Evoked potentials: challenges for clinics and research

Introduction. From findings in the neurophysiological tests, especially with the recordings of the Evoked Potentials (EPs) it is possible to characterize the functional state of the Nervous System (NS) structures,in the course of diseases, in the Clinical Neurophysiologicaly Laboratory, and also can be performed during surgery and at Intensive Care Unit (ICU). Objective. To describe neurophysiological immediate and short-term changes that occur, in the NS structures in patients assessed in three different contexts of work: Intraoperative Neurophysiologic Monitoring (IONM), ICU, and in the Clinical Neurophysiological Laboratory. Methods. Here are presented the results of the neurophysiological evaluation in a case-study of patients during their admission at ICU, IONM. In addition, we provide evidences of the value of EPs in assessing neuroplasticity in deaf and deaf-blind subjects. In each section Auditory Brainstem Responses (ABR), Visual Evoked Potentials (VEP) and Somatosensory Evoked Potentials (SSEP) were used according to their pathology. In addition, other neurophysiological tests such as Electromyography (EMG), Nerve Conduction Study (NCS), and Motor Evoked Potentials (MEPs) were performed according to the clinical situation of patients. Results. It was possible to illustrate the practical utility of EPs in IONM and ICU. The neurophysiological changes are summarized using graphics showing the main findings obtained with EPs and other EDX tests. Electrophysiological responses change over time, being possible to provide evidences of the disease course through the measured parameters of each electrophysiological signal. On the other hand, the expansion of the SSEP cortical response to the left temporal region in subjects with sensory loss was interpreted as evidence of Cross-Modal-Plasticity. Conclusions. EPs associated with other neurophysiological tests provide means to noninvasively brain functional assessment in patients at ICU and IONM. EPs are largely used for supplement information obtained from clinics, neuroimage methods, and other laboratory tests. Nowadays, SSEP and ABR are the most important EPs used, and show interesting findings in the patient's assessment at IONM and ICU, while a characterization of the topographic distribution pattern of peaks in cortical evoked responses yields a complementary value to EPs assessment and interpretation for clinic and research.