Abnormal motor cortex plasticity in juvenile myoclonic epilepsy.

PURPOSE: Abnormal cortical plasticity has been hypothesized to play a crucial role in the pathogenesis of juvenile myoclonic epilepsy (JME). To study the motor cortical plasticity we used paired associative stimulation (PAS). When a repetitive electrical stimulus to the median nerve is paired with a transcranial magnetic stimulus (TMS) pulse over the controlateral motor cortex with at an interstimulus interval (ISI) of 21.5-25ms, a long term potentiation (LTP)-like synaptic plasticity is induced in the corticospinal system. Aim of this study was to investigate the motor cortex LTP-like synaptic plasticity by means of PAS in patients with JME. METHODS: Twelve adult patients with JME were compared with 13 healthy subjects of similar age and sex. PAS consisted of 180 electrical stimuli of the right median nerve paired with a single TMS over the hotspot of right abductor pollicis brevis (APB) at an ISI of 25ms (PAS25). We measured motor evoked potentials (MEPs) before and after each intervention for up to 30min. RESULTS: In healthy subjects the PAS25 protocol was followed by a significant increase of the MEP amplitude (p<0.001). On the contrary, in patients with JME, the MEP amplitude did not change. CONCLUSION: Defective motor cortex plasticity is likely involved in the pathogenesis of JME.

Human neural stem cell transplantation in ALS: initial results from a phase I trial.

BACKGROUND: We report the initial results from a phase I clinical trial for ALS. We transplanted GMP-grade, fetal human neural stem cells from natural in utero death (hNSCs) into the anterior horns of the spinal cord to test for the safety of both cells and neurosurgical procedures in these patients. The trial was approved by the Istituto Superiore di Sanità and the competent Ethics Committees and was monitored by an external Safety Board. METHODS: Six non-ambulatory patients were treated. Three of them received 3 unilateral hNSCs microinjections into the lumbar cord tract, while the remaining ones received bilateral (n = 3 + 3) microinjections. None manifested severe adverse events related to the treatment, even though nearly 5 times more cells were injected in the patients receiving bilateral implants and a much milder immune-suppression regimen was used as compared to previous trials. RESULTS: No increase of disease progression due to the treatment was observed for up to18 months after surgery. Rather, two patients showed a transitory improvement of the subscore ambulation on the ALS-FRS-R scale (from 1 to 2). A third patient showed improvement of the MRC score for tibialis anterior, which persisted for as long as 7 months. The latter and two additional patients refused PEG and invasive ventilation and died 8 months after surgery due to the progression of respiratory failure. The autopsies confirmed that this was related to the evolution of the disease. CONCLUSIONS: We describe a safe cell therapy approach that will allow for the treatment of larger pools of patients for later-phase ALS clinical trials, while warranting good reproducibility. These can now be carried out under more standardized conditions, based on a more homogenous repertoire of clinical grade hNSCs. The use of brain tissue from natural miscarriages eliminates the ethical concerns that may arise from the use of fetal material. TRIAL REGISTRATION: EudraCT:2009-014484-39 .

Impaired visual inhibition in migraine with aura.

OBJECTIVE: The pathophysiology of migraine with or without aura (MA, MO) is still a matter of debate. We thus studied patients with MA and MO by means of paired-pulse flash-visual evoked potentials (paired F-VEPs). This technique, recently revived, analyses the overall excitability of visual system as detected from the cortical occipital signal. METHODS: We enrolled 13 adult patients with MO and 13 with MA. Twenty-two normal subjects of similar age and sex acted as controls. Stimuli were single flashes, intermingled at random to flash pairs at critical interstimulus intervals (ISIs, 16.5-125ms) with closed and open eyes. The "single"(unconditioned) F-VEP was split into a "main complex" (50-200ms after the flash) and a "late response" (200-400ms). As for paired stimulation, the "test" F-VEP emerged from electronic subtraction of the "single" F-VEP to the "paired" F-VEP. Its size was expressed as "test"/"single"F-VEP∗100. RESULTS: As for paired F-VEPs, the "main complex" of the "test" F-VEP in the MA group did not show the size reduction (at ISIs 50-62.5ms) which was typical among the control and MO groups (p⩽0.016) in the "eyes-closed" state. CONCLUSIONS: Paired F-VEPs document a defective neural inhibition in the visual system of patients with MA. SIGNIFICANCE: Paired F-VEPs may warrant inclusion in future preclinical/clinical studies, to evaluate its potential role in the pathophysiology and management of MA.