Correlation of cerebral blood flow and treatment effects of repetitive transcranial magnetic stimulation in depressed patients

The aims of this study were to: (1) assess the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity in depressed patients as measured by single photon emission tomography (SPECT); (2) evaluate the predictive value of brain SPECT on the antidepressant efficacy of rTMS. Patients (n=17) received 1600 rTMS stimuli at a rate of 10 Hz, 5 days per week for 2 weeks to the left dorsolateral prefrontal cortex. Whole brain SPECT data were acquired using Tc99m-Bicisate. Regional cerebral blood flow (rCBF) was correlated with the % change in the 28-item Hamilton Depression Rating Scale Score (Delta-HDRS) and a semiquantitative region of interest (ROI) analysis was conducted. Prior to rTMS there was a significant left-right asymmetry favoring the right, whereas 2 weeks after the rTMS treatment this asymmetry was reversed. The rCBF in limbic structures was negatively correlated with the outcome and rCBF in several neocortical areas was positively correlated. Brain SPECT can provide information about mechanisms of action of rTMS and may have predictive value for the antidepressant efficacy of rTMS.     

Neurocognitive effects of repetitive transcranial magnetic stimulation in severe major depression.

OBJECTIVE: Repetitive transcranial magnetic stimulation (rTMS) is being investigated as a potential treatment for depression. Few studies have addressed the neurocognitive effects of a course of rTMS in severely depressed patients. We evaluated neurocognitive effects of a 1-4 week course (mean 3 weeks) of rTMS using an aggressive set of parameters, in 15 severely depressed subjects. METHODS: A battery of neurocognitive tests relevant to attention, working memory-executive function, objective memory and motor speed were administered to 15 subjects with treatment-resistant major depression (unipolar and bipolar), before and after a course of rTMS. Mean z scores were computed for each of 4 cognitive domains and analyzed using repeated measures multivariate analysis of covariance. Significant interactions were further clarified using univariate analysis of variance. RESULTS: There was no worsening of performance on any of the cognitive domains over the baseline-post rTMS period. On the contrary, evidence of modest but statistically significant improvement in performance was noted in working memory-executive function, objective memory and fine motor speed domains over the rTMS treatment period. CONCLUSIONS: There was no evidence of adverse neurocognitive changes over the baseline-post rTMS period in 15 treatment-resistant depressed subjects undergoing a 3 week (mean) trial of rTMS. Significant improvements in several domains observed over the rTMS treatment period could not be explained by improved mood. Practice effects as well as other factors potentially contributing to these findings are discussed. SIGNIFICANCE: rTMS is being increasingly studied as a neurophysiological probe as well as for its potential antidepressive effects. The effects on neuronal function raise appropriate questions of safety of its use at varying stimulus parameters and durations. This study contributes to the small body of evidence of the cognitive effects of rTMS in severely depressed patients.     

Side effects of repetitive transcranial magnetic stimulation

The side effects of repetitive transcranial magnetic stimulation are largely unexplored and the limits of safe exposure have not been determined except as regards the acute production of seizures. Although tissue damage is unlikely, however, cognitive and other adverse effects have been observed and the possibility of unintended long-term changes in brain function are theoretically possible.     

Antiepileptic effects of low frequency repetitive transcranial magnetic stimulation: A meta-analysis

Purpose

To evaluate the antiepileptic efficacy of low frequency repetitive transcranial magnetic stimulation (rTMS) in medically intractable epilepsy.

Methods

A comprehensive literature search was performed on articles published from 1990 to 2010 in Medline, Pubmed, CINAHL, and Cochrane using the following keywords: epilepsy, seizure, transcranial magnetic stimulation, repetitive transcranial magnetic stimulation. Two reviewers assessed article eligibility and extracted the data independently. For outcome measures, effect size and 95% confidence interval (CI) were calculated for seizure frequency, spike number, duration of epileptiform abnormalities (EAs), and resting motor threshold (RMT) by using fixed and random effect models.

