Study to Test Sensitivity and Specificity of Passive Wave Pressure Device in Determining Ischemic Stroke

In spite of the fact that approximately 800,000 strokes are diagnosed in the United States
each year, many physicians and patients have approached the management of stroke with a
sense of futility. However, within the past 2 decades, following the advent of computerized
tomography (CT), medical interest has turned toward stroke and effective interventions to
treat and prevent it have received attention.

CT and/or magnetic resonance imaging (MRI) are the typical diagnostic tools used in the
event of a stroke alert. These studies are done on an emergent or urgent basis, since, to
be effective, treatments for ischemic and hemorrhagic stroke must be delivered soon after
onset of the illness. In an effort to institute an appropriate therapeutic regime,
laboratory and structural diagnostic studies are required to be done as rapidly as possible
to determine pathological etiology, size, and location of concern.

The speed at which a diagnosis is made and a treatment plan established often determines
patient outcome and any associated complications. This is especially true when evaluating
patients for ischemic stroke where there is a narrow 3 hour window of opportunity in which
to resolve the clot with IV .before permanent neurological impairment results, and up to 8
additional hours with the use if intra arterial (IA) t-PA or interventional mechanical
embolectomy procedures are utilized. Current treatment modalities include pharmacologic
thrombolytic drugs utilized to disrupt or dissolve clots located in the distal vasculature
or mechanical intervention in larger vessels. Since many patients do not recognize the
symptoms of stroke they do not seek medical attention immediately. Significant time is then
often lost from the onset of the stroke before seeking medical help / treatment.

Although the current technologies are quite adequate as diagnostic tools for hemorrhagic
stroke and for identifying subdural hematomas, and other pooled blood abnormalities which
would preclude t-PA therapy, they are largely ineffective at positively identifying stroke
during the limited therapeutic window of time. Positive identification of ischemia itself is
rarely possible or practical with CT or within the limited therapeutic window. As such the
diagnostic determination and associated treatment decisions are based on the unsatisfactory
basis of exclusion.

Inclusion Criteria:

- Symptoms consistent with stroke with known onset < 12 hours prior to enrollment and
planned recording with the Nautilus NeuroWave System

- Suspected pathology of following vessels: internal carotid artery, ACA, MCA, PCA,
basilar or other anterior or posterior cerebral vessels or normal anatomy

- Subject is planned to undergo standard stroke triage imaging protocol

- Able to understand and provide signed informed consent, or have a Legally Authorized
Representative willing to provide informed consent on subject's behalf

Exclusion Criteria:

- Known to meet hospital criteria for brain death

- Not a candidate for CT, MRI

- unknown time of stroke symptom onset.

- Psychologically unstable and not able to cooperate

- Not suitable for participation in this study in the opinion of the Investigator