Symptoms of mild cerebral hypoxia include:

• Change in attention (inattentiveness)
• Poor judgment
• Uncoordinated movement

Symptoms of severe cerebral hypoxia include:

• Complete unawareness and unresponsiveness (coma)
• No breathing
• No response to light

If only blood pressure and heart function remain, then the brain may actually be completely dead.

Cerebral hypoxia can usually be diagnosed based on the person's medical history and a physical exam. Tests are done to determine the cause of the hypoxia, and may include:

• Blood work, including arterial blood gases and blood sugar level
• Echocardiogram
• Electrocardiogram (ECG), a measurement of the heart's electrical activity
• Electroencephalogram (EEG), a test of brain waves that can identify seizures and show how well brain cells work
• Evoked potentials, a test that determines whether certain sensations such as vision and touch reach the brain
• Magnetic resonance imaging (MRI)