Results

Eleven articles were identified, with a total of 164 participants. Based on seizure frequency, a significant effect size was found (effect size: 0.34, with a 95% CI at 0.10–0.57). Considering between-study heterogeneity, we conducted a second meta-analysis, and the underlying etiology was considered important for the treatment effect. Cortical dysplasia or neocortical epilepsy showed an effect size of 0.71, with a 95% CI at 0.30–1.12. In contrast, other epileptic disorders showed an effect size of 0.22.

Conclusion

Low frequency rTMS has a favorable effect on seizure reduction, particularly evident in patients with neocortical epilepsy or cortical dysplasia.     

高频与低频重复经颅磁刺激对脑外伤患者认知功能的影响

目的 探讨脑外伤患者行高频与低频重复经颅磁刺激对其认知功能的影响.方法 选取2017年7月～2019年5月之间我院收治的90例脑外伤患者,随机分为三组,各30例.A组采用常规康复治疗,B、C组在此基础上均给予重复经颅磁刺激治疗,B组为低频(1Hz)刺激、C组为高频(5Hz)刺激.比较三个组患者治疗前后MoCA、ADL、...     

高频重复经颅磁刺激治疗卒中后肩手综合征的临床疗效观察

目的 观察高频重复经颅磁刺激(rTMS)治疗卒中后肩手综合征的临床疗效.方法 选取2019年6月至2020年10月在淮安市康复医院康复科病房住院的60例卒中后肩手综合征患者,按照随机数字表法将其分为对照组(30例)和治疗组(30例).两组患者均接受常规止痛治疗和常规康复治疗.对照组在常规治疗的基础上给予伪rTMS治疗,...     

High frequency repetitive transcranial magnetic stimulation decreases cerebral vasomotor reactivity

ObjectiveRepetitive Transcranial Magnetic Stimulation (rTMS) has been recently employed as a therapeutic strategy for stroke, although its effects on cerebral hemodynamics has been poorly investigated. This study aims to examine the impact of high frequency rTMS on cerebral vasomotor reactivity (VMR).MethodsTwenty-nine healthy subjects were randomly assigned to real (19) or sham 17-Hz rTMS, applied on primary motor cortex (M1) of the dominant hemisphere. All subjects underwent Transcranial Doppler of the middle cerebral arteries to evaluate mean flow velocity and VMR before (T₀) and within 10 min (T₁) following rTMS. Four subjects underwent further VMR evaluations at 2 (T₂), 5 (T₃) and 24 h (T₄) after rTMS. As a control condition, 10 subjects underwent real (5) or sham rTMS on calcarine cortex. In addition, five acute stroke patients underwent five daily rTMS sessions on the affected hemisphere mimicking a therapeutic trial.ResultsFollowing real rTMS on M1 (p = 0.002) and calcarine cortex (p < 0.001) VMR decreased with respect to T₀ in both hemispheres, while no change was observed after sham rTMS (p > 0.6). VMR tended to remain lower than T₀ until T_3. Cerebral VMR decreased independently of the stimulated side also in the patients’ group.ConclusionsHigh frequency rTMS reduces cerebral VMR, possibly as a secondary effect on autonomic control of cerebral hemodynamics.SignificanceThe effect of rTMS on cerebral hemodynamics should be carefully considered before proceeding toward a therapeutic application in stroke patients.     

Resting motor threshold changes and clinical response to prefrontal repetitive transcranial magnetic stimulation in depressed patients

Aims: Several variables are able to influence the antidepressant effects of repetitive transcranial magnetic stimulation (rTMS), particularly the intensity of stimulation, which is generally expressed according to the resting motor threshold (RMT). The aim of our study was to investigate whether or not RMT changes during the treatment of resistant depression by rTMS and whether these fluctuations could alter treatment outcome. Methods: Seventy‐five inpatients suffering from unipolar or bipolar treatment‐resistant depression and who had been antidepressant‐free or taking a stable antidepressant drug and a daily dose of benzodiazepine for at least a month received a left prefrontal rTMS session once a day for 10 days at 10 Hz and 95% RMT. Results: For the whole group, no significant fluctuation of RMT was observed between the first and the second week of rTMS treatment. However, RMT increased, decreased or remained constant throughout treatment depending on the patient. These RMT changes influenced the outcome of the 10 sessions concerning the severity of depressive and anxiety symptoms, measured by the Beck Depression Inventory and State Trait Anxiety, respectively. Conclusions: Our results justify calculating RMT regularly, and suggest that its variations play a role in treatment outcome.     

