Seizures are the main characteristic of epilepsy and are caused by abnormal electrical activity in the brain. They can manifest in various ways, depending on the type of seizure and the area of the brain affected. During a seizure, individuals may experience changes in their behavior, consciousness, movement, sensations, or emotions. These changes can range from subtle and barely noticeable to intense and dramatic.

Seizures can be classified into two main categories: focal seizures and generalized seizures. Focal seizures, also known as partial seizures, occur when abnormal electrical activity is limited to a specific area of the brain. Depending on the part of the brain affected, focal seizures can cause symptoms such as muscle twitching, numbness or tingling, changes in vision, altered senses, or uncontrolled movements. Focal seizures can be further classified as focal aware seizures, where the person remains conscious during the seizure, or focal impaired awareness seizures, where there is a loss of consciousness or altered awareness.

On the other hand, generalized seizures involve abnormal electrical activity that spreads throughout both sides of the brain from the beginning. These seizures often result in loss of consciousness and can cause convulsions, muscle stiffness, jerking movements, staring spells, or brief periods of unconsciousness. Generalized seizures can be categorized into different types, including tonic-clonic seizures (formerly known as grand mal seizures), absence seizures, atonic seizures, myoclonic seizures, and tonic seizures.

Seizures can vary in frequency, duration, and intensity. They can last from a few seconds to several minutes and may occur as isolated events or in clusters. After a seizure, individuals may experience a period of confusion, fatigue, or other physical or cognitive changes. Proper diagnosis and understanding of the different types of seizures are essential for effective treatment and management of epilepsy.