Bilateral anterior cortical atrophy and subcortical atrophy in reduplicative paramnesia: a case-control study of computed tomography in 10 patients

Some Unusual Neuropsychological Syndromes: Somatoparaphrenia, Akinetopsia, Reduplicative Paramnesia, Autotopagnosia

Some unusual neuropsychological syndromes are rarely reported in the neuropsychological literature. This paper presents a review of four of these unusual clinical syndromes: (1) somatoparaphrenia (delusional belief in which a patient states that the limb contralateral to a brain pathology, does not belong to him/her); (2) akinetopsia (cortical syndrome in which patient losses the ability to perceive visual motion); (3) reduplicative paramnesia (believe that a familiar place, person, object, or body part has been duplicated); and (4) autotopagnosia (disturbance of body schema involving the loss of ability to localize, recognize, or identify the specific parts of one's body). It is concluded that regardless of their rarity, it is fundamental to take them into consideration in order to understand how the brain organizes cognition; their understanding is also crucial in the clinical analysis of patients with brain pathologies.

Modulation of environmental reduplicative paramnesia by perceptual experience

Environmental reduplicative paramnesia (ERP) is characterized by the involuntary attribution of a false identity to a place. ERP has rarely been examined experimentally; its mechanisms therefore remain speculative. Here, we describe a patient with extended traumatic right fronto-temporal damage and severe persistent ERP, in whom we were able to modulate ERP by exposing him to various typical landmarks of the town where he was hospitalized. When landmarks were ambiguous as regards location (e.g., unknown buildings), the patient erroneously localized himself in his hometown, which was more than two thousand kilometers away. In contrast, when he visited distinct landmarks of the place where he actually resided, his ERP was immediately corrected, and spatial orientation was restored. These findings indicate that ERP may be temporarily modifiable through perception of unequivocal topographic information.

An effective environmental intervention for management of the 'mirror sign' in a case of probable Lewy body dementia

The term 'mirror sign' refers to the inability to recognize the reflection of oneself in a mirror, while the ability to recognize others' faces often remains intact. In this article, we present a case of an 85-year-old woman, with probable Lewy body dementia, who stably exhibited a delusional 'mirror sign' for a period of 9 months. Following a straightforward, ecological, non-pharmacological intervention, her 'mirror sign' delusion was no longer present.

Reduplicative paramnesia: a review

BACKGROUND

Reduplicative paramnesia (RP) is a content-specific delusional misidentification syndrome (DMS) which has received little attention in the research literature relative to other DMS. RP is thought to result from an organic rather than psychiatric cause distinguishing it from other DMS. Our systematic review examines the research literature investigating the prevalence, symptomatology and potential neurologic mechanisms underlying RP.

SAMPLING AND METHODS

MEDLINE, PsycINFO, and the Cochrane Library were searched (from 1966 to February 10, 2012) with the reference lists of relevant articles examined. Case reports, clinical studies and post-mortem studies focusing on, or referring to, RP were included.

RESULTS

There is a paucity of literature regarding the potential mechanisms underlying the psychological, cognitive and neurological aspects of RP. The available literature is limited by the lack of systematic clinical studies and in vivo investigations with current findings remaining only speculative. However, there does appear to be a consensus that RP may have a neurologic rather than psychiatric cause and that right and bifrontal lesions as well as the cognitive dissonance associated with memory, visuospatial and impaired conceptual integration are common factors in RP presentation.

CONCLUSIONS

This area requires further extensive systematic research with supplementary in vivo data. Current studies suggest that focal lesions within the frontal lobe may account for the onset of RP.

Theories of delusional disorders. An update and review

Delusional syndromes can occur in a number of psychiatric, neurological or other disorders. They can also be caused by neurotoxic agents (e.g., heavy metals) as well as substance addiction. There are several hypotheses on the underlying cognitive or emotional processes associated with organic factors of delusional disorders, depending on the patient groups examined and the methods used. The aim of this paper is to provide a comprehensive review and critical assessment of the various, rather heterogeneous theories in this field.

