|Dysmetropsia (Alice in Wonderland Syndrome)|
|Classification and external resources|
Dysmetropsia (also known as Alice in Wonderland syndrome, Todd's syndrome, or lilliputian hallucinations) is a disorienting neurological condition that affects human perception. People experience micropsia, macropsia, pelopsia, teleopsia, or size distortion of other sensory modalities. It is often associated with migraines, brain tumors, and the use of psychoactive drugs. It can also present as the initial sign of the Epstein–Barr virus (see mononucleosis). Anecdotal reports suggest that the symptoms are fairly common in childhood, with many people growing out of them in their teens. It appears that dysmetropsia is also a common experience at sleep onset, and has been known to commonly arise due to a lack of sleep. Dysmetropsia can be caused by abnormal amounts of electrical activity causing abnormal blood flow in the parts of the brain that process visual perception and texture.
Signs and symptoms
The hallmark sign of dysmetropsia or Alice in Wonderland syndrome (AIWS) is a migraine, and AIWS may in part be caused by the migraine. AIWS affects the sense of vision, sensation, touch, and hearing, as well as one's own body image. 
A prominent and often disturbing symptom is an experiences of altered body image. The person may find that he or she is confused as to the size and shape of parts of (or all of) his or her body. He or she may feel as though his or her body is expanding or getting smaller. Alice in Wonderland syndrome also involves perceptual distortions of the size or shape of objects. Other possible causes and signs of the syndrome include migraines, use of hallucinogenic drugs, and infectious mononucleosis.
Patients with certain neurological diseases have experienced similar visual hallucinations. These hallucinations are called "Lilliputian," which means that objects appear either smaller or larger than they actually are.
Patients may experience either micropsia or macropsia. Micropsia is an abnormal visual condition, usually occurring in the context of visual hallucination, in which affected persons see objects as being smaller than those objects actually are. Macropsia is a condition where the individual sees everything larger than it actually is.
The relationship, if any, between the syndrome and mononucleosis remains unknown. One 17-year-old male described his odd symptoms. He said, "quite suddenly objects appear small and distant (teliopsia) or large and close (peliopsia). I feel as I am getting shorter and smaller 'shrinking' and also the size of persons are not longer than my index finger (a lilliputian proportion). Sometimes I see the blind in the window or the television getting up and down, or my leg or arm is swinging. I may hear the voices of people quite loud and close or faint and far. Occasionally, I experience attacks of migrainous headache associated with eye redness, flashes of lights and a feeling of giddiness. I am always conscious to the intangible changes in myself and my environment." 
The eyes themselves are normal, but the person will often 'see' objects as the incorrect size, shape or perspective angle. Therefore, people, cars, buildings, houses, animals, trees, environments, etc., look smaller or larger than they should be, or that distances look incorrect; for example a corridor may appear to be very long, or the ground may appear too close.
The person affected by Alice in Wonderland Syndrome may also lose the sense of time, a problem similar to the lack of spatial perspective. In other words, time seems to pass very slowly, akin to an LSD experience. The lack of time, and space, perspective leads to a distorted sense of velocity. For example, one could be inching along ever so slowly in reality, yet it would seem as if one were sprinting uncontrollably along a moving walkway, leading to severe, overwhelming disorientation. This can then cause the person to feel as if movement, even within his or her own home, is futile.
In addition, some people may, in conjunction with a high fever, experience more intense and overt hallucinations, seeing things that are not there and misinterpreting events and situations.
Other minor or less common symptoms may include loss of limb control and general dis-coordination, memory loss, lingering touch and sound sensations, and emotional experiences.
AIWS is a disturbance of perception rather than a specific physiological change to the body's systems. The diagnosis can be presumed when other causes have been ruled out and if the patient presents symptoms along with migraines and complains of onset during the day (although it can also occur at night). Another symptom of AIWS is sound distortion, such as every little movement making a clattering sound. This can cause person to experience paranoia.
Whatever the cause, the bodily related distortions can recur several times a day and may take some time to abate. Understandably, the person can become alarmed, frightened, and panic-stricken throughout the course of the hallucinations - maybe even hurt themselves or others around them. The symptoms of the syndrome themselves are not harmful and are likely to disappear with time.
The average age of the start Alice-in-Wonderland syndrome is six but it is very normal for some to experiences the syndrome from childhood to their late 20s. However, some still have problems in their 70's.
The syndrome is sometimes called Todd's syndrome, in reference to an influential description of the condition in 1955 by Dr. John Todd (1914-1987), who was a British Consultant Psychiatrist at High Royds Hospital at Menston in West Yorkshire. Todd discovered that several of his patients experienced severe migraine headaches causing them to see and perceive objects as greatly out of proportion. They have altered sense of time and touch, as well as distorted perceptions of their own body. Although having migraine headaches, none of these patients had brain tumours, damaged eyesight, or mental illness that could have caused similar symptoms. They were also all able to think lucidly and could distinguish hallucinations from reality. But their perceptions were skewed. Since Lewis Carroll had been a well-known with migraines with similar symptoms, Todd speculated that Carroll had used his own migraine experiences as a source of inspiration for his famous 1865 novel Alice’s Adventures in Wonderland. Carroll’s diary reveals that in 1856 he consulted William Bowman, an eminent ophthalmologist, about the visual manifestations of the migraines he regularly experienced. Since Carroll had these migraine symptoms for years before writing Alice’s Adventures, it seemed reasonable that Carroll had used his experiences as inspiration.
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