Partial-onset seizures, also known as focal seizures, originate in a specific area of the brain. They can affect a small part of the brain and may cause unusual sensations, movements, or emotions. Symptoms can vary widely depending on the area affected, and they may or may not involve loss of consciousness. These seizures are classified into two types: simple partial seizures, where consciousness remains intact, and complex partial seizures, which involve altered awareness. Epilepsy is a common condition associated with partial-onset seizures, but they can also occur due to other factors like brain injury or tumors.