Seizures occur when a group of nerves in the brain suddenly produce a surge of electrochemical impulses. This surge in brain activity interrupts normal functions resulting in symptoms thatoften mimic a stroke. A stroke, also a neurological event, occurs when oxygen fails to reach the brain, causing the death of brain cells and resulting in permanent damage. Although seizures produce stroke-like symptoms, the effects of seizures are temporary.
A focal seizure, also called a partial seizure, affects only a small area of the brain. This type of seizure can cause numbness and tingling leading to weakness on one side of the body. The side of the body affected depends upon the area of the brain where the seizure occurs. The numbness and weakness usually subsides with the seizure, which typically lasts a few seconds to a few minutes, according to the Merck Manual. Numbness and weakness on one side of the body, which lasts longer than the seizure, is known as Todd's paralysis.
The partial or complete paralysis on one side of the body caused by Todd's paralysis mimics the symptoms of a stroke. Those with Todd's paralysis also often exhibit speech or vision impairments. The paralysis and impairments of Todd's paralysis are temporary usually lasting from 30 minutes to 36 hours, with 15 hours as the average, according to the National Institute of Neurologic Disorders and Stroke. Unlike a stroke; however, patients completely recover from Todd's paralysis.
Some types of seizures cause a brief loss of consciousness and impair the memory, resulting in a lack of recollection of any of the events that occur during the seizure episode. Focal seizures are classified as either simple focal seizures or complex focal seizures. During simple focal seizures, the patient remains aware and awake during the seizure allowing for complete recall of the events. Complex focal seizures, on the other hand, cause a brief loss of consciousness leading to memory loss. Generalized seizures, those that affect both sides of the brain, also cause a loss of consciousness and impair the memory.
Seizures occurring in the specific parts of the brain affecting speech can cause speech impairments. The left hemisphere of the brain contains the Broca's area, which functions in speech production and articulation. Seizures affecting the left hemisphere therefore can result in slurred or slow speech. The frontal and temporal lobes of the brain also play a role in language through processing sounds and controlling the muscles around the mouth. Therefore ,frontal lobe seizures and temporal lobe seizures can cause temporary speech impairments.
Strokes can cause visual disturbances including double vision, blurred vision and the appearance of black areas in the vision field. Seizures that affect the occipital lobe of the brain, the area responsible for visual processing, can result in visual hallucinations, the sensation of blinking lights, blurred vision and rapid blinking.