In a patient with minimal conscious state has been reported an arousal with transient increase of meaningful behaviours and EEG changes after rTMS over the M1. This has raised interest in the ...scientific community but has also had disproportionate resonance in mass media and strong expectations among the patients’ families. We evaluated the effect of high-frequency rTMS in vegetative state (VS) by a randomised, double blind, sham-controlled trial with a cross-over design. Eleven VS patients were included. Twenty-Hz rTMS or sham stimulation were applied to the left M1 for 5 consecutive days. Daily sessions consisted of 10-min stimulation at 60% maximum stimulator output. Primary outcome measures were changes in the Coma Recovery Scale-Revised (CRS-R) total score and Clinical Global Impression (CGI) scale. Evaluations were performed at baseline, after the first day of treatment, immediately after the end of the treatment, and 1 week and 1 month later. Slight changes observed in CRS-R and CGI did not significantly differ between real or sham stimulation conditions. In addition, no concordance was seen between CGI changes observed by clinician and patients’ relatives. Findings do not provide evidence of therapeutic effect of rTMS in VS, at least with conventional coils and current safety parameters.
Cognitive effects of anti-epileptic drugs (AEDs) have been already extensively reported. In contrast, motor disturbances, frequently induced by these drugs, have not received similar attention. We ...review subjective and objective adverse motor effects of traditional and new AEDs. We discuss the methodological issues caused by the heterogeneous sources of information on drug adverse effects (controlled clinical studies, open studies, and case reports). We describe specific disturbances (vestibulocerebellar, dyskinesias, parkinsonism, tics, myoclonus, and tremor) as the effects of different AEDs on distinct motor circuitries. Finally, we summarize the role of sophisticated technical studies which provide a valuable insight into the specific or subtle effects of AEDs on the central nervous system.
In this study, we conducted two experiments to evaluate the effect of different types of odors on a time reproduction task, comparing performances of males to those of females. In the first ...experiment, subjects had to estimate short (510, 600, 690 ms) and long (1700, 2000, 2300 ms) interval durations under three odor conditions: positive, negative and neutral. A gender specific effect of olfactory stimulation on time estimation was found only for short durations. Namely, females were less accurate (overestimated) in reproducing short time intervals during the unpleasant odor presentation. This effect was confirmed and strengthened in the second experiment in which the intensity of the negative odor was enhanced. The present findings suggest that the neural network underlying time estimation is more “sensitive” to context manipulations in females than in men. PRACTICAL APPLICATIONS: The first important point is that there might be relevant gender differences in the processing of time (time estimation) that are mediated by olfactory stimulation. This new evidence might have important implications and applications in health issues and especially in workplace safety, for example in jobs or contexts in which fast processing and rapid decisions or choices are required. Therefore, the knowledge that females are more influenced by unpleasant odors than males during time estimation should be seriously considered in situations in which time plays a crucial role such as during rapid decision‐making, where automatic processes should be efficiently activated. Overall, the higher sensitivity to specific olfactory stimulation observed in women probably reflects individual differences in a complex process such as time processing.
In carotid endarterectomy (CEA), EEG and somatosensory evoked potentials (SEPs) are the most commonly used monitoring techniques to prevent perioperative stroke. However, which of these methods is ...the most appropriate is not definitely established. Here we evaluated retrospectively simultaneous EEG and SEP recordings. Our CEA series was analyzed backward to identify 30 patients requiring carotid shunt. Shunting was performed in 7.1% of 420 consecutive CEA over a 20-month period. All CEAs were continuously monitored by multi-channel EEG and SEPs before, during and 20 min following carotid cross-clamping. The most reliable SEP criterion for shunting was marked amplitude reduction or disappearance of cortical components (N20, P25), usually associated or preceded by a unilateral or bilateral suppression of EEG activity. Three of the shunted patients had minor postoperative neurological deficits. Amongst the 390 non-shunted patients, 1 had a postoperative ischemic stroke and 1 one had a cerebral hemorrhage. Findings confirm that SEPs are less sensitive but more specific than EEG for the detection of cerebral ischemia in CEA. The number of shunting and major ischemic events in non-shunted patients associated to simultaneous EEG and SEP monitoring was lower than those commonly reported in the literature of CEA.
Objective: To investigate the after-effects of 0.3 Hz repetitive transcranial magnetic stimulation (rTMS) on excitatory and inhibitory mechanisms at the primary motor cortex level, as tested by ...single-pulse TMS variables.
Methods: In 9 healthy subjects, we studied a wide set of neurophysiological and behavioral variables from the first dorsal interosseous before (Baseline), immediately after (Post 1), and 90 min after (Post 2) the end of a 30 min long train of 0.3 Hz rTMS delivered at an intensity of 115% resting motor threshold (RMT). Variables under investigation were: maximal M wave, F wave, and peripheral silent period after ulnar nerve stimulation; RMT, amplitude and stimulus–response curve of the motor evoked potential (MEP), and cortical silent period (CSP) following TMS; finger-tapping speed.
Results: The CSP was consistently lengthened at both Post 1 and Post 2 compared with Baseline. The other variables did not change significantly.
Conclusions: These findings suggest that suprathreshold 0.3 Hz rTMS produces a relatively long-lasting enhancement of the inhibitory mechanisms responsible for the CSP. These effects differ from those, previously reported, of 0.9–1 Hz rTMS, which reduces the excitability of the circuits underlying the MEP and does not affect the CSP. This provides rationale for sham-controlled trials aiming to assess the therapeutic potential of 0.3 Hz rTMS in epilepsy.
In healthy subjects, suprathreshold repetitive transcranial magnetic stimulation (rTMS) at frequencies >2 Hz prolongs the cortical silent period (CSP) over the course of the train. This progressive ...lengthening probably reflects temporal summation of the inhibitory interneurons in the stimulated primary motor cortex (M1). In this study, we tested whether high-frequency rTMS also modulates the ipsilateral silent period (ISP). In nine normal subjects, suprathreshold 10-pulse rTMS trains were delivered to the right M1 at frequencies of 3, 5, and 10 Hz during maximal isometric contraction of both first dorsal interosseous muscles. At 10 Hz, the second pulse of the train increased the area of the ISP; the other stimuli did not increase it further. During rTMS at 3 and 5 Hz, the ISP remained significantly unchanged. Control experiments showed that 10-Hz rTMS delivered at subthreshold intensity also increased the ISP. rTMS over the hand motor area did not facilitate ISPs in the biceps muscles. Finally, rTMS-induced ISP facilitation did not outlast the 10-Hz rTMS train. These findings suggest that rTMS at a frequency of 10 Hz potentiates the interhemispheric inhibitory mechanisms responsible for the ISP, partly through temporal summation. The distinct changes in the ISP and CSP suggest that rTMS facilitates intrahemispheric and interhemispheric inhibitory phenomena through separate neural mechanisms. The ISP facilitation induced by high-frequency rTMS is a novel, promising tool to investigate pathophysiological abnormal interhemispheric inhibitory transfer in various neurological diseases.
