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"Petrone, Valeria"
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Hierarchical psychophysiological pathways subtend perceptual asymmetries in Neglect
•Connectivity in the visuospatial perceptual network (VPN) is impaired in Neglect.•Pre-stimulus alpha oscillatory activity is asymmetric and impaired in Neglect.•Post-stimulus N100 is impaired and delayed for right presented stimuli in Neglect.•Generative models show pre-and post-stimulus EEG relations in the VPN.•The model predicts visuospatial deficits and behavioral asymmetries in Neglect.
Stroke patients with left Hemispatial Neglect (LHN) show deficits in perceiving left contralesional stimuli with biased visuospatial perception towards the right hemifield. However, very little is known about the functional organization of the visuospatial perceptual neural network and how this can account for the profound reorganization of space representation in LHN.
In the present work, we aimed at (1) identifying EEG measures that discriminate LHN patients against controls and (2) devise a causative neurophysiological model between the discriminative EEG measures. To these aims, EEG was recorded during exposure to lateralized visual stimuli which allowed for pre-and post-stimulus activity investigation across three groups: LHN patients, lesioned controls, and healthy individuals. Moreover, all participants performed a standard behavioral test assessing the perceptual asymmetry index in detecting lateralized stimuli. The between-groups discriminative EEG patterns were entered into a Structural Equation Model for the identification of causative hierarchical associations (i.e., pathways) between EEG measures and the perceptual asymmetry index.
The model identified two pathways. A first pathway showed that the combined contribution of pre-stimulus frontoparietal connectivity and individual-alpha-frequency predicts post-stimulus processing, as measured by visual-evoked N100, which, in turn, predicts the perceptual asymmetry index. A second pathway directly links the inter-hemispheric distribution of alpha-amplitude with the perceptual asymmetry index. The two pathways can collectively explain 83.1% of the variance in the perceptual asymmetry index.
Using causative modeling, the present study identified how psychophysiological correlates of visuospatial perception are organized and predict the degree of behavioral asymmetry in LHN patients and controls.
Journal Article
Clinical and neurophysiological predictors of the functional outcome in right-hemisphere stroke
•A machine learning model was used to identify clinical and EEG predictors of the functional outcome in stroke patients.•Motor/cognitive functioning, fronto-parietal connectivity and beta power predict functional independence at discharge.•The combination between motor/cognitive and EEG measures can also predict the length of stay in hospital settings.
The aim of the present study is to examine the relationship between EEG measures and functional recovery in right-hemisphere stroke patients.
Participants with stroke (PS) and neurologically unimpaired controls (UC) were enrolled. At enrolment, all participants were assessed for motor and cognitive functioning with specific scales (motricity index, trunk control test, Level of Cognitive Functioning, and Functional Independence Measure (FIM). Moreover, EEG data were recorded. At discharge, participants were re-tested with the FIM
Powers in the delta, theta, alpha, and beta bands and connectivity within the fronto-parietal network were compared between groups. Then, the between-group discriminative EEG measures and the motor/cognitive scales were used to feed a machine learning algorithm to predict FIM scores at discharge and the length of hospitalization (LoH). Higher delta, theta, and beta and impaired connectivity were found in PS compared to UC. Moreover, motor/cognitive functioning, beta power, and fronto-parietal connectivity predicted the FIM score at discharge and the LoH (accuracy=73.2 % and 85.2 % respectively).
Results show that the integration of motor/cognitive scales and EEG measures can reveal the rehabilitative potentials of PS predicting their functional outcome and LoH.
Synergistic clinical and electrophysiological models can support rehabilitative decision-making.
Journal Article
The pup speaks up : a phonics reader
After Bo and Pal, his silent new puppy, go for a walk and hear the various sounds of animals and objects around them, Pal finally speaks up.
