461 research outputs found
Cotelli (M) or Couteau P.
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/342156Reference: P Couteau, 1957, Contribution à la théorie du spectre des naines blanches, Sennac, Paris. Reference note: Supplements aux annale d'astrophysique S.E. 74/53 (2).138608
item: [2014.0039.00319] "Cotelli (M) or Couteau P.
Non-pharmacological intervention for memory decline
No full textNon-pharmacological treatment of memory difficulties in healthy older adults, as well as those with brain damage and neurodegenerative disorders, has gained much attention in recent years (Ball et al., 2002, Willis et al., 2006, Acevedo and Loewenstein, 2007). The two main reasons that explain this growing interest in memory rehabilitation are the limited efficacy of current drug therapies and the plasticity of the human central nervous system (Cotelli et al., 2011c) and the discovery that during aging, the connections in the brain are not fixed but retain the capacity to change with learning.Moreover, several studies have reported enhanced cognitive performance in patients with neurological disease, following non-invasive brain stimulation (i.e., repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) to specific cortical areas). The present review provides an overview of memory rehabilitation in individuals with Mild Cognitive Impairment (MCI) and in patients with Alzheimer’s Disease (AD) with particular regard to cognitive rehabilitation interventions focused on memory and non-invasive brain stimulation. Reviewed data suggest that in patients with memory deficits, memory intervention therapy could lead to performance improvements in memory, nevertheless further studies need to be conducted in order to establish the real value of this approach
Effortful speech with distortion of prosody following SARS-CoV-2 infection
No full textCoronavirus disease 2019 (COVID-19) infection has the potential for targeting the central nervous system, and several neurological symptoms have been reported in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We describe a 48-year-old Caucasian woman with SARS-CoV-2 infection followed by the onset of word finding difficulties, effortful speech along with prosody distortion, in the context of spared semantic and syntactic abilities. The clinical picture, perceived as foreign accent syndrome (FAS), was not associated with structural and functional imaging changes or neurophysiological assessment abnormalities. We suggest that FAS, herein perceived as a regional accent syndrome, should be considered a possible additional neurological manifestation of SARS-CoV-2
Effects of transcranial direct current stimulation on episodic memory in amnestic mild cognitive impairment: a pilot study
No full textObjectives: Episodic memory is impaired in amnestic mild cognitive impairment (aMCI), which is posited as a potential prodromal form of Alzheimer's disease. Reactivated existing memories become sensitive to modification during reconsolidation. There is evidence that the lateral prefrontal cortex (PFC) plays causal role in episodic memory reconsolidation. Transcranial direct current stimulation (tDCS) applied to the PFC after a contextual reminder enhanced episodic memory performance up to 1 month, conceivably through reconsolidation, in older adults with subjective memory complaints, a condition that may represent a "pre-mild cognitive impairment"stage. The aim of this pilot study was to test the effect of PFC-tDCS (anode over left lateral PFC, cathode over right supraorbital area) after a contextual reminder on episodic memory in older adults with aMCI. Method: Older adults with aMCI learned a list of words. Twenty-four hours later, tDCS (Active or Sham) was applied after a contextual reminder. Memory retrieval (free recall and recognition) was tested 48 hrs and 1 month after the learning session. Results: Active tDCS enhanced recognition memory relative to Sham stimulation. Discussion: Modulating reconsolidation with PFC-tDCS might be a novel intervention to enhance episodic memories in aMCI
Effects of transcranial electrical stimulation on episodic memory in physiological and pathological ageing
No full textMemory for personally-relevant past events (episodic memory) is critical for activities of daily living. Decline in this type of declarative long-term memory is a common characteristic of healthy ageing, a process accelerated in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Transcranial electrical stimulation (tES) has been used as a strategy to ameliorate episodic memory. Here, we critically review studies investigating whether tES may improve episodic memory in physiological and pathological ageing. Most of the studies suggest that tES over the prefrontal or temporoparietal cortices can have a positive effect on episodic memory, but the transfer to improvement of execution of daily living activities is still unknown. Further work is needed to better understand the mechanisms underlying the effects of stimulation, combine tES with neuroimaging and optimizing the dosing of stimulation. Future studies should also investigate the optimal timing of stimulation and the combination with medications to induce long-lasting beneficial effects in pathological ageing. More open science efforts should be done to improve rigor and reliability of tES in ageing research
Transcranial stimulation in frontotemporal dementia: a randomized, double-blind, sham-controlled trial
No full textIntroduction: Frontotemporal dementia (FTD) is a progressive disease for which no curative treatment is currently available. We aimed to determine whether transcranial direct current stimulation (tDCS) can modulate intracortical connectivity and improve cognition in symptomatic FTD patients and presymptomatic FTD subjects. Methods: We performed a double-blind, randomized, sham-controlled trial with anodal tDCS or sham stimulation over the left prefrontal cortex in 70 participants (15 presymptomatic and 55 symptomatic FTD). Results: We observed a significant increase of intracortical connectivity (short interval intracortical inhibition and facilitation) and improvement in clinical scores and behavioral disturbances in both symptomatic FTD patients and presymptomatic carriers after real tDCS but not after sham stimulation. Discussion: A 2-weeks’ treatment with anodal left prefrontal tDCS improves symptoms and restores intracortical inhibitory and excitatory circuits in both symptomatic FTD patients and presymptomatic carriers. tDCS might represent a promising future therapeutic and rehabilitative approach in patients with FTD
Reply to letter to the editor "tDCS effect on cognitive performance in Parkinson's disease" by Biundo et al.
