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Abstract: Objective: To evaluate the after-effects of low frequency, sub-threshold repetitive Transcranial Magnetic Stimulation (rTMS) of primary motor cortex, on the excitability of Blink Reflex (BR) in healthy subjects. Methods: The BR recovery cycle was carried out in 10 healthy volunteers in basal conditions, immediately after rTMS (30s), 15 and 60min later. A paired electric supraorbital stimulus paradigm with inter-stimulus intervals (ISI) of 100–600–1000–1500ms was used. The “real” rTMS consisted of a 200 stimuli long train delivered at 1Hz and intensity 80% of rest Motor Threshold of the FDI muscle, using a focal coil applied over the primary motor cortex region. The basal BR recovery cycle was also compared with that obtained after a “sham” rTMS. Results: The recovery of the R2 component of the BR was significantly suppressed 30s after rTMS. This effect was also observed at 15min, though of lower magnitude and only at long ISIs (1000-1500ms). No significant effect on R2 recovery was observed 60min after real rTMS as well as after sham rTMS. Conclusions: rTMS of motor cortex modulates the excitability of BR through its action on cortical excitability and on the cortical facilitatory drive to the brainstem reflex pathways. Significance: Slow (1Hz), sub-threshold rTMS of motor cortex determines a long-lasting reduction of excitability of BR. [Copyright &y& Elsevier]

Objective: To evaluate the differences in the recovery cycle of the masseter inhibitory reflex (MIR) obtained with electrical and magnetic stimulation.Methods: In 31 healthy subjects we studied the MIR evoked by electrical or magnetic stimulation of the mental territory and the recovery cycle of this reflex with the paired stimuli technique at different interstimulus intervals (ISI), between 100 and 600 ms.Results: Latency and area of the early and late silent periods (SPs) of the MIR were similar after electrical and magnetic stimulation. The recovery cycle of the test late SP was similar with the two kinds of stimulation, except for short ISIs. The main difference between the two kinds of stimulation was in the painful quality of the stimulus: the magnetic stimuli were always below pain threshold.Conclusions: As with electrical stimulation, it is possible to obtain a MIR with magnetic peripheral stimulation. The magnetic paired stimuli are equally effective in the evaluation of the recovery cycle of the MIR. The results demonstrate that magnetic stimulation is a useful tool in the evaluation of excitability of the trigeminal motoneuronal system, with little discomfort for the patient. They also confirm the unlikelihood of nociceptive afferences involvement. [Copyright &y& Elsevier]

We present a little series of child Guillain–Barré syndrome (GBS), 4 males, 1 female, mean age 100 (16–187)months. All patients presented limb weakness, difficulty in walking, and a preceding infectious disease 0–14days before the GBS related symptoms, in majority (4/5) gastroenteritis. All patients showed neurophysiological alteration, in 4 out of 5 patients with demyelinating features, whereas in only 2 patients an albumino-citological dissociation was evident. All patients underwent an intravenous immunoglobulin (IVIG) treatment, with a good/excellent outcome. In one child we repeated IVIG treatment after 3weeks with a clear benefit only after the second cycle. The 2 younger children (16 and 29months old) showed the best and the fastest recovery (one week), only in one of the others the recovery was incomplete at 6months, both clinically and according to neurophysiological examination. The other children showed a normalization of electrophysiological parameters in 3–9months. In conclusion our little series of child GBS confirms the presence of a good prognosis in children, the possibility of success with IVIG treatment repetition and the importance and efficacy of the neurophysiological early and late repeated examination for diagnosis and follow-up. [ABSTRACT FROM AUTHOR]

Objective: To test the variations in cerebral motor excitability in patients with primary restless legs syndrome (RLS) by using electrophysiological techniques. In RLS patients periodic legs movements (PLMs) in sleep and wake have been described and it is hypothesised that PLMs result from a sleep-related disinhibition of descending central motor inhibitory pathways. Moreover, in primary RLS, these modifications are still debated.Methods: In 15 patients with primary RLS, transcranial magnetic stimulation (TMS) was carried out using several paradigms, particularly paired pulse TMS with short interstimulus intervals (ISI) in abductor digiti minimi (ADM) and tibialis anterior (TA) muscles.Results: Short ISI paired TMS showed a significant decrease in inhibition and increase in facilitation in ADM muscles. This result was even more evident in TA muscles of patients as compared to the controls and these modifications were more evident in the limbs which were more affected by PLM. Moreover, intracortical (corticocortical) inhibition (ICI) and intracortical facilitation (ICF) unchanged their biphasic time course.Conclusions: In our study the changes in short paired-pulse ICI and ICF revealed the presence of an altered excitability of central motor pathways, with good correlation with asymmetric distribution of symptoms. [Copyright &y& Elsevier]

The role of event-related evoked potentials (ERPs) in multiple sclerosis (MS) is controversial. Previously we found P300 abnormalities (increased latency and lower amplitude) related with attention and executive functions in advanced MS patients. Our aim was to evaluate possible impairment of P300 in early stages of disease related to cognitive dysfunctions. We recruited 11 patients (mean age 33.5±8.1years, EDSS 2 ± 1.1). Registration of ERPs was performed by random double auditory discrimination task paradigm and recorded through scalp electrodes placed at Fz, Cz and Pz and linked to the referred ears. RAO battery was used to examine patients cognitive functions. Spearman test was used to evaluate correlation between neurophysiologic and neuropsychological parameters. No significant change in P300 parameters compared to reference values of our laboratory normalized to age and gender stratified population. Neuropsychological Tests showed mild alterations in procedural memory and attention functions not statistically correlating with a non significant reduction in amplitude of P300 in only 2 cases. Despite the limited MS-cohort we find it useful to undergo ERP and neuropsychological tests in MS early phases to identify subclinical cognitive impairment possibly present in a small percentage of cases. [ABSTRACT FROM AUTHOR]