Neuronal tissue polarization induced by repetitive transcranial magnetic stimulation?

In a blinded cross-over design, 10 healthy controls received 900 monophasic and biphasic repetitive transcranial magnetic stimuli over the primary motor cortex. Stimulation frequency was 1 Hz, and stimulation intensity 90% of the individual resting motor threshold. Suprathreshold stimuli applied at 0.1 Hz before and after repetitive stimulation controlled for changes in corticospinal excitability. We found a lasting corticospinal inhibition that was significantly more pronounced after monophasic than after biphasic repetitive transcranial magnetic stimulation (motor evoked potential amplitude reduced by 35 +/- 20% vs 12 +/- 37%, mean+/- s.d.). We propose that the current flow in the coil plays a significant role in optimising after effects, and asymmetric current flow may be particularly efficient in building up tissue polarization.     

Is it time to introduce repetitive transcranial magnetic stimulation into standard clinical practice for the treatment of depressive disorders?

OBJECTIVE: To examine issues relating to the potential introduction of repetitive transcranial magnetic stimulation (rTMS) into clinical practice as a treatment for depression. METHOD: A review of the outcomes literature accompanied by an analysis of issues relating to the potential advantages and pitfalls of the introduction of rTMS as a treatment strategy. RESULTS: Evidence is progressively accumulating that rTMS has antidepressant properties that are clinically relevant. These effects are biologically plausible and supported by basic research. Patients with therapy-resistant depression have few treatment alternatives and experience significant suffering, thus justifying the early introduction of a new treatment such as rTMS for this patient group. However, this must be balanced by a need to foster considerable further research and not to raise expectations unreasonably. CONCLUSIONS: It is timely for rTMS to be made more available to patients with treatment-resistant mood disorders. This need not be limited to clinical research trials but should only occur in medical settings where continual evaluation and research is conducted.     

Effects of repetitive facilitative exercise with neuromuscular electrical stimulation,vibratory stimulation and repetitive transcranial magnetic stimulation of the hemiplegic hand in chronic stroke patients

Aim: Repetitive facilitative exercise (RFE) is a developed approach to the rehabilitation of hemiplegia. RFE can be integrated with neuromuscular electrical stimulation (NMES), direct application of vibratory stimulation (DAVS) and repetitive transcranial magnetic stimulation (rTMS). The aims of the present study were to retrospectively compare the effects of RFE and NMES, DAVS with those of RFE and rTMS, and to determine the maximal effect of the combination of RFE with NMES, DAVS, rTMS and pharmacological treatments in stroke patients. Subjects and methods: Thirty-three stroke patients were enrolled and divided into three groups: 15 who received RFE with rTMS (4 min) (TMS₄ alone), 9 who received RFE with NMES, DAVS (NMES, DAVS alone) and 9 who received RFE with NMES, DAVS and rTMS (10 min) (rTMS₁₀ + NMES, DAVS). The subjects performed the Fugl-Meyer Assessment (FMA) and Action Research Arm Test (ARAT) before and after the 2-week session. The 18 patients in the NMES, DAVS alone and rTMS₁₀ + NMES, DAVS group underwent the intervention for 4 weeks. Result: There were no significant differences in the increases in the FMA, ARAT scores in the three groups. The FMA or ARAT scores in the NMES, DAVS alone and the rTMS₁₀ + NMES, DAVS group were increased significantly. The FMA and ARAT scores were significantly improved after 4 weeks in the NMES, DAVS alone group. Discussion: RFE with NMES, DAVS may be more effective than RFE with rTMS for the recovery of upper-limb function. Patients who received RFE with NMES, DAVS and pharmacological treatments showed significant functional recovery.     

Theory of mind deficit in bipolar disorder: is it related to a previous history of psychotic symptoms?

It has been hypothesized that a Theory of Mind (ToM) deficit could be a vulnerability marker for psychosis. Recent studies, however, have shown ToM deficits in affective relapses of bipolar disorder as well as in the euthymic phase. This study analyzes the relationship between ToM and a previous history of psychotic symptoms in bipolar disorder. ToM, sustained attention and executive functions were analyzed in 75 bipolar euthymic patients with three or more previous relapses (42 of them had a history of psychotic symptoms and 33 did not) and 48 healthy subjects. ToM was assessed with the Advanced Test by Happé. ToM performance was similar in bipolar patients with or without a history of psychotic symptoms, and in both cases it was significantly reduced as compared with the healthy control group. Similarly, both bipolar groups showed impaired sustained attention and executive functions. This general cognitive deficit partially explains the differences obtained in ToM. The ToM instrument used shows low sensitivity for assessing ToM in bipolar patients and it could partially reflect general cognitive functioning rather than a specific deficit in psychosis. ToM deficit is not a trait marker for psychosis, given that it is present in bipolar disorder regardless of a previous history of psychotic symptoms.     

