Allochiria is a condition in which stimuli
presented on one side of the body is perceived
as occurring on the opposite side of the body.
There are different types of allochiria
depending on the particular sensation effected.
The most commonly referred to type is
somatosensory allochiria (sometimes referred
to as allesthesia), which refers to touch
sensation, particularly in the limb (arm or leg).
When one side of the body is
touched it is felt on the other side.
An example is being touched on the left leg but feeling it on the right leg instead. In
auditory allochiria, a sound presented to one side of the body will be perceived as if it
came from the other side. In visual allochiria, a visual stimuli presented to one side of
the body will be reported as if it was presented on the other side of the body. In
gustatory allochiria, stimuli on one side of the tongue is tasted or felt on the opposite
side of the tongue.
Allochiria can also be classified based on the particular function affected. Specifically,
there is reflex allochiria, motor allochiria, and electromotor allochiria. In reflex allochiria,
stimulation presented on one side of the body (e.g., knee, sole of foot, inner thigh)
causes a reflex on the other side of the body. In motor allochiria, striking or touching one
limb causes a muscle contraction on the other side of the body. Electromotor allochiria
includes conditions in which a stimulated muscle responds as well as the muscle on the
opposite side of the body. This occurs due to crossing of electrical impulses.
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A person with allochiria usually has doubt about the side being
touched but picks the opposite side nonetheless. The condition can
occur in any part of the body, can occur only as a problem on one
side of the body (e.g., only mistaking right stimuli as perceived on
the left), or can occur on both sides (i.e. mistaking right-sided stimuli
as coming from the left and vice versa).
In some cases, there are certain types of stimuli that can elicit a
sensation on the proper (i.e., actual) side of the body that was
Allochiria often occurs due to damage to the right parietal lobe. The parietal lobe is the middle area of
the top part of the brain (on both sides) and is responsible for integrating sensory information to form
perceptions and spatial sense. It also plays an important role in insight and self-awareness. Another
condition that is often caused by right parietal lobe damage and often co-occurs with allochiria, is
Unilateral neglect is an impairment in attention to one side of space (usually the left). There are some causes of
allochiria that are psychological in nature. Allochiria can resolve if the area of brain damage improves (e.g.,
decreased size of a bleed), which frees up the tracks of sensory fibers in the brain or spinal cord that have been
Conditions known to cause multiple sclerosis are those causing damage to the brain and/or spine. Examples include
traumatic spinal cord injury, traumatic brain injury, stroke (a burst artery or a blockage of an artery in the brain),
multiple sclerosis, Meniere’s disease, symmetrical gangrene, and tabes dorsalis. Multiple sclerosis is a condition in
which multiple areas of abnormal patches (known as plaques) develop in the brain and/or spinal cord (depending on
the stage of the illness). Meniere’s disease is a condition characterized by dizziness, vomiting, nausea, ringing in the
ears, and other symptoms due to inflammation of a tube in the ear. Gangrene is death of a tissue, usually due to a
loss of blood supply. Tabes dorsalis is a loss of myelin in the sensory neurons (nerve cells) that carries information
to the brain.
Allochiria is a form of a condition called allachesthesia, in which sensations are referred to another part of the body.
Allochiria is also known as allocheiria, allesthesia, alloesthesia, and Bamberger sign. Allochiria comes from the
Greek word "allos" meaning "other," and the Greek word "cheir" meaning "hand." Put the two words together and
you get "other hand."