, but distinct components, for consciously perceived stimuli and unconscious face processing.
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