Book
Accuracy of EEG Biomarkers in the Detection of Clinical Outcome in Disorders of Consciousness after Severe Acquired Brain Injury: Preliminary Results of a Pilot Study Using a Machine Learning Approach
Accurate outcome detection in neuro-rehabilitative settings is crucial for appropriate long-term rehabilitative decisions in patients with disorders of consciousness (DoC). EEG measures derived from high-density EEG can provide helpful information regarding diagnosis and recovery in DoC patients. However, the accuracy rate of EEG biomarkers to predict the clinical outcome in DoC patients is largely unknown. This study investigated the accuracy of psychophysiological biomarkers based on clinical EEG in predicting clinical outcomes in DoC patients. To this aim, we extracted a set of EEG biomarkers in 33 DoC patients with traumatic and nontraumatic etiologies and estimated their accuracy to discriminate patients’ etiologies and predict clinical outcomes 6 months after the injury. Machine learning reached an accuracy of 83.3% (sensitivity = 92.3%, specificity = 60%) with EEG-based functional connectivity predicting clinical outcome in nontraumatic patients. Furthermore, the combination of functional connectivity and dominant frequency in EEG activity best predicted clinical outcomes in traumatic patients with an accuracy of 80% (sensitivity = 85.7%, specificity = 71.4%). These results highlight the importance of functional connectivity in predicting recovery in DoC patients. Moreover, this study shows the high translational value of EEG biomarkers both in terms of feasibility and accuracy for the assessment of DoC.
Journal Article
Efficacy of repetitive transcranial magnetic stimulation combined with visual scanning treatment on cognitive and behavioral symptoms of left hemispatial neglect in right hemispheric stroke patients: study protocol for a randomized controlled trial
Background
Left hemispatial neglect (LHN) is a neuropsychological syndrome often associated with right hemispheric stroke. Patients with LHN have difficulties in attending, responding, and consciously representing the right side of space. Various rehabilitation protocols have been proposed to reduce clinical symptoms related to LHN, using cognitive treatments, or on non-invasive brain stimulation. However, evidence of their benefit is still lacking; in particular, only a few studies focused on the efficacy of combining different approaches in the same patient.
Methods
In the present study, we present the SMART ATLAS trial (
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timolazione
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gnetica
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ipetitiva
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ranscranica nell’
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tenzione
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teralizzata dopo
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troke), a multicenter, randomized, controlled trial with pre-test (baseline), post-test, and 12 weeks follow-up assessments based on a novel rehabilitation protocol based on the combination of brain stimulation and standard cognitive treatment. In particular, we will compare the efficacy of inhibitory repetitive-transcranial magnetic stimulation (r-TMS), applied over the left intact parietal cortex of LHN patients, followed by visual scanning treatment, in comparison with a placebo stimulation (SHAM control) followed by the same visual scanning treatment, on visuospatial symptoms and neurophysiological parameters of LHN in a population of stroke patients.
Discussion
Our trial results may provide scientific evidence of a new, relatively low-cost rehabilitation protocol for the treatment of LHN.
Trial registration
ClinicalTrials.gov
NCT04080999
. Registered on September 2019.
Journal Article
Coherence and Consciousness: Study of Fronto-Parietal Gamma Synchrony in Patients with Disorders of Consciousness
Evaluation of consciousness needs to be supported by the evidence of brain activation during external stimulation in patients with unresponsive wakefulness syndrome (UWS). Assessment of patients should include techniques that do not depend on overt motor responses and allow an objective investigation of the spontaneous patterns of brain activity. In particular, electroencephalography (EEG) coherence allows to easily measure functional relationships between pairs of neocortical regions and seems to be closely correlated with cognitive or behavioral measures. Here, we show the contribution of higher order associative cortices of patients with disorder of consciousness (N = 26) in response to simple sensory stimuli, such as visual, auditory and noxious stimulation. In all stimulus modalities an increase of short-range parietal and long-range fronto-parietal coherences in gamma frequencies were seen in the controls and minimally conscious patients. By contrast, UWS patients showed no significant modifications in the EEG patterns after stimulation. Our results suggest that UWS patients can not activate associative cortical networks, suggesting a lack of information integration. In fact, fronto-parietal circuits result to be connectively disrupted, conversely to patients that exhibit some form of consciousness. In the light of this, EEG coherence can be considered a powerful tool to quantify the involvement of cognitive processing giving information about the integrity of fronto-parietal network. This measure can represent a new neurophysiological marker of unconsciousness and help in determining an accurate diagnosis and rehabilitative intervention in each patient.