Usefulness of repetitive transcranial magnetic stimulation as a maintenance treatment in patients with major depression

Objectives: To investigate the clinical efficacy of repetitive transcranial magnetic stimulation (rTMS), venlafaxine or a combination of both treatments as a maintenance treatment in patients with treatment-resistant depression (TRD).

Methods: In a three-arm open-label study, 66 patients, including 45 remitters, who responded to rTMS (n?=?25), venlafaxine (n?=?22), or a combination of both treatments (n?=?19) continued to receive the treatment that led to a response as a maintenance treatment over 12 months. Maintenance rTMS was administered twice per week for 1 month, once per week for 2 months, and once every 2 weeks for 9 months. Venlafaxine was maintained at the dose that induced a clinical response (150 or 225?mg/day).

Results: After the 12-month follow-up, the rates of remitters (HDRS?2?=^?1.25; P?=?.3). The rates of patients who not relapsed (HDRS?2?=^?0.33; P?=?.8): 40.0% in the rTMS group, 45.1% in the venlafaxine group and 36.9% in the combination group.

Conclusions: The three maintenance approaches exhibited similar efficacies in relapse prevention and the maintenance of remission in patients with TRD.     

Influence of repetitive transcranial magnetic stimulation on psychomotor symptoms in major depression

Psychomotor symptoms related to an impairment of the nigrostriatal dopaminergic system are frequent in major depression (MD). Repetitive transcranial magnetic stimulation (rTMS) has been discussed as a new treatment option for MD. In neurobiological terms, an influence of high-frequency rTMS on dopaminergic neurotransmission has previously been shown by several studies in animals and humans. Therefore, an improvement of psychomotor symptoms by rTMS could be assumed. The aim of this pilot study was to investigate the effect of high-frequency rTMS on psychomotor retardation and agitation in depressive patients. We investigated the effect of left prefrontal 10 Hz rTMS on psychomotor retardation and agitation in 30 patients with MD. Patients were randomly assigned to real or sham rTMS in addition to a newly initiated standardized antidepressant medication. We found a trend in the reduction of agitation (t ₂₈ = 1.76, p = 0.09, two-tailed), but not in the reduction of retardation. Furthermore, no general additional antidepressant effect of rTMS was observed. Although there was no statistical significant influence of high-frequency rTMS on psychomotor symptoms in depressive patients, the results showed a trend in the reduction of psychomotor agitation in MD. This effect should be systematically investigated as the primary end point in further studies with larger sample sizes.     

Low frequency repetitive transcranial magnetic stimulation improves source monitoring deficit in hallucinating patients with schizophrenia

Auditory hallucinations have been associated with a disruption in monitoring one's own speech suggesting an autonoetic agnosia in schizophrenia. This deficit can be measured by a source monitoring task. Low frequency transcranial magnetic stimulations (rTMS) applied to the left temporoparietal cortex can inhibit cortical areas involved both in autonoetic agnosia (which means 'the inability to identify self-generated mental events') and in auditory hallucinations (AH) phenomena. Although improvements in AH have been repeatedly reported following rTMS treatment, effects on autonoetic agnosia measured by source monitoring have never been investigated. We aimed to investigate the relation between improvements in AH and source monitoring performance after rTMS treatment. Twenty four right-handed refractory schizophrenic patients with hallucinations randomly received sham or active 10.0001-Hz rTMS to the left temporoparietal cortex and performed 2 source monitoring tasks requiring discrimination between silent- and overt-reading words before and after rTMS sessions. Compared to sham, active rTMS significantly improved AH. Source monitoring performances and the improvements tended to correlate, which would support a specific relation between autonoetic agnosia and auditory hallucinations.     

