Reflex seizures are epileptic seizures that are consistently induced by a specific stimulus or trigger making them distinct from other epileptic seizures, which are usually unprovoked. Reflex seizures are otherwise similar to unprovoked seizures and may be focal (simple or complex), generalized, myoclonic, or absence seizures. Epilepsy syndromes characterized by repeated reflex seizures are known as reflex epilepsies. Photosensitive seizures are often myoclonic, absence, or focal seizures in the occipital lobe, while musicogenic seizures are associated with focal seizures in the temporal lobe.Triggers may include various stimuli with the most common (75 to 80%) being flickering lights resulting in photosensitive seizures. Reflex epilepsies are generally thought to be genetic in origin. The inheritance pattern is dependent on the type of reflex epilepsy with some types lacking a specific genetic inheritance patterns. For example, photogenic epilepsy is thought to follow an autosomal dominant pattern with incomplete penetrance, while seizures triggered by proprioceptive stimuli do not follow an observable inheritance pattern. The underlying mechanism involves the stimulation of existing network of neurons by the specific trigger.The treatment of reflex epilepsy generally involves decreasing exposure to a persons triggers as well as anti-epileptic medications. Reflex epilepsy is relatively rare, making up approximately 5% of epilepsy syndromes. Signs and symptoms
Reflex seizures can be either generalized or focal seizures or both. However, for any given stimulus there may be a large variation in the kind of elicited seizure.
Focal seizures can be located only in the area of the brain responsible for the stimulus, spread to other areas of the brain, or even develop into a generalized seizure. Triggers
Stimuli that cause reflex seizures can be categorized as either intrinsic or extrinsic. For a given person, the stimulus that triggers may be intrinsic, extrinsic, or a combination of both. Extrinsic stimuli
Extrinsic stimuli are sensory stimuli that originate from the persons environment. Similar to intrinsic stimuli, extrinsic stimuli can be divided into two categories, either simple or complex. Examples of simple extrinsic stimuli include flashing lights or touch while complex extrinsic stimuli can include music, language, reading, or stimulation from eating. Some of the more common types of reflex epilepsy include light and music.Photosensitive epilepsy is an abnormal sensitivity of the brain to visual stimuli and is the most common trigger in reflex seizures. Reflex seizures can be induced by both flickering or non-flicking light, television, video games, or other visual patterns. Most people who have photosensitive epilepsy are sensitive to specific patterns for visual stimuli. Visual stimuli of a particular frequency (15-25  flashes/second), wavelength (red light at 660-720 nm), and at high contrast have been shown to have a higher risk of inducing seizures in people who are photosensitive. In addition, emotional excitement, fatigue, or length of exposure can all effect the risk of seizures.Musicogenic epilepsy is a rare reflex epilepsy that is thought to be an abnormal sensitivity of the brain to musical stimuli, however, the exact mechanism of these seizures is unknown.