DerealizationDerealization is an alteration in the perception of the external world, causing those with the condition to perceive it as unreal, distant, distorted or falsified. Other symptoms include feeling as if one's environment is lacking in spontaneity, emotional coloring, and depth. It is a dissociative symptom that may appear in moments of severe stress. Derealization is a subjective experience pertaining to a person's perception of the outside world, while depersonalization is a related symptom characterized by dissociation towards one's own body and mental processes.
Visual snow syndromeVisual snow syndrome (VSS) is an uncommon neurological condition in which the primary symptom is that affected individuals see persistent flickering white, black, transparent, or coloured dots across the whole visual field. Other common symptoms are palinopsia, enhanced entoptic phenomena, photophobia, and tension headaches. The condition is typically always present and has no known cure, as viable treatments are still under research. Astigmatism, although not presumed connected to these visual disturbances, is a common comorbidity.
Focal seizureFocal seizures (also called partial seizures and localized seizures) are seizures which affect initially only one hemisphere of the brain. The brain is divided into two hemispheres, each consisting of four lobes – the frontal, temporal, parietal and occipital lobes. A focal seizure is generated in and affects just one part of the brain – a whole hemisphere or part of a lobe. Symptoms will vary according to where the seizure occurs. When seizures occur in the frontal lobe the patient may experience a wave-like sensation in the head.
Scintillating scotomaScintillating scotoma is a common visual aura that was first described by 19th-century physician Hubert Airy (1838–1903). Originating from the brain, it may precede a migraine headache, but can also occur acephalgically (without headache), also known as visual migraine or migraine aura. It is often confused with retinal migraine, which originates in the eyeball or socket. Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area.
Jamais vuIn psychology, jamais vu (ˌʒæmeɪ_ˈvuː , USˌʒɑːm- , ʒamɛ vy), a French loanword meaning "never seen", is the phenomenon of experiencing a situation that one recognizes in some fashion, but that nonetheless seems novel and unfamiliar. Jamais vu is often described as the opposite of déjà vu. Jamais vu involves a sense of eeriness and the observer’s impression of experiencing something for the first time, despite rationally knowing that they have experienced it before.
ProdromeIn medicine, a prodrome is an early sign or symptom (or set of signs and symptoms) that often indicates the onset of a disease before more diagnostically specific signs and symptoms develop. It is derived from the Greek word prodromos, meaning "running before". Prodromes may be non-specific symptoms or, in a few instances, may clearly indicate a particular disease, such as the prodromal migraine aura. For example, fever, malaise, headache and lack of appetite frequently occur in the prodrome of many infective disorders.
Generalized tonic–clonic seizureA generalized tonic–clonic seizure, commonly known as a grand mal seizure or GTCS, is a type of generalized seizure that produces bilateral, convulsive tonic and clonic muscle contractions. Tonic–clonic seizures are the seizure type most commonly associated with epilepsy and seizures in general and the most common seizure associated with metabolic imbalances. It is a misconception that they are the sole type of seizure, as they are the main seizure type in approximately 10% of those with epilepsy.
Déjà vuDéjà vu (ˌdeɪʒɑː_ˈv(j)uː , deʒa vy; "already seen") is a French loanword for the phenomenon of feeling as though one has lived through the present situation before. It is an illusion of memory whereby — despite a strong sense of recollection — the time, place, and context of the "previous" experience are uncertain or impossible. Approximately two-thirds of surveyed populations report experiencing déjà vu at least one time in their lives.
VertigoVertigo is a condition in which a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties walking. It is typically worse when the head is moved. Vertigo is the most common type of dizziness. The most common disorders that result in vertigo are benign paroxysmal positional vertigo (BPPV), Ménière's disease, and vestibular neuritis.
PhotopsiaPhotopsia is the presence of perceived flashes of light in the field of vision. It is most commonly associated with: posterior vitreous detachment migraine aura (ocular migraine / retinal migraine) migraine aura without headache scintillating scotoma retinal break or detachment occipital lobe infarction (similar to occipital stroke) sensory deprivation (ophthalmopathic hallucinations) age-related macular degeneration vertebrobasilar insufficiency optic neuritis visual snow syndrome Vitreous shrinkage or liquefaction, which are the most common causes of photopsia, cause a pull in vitreoretinal attachments, irritating the retina and causing it to discharge electrical impulses.