An<unk>  recording setup<unk>  is one of the main diagnostic tests for epilepsy. A routine clinical<unk>  recording typically lasts 20–30 minutes (plus preparation time). It is a test that detects electrical activity in the brain using small, metal discs (electrodes) attached to the scalp. Routinely,<unk>  is used in clinical circumstances to determine changes in brain activity that might be useful in diagnosing brain disorders, especially epilepsy or another seizure disorder. An<unk>  might also be helpful for diagnosing or treating the following disorders: * Brain tumor * Brain damage from head injury * Brain dysfunction that can have a variety of causes (encephalopathy) * Inflammation of the brain (encephalitis) * Stroke * Sleep disorders It can also: * distinguish epileptic seizures from other types of spells, such as psychogenic non-epileptic seizures, syncope (fainting), sub-cortical movement disorders and migraine variants * differentiate "organic" encephalopathy or delirium from primary psychiatric syndromes such as catatonia * serve as an adjunct test of brain death in comatose patients * prognosticate in comatose patients (in certain instances) * determine whether to wean anti-epileptic medications. At times, a routine<unk>  is not sufficient to establish the diagnosis or to determine the best course of action in terms of treatment. In this case, attempts may be made to record an<unk>  while a seizure is occurring. This is known as an ictal recording, as opposed to an inter-ictal recording which refers to the<unk>  recording between seizures. To obtain an ictal recording, a prolonged<unk>  is typically performed accompanied by a time-synchronized video and audio recording. This can be done either as an outpatient (at home) or during a hospital admission, preferably to an Epilepsy Monitoring Unit (EMU) with nurses and other personnel trained in the care of patients with seizures. Outpatient ambulatory video<unk> s typically last one to three days. An admission to an Epilepsy Monitoring Unit typically lasts several days but may last for a week or longer. While in the hospital, seizure medications are usually withdrawn to increase the odds that a seizure will occur during admission. For reasons of safety, medications are not withdrawn during an<unk>  outside of the hospital. Ambulatory video<unk> s, therefore, have the advantage of convenience and are less expensive than a hospital admission, but the disadvantage of a decreased probability of recording a clinical event. Epilepsy monitoring is typically done to distinguish epileptic seizures from other types of spells, such as psychogenic non-epileptic seizures, syncope (fainting), sub-cortical movement disorders and migraine variants, to characterize seizures for the purposes of treatment, and to localize the region of brain from which a seizure originates for work-up of possible seizure surgery. Hospitals use an<unk>  monitor to help diagnose a seizure. They use that information to help with the treatment process as well as discovering risks. "Many professionals have stated the importance of<unk> ’s when it comes to suspected seizures, for diagnosis and evaluation". Doctors will be able to use the<unk>  monitoring system to help look at some treatment options as well as some risk factors. As technology advances, researchers are finding new monitors that are more accurate in regards to seizures. "Advanced techniques with continuous<unk>  and simplified technique with aEEG allows clinicians to detect more seizures at the bedside”. An aEEG stands for amplitude integrated<unk>  and can detect any electrical brain activity just like an<unk>  monitor. An aEEG monitor can monitor the brain function for a long period, whereas an<unk>  monitor can only monitor brain function for a couple hours to days. This helps the improvement of detecting more seizures faster, and the preterm babies suffering with seizures can be treated earlier and have less long term effects. Additionally,<unk>  may be used to monitor the depth of anesthesia, as an indirect indicator of cerebral perfusion in carotid endarterectomy, or to monitor amobarbital effect during the Wada test.<unk>  can also be used in intensive care units for brain function monitoring to monitor for non-convulsive seizures/non-convulsive status epilepticus, to monitor the effect of sedative/anesthesia in patients in medically induced coma (for treatment of refractory seizures or increased intracranial pressure), and to monitor for secondary brain damage in conditions such as subarachnoid hemorrhage (currently a research method). If a patient with epilepsy is being considered for resective surgery, it is often necessary to localize the focus (source) of the epileptic brain activity with a resolution greater than what is provided by scalp<unk> . This is because the cerebrospinal fluid, skull and scalp smear the electrical potentials recorded by scalp<unk> . In these cases, neurosurgeons typically implant strips and grids of electrodes (or penetrating depth electrodes) under the dura mater, through either a craniotomy or a burr hole. The recording of these signals is referred to as electrocorticography (ECoG), subdural<unk>  (sdEEG) or intracranial<unk>  (icEEG)--all terms for the same thing. The signal recorded from ECoG is on a different scale of activity than the brain activity recorded from scalp<unk> . Low voltage, high frequency components that cannot be seen easily (or at all) in scalp<unk>  can be seen clearly in ECoG. Further, smaller electrodes (which cover a smaller parcel of brain surface) allow even lower voltage, faster components of brain activity to be seen. Some clinical sites record from penetrating microelectrodes.<unk>  is not indicated for diagnosing headache. Recurring headache is a common pain problem, and this procedure is sometimes used in a search for a diagnosis, but it has no advantage over routine clinical evaluation.
Electroencephalography
Quantitative electroencephalography
Magnetoencephalography
Stereoelectroencephalography
Echoencephalography
Amplitude integrated electroencephalography
Polysomnography
Hemoencephalography