Psychophysiological differences in schizophrenics with and without delusional misidentification syndromes: a P300 study

There is a debate on whether delusional misidentification syndromes (DMSs) and schizophrenia are distinct disorders. Information-processing deficits have been found in both. Since the P300 component of event-related potentials (ERPs) reflects attention and working memory (WM) mechanisms, the P300 elicited during a WM test was studied in schizophrenic patients with DMS in comparison to schizophrenic patients without DMS and controls. Nine schizophrenic patients with DMS, 11 without DMS and 11 healthy controls were tested with a computerized version of the digit span test of the Wechsler batteries. Auditory ERPs were measured during the anticipatory period of the test. P300 amplitude in prefrontal areas was found to be significantly reduced in schizophrenics without DMS and markedly less in DMS patients compared to controls. P300 latency in the central midline brain region was significantly prolonged in DMS patients compared to the other groups. Memory performance was significantly reduced in both patient groups as compared to healthy controls. The results may indicate abnormalities in both allocation of attentional resources and automatic orienting in schizophrenic patients with DSM. In contrast, even though schizophrenic patients without DMS exhibit partial similarities with patients suffering from DMS, they show excessive reduction of P300 amplitude located at the left frontal area. Future studies might clarify these issues.

Psychophysiological evidence for altered information processing in delusional misidentification syndromes

Recent research provides evidence that delusional misidentification syndromes (DMS) are associated with cognitive deficits. However, the underlying mechanisms of these deficits are not known. Since the P300 component of event-related potentials (ERPs) is related to fundamental aspects of working memory (WM), the present study is focused on P300 elicited during a WM test in DMS patients, as compared to those of healthy controls. Nine patients with DMS and 11 healthy controls, matched for age, sex and educational level were tested with a computerized version of the digit span test of the Wechsler batteries. Auditory ERPs were measured during the anticipatory period of the test. DMS patients showed significant reductions in P300 amplitude at the right frontal region compared to healthy controls. P300 latency in the central midline brain region was significantly prolonged in the DMS group. Each of these measures classified correctly 90% of the two groups. Moreover, the memory performance of the patient group was significantly lower, relatively to healthy controls. These findings provide evidence supporting the suggestion that DMS is associated with psychophysiological alterations occurring at the right frontal region, which mediates automatic processes, as well as with an irregular allocation of attentional resources, involving the interhemispheric circuitry, possibly due to gray matter degeneration. Finally, present work points to a need for further research investigating the characteristics, causes, course and treatment of severe cognitive deficits associated with DMS.

Abnormal P300 in a case of delusional misidentification with coinciding Capgras and Frégoli symptoms

The Delusional Misidentification Syndrome (DMS) is thought to be related to dissociation between recognition and identification processes. Working memory (WM) is considered responsible for the integration and online manipulation of information, so that it is available for further processing. Since the P300 component of event-related potentials (ERPs) is considered as an index of the on-line updating of WM, the present study is focused on auditory P300 elicited during a WM test in DMS, compared with that in healthy controls. ERPs, elicited during a WM test, in a case suffering from coinciding Capgras and Frégoli symptoms, were recorded. Peak amplitude and latency of the averaged P300 waveforms, as well as memory performance of this case, were compared to the patterns obtained from healthy controls. In relation to normal controls, the patient exhibited significantly attenuated amplitude of P300 at the F4, P3 and Pz abductions. The patient also showed significantly prolonged latencies of P300 at all abductions used. These findings suggest that DMS may be accompanied by WM dysfunction affecting brain regions outside the prefrontal cortex, as well as within, and by diffuse failure to allocate attention resources to a stimulus, as they are reflected by P300 amplitudes and latencies respectively. Additionally, it may be suggested that techniques designed to explore cognitive operations, such as recording of ERPs, and more specifically P300, during WM tasks, could provide further insights into the relationship between neural functioning and the cognitive deficits in DMS.

Emotions, behaviours and mood changes in stroke

The brain mediates and integrates all cognitive activities, emotional experiences and finally behaviours. Stroke is undoubtedly a privileged disease for human behavioural studies, because of its high incidence. Recent advances in high-resolution magnetic resonance imaging techniques and functional neuroimaging allow both the precise localization of lesions and on-line visualization of the activity of cerebral areas and networks. Nevertheless, the neuropsychiatry of stroke remains uncertain in its relationship with brain dysfunction. Clinical studies on registry populations, single case studies, and functional neuroimaging data provide interesting findings, but differences in methods and great individual intervariability still prevent a complete understanding of emotional perception and behavioural responses in stroke. We adopted an anatomical-functional model as an operational framework in order to systematize the recent literature on emotional, behavioural and mood changes after stroke. The dysfunction of the areas subserving fundamental and executive functions induces behavioural and affective changes (such as depression, anxiety, apathy) that reflect the dysfunction of the whole system. Conversely, lesions in the system of instrumental functions induce signature syndromes (aphasia, anosognosia). At any delay from stroke, the diagnosis and treatment of mood and behavioural changes are a priority for clinicians and healthcare professionals to improve the quality of life of patients.