The purpose of this study is Collecting data for an Electroencephalograph based algorithm for detection of onset and deterioration of Acute Ischemic Stroke by Comparison to NIHSS.

Inclusion criteria study population Age > 18 years old. Acute stroke symptoms onset within 120 hours of inclusion, and as proximate to event as possible.

Acute ischemic moderate or severe hemispheric stroke (assessed as 5 points or more by NIHSS) and including patients treated by t-PA

Exclusion criteria study population Primary intracranial hemorrhage on admission by CT. Significant movement disorder. Previous major hemispheric stroke. Local skull or skin affliction which prevents electrodes application. Any known condition which in the opinion of the investigator may interfere with the protocol implementation.

Inclusion criteria Control Population

Age > 18 years old.

Exclusion criteria Control Population Primary intracranial hemorrhage on admission by CT. Significant movement disorder. Previous major hemispheric stroke. Local skull or skin affliction which prevents electrodes application. Migraine Any known condition which in the opinion of the investigator may interfere with the protocol implementation.

Inclusion Criteria:

• Age > 18 years old.
• Acute stroke symptoms onset within 120 hours of inclusion, and as proximate to event as possible.
• Acute ischemic moderate or severe hemispheric stroke (assessed as 5 points or more by NIHSS) and including patients treated by t-PA

Exclusion Criteria:

• Primary intracranial hemorrhage on admission by CT.
• Significant movement disorder.
• Previous major hemispheric stroke.
• Local skull or skin affliction which prevents electrodes application.
• Any known condition which in the opinion of the investigator may interfere with the protocol implementation

Stroke patients