Achiria, also referred to as "Simple Allochiria", is a neurological disorder in which a patient is unable to recognise or perceive one side of their body.

Psychologists in the past defined dyschiria as the inability of patients to distinguish the side of which a given stimulus is generated from.

[3][4] However, in actual clinical practice, achiria is also referred to the inability to localize stimuli from other parts of the body.

Sensory achiria describes the situation when the patient is not able to feel the sidedness of a stimulus when it is applied to a body part.

[2] The modern term with approximately the same meaning is motor neglect, where the patients rarely use their contralateral limbs.

Introspective achiria describes the situation when the patient is not able to feel or retain sensory memory of the body part in question.

[8] In 1891, Albert Paul Weiss tried to validate this theory by blocking the posterior columns of the spinal cord.

[2] Jones argued that Hammond's theory was merely a speculation because it ignored observable facts about achiria and allochiria, such as their associations with Brown-Sequard hemisection syndrome.

[2] Jones posits that achiria is a dissociation disorder resulting from the loss of the chirognostic sense, or the sensation of "sidedness".

[2] Jones regarded achiria as the primary stage of dyschiria, of which the patients have a complete loss of their chirognostic senses.

[2] The improvement of motor function and the redemption of memory senses, which were absent or incomplete in achiria patients, enhances their general well-being and their feelings of strength, power and completeness.

[12] In the study, Kinsbourne briefly mentioned the lack of awareness to the contralateral side to the brain lesion.