Ibáñez, JaimeGonzález de la Aleja, JesúsGallego, Juan A.Romero Muñoz, Juan PabloSaíz Díaz, Rosana A.Benito León, JuliánRocón, Eduardo2020-01-202020-01-2020141932-6203http://hdl.handle.net/10641/1824Background: Essential tremor (ET) is characterised by postural and action tremors with a frequency of 4–12 Hz. Previous studies suggest that the tremor activity originates in the cerebello-thalamocortical pathways. Alprazolam is a short-acting benzodiazepine that attenuates tremors in ET. The mechanisms that mediate the therapeutic action of alprazolam are unknown; however, in healthy subjects, benzodiazepines increase cortical beta activity. In this study, we investigated the effect of alprazolam both on beta and tremor-related cortical activity and on alterations in tremor presentation in ET patients. Therefore, we characterised the dynamics of tremor and cortical activity in ET patients after alprazolam intake. Methods: We recorded hand tremors and contralateral cortical activity in four recordings before and after a single dose of alprazolam. We then computed the changes in tremors, cortico-muscular coherence, and cortical activity at the tremor frequency and in the beta band. Results: Alprazolam significantly attenuated tremors (EMG: 76.2622.68%), decreased cortical activity in the tremor frequency range and increased cortical beta activity in all patients (P,0.05). At the same time, the cortico-muscular coherence at the tremor frequency became non-significant (P,0.05). We also found a significant correlation (r = 0.757, P, 0.001) between the reduction in tremor severity and the increased ratio of cortical activity in the beta band to the activity observed in the tremor frequency range. Conclusions: This study provides the first quantitative analysis of tremor reduction following alprazolam intake. We observed that the tremor severity decreased in association with an increased ratio of beta to tremor-related cortical activity. We hypothesise that the increase in cortical beta activity may act as a blocking mechanism and may dampen the pathological oscillatory activity, which in turn attenuates the observed tremor.engAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/journal articleopen access10.1371/journal.pone.0093159