Visor for Prehospital Stroke Diagnosis

A stroke refers to the situation where the sudden loss of brain function due to cell death because of poor or interrupted blood flow within the brain. Symptoms of stroke include sudden weakness, inability to move or feel on one side of the body i.e., paralysis, problems of understanding or speaking, dizziness, loss of vision, severe headache, and loss of consciousness. Strokes are classified as:-

• Either ischemic, due to lack of blood flow
• Hemorrhagic, which are caused by uncontrolled bleeding in the brain causing about 40 percent of stroke deaths.

Clinical diagnosis of stroke can be made using patient history and physical examination, diagnostic tests like blood glucose, oxygen saturation, prothrombin time, and electrocardiography, and various neuroimaging techniques such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). 

But today, a number of new and advanced stroke diagnostic devices such as the hemorrhage scanning visor, have been developed in order to speed up a stroke diagnosis, which is important because the early identification and treatment of stroke are critical for improving clinical outcomes and ensuring that patients are given essential medical attention. There is a critical, highly-visible unmet need for effective, accurate pre-hospital stroke triage in ambulances and emergency rooms, to distinguish between the different types of stroke.

This Cerebrotech Visor, developed by Cerebrotech Medical Systems of Pleasanton, California, that clinicians or paramedics can place on patients suspected of having a stroke has demonstrated 92% accuracy when compared to the diagnostic results from standard physical examination which were only 40–89% correct. It diagnoses severe cases of the condition and simplify their decision as to where to take patients first. Patients with large-vessel occlusions can then be routed to a Comprehensive Stroke Center with endovascular capabilities. Transfer between hospitals takes a lot of time. If we can give the information to emergency personnel out in the field that this is a large-vessel occlusion, this will help in triage as to which hospital they should go to.

The Cerebrotech Visor which is expected to be a top innovation for 2019, operates by sending low-energy radio waves through the brain and detecting their nature after they pass through the left and right lobes, thus providing diagnosis within seconds. The frequency of the waves changes when they pass through fluid in the brain. A severe stroke can cause changes in this fluid which indicate a stroke or bleeding in the brain, resulting in asymmetry in the waves detected by the visor. The greater the asymmetry, the more severe the stroke.  The technique is called volumetric impedance phase shift spectroscopy (VIPS).

Each procedure takes approximately 30 seconds per patient where three readings are taken and then averaged. The VIPS device requires very little training to operate compared to that required to learn standard emergency examination skills and its simplicity reduces the risk of human error in assessments. 

In their next steps, the researchers are undertaking the VITAL 2.0 study to determine if the VIPS device can use complex machine learning algorithms to “teach” the device to independently distinguish between minor and severe stroke, without the input of a neurologist.

The VIPS device is used in detecting severe stroke to the use of electrocardiography (ECG) to definitively detect acute myocardial infarction. It can be used widely by emergency personnel just like a defibrillator is used to check if a patient has heart attack.