Suppression of visual perception by transcranial magnetic stimulation — experimental findings in healthy subjects and patients with optic neuritis

The influence of noninvasive magnetic brain stimulation by a magnetic coil (MC) placed over the occiput on perception and correct reporting of a briefly presented set of 3 letters of the alphabet was examined in 15 patients with prolonged VEP latencies due to neuritis of the optic nerve. The results derived from observing these patients were compared to the results obtained from an age-matched control group of 20 healthy voluntary subjects examined under the same experimental conditions. In both groups it was possible to demonstrate that transcranial magnetic stimulation is able to suppress recognition of the letters if applied with a certain delay time after a brief presentation of the visual stimulus. The groups were compared to each other with regard to the delay with which it was possible to demonstrate the most effective suppression. In the healthy subjects, this delay was found between 60 and 100 msec. In the patients, it was prolonged to 80–140 msec. This prolongation was closely related to the VEP latencvy (P100).Furthermore, visual suppression and the influence on it by different parameters were studied in detail in healthy subjects; the visual suppression depends on visual (e.g., brightness, duration) and magnetic (e.g., intensity) stimulus conditions.The method describes seems to be of considerable value in the investigation of basic mechanisms of visual perception. This includes pathophysiological changes caused by optic neuritis and possibly other disorders affecting the visual system.     

How many subjects with major depressive disorder meet eligibility requirements of an antidepressant efficacy trial?

OBJECTIVE: To evaluate the generalizability of the results of antidepressant efficacy trials by determining how many subjects with DSM-IV major depressive disorder who apply for entry into such trials are ultimately enrolled. METHOD: The screening results of 378 subjects who inquired about participating in 1 of 2 separate antidepressant efficacy trials performed at Rhode Island Hospital between 1997 and 2002 were reviewed. The number of subjects who enrolled, as well as the reasons for exclusion of those who did not meet eligibility requirements, were determined. RESULTS: Of the 378 inquiries, 186 subjects expressed interest and received a current major depressive disorder diagnosis. From this sample, 27 (14.5%) were ultimately enrolled in 1 of the 2 antidepressant trials. The most common reasons for exclusion were bipolar disorder (17.2%), drug or alcohol abuse (15.6%), mild depression (14.0%), medical contraindication (12.9%), and the use of prohibited psychotropic medications (12.4%). CONCLUSION: The majority of subjects with major depressive disorder who apply to participate in an antidepressant efficacy trial do not meet eligibility requirements. When prescribing antidepressants, clinicians should bear in mind that the results of these trials may only be directly applicable to a small subset of patients treated in clinical practice.     

Does anxiety increase impulsivity in patients with bipolar disorder or major depressive disorder?

The objective of this study was to examine whether anxiety increases impulsivity among patients with bipolar disorder (BPD) and major depressive disorder (MDD). Subjects comprised 205 BPD (mean age ± SD 36.6 ± 11.5 y; 29.3% males) and 105 with MDD (mean age ± SD 38 ± 13.1 y; 29.5% males) diagnosed using the DSM-IV-SCID. Impulsivity was assessed with the Barratt Impulsivity Scale and anxiety with the Hamilton Anxiety Rating Scale. Comorbid anxiety disorders were present in 58.9% of the BPD and 29.1% of MDD. BPD were significantly more impulsive than MDD (p < 0.001), and both BPD and MDD subjects showed significantly higher impulsivity when anxiety was present either as a comorbidity (p = 0.010) or as a symptom (p = 0.011). Impulsivity rose more rapidly with increasing anxiety symptoms in MDD than in BPD. The presence of anxiety, either as a comorbid disorder or as current anxiety symptoms, is associated with higher impulsivity in subjects with either BPD or MDD.     

Seizure threshold manipulation in electroconvulsive therapy via repetitive transcranial magnetic stimulation. A novel way of augmentation?

IntroductionA high seizure threshold (ST) is an impeding factor in certain patients, potentially preventing a successful electroconvulsive therapy (ECT) treatment. Several pharmacological and non-pharmacological methods have been put forward to augment ECT in such patients, however, to this date, only a handful of case reports existed about the potential role of repetitive transcranial magnetic stimulation (rTMS), as an augmentation method.Objectivesand Methods: In this randomized, double-blinded, sham controlled study, we set out to test the hypothesis of whether the application of high frequency transcranial magnetic stimulation (HF rTMS) lowers the seizure threshold for electroconvulsive therapy and whether it has an effect on other aspects of ECT treatment, such as seizure duration (SD), efficacy and safety.Results46 patients treated for a major depressive episode, indicated for ECT, were recruited to this study. A significantly lower seizure threshold was observed in the experimental group during ECT titration, on average a decrease by 34.55%, from 34.23 mC to 22.4 mC, p < 0.001 (Wilcox test). We had not observed a significant effect of TMS stimulation before ECT on seizure duration or clinical outcome. Another potentially important observation of this study is that 4 patients in the experimental group developed transient symptoms of hypomania/mania, all of which were stabilized after the combined stimulation protocol was halted spontaneously within a week, without the need to administer mood stabilizers.ConclusionIt is likely that HF rTMS stimulation prior to ECT is a novel and simple way of reducing the ST, which is useful in certain groups of patients undergoing this important treatment modality.