1,720,959 research outputs found
Experimental protocol to investigate cortical, muscular and body representation alterations in adolescents with idiopathic scoliosis
Full text linkBackground: Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis. AIS is a three-dimensional morphological spinal deformity that affects approximately 1-3% of adolescents. Not all factors related to the etiology of AIS have yet been identified. Objective: The primary aim of this experimental protocol is to quantitatively investigate alterations in body representation in AIS, and to quantitatively and objectively track the changes in body sensorimotor representation due to treatment. Methods: Adolescent girls with a confirmed diagnosis of mild (Cobb angle: 10°-20°) or moderate (21°-35°) scoliosis as well as age and sex-matched controls will be recruited. Participants will be asked to perform a 6-min upright standing and two tasks-named target reaching and forearm bisection task. Eventually, subjects will fill in a self-report questionnaire and a computer-based test to assess body image. This evaluation will be repeated after 6 and 12 months of treatment (i.e., partial or full-time brace and physiotherapy corrective postural exercises). Results: We expect that theta brain rhythm in the central brain areas, alpha brain rhythm lateralization and body representation will change over time depending on treatment and scoliosis progression as a compensatory strategy to overcome a sensorimotor dysfunction. We also expect asymmetric activation of the trunk muscle during reaching tasks and decreased postural stability in AIS. Conclusions: Quantitatively assess the body representation at different time points during AIS treatment may provide new insights on the pathophysiology and etiology of scoliosis
EEG markers of improved proprioception and posture in older women with osteoporosis
No full textThe age-related decline in proprioception contributes to poor balance and motor coordination, increasing the risk of falls. Ten female participants (> 65 years) with osteoporosis underwent the Mini Balance Evaluation System test before (T0) and after (T1) a three-week programme involving the application of neuro-muscular taping to the lumbar, rhomboid and gastrocnemius muscles, alongside 15 minutes of simple physical exercises each day to improve proprioception. High-density electroencephalography (EEG) data were collected during the sensory orientation tasks, i.e., standing with eyes open or closed on solid and foam surfaces. Changes in spectral power over time (T0, T1) and across tasks were assessed using linear mixed effects regression models. Participants showed a significant increase in absolute theta power (p < 0.001) and a decrease in absolute beta power (p < 0.001) at T1, compared to T0. When standing on the foam, there was a significant decrease in both theta (p < 0.001) and alpha (p < 0.01) absolute power values at T0, with the decrease in theta being significantly attenuated by T1 (p < 0.001). The EEG results, together with improvements in balance test scores, suggest that participants experienced improved attentional control to monitor and maintain balance
High-density EEG and cognitive assessment in COVID-19 survivors
Full text linkopenA distanza di settimane o mesi dalla guarigione, in diversi contagiati dal virus SARS-CoV-2 persistono o insorgono alcuni sintomi. Queste manifestazioni sono di diversa natura. Stanchezza, deficit di memoria e attenzione, disturbi del sonno, ansia e depressione sono i sintomi condivisi dalla maggior parte dei soggetti.
Questa tesi ha l’obiettivo di valutare la fisiopatologia del deterioramento cognitivo/affettivo a lungo termine nei sopravvissuti al COVID-19.
Sono stati reclutati 33 partecipanti: 16 dimessi dal reparto di terapia intensiva (ICU) e 17 dal reparto di terapia sub-intensiva (noICU) del Policlinico Universitario di Padova tra marzo e maggio 2020. A questi sono stati poi aggiunti 12 soggetti che non sono mai stati contagiati dal virus (CTRL). A partire da giugno 2021, i controlli e i due gruppi di pazienti, ICU e noICU, sono stati sottoposti ad un'esaustiva valutazione neuropsicologica e ad una registrazione elettroencefalografica (EEG) ad alta densità (256 canali) effettuata durante il sonno pomeridiano.
Dopo una prima fase di pre-elaborazione, i tracciati EEG sono stati segmentati in epoche da 30 secondi, quindi classificati in base allo stadio del sonno . I fusi del sonno (sleep spindle) lenti ([9-12] Hz) e veloci ([12-16] Hz) sono stati rilevati automaticamente e utilizzati come input nell'analisi in sorgente (Electrical Source Imaging (ESI)), la quale mira a localizzare i generatori corticali di ciascuno spindle. Successivamente, sono stati calcolati alcuni parametri importanti per l'analisi dei fusi, come la densità, la frequenza di picco, l'ampiezza massima e la potenza.
I sopravvissuti al COVID-19 hanno mostrato sintomi depressivi e post-traumatici, hanno ottenuto il punteggio più basso nell'indagine riguardante la qualità di vita percepita e hanno mostrato una parziale compromissione della memoria e delle funzioni attentive. Questa evidenza è più marcata nel gruppo di pazienti che durante la loro degenza ospedaliera sono stati curati esclusivamente con ossigenoterapia, ovvero i noICU. Lo stesso gruppo ha presentato anche una diversa organizzazione dei generatori corticali dei fusi e variazioni nei valori dei parametri calcolati.
