What Happens in Your Brain When You Have Seizure?
Seizures are characterized by sudden, excessive electrical discharges in the brain. These abnormal brain activities can cause a wide range of symptoms, depending on the area of the brain affected and the nature of the seizure. Understanding the brain processes involved in seizures can provide insights into their causes, mechanisms, and potential treatments.
Initiation of Seizure:
- Neurons: Seizures begin when a group of neurons in the brain fire excessively and synchronously. Normally, neurons communicate with each other through controlled electrical signals.
- Epileptic Foci: In individuals with epilepsy (the tendency to have recurrent seizures), there may be specific regions in the brain known as "epileptic foci" or "seizure foci" where abnormal electrical activity can originate.
Spread of Seizure:
- Localized Seizure: In some cases, the excessive electrical activity remains confined to a specific region of the brain, causing localized seizures. These are often referred to as focal seizures or partial seizures.
- Generalized Seizure: In generalized seizures, the abnormal electrical discharges rapidly spread throughout the entire brain, involving both hemispheres. These seizures result in a loss of consciousness and characteristic motor symptoms.
Types of Seizures:
1. Focal Seizures (Partial Seizures):
- Simple Focal Seizures: These seizures affect a limited area of the brain and do not impair consciousness. Symptoms can include involuntary movements, sensory changes, or altered emotions.
- Complex Focal Seizures: In addition to the symptoms of simple focal seizures, complex focal seizures also involve impairment of consciousness. Individuals may experience blank stares, confusion, and difficulty responding during these seizures.
2. Generalized Seizures:
- Absence Seizures: These brief seizures, also called "petit mal" seizures, cause brief lapses in consciousness that may go unnoticed. They typically occur in childhood.
- Myoclonic Seizures: Myoclonic seizures are characterized by sudden muscle jerks or twitching.
- Clonic Seizures: Rhythmic, jerking movements of the limbs or the entire body are the hallmark of clonic seizures.
- Tonic Seizures: Prolonged muscle stiffness or rigidity occurs in tonic seizures.
- Tonic-Clonic Seizures (Grand Mal Seizures): These are generalized seizures that involve both tonic and clonic phases, often resulting in loss of consciousness, muscle contractions, and potential loss of bladder control.
Electrical Changes:
During a seizure, the abnormal electrical discharges in the brain disrupt normal brain activity. Electroencephalography (EEG), a tool that records electrical activity in the brain, can detect and characterize the patterns of these abnormal electrical discharges, helping in the diagnosis and classification of seizures.
Post-Seizure Effects:
- Post-Ictal Phase: After a seizure, individuals may enter a post-ictal phase, which can last from minutes to hours. This phase is characterized by confusion, disorientation, and drowsiness.
- Todd's Paralysis: Temporary weakness or paralysis on one side of the body can occur after a seizure. This is known as Todd's paralysis and usually resolves over time.
Understanding the brain processes involved in seizures is essential for developing effective treatment strategies. Medications, surgical interventions, and other approaches aim to control or eliminate the abnormal electrical discharges, thereby reducing the frequency and severity of seizures.