Reduplicative paramnesia
Encyclopedia
Reduplicative paramnesia is the delusion
Delusion
A delusion is a false belief held with absolute conviction despite superior evidence. Unlike hallucinations, delusions are always pathological...

al belief that a place or location has been duplicated, existing in two or more places simultaneously, or that it has been 'relocated' to another site. It is one of the delusional misidentification syndrome
Delusional misidentification syndrome
Delusional misidentification syndrome is an umbrella term, introduced by Christodoulou for a group of delusional disorders that occur in the context of mental or neurological illness. They all involve a belief that the identity of a person, object or place has somehow changed or has been altered...

s and, although rare, is most commonly associated with acquired brain injury
Acquired brain injury
An acquired brain injury is brain damage caused by events after birth, rather than as part of a genetic or congenital disorder such as fetal alcohol syndrome, perinatal illness or perinatal hypoxia. ABI can result in cognitive, physical, emotional, or behavioural impairments that lead to permanent...

, particularly simultaneous damage to the right cerebral hemisphere
Cerebral hemisphere
A cerebral hemisphere is one of the two regions of the eutherian brain that are delineated by the median plane, . The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter called the cerebral cortex that is...

 and to both frontal lobes.

History

The term reduplicative paramnesia was first used in 1903 by neurologist
Neurologist
A neurologist is a physician who specializes in neurology, and is trained to investigate, or diagnose and treat neurological disorders.Neurology is the medical specialty related to the human nervous system. The nervous system encompasses the brain, spinal cord, and peripheral nerves. A specialist...

 Arnold Pick
Arnold Pick
Arnold Pick was a Czech neurologist and psychiatrist. He is known for identifying the clinical syndrome of Pick's Disease and the Pick bodies that are characteristic of the disorder. He was the first to name reduplicative paramnesia. He was also to use the term dementia praecox .- External links...

 to describe a condition in a patient with suspected Alzheimer's disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

 who insisted that she had been moved from Pick's city clinic, to one she claimed looked identical but was in a familiar suburb. To explain the discrepancy she further claimed that Pick and the medical staff worked at both locations.

In retrospect, however, the phenomenon has been found to have been first reported by the Swiss naturalist
Natural history
Natural history is the scientific research of plants or animals, leaning more towards observational rather than experimental methods of study, and encompasses more research published in magazines than in academic journals. Grouped among the natural sciences, natural history is the systematic study...

 Charles Bonnet
Charles Bonnet
Charles Bonnet , Swiss naturalist and philosophical writer, was born at Geneva, of a French family driven into Switzerland by the religious persecution in the 16th century.-Life and work:Bonnet's life was uneventful...

 in 1788, who described a woman who also had what would now be called Cotard delusion
Cotard delusion
The Cotard delusion or Cotard's syndrome or Walking Corpse Syndrome is a rare neuropsychiatric disorder in which people hold a delusional belief that they are dead , do not exist, are putrefying, or have lost their blood or internal organs...

. Henry Head
Henry Head
Sir Henry Head, FRS was an English neurologist who conducted pioneering work into the somatosensory system and sensory nerves. Much of this work was conducted on himself, in collaboration with the psychiatrist W. H. R. Rivers, by severing and reconnecting sensory nerves and mapping how sensation...

 and Paterson and Zangwill later reported on soldiers who had the delusional belief that their hospital was located in their home town, although in these cases traumatic brain injury
Traumatic brain injury
Traumatic brain injury , also known as intracranial injury, occurs when an external force traumatically injures the brain. TBI can be classified based on severity, mechanism , or other features...

 seemed to be the most likely cause.

It wasn't until 1976 that serious consideration was given to the disorder, when three cases were reported by Benson and colleagues. Benson not only described striking reduplication syndromes in his patients, but also attempted to explain the phenomena in terms of the neurocognitive deficits also present in the patients. This was one of the first attempts to give a neuropsychological
Neuropsychology
Neuropsychology studies the structure and function of the brain related to specific psychological processes and behaviors. The term neuropsychology has been applied to lesion studies in humans and animals. It has also been applied to efforts to record electrical activity from individual cells in...

 explanation for the disorder.