No full textN/
Alpha tACS Improves Cognition and Modulates Neurotransmission in Dementia with Lewy Bodies
No full textBackground: Dementia with Lewy bodies (DLB) is characterized by a marked shift of electroencephalographic (EEG) power and dominant rhythm, from the α toward the θ frequency range. Transcranial alternate current stimulation (tACS) is a non-invasive brain stimulation technique that allows entrainment of cerebral oscillations at desired frequencies. Objectives: Our goal is to evaluate the effects of occipital α-tACS on cognitive functions and neurophysiological measures in patients with DLB. Methods: We conducted a double-blind, randomized, sham-controlled, cross-over clinical trial in 14 participants with DLB. Participants were randomized to receive either α-tACS (60 minutes of 3 mA peak-to-peak stimulation at 12 Hz) or sham stimulation applied over the occipital cortex. Clinical evaluations were performed to assess visuospatial and executive functions, as well as verbal episodic memory. Neurophysiological assessments and EEG recordings were conducted at baseline and following both α-tACS and sham stimulations. Results: Occipital α-tACS was safe and well-tolerated. We observed a significant enhancement in visuospatial abilities and executive functions, but no improvement in verbal episodic memory. We observed an increase in short latency afferent inhibition, a neurophysiological marker indirectly and partially dependent on cholinergic transmission, coinciding with an increase in α power and a decrease in Δ power following α-tACS stimulation, effects not seen with sham stimulation. Conclusions: This study demonstrates that occipital α-tACS is safe and enhances visuospatial and executive functions in patients with DLB. Improvements in indirect markers of cholinergic transmission and EEG changes indicate significant neurophysiological engagement. These findings justify further exploration of α-tACS as a therapeutic option for DLB patients. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
Human brain networks: a graph theoretical analysis of cortical connectivity normative database from EEG data in healthy elderly subjects
No full textMoving from the hypothesis that aging processes modulate brain connectivity networks, 170 healthy elderly volunteers were submitted to EEG recordings in order to define age-related normative limits. Graph theory functions were applied to exact low-resolution electromagnetic tomography on cortical sources in order to evaluate the small-world parameter as a representative model of network architecture. The analyses were carried out in the whole brain—as well as for the left and the right hemispheres separately—and in three specific resting state subnetworks defined as follows: attentional network (AN), frontal network (FN), and default mode network (DMN) in the EEG frequency bands (delta, theta, alpha 1, alpha 2, beta 1, beta 2, gamma). To evaluate the stability of the investigated parameters, a subgroup of 32 subjects underwent three separate EEG recording sessions in identical environmental conditions after a few days interval. Results showed that the whole right/left hemispheric evaluation did not present side differences, but when individual subnetworks were considered, AN and DMN presented in general higher SW in low (delta and/or theta) and high (gamma) frequency bands in the left hemisphere, while for FN, the alpha 1 band was lower in the left with respect to the right hemisphere. It was also evident the test-retest reliability and reproducibility of the present methodology when carried out in clinically stable subjects. Evidences from the present study suggest that graph theory represents a reliable method to address brain connectivity patterns from EEG data and is particularly suitable to study the physiological impact of aging on brain functional connectivity networks
A low-dimensional cognitive-network space in Alzheimer’s disease and frontotemporal dementia
No full textBackground: Alzheimer’s disease (AD) and frontotemporal dementia (FTD) show network dysfunctions linked with cognitive deficits. Within this framework, network abnormalities between AD and FTD show both convergent and divergent patterns. However, these functional patterns are far from being established and their relevance to cognitive processes remains to be elucidated. Methods: We investigated the relationship between cognition and functional connectivity of major cognitive networks in these diseases. Twenty-three bvFTD (age: 71±10), 22 AD (age: 72±6), and 20 controls (age: 72±6) underwent cognitive evaluation and resting-state functional MRI. Principal component analysis was used to describe cognitive variance across participants. Brain network connectivity was estimated with connectome analysis. Connectivity matrices were created assessing correlations between parcels within each functional network. The following cognitive networks were considered: default mode (DMN), dorsal attention (DAN), ventral attention (VAN), and frontoparietal (FPN) networks. The relationship between cognition and connectivity was assessed using a bootstrapping correlation and interaction analyses. Results: Three principal cognitive components explained more than 80% of the cognitive variance: the first component (cogPC1) loaded on memory, the second component (cogPC2) loaded on emotion and language, and the third component (cogPC3) loaded on the visuo-spatial and attentional domains. Compared to HC, AD and bvFTD showed impairment in all cogPCs (p<0.002), and bvFTD scored worse than AD in cogPC2 (p=0.031). At the network level, the DMN showed a significant association in the whole group with cogPC1 and cogPC2 and the VAN with cogPC2. By contrast, DAN and FPN showed a divergent pattern between diagnosis and connectivity for cogPC2. We confirmed these results by means of a multivariate analysis (canonical correlation). Conclusions: A low-dimensional representation can account for a large variance in cognitive scores in the continuum from normal to pathological aging. Moreover, cognitive components showed both convergent and divergent patterns with connectivity across AD and bvFTD. The convergent pattern was observed across the networks primarily involved in these diseases (i.e., the DMN and VAN), while a divergent FC-cognitive pattern was mainly observed between attention/executive networks and the language/emotion cognitive component, suggesting the co-existence of compensatory and detrimental mechanisms underlying these components
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