A Critical Review of Alien Limb-Related Phenomena and Implications for Functional Magnetic Resonance Imaging Studies

Acute transitory head mislocalization - a novel syndrome of pathological embodiment in a patient with traumatic brain injury - a case study

Feeling of body ownership is a complex process with different brain mechanisms involved in integrating the varied and multiple representations of the body . The ability to discriminate between one's own and others' body parts can be lost after brain damage. We report a unique case study of a patient with head injury who experienced a phenomenon where he felt that his head was positioned with another person standing next to him. We describe this as a form of pathological embodiment and call it the "head mislocalization" phenomenon. We report his clinical findings and using the methods of lesion mapping and lesion network mapping postulate the neural mechanisms for this symptom.

Functional Neurologic Disorders, disorders to be managed by neurologists, or are neurologists wandering in a dangerous field with inadequate resources?

In recent years, some neurologists reconsidered their approach to Medically Unexplained Symptoms and proposed Functional Neurologic Disorders (FND) as a new entity, claiming that neurology could offer alternative treatment options to the psychotherapies provided in psychiatry settings. FNDs, for this purpose, should include only the disorders listed as Conversion from the Somatic Symptom and Related Disorders (SSRD) group. The present review analyzes the rationale of this position and challenges the arguments provided for its support. The review also discusses the systematization of these disorders as provided by public health systems. It outlines risks stemming from economic support and public funding uncertainty, given their negligible epidemiological dimensions resulting from the parcellation of SSRD. The review underlines the unresolved issue of Factitious Disorders, which are in the same SSRD category of the international classification but are, nonetheless, overlooked by the theoretical proponents of the FND entity. Comorbidity with other psychiatric disorders is also analyzed. We propose a model that supports the continuum between different SSRD conditions, including Factitious Disorders. The model is based on the emergence of feigned death reflex and deception from frontal lobe dysfunction. Finally, the paper summarizes the wealth of historical psychiatric and psychodynamic approaches and critical reviews. The study also puts in context the categorization and interpretation efforts provided by the most eminent researchers of the past century.

Patient with Corticobasal Syndrome Showing Disease-Associated Biomarkers of Dementia with Lewy Bodies: A Treviso Dementia (TREDEM) Registry Case Report

Background

An 82-year-old right-handed man, a retired teacher, reported the occurrence, three years earlier, of difficulties in moving his left arm and foot, tremor in his left hand, and gestures of the left upper limb that appeared to be independent of the patient's will.

Objective

We describe an unusual case of corticobasal syndrome (CBS) showing disease-associated biomarkers of dementia with Lewy bodies (DLB).

Methods

Clinical, neuropsychological, imaging, and biomarker evaluations were conducted, including tau and amyloid-β levels in the cerebrospinal fluid (CSF) and a RT-QuIC assay for α-synuclein both in the CSF and olfactory mucosa (OM), as well as a QEEG assessment.

Results

The patient presented resting tremor, mild extrapyramidal hypertonus, mild bradykinesia on the left side, and severe apraxia on the left upper limb. Brain MRI showed a diffuse right hemisphere atrophy which was prominent in the posterior parietal and temporal cortices, and moderate in the frontal cortex and the precuneus area. 18F-FDG PET imaging showed reduced glucose metabolism in the right lateral parietal, temporal, and frontal cortices with involvement of the right precuneus. The putamen did not appear to be pathological at DaTQUANT. Neuropsychological tests showed memory and visual-perceptual deficits. CSF tau and amyloid measurements did not show clear pathological values. RT-QuIC for α-synuclein in CSF and OM samples were positive. The QEEG analysis showed a pre-alpha dominant frequency in posterior derivations, typical of early stages of DLB.

Conclusion

Although in the present patient the clinical diagnosis was of probable CBS, unexpectedly positive biomarkers for DLB suggested the co-presence of multiple pathologies.

The Alien Limb Phenomenon in Creutzfeldt-Jakob Disease: A Systematic Review of Case Reports

Alien limb phenomenon (ALP) is a clinical finding seen in numerous neurological disorders, including Creutzfeldt-Jakob disease (CJD). We aimed to conduct a systematic review to update advances in understanding the classification and pathophysiology of ALP in CJD. We used PubMed advanced-strategy searches and only included full-text observational studies and case reports conducted on humans and written in English. We used the PRISMA protocol for this systematic review and the Methodological Quality of Case Reports tool to assess the bias encountered in each study. After applying the inclusion/exclusion criteria, 10 case reports were reviewed. Two independent reviewers analyzed data and confirmed the phenotype of each case of the alien limb in CJD separately. Overall, the most prevalent ALP phenotype presenting in patients with CJD was the posterior phenotype, usually in the early stages of the disease. Our findings corroborate previous research in demonstrating the pathophysiology behind ALP in CJD. We suggest physicians suspect CJD whenever patients present with ALP as the initial symptom.