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Cortex; a Journal Devoted To the Study... Sep 2023Unawareness of memory deficits is an early manifestation in patients with Alzheimer's disease (AD), which often delays diagnosis. This intriguing behavior constitutes a...
Unawareness of memory deficits is an early manifestation in patients with Alzheimer's disease (AD), which often delays diagnosis. This intriguing behavior constitutes a form of anosognosia, whose neural mechanisms remain largely unknown. We hypothesized that anosognosia may depend on a critical synaptic failure in the error-monitoring system, which would prevent AD patients from being aware of their own memory impairment. To investigate, we measured event-related potentials (ERPs) evoked by erroneous responses during a word memory recognition task in two groups of amyloid positive individuals with only subjective memory complaints at study entry: those who progressed to AD within the five-year study period (PROG group), and those who remained cognitively normal (CTRL group). A significant reduction in the amplitude of the positivity error (Pe), an ERP related to error awareness, was observed in the PROG group at the time of AD diagnosis (vs study entry) in intra-group analysis, as well as when compared with the CTRL group in inter-group analysis, based on the last EEG acquisition for all subjects. Importantly, at the time of AD diagnosis, the PROG group exhibited clinical signs of anosognosia, overestimating their cognitive abilities, as evidenced by the discrepancy scores obtained from caregiver/informant vs participant reports on the cognitive subscale of the Healthy Aging Brain Care Monitor. To our knowledge, this is the first study to reveal the emergence of a failure in the error-monitoring system during a word memory recognition task at the early stages of AD. This finding, along with the decline of awareness for cognitive impairment observed in the PROG group, strongly suggests that a synaptic dysfunction in the error-monitoring system may be the critical neural mechanism at the origin of unawareness of deficits in AD.
Topics: Humans; Male; Female; Aged; Aged, 80 and over; Alzheimer Disease; Memory Disorders; Electroencephalography; Evoked Potentials; Agnosia; Synapses; Neuropsychological Tests; Recognition, Psychology
PubMed: 37423786
DOI: 10.1016/j.cortex.2023.05.014 -
Cureus Mar 2024Prosopagnosia, also referred to as "face blindness," is a type of visual agnosia characterized by a decreased capacity to recognize familiar faces with a preserved...
Prosopagnosia, also referred to as "face blindness," is a type of visual agnosia characterized by a decreased capacity to recognize familiar faces with a preserved ability to identify individuals based on non-facial visual traits or voice. Prosopagnosia can be categorized as developmental (DP) or acquired (AP) owing to a variety of underlying conditions, including trauma, neurodegenerative diseases, stroke, neuroinfections, and, less frequently, malignancies. Facial recognition is a complex process in which different neuronal networks are involved. The infrequent but notable higher visual-processing abnormalities can be caused by lesions of the inferior longitudinal fasciculus (ILF) in the non-dominant temporal lobe. We report a rare case of AP in a 69-year-old patient who is right-hand dominant with rectal carcinoma cerebral metastases. The patient complained of dizziness, vertigo, falls, and trouble recognizing her family members' faces. The CT scan of the head with contrast revealed two metastatic brain lesions with vasogenic edema, as one of them was in the right cerebellar hemisphere, causing dislocation and compression of the ILF. Corticosteroids and osmotherapy were utilized as a conservative treatment approach, which resulted in the prosopagnosia being completely withdrawn. In conclusion, patients with primary brain tumors or metastatic disease rarely present with an isolated cognitive deficit such as prosopagnosia. Based on the anatomical features and the personalized approach, a conservative or surgical approach may be useful to improve higher cortical functioning.
PubMed: 38559526
DOI: 10.7759/cureus.55349 -
Dental Research Journal 2024The COVID-19 pandemic which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created a major global health crisis in recent years....
BACKGROUND
The COVID-19 pandemic which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created a major global health crisis in recent years. Despite this, there have been few studies that have utilized reliable methods to assess changes in taste and smell perception. Therefore, our study aims at the number of fungiform papillae and objective measures of taste perception relationship among COVID-19 patients with olfactory and gustatory disorders.
MATERIALS AND METHODS
This was a cross-sectional analytical study in which 57 COVID-19 patients were recruited who confirmed the dysfunction of taste and smell. Objective assessment of the sense of taste was evaluated using four different standardized solution preparations, and the scores were given according to the patient's statements. Digitalized quantification of fungiform papillae was counted. The data were analyzed with the Pearson's correlation coefficient using the SPSS version. 23 [Licensed JSSAHER, Mysuru, Karnataka, India], and the level of significance was set at <0.001.
RESULTS
In terms of altered or reduced taste and smell, male patients exhibited a higher incidence compared to females. Compared to the sour taste, a substantial number of COVID-19 patients have displayed a notable decrease in their ability to taste sweet, salty, and bitter flavors. However, a statistically significant positive correlation was observed between taste scores and fungiform papillae density ( = 0.518, < 0.001).