Electroencephalogram and repetitive transcranial magnetic stimulation

Scalp recordings of the electroencephalogram (EEG) have been used in association with repetitive transcranial magnetic stimulation (rTMS) investigations as a safety measure in monitoring ongoing EEG activity and as a neurophysiologic tool in examining the specific effects induced by the magnetic stimulus on the EEG or evoked potentials (EPs). Medline review on the use of EEG or EPs with rTMS reveals that this area has been largely unexplored. Limited available studies attest to the potential for studies combining EEG/EPs and rTMS to be useful in further elucidating the normal brain physiology. Herein, we report on our experience with continuous EEG sampling combined with rTMS in patients with major depression (n = 14), schizophrenia (n = 7), and obsessive-compulsive disorder (n = 5). Our data support the practice of using continuous EEG monitoring when the stimulation parameters fall outside established safety guidelines.     

Effects of high frequency repetitive transcranial magnetic stimulation on P(300) event-related potentials.

OBJECTIVE: Auditory event-related potentials (P(300)-ERPs) were analyzed before and after repetitive transcranial magnetic stimulation (rTMS). METHODS: Two rTMS trains (10 Hz, 3 s, 100% motor threshold and 5 min interval) were delivered over the left frontal area in healthy subjects. P(300)-ERPs were recorded at 14 electrode sites on the scalp using a typical oddball paradigm before and after rTMS. The latencies and amplitudes of N(100), P(200), N(200) and P(300) were measured and compared. The directed coherence (DCOH) was estimated to demonstrate information flow between different cortical areas. RESULTS: rTMS significantly influenced P(300)-ERPs. The effects differed on the different components (P<0.001). The latency of P(300) significantly increased after stimulation, which was more obvious in the frontal and central areas. The changes in P(300) amplitude were not significant (P>0.05). The DCOH from the frontal, central, parietal and occipital areas to the temporal area was significantly higher than the DCOH from the temporal area to the former 4 areas (P<0.01). CONCLUSIONS: rTMS with the present parameters can affect P(300)-ERPs, leading to a delayed P(300) component and changes in information connections around the stimulated site. Our data suggest that rTMS may postpone neuronal activities related to cognitive processing.     

Long-lasting effects of transcranial static magnetic field stimulation on motor cortex excitability

Background

Transcranial static magnetic field stimulation (tSMS) was recently added to the family of inhibitory non-invasive brain stimulation techniques. However, the application of tSMS for 10–20?min over the motor cortex (M1) induces only short-lasting effects that revert within few minutes.

A controlled study of repetitive transcranial magnetic stimulation in medication-resistant major depression.

BACKGROUND: Repetitive transcranial magnetic stimulation (TMS) as a treatment for depression has shown statistically significant effects, but the clinical significance of these effects has been questioned. METHODS: Patients with medication-resistant depression were randomized to receive 15 sessions of active or sham repetitive TMS delivered to the left dorsolateral prefrontal cortex at 110% the estimated prefrontal cortex threshold. Each session consisted of 32 trains of 10 Hz repetitive TMS delivered in 5-second trains. The primary end point was treatment response defined as a >or=50% decrease in Hamilton Depression Rating Scale (HDRS) score at both 1 and 2 weeks following the final repetitive TMS treatment. Remission was defined as a HDRS score < 8. RESULTS: The response rate for the TMS group was 30.6% (11/35), significantly (p = .008) greater than the 6.1% (2/33) rate in the sham group. The remission rate for the TMS group was 20% (7/35), significantly (p = .033) greater than the 3% (1/33) rate in the sham group. The HDRS scores showed a significantly (p < .002) greater decrease over time in the TMS group compared with the sham group. CONCLUSIONS: Transcranial magnetic stimulation can produce statistically and clinically significant antidepressant effects in patients with medication-resistant major depression.