Single-pulse transcranial magnetic stimulation in amyotrophic lateral sclerosis.

INTRODUCTION: Transcranial magnetic stimulation (TMS) is one of the best methods to identify changes in the corticospinal tract. We used single-pulse TMS at the beginning of the disease and in the follow-up in a group of patients with amyotrophic lateral sclerosis (ALS). METHODS: We evaluated the corticospinal tract in the bulbar, upper, and lower regions in 55 patients with ALS, and we monitored them for a period of 24 months. Data were correlated with clinical scales. RESULTS: An increase of central motor conduction time (CMCT) was the most sensitive marker of upper motor neuron involvement. The resting motor threshold, CMCT, and the central silent period increased linearly with disease duration and upper/lower motor neuron involvement. DISCUSSION: Transcranial magnetic stimulation could be an essential neurophysiological technique in the early phase of ALS because it has been shown to be useful in detecting subclinical upper motor neuron involvement. Multiple evaluations of several regions increase TMS sensitivity.

Effects of slow repetitive transcranial magnetic stimulation in patients with corticobasal syndrome.

Corticobasal syndrome is characterized by asymmetric cortical sensorimotor dysfunction and parkinsonism; an altered cortical excitability has been reported. We explored with transcranial magnetic stimulation the motor cortical excitability in corticobasal syndrome, and the effects of slow repetitive transcranial magnetic stimulation. With transcranial magnetic stimulation, we studied two corticobasal syndrome patients. We determined bilaterally from the first dorsal interosseous muscle: relaxed threshold, and contralateral and ipsilateral silent period. We also evaluated the contralateral silent period after active/sham slow repetitive transcranial magnetic stimulation on the most affected side. At T0 the silent period was bilaterally short. On the most affected side, active slow repetitive transcranial magnetic stimulation induced a short lasting prolongation of the contralateral silent period. In corticobasal syndrome, transcranial magnetic stimulation showed a reduction cortical inhibitory phenomenon potentially reversed transiently by slow repetitive transcranial magnetic stimulation.

Vasogenic erectile dysfunction Topiramate-induced.

Reversible erectile dysfunction due to Topiramate has been linked to the effect of this antiepileptic drug on reproductive hormones levels. We described two epileptic male patients which experienced erectile dysfunction during Topiramate treatment. Serum sexual hormones were tested during treatment and at several time intervals following drug discontinuation. Topiramate did not seem to affect plasma levels of total, free and bioavailable testosterone and sex hormone-binding globulin. Since Topiramate erectile dysfunctions could not be related to changes in reproductive hormones levels, a vasogenic mechanism must be considered.

Motor cortical organization in an adult with hemimegalencephaly and late onset epilepsy.

Hemimegalencephaly is a rare brain malformation whose physiology is largely obscure. In a single patient, we studied motor cortex using several transcranial magnetic stimulation variables testing cortical excitability, and mapping motor area. The megalencephalic hemisphere showed an enlargement of cortical motor map with abnormal axonal orientation and an excess spread of corticospinal excitation, associated with multiple defects of cortical inhibition. TMS gave new information on the anatomic/functional features and epileptogenesis in this complex and physiologically obscure syndrome.

Applications of transcranial magnetic stimulation in sleep medicine.

Transcranial magnetic stimulation (TMS) is a new method, developed nearly 20 years ago, that allows the study of cortical excitability. The whole brain undergoes profound changes in sleep. Motor evoked potentials (MEPs) have been used to trace the effects of sleep on cortical excitability and to the corticomotoneuron connections. Although in the past some technical aspects limited the application of TMS in sleep, recently we observed a new explosion of interest in this field. The main body of data was gathered on sleep physiology, but its diseases or syndromes were also studied in detail. Many single and paired pulse-TMS variables were applied. Moreover, TMS variables were investigated as a potential tool for the diagnosis or the differential diagnosis of sleep disorders. In the recent years, the advent of repetitive TMS offered some therapeutic perspectives, which are under current investigation in few of these disorders. Combining repetitive TMS with electroencephalogram (EEG) represents a new and probably useful approach to sleep. Among the main entities classified in the sleep disease group, the following were subject to TMS studies: obstructive sleep apnoea syndrome (OSAS), propriospinal myoclonus, restless legs syndrome (RLS) with periodic limb movement and narcolepsy. For each of these, we examine the applications of TMS separately.