EEG controlled triage in the ambulance for acute ischemic stroke

Endovascular thrombectomy (EVT) is standard treatment for acute ischemic stroke
(AIS) if there is a large vessel occlusion in the anterior circulation (LVO-a).
Because of its complexity, EVT is performed in selected hospitals only.
Currently, approximately half of EVT eligible patients are initially admitted
to hospitals that do not provide this therapy. This delays initiation of
treatment by approximately an hour, which decreases the chance of a good
clinical outcome. Direct presentation of all patients with a suspected AIS in
EVT capable hospitals is not feasible, since only circa 7% of these patients
are eligible for EVT. Therefore, an advanced triage method that reliably
identifies patients with an LVO-a in the ambulance is necessary.
Electroencephalography (EEG) may be suitable for this purpose, as preliminary
studies suggest that slow EEG activity in the delta frequency range correlates
with lesion location on cerebral imaging. Using dry electrode EEG caps will
enable relatively unexperienced paramedics to perform a reliable measurement
without the EEG preparation time associated with *wet* EEGs. Combined with
algorithms for automated signal analysis, we expect the time of EEG recording
and analysis to eventually be below five minutes, which would make stroke
triage in the ambulance by EEG logistically feasible.

To determine the diagnostic accuracy of dry electrode cap EEG for diagnosis of
LVO-a, when performed by paramedics in the ambulance in patients with a
suspected AIS.

This diagnostic study consists of four phases:
Phase 1: Optimization of measurement time and software settings of the dry
electrode cap EEG in a non-emergency setting in patients in whom a regular EEG
is/will be performed for standard medical care.
Phase 2: Optimization of measurement time, software settings and data transfer
logistics in patients close to our target population in a non-emergency setting.
Phase 3: Validation of several existing algorithms and development of one or
more new algorithms.
Phase 4: Validation of the algorithms with data of suspected AIS patients in
the ambulance, as well as assessment of technical and logistical feasibility of
performing EEG with dry electrode caps in suspected AIS patients in the
ambulance.

A single EEG is performed on each patient. The EEG is a safe, non-invasive and
painless procedure that is used regularly in standard medical practice. It does
not involve electromagnetic radiation. The use of dry electrodes makes the
procedure less time-consuming. After optimization of measurement time in phase
1 and 2, the procedure will take less than five minutes in total. Therefore,
when the measurements are performed in an emergency setting in phases 3 and 4,
the procedure can be completed within the time it takes the treating physician
or paramedic to perform their regular work-up. This way, initiation of
treatment will not be delayed. We expect the dry electrode cap to cause no to
minimal discomfort, and only during the measurement. We will use CE marked
products for performing the dry electrode cap EEGs. The results of the EEG will
only be analyzed after admission or discharge, and will therefore not influence
the choice of hospital by the paramedic. As soon as feasible, preferably within
72 hours after arrival at the hospital, deferred informed consent will be
asked. If informed consent is given, a CRF will be filled out containing
information on patient characteristics, medical history, medication use, data
of physical and neurological examination performed by the treating physician,
results of imaging studies, diagnosis and treatment as well as logistical and
technical information, obtained from the patient, the treating physician and
the ambulance service. There are no follow up visits. For the patient, there is
no benefit of participation in the study.