CONCLUSION
Our Study demonstrated that the quantitative evaluation of taste perception and the count of fungiform papillae can serve as important indicators of SARS-CoV-2 infection, and could potentially help in the early detection and treatment of COVID-19 patients, as reduced taste function is a significant marker of the disease.
PubMed: 38476719
DOI: No ID Found -
Brain Research Jun 2024Peripheral vestibular activation results in multi-level responses, from brainstem-mediated reflexes (e.g. vestibular ocular reflex - VOR) to perception of self-motion....
Peripheral vestibular activation results in multi-level responses, from brainstem-mediated reflexes (e.g. vestibular ocular reflex - VOR) to perception of self-motion. While VOR responses indicate preserved vestibular peripheral and brainstem functioning, there are no automated measures of vestibular perception of self-motion - important since some patients with brain disconnection syndromes manifest a vestibular agnosia (intact VOR but impaired self-motion perception). Electroencephalography ('EEG') - may provide a surrogate marker of vestibular perception of self-motion. A related objective is obtaining an EEG marker of vestibular sensory signal processing, distinct from vestibular-motion perception. We performed a pilot study comparing EEG responses in the dark when healthy participants sat in a vibrationless computer-controlled motorised rotating chair moving at near threshold of self-motion perception, versus a second situation in which subjects sat in the chair at rest in the dark who could be induced (or not) into falsely perceiving self-motion. In both conditions subjects could perceive self-motion perception, but in the second there was no bottom-up reflex-brainstem activation. Time-frequency analyses showed: (i) alpha frequency band activity is linked to vestibular sensory-signal activation; and (ii) theta band activity is a marker of vestibular-mediated self-motion perception. Consistent with emerging animal data, our findings support the role of theta activity in the processing of self-motion perception.
PubMed: 38844198
DOI: 10.1016/j.brainres.2024.149048 -
Genetics Jun 2024Face recognition is important for both visual and social cognition. While prosopagnosia or face blindness has been known for seven decades and face-specific neurons for...
Face recognition is important for both visual and social cognition. While prosopagnosia or face blindness has been known for seven decades and face-specific neurons for half a century, the molecular genetic mechanism is not clear. Here we report results after 17 years of research with classic genetics and modern genomics. From a large family with 18 congenital prosopagnosia (CP) members with obvious difficulties in face recognition in daily life, we uncovered a fully cosegregating private mutation in the MCTP2 gene which encodes a calcium binding transmembrane protein expressed in the brain. After screening through cohorts of 6589, we found more CPs and their families, allowing detection of more CP associated mutations in MCTP2. Face recognition differences were detected between 14 carriers with the frameshift mutation S80fs in MCTP2 and 19 noncarrying volunteers. Six families including one with 10 members showed the S80fs-CP correlation. Functional magnetic resonance imaging found association of impaired recognition of individual faces by MCTP2 mutant CPs with reduced repetition suppression to repeated facial identities in the right fusiform face area. Our results have revealed genetic predisposition of MCTP2 mutations in CP, 76 years after the initial report of prosopagnosia and 47 years after the report of the first CP. This is the first time a gene required for a higher form of visual social cognition was found in humans.
Topics: Humans; Prosopagnosia; Female; Male; Facial Recognition; Pedigree; Adult; Middle Aged; Mutation; Aged; Membrane Proteins; Magnetic Resonance Imaging
PubMed: 38547502
DOI: 10.1093/genetics/iyae047 -
Neuropsychological Rehabilitation Mar 2024In some patients with unilateral spatial neglect, symptoms reflect impaired lateralized spatial attention and representation (perceptual bias) whereas in others the...
In some patients with unilateral spatial neglect, symptoms reflect impaired lateralized spatial attention and representation (perceptual bias) whereas in others the inability to respond to stimuli located in contralesional space (response bias). Here, we investigated whether prismatic adaptation (PA) and visual scanning training (VST) differentially affect perceptual and response bias and whether rehabilitation outcome depends on the type of bias underlying symptoms. Two groups of neglect patients in the subacute phase were evaluated before, immediately after, and two weeks following 10 days of PA ( = 9) or VST ( = 9). Standard neuropsychological tests (i.e., Behavioural Inattentional Test, Diller cancellation test, and Line Bisection test) were administered to assess neglect symptoms, while the Landmark task was used to disentangle perceptual and response biases. Performance on the Landmark task revealed that PA was more effective in improving the perceptual bias, while VST mainly modulated the response bias. Neuropsychological tests performance suggested that VST is better suited to modulate neglect in patients with response bias, while PA may be effective in patients with both types of bias. These findings may offer novel insights into the efficacy of PA and VST in the rehabilitation of perceptual and response biases in patients with neglect.
Topics: Humans; Perceptual Disorders; Agnosia; Treatment Outcome; Neuropsychological Tests; Adaptation, Physiological; Functional Laterality; Space Perception
PubMed: 36652376
DOI: 10.1080/09602011.2022.2158876 -
Acta Neurologica Belgica Dec 2023
Topics: Humans; Prosopagnosia; Temporal Lobe; Epilepsy, Temporal Lobe; Hemangioma, Cavernous, Central Nervous System
PubMed: 36622525
DOI: 10.1007/s13760-023-02185-2 -
Journal of Orthopaedic Surgery and... Feb 2024The reconstruction of medium-sized soft tissue defects of the fingertip remains a challenge for hand surgeons. The aim of this study was to compare the outcomes of...