Clinical phenomena

Reduplicative paramnesia has been reported in the context of a number of neurological disorder
Neurological disorder
A neurological disorder is a disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or in the nerves leading to or from them, can result in symptoms such as paralysis, muscle weakness, poor coordination, loss of sensation, seizures,...

s, including stroke, intracerebral hemorrhage, tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

, dementia
Dementia
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...

, encephalopathy
Encephalopathy
Encephalopathy means disorder or disease of the brain. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of global brain dysfunction; this syndrome can be caused by many different illnesses.-Terminology:...

 and various psychiatric disorders.

Taken from the Benson and colleagues study, the following excerpt illustrates some of the core features of the delusion. The patient had suffered a head injury after a fall in his home. The impact had caused a fractured skull
Skull fracture
A skull fracture is a break in one or more of the bones in the skull usually occurring as a result of blunt force trauma. If the force of the impact is excessive the bone may fracture at or near the site of the impact...

 and frontal lobe
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...

 damage to both sides (although more pronounced on the right) owing to the formation of intracerebral hematoma
Hematoma
A hematoma, or haematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise...

s:
The illusory relocation to a familiar place, such as a home or town the patient knows well, is a common theme, although occasionally the patient believes they are resident in more fantastical or exotic locations (such as, in one case, Timbuktu
Timbuktu
Timbuktu , formerly also spelled Timbuctoo, is a town in the West African nation of Mali situated north of the River Niger on the southern edge of the Sahara Desert. The town is the capital of the Timbuktu Region, one of the eight administrative regions of Mali...

).

Medical explanations

Early psychodynamic explanations suggested that reduplicative paramnesia was not directly connected to brain injury, but arises from a motivated denial of illness, particularly, as Weinstein and Kahn claimed, in those that regard illness as a "imperfection, weakness or disgrace". Other early investigators, did accept that brain injury was an important factor, but suggested that the disorientation was a "hysterical
Conversion disorder
Conversion disorder is a condition in which patients present with neurological symptoms such as numbness, blindness, paralysis, or fits without a neurological cause. It is thought that these problems arise in response to difficulties in the patient's life, and conversion is considered a psychiatric...

 reaction" motivated by a desire to return home.

The majority of modern theories, however, suggest that the disorder is caused by disruption to the brain systems involved in memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....

 and familiarity. Interestingly, this was the theme of Pick's original explanation, in which he suggested that the crucial mechanism was a "convulsive attack" that disrupted conscious memory.

Benson and colleagues later argued that damage to the right hemisphere of the brain left patients unable to maintain orientation owing to impaired visuospatial perception
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...

 and visual memory
Visual memory
Visual memory describes the relationship between perceptual processing and the encoding, storage and retrieval of the resulting neural representations. Visual memory occurs over a broad time range spanning from eye movements to years in order to visually navigate to a previously visited location...

, while frontal lobe damage made it difficult to inhibit the false impressions caused by disorientation.

More recent research has broadly supported this view, and links have been made to the literature on confabulation
Confabulation
Confabulation is the process in which a memory is remembered falsely. Confabulations are indicative of a complicated and intricate process that can be led astray at any given point during encoding, storage, or recall of a memory. Two distinct types of confabulation are often distinguished...

, where patients seem to recall false memories without any realisation that they are false, often also in the context of frontal lobe damage. Right hemisphere damage is also linked to anosognosia
Anosognosia
Anosognosia /æˌnɒsɒgˈnəʊsɪə/ is a condition in which a person who suffers disability seems unaware of the existence of his or her disability. Unlike denial, which is a defense mechanism, anosognosia is rooted in physiology...

, where patients seems unaware of often striking disabilities present after brain injury, also suggesting a link to the lack of insight seen in this disorder.

One case study has suggested a more refined explanation, suggesting that damage to the ventral stream of the visual system
Visual system
The visual system is the part of the central nervous system which enables organisms to process visual detail, as well as enabling several non-image forming photoresponse functions. It interprets information from visible light to build a representation of the surrounding world...

, that connects the visual cortex
Visual cortex
The visual cortex of the brain is the part of the cerebral cortex responsible for processing visual information. It is located in the occipital lobe, in the back of the brain....

 to areas in the temporal lobe
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....

s, could produce the required visuospatial disorientation and poor memory integration. The temporal areas (including the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...

) are known strongly to interact with the frontal lobe
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...

s during memory formation and retrieval, suggesting an explanation for why frontal damage could also lead to the condition.
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