Transient ischemic attack (TIA) has classically been defined as an ischemic episode, in
which patients can present with transient neurological symptoms, in the absence of brain
injury. However, recent literature showed evidence of cerebral tissue injury in TIA,
which suggests that focal cerebral ischemic events are essentially cerebral infarctions.
Based on this, TIA should be considered a minor ischemic stroke. TIA/minor stroke, as all
strokes, should be considered a medical emergency. Identifying and treating patients with
TIA in a timely manner is important for stroke prevention. Literature suggests that more
than 10% of patients diagnosed with TIA have a stroke within the next 90 days, of which
half of these cases occur in the first 48 hours.
When a patient presents to the emergency department or an outpatient clinic with
transient or mildly observable neurologic symptoms, it is difficult to diagnose an
ischemic event from other TIA/stroke mimics such as migraine, seizure, etc. This is
mostly because diagnosis of TIA/minor stroke relies on subjective, retrospective report.
One study found that about 45% of referrals to a rapid stroke prevention clinic for query
TIA/stroke were TIA mimics. Diagnosis also becomes more uncertain for patients who
present with symptoms other than motor and speech deficits, which are more classically
seen with brain ischemia, such as dizziness or sensory symptoms.
Advances in brain imaging have facilitated the evaluation of brain injury in the context
of transient neurological symptoms. Diffusion-weighted MRI can show infarcts in one-third
of patients with TIA. However, this poses the risk of missing patients who are
MRI-negative and discharging patients without appropriate stroke preventative care.
Furthermore, there are also resource limitations, which make it difficult to do an MRI
brain in all patients who present with transient or mildly observable neurological
symptoms. For example, there is limited time during a code stroke, which makes a CT scan
the more feasible option, and additionally there are resource constraints depending on
the setting of care (ie rural setting, outpatient clinic). Therefore, this warrants the
need for a portable diagnostic device to assist with timely and accurate evaluation of
possible TIA/stroke.
Electroencephalogram (EEG), which is typically used in the context of epilepsy, provides
a non-invasive measure of brain function. EEG also has potential to detect cerebral
ischemia, given that there are metabolic and electrical changes of cortical neurons
during times of reduced cerebral blood flow. However, the use of EEG and specifically
portable EEG, in the context of acute stroke and TIA is limited.
In the literature, one study found that a 3-minute portable resting EEG accurately
identified patients with large acute ischemic strokes in the emergency department and
correlated with infarct volume. Another study, which used a 3-minute EEG obtained from a
single electrode over the left frontal lobe, found unique EEG profiles for TIA versus
ischemic stroke patients. However, these preliminary findings were limited due to small
sample size and EEG data typically was obtained on the second day after symptom onset.
This study involves the use of portable EEG device, CGX Systems Quick-20m device, to
diagnose TIA/stroke by aiming to find an electrical signature that is specific to
TIA/stroke versus cerebral perfusion. The investigators anticipate doing this by
comparing EEG data in patients who present with transient neurological symptoms or have
known stroke and are candidates for hyperacute treatment, such as thrombolysis or
thrombectomy, with EEG data in patients who obtained revascularization and resumption of
cerebral perfusion following hyperacute treatment for stroke or in generally healthy
individuals with no stroke history.
Primary Objective: To assess the feasibility of administering a portable EEG device in
the context of acute TIA/stroke.
Secondary Objectives:
i. To evaluate the effectiveness of portable EEG in accurately diagnosing TIA/stroke.
ii. To explore potential EEG changes from stroke-related reperfusion
