[Basic techniques of electroencephalography: principles and clinical applications]

The electroencephalogram is a technique for the functional exploration of the central nervous system (CNS). It is a relatively old technique but even today it continues to be a tool of great assistance to the clinician in diagnosing and treating certain pathologies, such as epilepsy, encephalopathies, alterations to the state of consciousness, CNS infections, etc. On the other hand, it is a diagnostic tool whose applications are expanding in combination with other neurophysiological techniques, such as in the field of the study and diagnosis of sleep pathology (polysomnography, multiple sleep latency test...) and in intraoperative monitoring together with somasensory evoked potentials. This article describes the basic techniques of electroencephalography, with special emphasis on its main clinical applications and on future perspectives.

[Intraoperative neurophysiological monitoring in spine surgery]

Intraoperative neurophysiological monitoring (IONM) makes it possible to determine the status of neurological function during surgery. It guides the surgeon and minimises the risk of injury. This paper describes the different techniques available for IONM in spine surgery (somatosensory evoked potentials, motor evoked potentials, neurography, electromyography, reflexes and dermatomic evoked potentials), which neurophysiologists employ depending on the nerve structures at risk. In order for monitoring to be successful, coordination between all members of the surgical team is essential. In the event of IONM registering alterations, the neurophysiologist must first check the integrity of the recording system. The anaesthetist should then assess blood pressure, oxygen levels, ventilation and haematocrit values, and revert recent anaesthetic changes. Finally, the surgeon must stop the procedure and try to determine the cause of the event, and correct it if possible.

[Intraoperative neurophysiological monitoring: methods in neurosurgery]

IONM uses different neurophysiological techniques during surgery time, thus avoiding possible lesions to the neurological structures, making surgery safer and better. We describe two types of IONM: mapping techniques and monitoring techniques, as well as their advantages, disadvantages and complications. We look into the more useful techniques in this field, as well as providing orientation about its use according to the surgical areas and the neurological structures under risk. In conclusion, we affirm that IONM is one of the most important advances in modern neurosurgery.