315 research outputs found
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
A complex craniovertebral junction malformation in a patient with late onset glycogenosis 2
No full textGlycogenosis II (GSDII) is an autosomal recessive lysosomal storage disorder resulting from deficiency of acid alpha-glucosidase and subsequent lysosomal accumulation of glycogen in skeletal, cardiac and smooth muscles. The late-onset form is characterized by wide variability of the phenotypical spectrum. Clinical findings may include muscle weakness, respiratory insufficiency, vascular abnormalities, low bone mineral density and higher risk of developing osteoporosis. Craniovertebral junction (CVJ) malformations have never been described so far. We here report on a GSDII 43-year-old woman who harbored the mutations IVS1-13T>G and c.2237G>A in the acid alpha-glucosidase gene. She recurrently suffered from headache, neck pain and dizziness. Brain MRI and CT scan showed the presence of a very rare complex CVJ malformation composed of basilar invagination, basiocciput hypoplasia, partial C1 assimilation, C1 posterior arch aplasia and C1 lateral mass hypoplasia and offset. Although we cannot rule out their coincidental occurrence, the rarity of multiple CVJ malformations in the general population as well as the well-known GSDII multisystem involvement should suggest to study the CVJ in the diagnostic process of GSDII patients in order to assess the CVJ malformation frequency in GSDII population and verify a possible relationship between these two conditions
Age-related changes in implicit emotion processing
No full textThe aim of the present study was to compare the performance of older and younger adults on an emotional priming task. Moreover, a nonemotional priming paradigm was used as a control task to disentangle age-related changes due to emotional processing difficulties from modifications due to a decline of executive inhibitory control abilities. Twenty-two young and 22 older healthy participants completed an emotional priming task and a nonemotional priming task. In the older adult group, reaction times in the emotional priming paradigm were not influenced by any of the prime conditions, whereas both groups exhibited similar facilitation effects induced by the congruent prime in the nonemotional task. The selective lack of an emotional priming effect in older adults shown in this preliminary report suggests that aging-induced changes in the ability to recognize emotions implicitly are directly dependent on emotional processing difficulties and not due to a general age-related modification of cognitive processes
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
Better together: Left and right hemisphere engagement to reduce age-related memory loss
No full textEpisodic memory is a cognitive function that appears more susceptible than others to the effects of aging. The main aim of this study is to investigate if the magnitude of functional hemispheric lateralization during episodic memory test was positively correlated with memory performance, proving the presence of a beneficial pattern of neural processing in high-performing older adults but not in low-performing participants.We have applied anodal transcranial Direct Current Stimulation (tDCS) or sham stimulation over left and right hemisphere in a group of young subjects and in high-performing and low-performing older participants during an experimental verbal episodic memory task.Remarkably, young individuals and high-performing older adults exhibited similar performances on episodic memory tasks and both groups showed symmetrical recruitment of left and right areas during memory retrieval. In contrast, low-performing older adults, who obtained lower scores on the memory tasks, demonstrated a greater engagement of the left hemisphere during verbal memory task. Furthermore, structural equation model was performed for analyzing the interrelations between the index of interhemispheric asymmetry and several neuropsychological domains. We found that the bilateral engagement of dorsolateral prefrontal cortex and parietal cortex regions had a direct correlation with memory and executive functions evaluated as latent constructs. These findings drew attention to brain maintenance hypothesis. The potential of neurostimulation in cognitive enhancement is particularly promising to prevent memory loss during aging
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
The role of the motor system in action naming in patients with neurodegenerative extrapyramidal syndromes
No full textPrevious studies of patients with brain damage have suggested a close relationship between aphasia and movement disorders. Neurodegenerative extrapyramidal syndromes associated with cognitive impairment provide an interesting model for studying the neural substrates of cognitive and motor symptoms. In this review, we focused on studies investigating language production abilities in patients with Parkinson's disease (PD), Corticobasal Syndrome (CBS) and Progressive Supranuclear Palsy (PSP). According to some reports, these patients exhibit a reduction in performance in both action and object naming or verb production compared to healthy individuals. Furthermore, a disproportional impairment of action naming compared to object naming was systematically observed in patients with these disorders. The study of these clinical conditions offers the unique opportunity to examine the close link between linguistic features and motor characteristics of action. This particular pattern of language impairment may contribute to the debate on embodiment theory and on the involvement of the basal ganglia in language and in integrating language and movement. From a translational perspective, we suggest that language ability assessments are useful in the clinical work-up, along with neuropsychological and motor evaluations. Specific protocols should be developed in the near future to better characterize language deficits and to permit an early cognitive diagnosis. Moreover, the link between language deficits and motor impairment opens a new issue for treatment approaches. Treatment of one of these two symptoms may ameliorate the other, and treating both may produce a greater improvement in patients' global clinical conditions
Reply to letter to the editor "tDCS effect on cognitive performance in Parkinson's disease" by Biundo et al.
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Transcranial direct current stimulation combined with cognitive training for the treatment of Parkinson Disease: a randomized, placebo-controlled study
No full textBackground: A number of non-motor symptoms occurs in Parkinson Disease (PD), cognitive decline and mood disturbances representing the most prevalent. Recent studies reported that cognitive training could potentially help to attenuate cognitive deficits in patients with PD and several researches demonstrated a beneficial effect of active transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex (anode over left dorsolateral prefrontal cortex, cathode over right supraorbital area) on cognitive deficits and mood disturbances. Objective: To investigate the effects of active tDCS combined with computerized cognitive training on cognition and mood disturbances in PD patients. Methods: Twenty-two patients with PD were assigned to either active tDCS plus computerized cognitive training (CCT) or sham tDCS plus CCT groups. Each patient underwent two weeks’ treatment of daily application of tDCS for 25 minutes during CCT focalized on functions related with prefrontal cortex. Each patient was evaluated at baseline, after treatment and at 3-month follow-up. Results: A significant reduction of depressive symptoms was observed in the active tDCS group from baseline to post-treatment assessment and from baseline to 3-month follow-up. An improvement in cognitive performances, referring more specifically to language, attentional and executive functions, was observed in both groups post-treatment and at follow-up. However, phonemic verbal fluency showed significant greater changes from baseline in the active tDCS group. Conclusions: We concluded that cognitive training along with active tDCS is a useful combined approach in the management of mood and cognitive dysfunctions in PD
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
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