Epilepsy is a neurological condition that makes people susceptible to having two or more unprovoked seizures. It is a chronic non-communicable disease with high prevalence in low- and middle-income countries. Epilepsy is one of the world’s oldest recognized brain disorders affecting nearly 50 million people across the globe, making it one of the most prevalent neurological conditions. Despite the extensive research on the causes of epilepsy, the cause cannot be determined in many of the cases. Nonetheless, several factors, including head trauma, stroke, brain injury, brain tumor, dementia, genetic or developmental disorders, and imbalance of nerve-signaling chemicals, are known to contribute to the development of seizures.
Focal epilepsies occur when an abnormal brain function occurs in the brain’s lobe and are common among individuals who have suffered head injuries, febrile seizures in childhood, birth abnormalities, and brain infections. It is the most common type of epilepsy, accounting for more than half of the reported cases. The symptoms of focal epilepsies vary depending on their location in the brain and can be categorized into three kinds of focal seizures.
Simple Focal Seizures
Simple focal seizures (auras) occur when an unusual electrical activity affects one side of the brain but doesn’t result in loss of consciousness. The seizure activity is usually limited to an isolated muscle group and lasts less than one to two minutes. A person who experiences simple focal seizures will stay conscious and aware of the surroundings but might not fully respond. Common symptoms of simple focal seizures include hallucinations, anxiety, muscle jerking, a feeling of déjà vu, and strange sensations.
Complex Focal Seizures
Complex focal seizures occur in the brain’s temporal lobe and are often preceded by a simple focal seizure. It is the most common type of epilepsy in adults and can last between 30 seconds and 2 minutes. Complex focal seizures result in loss of consciousness, and the patient may stare blankly into space and experience automatisms, such as grunting, smacking, blinking, shouting, or gulping. Sometimes, a person experiencing complex focal seizures might endanger themselves because it affects the area of the brain that controls emotion and memory function.
Secondary Generalized Seizures
Secondary generalized seizures result from genetic and neurochemical abnormalities, which start in one area of the brain and spread to the nerve cells. They are partial seizures that have evolved into generalized seizures, characterized by tonic-clonic convulsions or muscle slackness. Electroencephalogram (EEG) is the most common method used to diagnose epilepsy, and it involves using electrodes to record brain electrical activity. Technological advancement has resulted in a consumer-grade wearable EEG headset that can distinguish epileptic and nonepileptic events.
Generalized seizures occur when an unusual electrical activity begins in both hemispheres of the brain concurrently. These seizures are often characterized by loss of consciousness and widespread motor manifestations of tonic-clonic convulsions. Generalized seizures usually follow a basic pattern, beginning with muscle stiffness followed by violent muscle contractions. A person experiencing a generalized seizure might lock their jaw, turn blue in the face, bite their tongue or neck, and lose control of their bowels or bladder, and can be controlled through these treatments. Types of generalized epilepsies include the following:
Absence seizures involve a sudden loss of consciousness and are common among children. The seizure usually lasts less than 30 seconds but may occur several times a day. Absence seizures symptoms include lip-smacking, a sudden stop in motion, chewing motions, finger rubbing, eyelid flutters, and small hand movements.
Generalized Tonic-Clonic Seizures
Tonic-clonic seizures are characterized by muscle stiffness and loss of consciousness, lasting up to 20 minutes. Tonic-clonic seizures result in more severe symptoms, such as loss of bladder and bowel control, jerking movements of legs and arms, facial muscle contractions, falling, and foaming at the mouth.
Atonic seizures, also known as drop attacks, involve a sudden decline in muscle tone, causing a person to become limp and fall to the ground. Common symptoms of atonic seizures in children include drooping eyelids, nodding head, jerking, sudden loss of muscle tone, and going limp and falling.
A myoclonic seizure causes muscle jerking and often lasts one to two seconds. The symptoms of myoclonic seizures include rhythmic movements, unusual clumsiness, quick jerking, and the sensation of an electric shock.
With an estimated 5 million people diagnosed with epilepsy yearly, the neurological condition represents a significant portion of the world’s disease burden. Even though epilepsy is not a contagious disease, there are several causes, ranging from structural and genetic to infectious and metabolic. Despite the high prevalence and severe symptoms, 70% of cases can be controlled using anti seizure medicines.