Journal Article
Effectiveness of BNT162b2 vaccine against SARS-CoV-2 infection and severe COVID-19 in children aged 5–11 years in Italy: a retrospective analysis of January–April, 2022
By April 13, 2022, more than 4 months after the approval of BNT162b2 (Pfizer–BioNTech) for children, less than 40% of 5–11-year-olds in Italy had been vaccinated against COVID-19. Estimating how effective vaccination is in 5–11-year-olds in the current epidemiological context dominated by the omicron variant (B.1.1.529) is important to inform public health bodies in defining vaccination policies and strategies.
In this retrospective population analysis, we assessed vaccine effectiveness against SARS-CoV-2 infection and severe COVID-19, defined as an infection leading to hospitalisation or death, by linking the national COVID-19 surveillance system and the national vaccination registry. All Italian children aged 5–11 years without a previous diagnosis of infection were eligible for inclusion and were followed up from Jan 17 to April 13, 2022. All children with inconsistent vaccination data, diagnosed with SARS-CoV-2 infection before the start date of the study or without information on the municipality of residence were excluded from the analysis. With unvaccinated children as the reference group, we estimated vaccine effectiveness in those who were partly vaccinated (one dose) and those who were fully vaccinated (two doses).
By April 13, 2022, 1 063 035 (35·8%) of the 2 965 918 children aged 5–11 years included in the study had received two doses of the vaccine, 134 386 (4·5%) children had received one dose only, and 1 768 497 (59·6%) were unvaccinated. During the study period, 766 756 cases of SARS-CoV-2 infection and 644 cases of severe COVID-19 (627 hospitalisations, 15 admissions to intensive care units, and two deaths) were notified. Overall, vaccine effectiveness in the fully vaccinated group was 29·4% (95% CI 28·5–30·2) against SARS-CoV-2 infection and 41·1% (22·2–55·4) against severe COVID-19, whereas vaccine effectiveness in the partly vaccinated group was 27·4% (26·4–28·4) against SARS-CoV-2 infection and 38·1% (20·9–51·5) against severe COVID-19. Vaccine effectiveness against infection peaked at 38·7% (37·7–39·7) at 0–14 days after full vaccination and decreased to 21·2% (19·7–22·7) at 43–84 days after full vaccination.
Vaccination against COVID-19 in children aged 5–11 years in Italy showed a lower effectiveness in preventing SARS-CoV-2 infection and severe COVID-19 than in individuals aged 12 years and older. Effectiveness against infection appears to decrease after completion of the current primary vaccination cycle.
None.
For the Italian translation of the summary see Supplementary Materials section.
Journal Article
SUMO conjugation susceptibility of Akt/protein kinase B affects the expression of the pluripotency transcription factor Nanog in embryonic stem cells
Akt/PKB is a kinase involved in the regulation of a wide variety of cell processes. Its activity is modulated by diverse post-translational modifications (PTMs). Particularly, conjugation of the small ubiquitin-related modifier (SUMO) to this kinase impacts on multiple cellular functions, such as proliferation and splicing. In embryonic stem (ES) cells, this kinase is key for pluripotency maintenance. Among other functions, Akt is known to promote the expression of Nanog, a central pluripotency transcription factor (TF). However, the relevance of this specific PTM of Akt has not been previously analyzed in this context. In this work, we study the effect of Akt1 variants with differential SUMOylation susceptibility on the expression of Nanog. Our results demonstrate that both, the Akt1 capability of being modified by SUMO conjugation and a functional SUMO conjugase activity are required to induce Nanog gene expression. Likewise, we found that the common oncogenic E17K Akt1 mutant affected Nanog expression in ES cells also in a SUMOylatability dependent manner. Interestingly, this outcome takes places in ES cells but not in a non-pluripotent heterologous system, suggesting the presence of a crucial factor for this induction in ES cells. Remarkably, the two major candidate factors to mediate this induction, GSK3-β and Tbx3, are non-essential players of this effect, suggesting a complex mechanism probably involving non-canonical pathways. Furthermore, we found that Akt1 subcellular distribution does not depend on its SUMOylatability, indicating that Akt localization has no influence on the effect on Nanog, and that besides the membrane localization of E17K Akt mutant, SUMOylation is also required for its hyperactivity. Our results highlight the impact of SUMO conjugation in the function of a kinase relevant for a plethora of cellular processes, including the control of a key pluripotency TF.
Journal Article