Effects of repetitive transcranial magnetic stimulation on nicotine consumption and craving: A systematic review.

We performed a systematic review of the studies employing repetitive transcranial magnetic stimulation (rTMS) in subjects with smoking addiction. High-frequency (HF) rTMS over the prefrontal cortex (PFC), in particular the left dorsolateral PFC (DLPFC), might represent a save and innovative treatment tool for tobacco consumption and craving in nicotine-dependent otherwise healthy people. rTMS can be effective for this indication also in patients with schizophrenia, but the results are conflicting and sufficient evidence from large-scale trials is still lacking. Promising results have been obtained using particular techniques for brain stimulation, such as deep rTMS and theta burst stimulation. Multiple-target HF rTMS can also have a potential in smoking cessation. fMRI and EEG recordings have proven to be useful for objectively assessing the treatment effects. TMS is likely to be most effective when paired with an evidence-based self-help intervention, cognitive-behavioral interventions and nicotine replacement therapy. However, the most recent studies employed different protocols and yielded heterogeneous results, which should be replicated in further controlled studies with larger sample sizes and rigorous standards of randomization. To date, no recommendation other than that a possible efficacy of HF-rTMS of the left DLPFC can be made for alternative rTMS procedures in nicotine craving and consumption.

Transcranial magnetic stimulation in subjects with phantom pain and non-painful phantom sensations: A systematic review.

Several studies have applied transcranial magnetic stimulation (TMS) in the attempt to further explore the pathophysiological mechanisms of phantom-limb pain (PLP) and non-painful phantom sensations (PS). We performed a systematic review of available evidence of this emerging technology in this indication. We identified studies which report a reduced intracortical inhibition and increased intracortical facilitation in the hemisphere contralateral to the PLP. TMS mapping revealed a significant lateralization of the center of gravity and an enlargement of the excitable area on the hemisphere contralateral to the amputation. N-Methyl-d-Aspartate-mediated mechanisms influence the changes of intracortical inhibition and facilitation occurring after limb amputation; however, these cortical excitability changes and PLP are independent of each other. TMS can also influence brain function if applied repetitively. A few studies have begun to therapeutically use repetitive TMS (rTMS) to relief PLP and non-painful PS. rTMS of the contralateral parietal cortex lead to a transient reduction in pain intensity. High frequency rTMS applied over the contralateral motor cortex (M1) or low frequency rTMS over the unaffected hemisphere might also induce significant clinical improvement in PLP. On the other hand, serum beta-endorphin increased significantly after real stimulation over contralateral M1. This systematic review illustrates that TMS technique is an emerging tool to gain insights to pathophysiological aspects of pain and non-painful phantom phenomena. Moreover, TMS could support appropriate patient selection for different therapies and may also have therapeutic utility in subjects with PLP or PS, though the evidence is still very preliminary and well-designed studies in larger cohort of patients are warranted.

Ipsilateral motor evoked potentials in a patient with unihemispheric cortical atrophy due to Rasmussen encephalitis.

The role of the ipsilaterally descending motor pathways in the recovery mechanisms after unilateral hemispheric damage is still poorly understood. Motor output reorganization was investigated in a 56-year-old male patient with acquired unilateral hemispheric atrophy due to Rasmussen encephalitis. In particular, the ipsilateral corticospinal pathways were explored using focal transcranial magnetic stimulation. In the first dorsal interosseous and wrist extensors muscles, the median amplitudes of the ipsilateral motor evoked potentials induced by transcranial magnetic stimulation in the patient were higher than those of 10 age-matched healthy control subjects. In the biceps brachii muscle, the median amplitudes of the ipsilateral motor evoked potentials were the second largest in the patient compared to the controls. This study demonstrated a reinforcement of ipsilateral motor projections from the unaffected motor cortex to the hemiparetic hand in a subject with acquired unihemispheric cortical damage.