Comparison treatment of medium-sized volar fingertips defects with modified triangular neurovascular unilateral advancement flap versus digital artery dorsal perforator flap.
PURPOSE
The reconstruction of medium-sized soft tissue defects of the fingertip remains a challenge for hand surgeons. The aim of this study was to compare the outcomes of modified triangular neurovascular unilateral advancement flap and digital artery dorsal perforator flap in the treatment of this injury.
METHODS
From May 2018 to May 2022, 70 patients with medium-sized volar soft tissue defects were enrolled. The patients were divided into two groups based on the flap type: modified triangular neurovascular unilateral advancement flap (Group A) and digital artery dorsal perforator flap (Group B). The debridement times, defect size, operation time, and flap survival rate were recorded. At follow-up, hand function, aesthetics, and complications were evaluated. Function was evaluated using the TAM score. The aesthetics of the reconstructed and donor sites were assessed using the vancouver scar scale (VSS). The static two-point discrimination of the finger pulp served as a measure of tactile agnosia.
RESULTS
A total of 10 patients were lost to follow-up for various reasons, resulting in 30 cases remaining in each group. The general information of the two groups showed no significant differences in age, sex, injury side, cause of injury, time from injury to surgery, and operation time (P > 0.05). Additionally, the debridement times and size of the defect were similar between the groups (P > 0.05). However, the operation time was significantly shorter in Group A compared to Group B (P = 0.001). With regard to complications, there was no significant difference between them. At one-month follow-up, TAM scores indicated that Group B performed significantly better than Group A. However, at the final follow-up period, there was no significant difference in TAM scores between the two groups. When considering the VSS, significant differences were observed between the two groups in both the reconstructed site and donor site.
CONCLUSION
Both flaps can effectively repair medium-sized fingertip defects. Furthermore, the modified triangular neurovascular unilateral advancement flap offers anatomical reconstruction possibilities, ensuring satisfactory sensation and cosmetic contour.
Topics: Humans; Perforator Flap; Plastic Surgery Procedures; Skin Transplantation; Finger Injuries; Soft Tissue Injuries; Arteries; Treatment Outcome
PubMed: 38310285
DOI: 10.1186/s13018-024-04608-z -
Neurological Sciences : Official... May 2024To explore efficacy of the "Rey-Osterrieth complex figure (ROCF) tracing task" as a new test to detect unilateral spatial neglect (USN).
PURPOSE
To explore efficacy of the "Rey-Osterrieth complex figure (ROCF) tracing task" as a new test to detect unilateral spatial neglect (USN).
METHODS
Subjects were 40 healthy control (HC) and 20 right brain-damaged patients with (USN + , n = 10) or without USN (USN - , n = 10). After the ROCF copying task, the tracing task was performed under conditions that did not leave any tracing lines on the sample figure. Evaluation used the conventional 36-point scoring system, laterality index (LI) as the ratio of the left and right structure scores, and the number of overlaps for each of the left and right structures scored.
RESULTS
In the tracing task, USN + showed a lower LI than HC. Furthermore, left-sided neglect was sometimes more evident than in the copying task. Regarding the total overlapping score, USN + showed a greater score than HC. The right-sided overlapping scores in USN + and USN - were also greater than that in HC. In the right brain-damaged subjects, clinically meaningful correlations were not found between evaluations in the ROCF tracing task and in conventional USN screening tests. Receiver-operating-characteristic analysis to test the power of detection showed moderate performance for the tracing LI (AUC = 0.76, 95% CI = 0.54-0.97), which was greater than that of other tests. Further, the total overlapping score in the tracing task showed sensitivity 0.9 (highest among the tests performed), specificity 0.5, and AUC 0.68 (95% CI = 0.43-0.92).
CONCLUSION
The ROCF tracing task might be a convenient method to detect USN and to reveal the extent of spatial working memory impairment.
PubMed: 38717579
DOI: 10.1007/s10072-024-07540-6 -
Rinsho Shinkeigaku = Clinical Neurology Oct 2023A 76-year-old male patient was admitted to our hospital for the treatment of acute cerebral infarction in the right temporal stem, right lateral thalamus, and right...
A 76-year-old male patient was admitted to our hospital for the treatment of acute cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions. Although his overall cognitive function was almost normal, he exhibited reduced visual sensitivity in the homonymous lower left quadrant of the visual field, left unilateral spatial neglect (USN), and simultanagnosia. Left USN improved 4 months after the onset of infarction; however, simultanagnosia persisted. To the best of our knowledge, this is the first case of simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions.
Topics: Male; Humans; Aged; Pulvinar; Thalamus; Cerebral Infarction; Agnosia; Perceptual Disorders
PubMed: 37779025
DOI: 10.5692/clinicalneurol.cn-001846