EEG Cap for Identification of Non-Convulsive Status Epilepticus

Altered mental status (AMS) is one of the most common reasons for inpatient neurology consultation. Non-convulsive status epilepticus (NCSE) is frequently on the differential diagnosis of the patient with AMS. NCSE becomes more refractory to treatment after one hour of seizure activity, making rapid identification and treatment of NCSE of great clinical importance. Currently, an electroencephalogram (EEG) technologist must be called in from home during non-workday hours in order to obtain a stat EEG. The investigators propose the time required for diagnosis of NCSE at Mayo Clinic can be significantly decreased with rapid placement of an EEG cap by the onsite neurology residents.

At the completion of neurology evaluation, if NCSE is in the differential diagnosis according to institution best practice, then consented participants will undergo placement of a large size, 20-channel EEG cap from Electro-Cap International with a Natus E-2-2520-26 electrode board adapter with initiation of recording. The placement of the EEG cap will be restricted to residents formally trained in its placement by an EEG tech. This study will only be performed during times when EEG techs are not available onsite for rapid placement of standard 21-channel EEG electrodes, such as during night-call shifts. Prior to placement of EEG cap, evaluating staff member will request immediate standard-electrode EEG. The investigators will record time from neurology consultation request to placement of EEG cap as well as time from consultation request to obtaining a standard EEG. The investigators will also record time to confirmation or exclusion of NCSE. Initial diagnosis or exclusion of NCSE will be performed by on call resident, if the resident received prior training regarding EEG cap placement, and attending. Secondary quality assessment will be performed by two independent EEG interpreters blinded to clinical history. Secondary assessment will be qualified as acceptable or inacceptable interpretation based on whether greater or less than 50% of the recording is judged interpretable. Secondary assessment will also include interpretation of NCSE by a third independent reader if there is disagreement between first two. The number of patients excluded from the study will also be recorded, including the reason for exclusion.

Nonconvulsive Status Epilepticus, Subclinical Seizure, Altered Mental Status, Nonepileptic Seizures, Encephalopathy

Subjects may be treated for NCSE based on EEG cap findings, but only following standard practice. The study is designed to identify NCSE, not to assess treatment of NCSE.

Single arm study, where every participant gets assessed by EEG cap and then standard EEG. Some subjects may be treated with anti-seizure medications before standard EEG, due to ethical responsibility, if clear NCSE is identified on cap EEG. If the subject is treated with anti-seizure medication, the primary care provider will choose which medication will be given.

Patients may be treated for NCSE or seizures based on EEG cap findings, if the findings are clear to an attending EEG reviewer. If the subject is treated with anti-seizure medication, the primary care provider will choose which medication will be given.

An electroencephalogram (EEG) is a test used to find problems related to electrical activity of the brain. An EEG tracks and records brain wave patterns. Small metal discs with thin wires (electrodes) are placed on the scalp, and then send signals to a computer to record the results.

The difference between EEG Cap results reporting time compared to Standard EEG results reporting time measured in minutes.

The recording will be qualified as acceptable interpretation if greater than 50% of the recording is judged interpretable by board certified electroencephalographers.

Number of Subjects for Which the EEG Cap and Standard EEG Results Are in Agreement for the Diagnosis of NCSE

Inclusion criteria: Patients with suspected NCSE in the Mayo Clinic Florida hospital, emergency room or intensive care unit. Age: Patients of 18 years or older will be included in this study Education: All education levels will be included Exclusion criteria: Patients younger than 18 years of age. Patients with open head trauma. Patients with anatomy that would preclude EEG cap placement. Patients excluded for anatomical or age-related reasons will be tracked to determine applicability of the EEG cap to the patient population at Mayo Clinic. Pregnant females Large head size not amenable to cap placement Scalp infection Inability to obtain informed consent

Ferlisi M, Shorvon S. The outcome of therapies in refractory and super-refractory convulsive status epilepticus and recommendations for therapy. Brain. 2012 Aug;135(Pt 8):2314-28. doi: 10.1093/brain/aws091. Epub 2012 May 9. Erratum In: Brain. 2013 Jul;136(Pt 7):2326.