An identifiable model to assess frequency-domain granger causality in the presence of significant instantaneous interactions

We present a new approach for the investigation of Granger causality in the frequency domain by means of the partial directed coherence (PDC). The approach is based on the utilization of an extended multivariate autoregressive (MVAR) model, including instantaneous effects in addition to the lagged effects traditionally studied, to fit the observed multiple time series prior to PDC computation. Model identification is performed combining standard MVAR coefficient estimation with a recent technique for instantaneous causal modeling based on independent component analysis. The approach is first validated on simulated MVAR processes showing that, in the presence of instantaneous effects, only the extended model is able to interpret the imposed Granger causality patterns, while the traditional MVAR approach may yield strongly biased PDC estimates. The subsequent application to multichannel EEG time series confirms the potentiality of the approach in real data applications, as the importance of instantaneous effects led to significant differences in the PDC estimated after traditional and extended MVAR identification

Early Guillain-Barr\ue9 syndrome in coronavirus disease 2019 (COVID-19): a case report from an Italian COVID-hospital

Guillain-Barr\ue9 syndrome (GBS) is an acute polyradiculoneuropathy associated with dysimmune processes, often related to a previous infectious exposure. During Italian severe acute respiratory syndrome coronavirus-2 outbreak, a woman presented with a rapidly progressive flaccid paralysis with unilateral facial neuropathy after a few days of mild respiratory symptoms. Coronavirus was detected by nasopharyngeal swab, but there was no evidence of its presence in her cerebrospinal fluid, which confirmed the typical albumin-cytological dissociation of GBS, along with consistent neurophysiological data. Despite immunoglobulin infusions and intensive supportive care, her clinical picture worsened simultaneously both from the respiratory and neurological point of view, as if reflecting different aspects of the same systemic inflammatory response. Similar early complications have already been observed in patients with para-infectious GBS related to Zika virus, but pathological mechanisms have yet to be established

Progressive and Fatal Brainstem Stroke in Systemic Giant Cell Arteritis

9N/AreservedmixedmixedPoretto, Valentina; Piffer, Silvio; Bignamini, Valeria; Tranquillini, Enzo; Donner, Davide; Cavatorta, Francesco Paolo; Barbareschi, Mattia; Petralia, Benedetto; Giometto, BrunoPoretto, Valentina; Piffer, Silvio; Bignamini, Valeria; Tranquillini, Enzo; Donner, Davide; Cavatorta, Francesco Paolo; Barbareschi, Mattia; Petralia, Benedetto; Giometto, Brun