RESUMO
Internal stochastic resonance (internal SR) is a phenomenon of non-linear systems in which the addition of a non-zero level of noise produces an enhancement in the coherence between two or more signals. In a previous study, we found that the simultaneous administration of multisensory visual and auditory noise augments global coherence in electroencephalographic (EEG) signals via this phenomenon. Here, we examined whether such global coherence can also be augmented with at least one noisy acoustic source. We performed experiments on healthy subjects and applied the following binaural and monaural noise-stimulation protocols. First, we administered to the left ear Gaussian noise of fixed intensity, while we delivered to the right ear a second Gaussian noise of variable intensity levels (binaural protocol). Second, we applied the Gaussian noise of the same variable intensity levels but only to one ear (monaural protocol). We performed a permutation test analysis, finding that during both noise protocols there was a significant enhancement in the global coherence in EEG signals via the occurrence of internal SR within central pathways of the auditory system.
Assuntos
Eletroencefalografia , Ruído , Estimulação Acústica , HumanosRESUMO
Invasive measurement of blood pressure has many advantages. Although arterial canalization is a low-risk technique of great benefit to the patient, complications must be looked for. We report the case of a man who underwent triple coronary bypass with arterial canalization requiring several punctures to achieve. Two weeks after the procedure the patient showed signs of hand ischemia and acute carpal tunnel syndrome, which evolved favorably after treatment with heparin sodium and prostaglandin E1. We emphasize the importance of an earlier wrist fracture as the predisposing factor for both conditions and the need to examine collateral circulation in the hand and look for carpal tunnel syndrome before canalization.