Seizures are sudden bursts of abnormal electrical activity in the brain. They can result in changes in movement, consciousness, and behaviour of an individual. Two or more episodes of seizures are termed as epilepsy.

There are two groups of seizures:
Focal seizures - These involve only one part of the brain and happen with or without loss of consciousness. They are also known as partial seizures.
Generalised seizures - They involve both sides of the brain. Tonic-clonic, atonic, and absence seizures are types of generalised seizures.

The doctor will ask for your medical history and symptoms after a seizure occurs. In addition, some tests which are used for diagnosis include:
Blood tests to check for electrolyte imbalances, infection or blood sugar levels
Lumbar puncture
Neurological exam
Electroencephalogram (EEG)
Imaging techniques such as a CT scan or MRI scan

During an episode of seizure, the following symptoms are observed:
Loss of consciousness
Confusion
Rapid jerking movement of arms and legs
Falling
Fear and anxiety
Sudden and rapid blinking
Inability to communicate and feeling dazed
Changes in touch, taste, smell, and sound
Frothing or drooling from the mouth
Clenching of teeth
Biting tongue
Staring into space

Seizures can prove to be dangerous if:
The seizures repeatedly happen one after the other
There are injuries such as on the head after falling or by inhaling their vomit
They drown while bathing in a tub or while swimming
It leads to sudden unexpected death in epilepsy (SUDEP), which is believed to be caused by pauses in breathing, irregular heart rhythm, or cardiac stroke during a seizure