La correlazione tra i punteggi dei test neuropsicologici e le caratteristiche dei fusi ha evidenziato una relazione tra i punteggi delle valutazioni psicologiche sia con le prestazioni cognitive sia con le caratteristiche dei fusi e il potenziale predittivo dei punteggi delle valutazioni psicologiche rispetto alle altre variabili.
La neurofisiologia si è rivelata un valido strumento per indagare la natura dell’indebolimento delle funzioni cognitive ed esecutive manifestato nei sopravvissuti al COVID-19, sia nei pazienti ricoverati in terapia intensiva sia in quelli ricoverati in terapia sub-intensiva. In base ai
risultati emersi dalle analisi, si è ipotizzato che lo stato depressivo e i sintomi da disturbo da stress post-traumatico, mostrati dai soggetti guariti da COVID-19, fossero causati dall'esperienza traumatica vissuta, principale causa sia del parziale deterioramento delle funzioni cognitive ed esecutive sia delle variazioni delle caratteristiche dei fusi del sonno evidenziati in questi soggetti.SARS-CoV-2 survivors experience new or persistent symptoms up to weeks or months after recovery. These manifestations are of different nature and can arise in both hospitalized and non-hospitalized individuals. Fatigue, memory and attentive disorders, sleep troubles, anxiety and depression are those shared by most of the subjects.
The aim of the thesis is to disentangle the physiopathology of long-term cognitive / affective impairment in COVID-19 survivors.
We recruited 33 participants: 16 and 17 patients respectively discharged from intensive care unit (ICU) and sub-intensive ward (noICU) of the Padova Teaching Hospital between March and May 2020 and 12 subjects who have never been infected by the virus (CTRL). Starting from June 2021, the controls and the COVID-19 survivors underwent a neuropsychological and sleep assessment. Our experimental protocol included a battery of cognitive and psychological tests, lasting approximately one hour, and a nap high-density (256 channels) electroencephalography (EEG) recording.
After the initial preprocessing step, the EEG patterns were segmented in 30-s epochs, then classified according to the patient’s current sleep stage. Slow (i.e., [9-12] Hz) and fast (i.e., [12- 16] Hz) sleep spindles were automatically detected and used as input of the EEG source analysis (ESI), aimed at localizing the spindle cortical generators. Some important parameters for the spindle analysis, such as the slow and fast spindle density, the peak frequency, the corresponding amplitude, and the spindle power, were then calculated.
COVID-19 survivors showed depressive and post-traumatic symptoms, scored the lowest on the physical quality of life survey and exhibited a memory and attentive functions’ impairment. This evidence is more marked in the noICU population. The same group presented a different organization of the spindles’ cortical generators and changes in the spindle parameters.
A correlation analysis, computed between the neuropsychological scores and spindle features, highlighted a relationship between the psychological evaluations with both the cognitive performances and the sleep spindle characteristics and the predictive potential of the Beck’s Depression Inventory (BDI) and post-traumatic stress disorder (PTSD) scores with respect to the other variables.
Sleep neurophysiology turned out to be a valid tool to investigate the nature of the cognitive and executive functions' impairment manifested by the COVID-19 survivors, i.e., the ICU and noICU groups. According to spindle and correlation analysis’ results, we hypothesized that the depressive state and the post-traumatic stress disorder, shown by COVID-19 recovered patients
and probably caused by the traumatic experience lived, involved both cognitive impairment and changes in sleep spindle features and distribution
A neurophysiological and genetic assessment of a case of rapidly progressive scoliosis
Full text linkScoliosis is a three-dimensional spinal deformity characterized by a lateral deviation of at least 10° Cobb, categorized into idiopathic and non-idiopathic forms, caused by identifiable factors like congenital abnormalities, neuromuscular conditions, or genetic syndromes.
This case report discusses a 15-year-old girl with growth delay and growth hormone (GH) deficiency who experienced rapid scoliosis progression. Initial evaluations were normal, and electroencephalography (EEG) showed nonspecific alterations, but further assessment revealed a MYH3 gene variant associated with scoliosis, short stature, and distinct facial features. Treatment with a Lyon ARTbrace and tailored exercises stopped curve progression. This case highlights the need for thorough evaluations in atypical AIS cases to uncover potential causes.
Analysis of brain connectivity using the Horizontal Visibility Graph - Transfer Entropy during balance tasks in adolescents with idiopathic scoliosis
No full textreservedLa scoliosi idiopatica adolescenziale (AIS) causa asimmetrie fisiche e può portare a deficit propriecettivi, compromettendo la postura o/e l’equilibrio.
Questa tesi propone l’analisi dei segnali elettroencafalografici (EEG) di nove adolescenti con AIS durante semplici compiti di equilibrio, con lo scopo di stimare la connettività diretta tra regioni corticali tramite l’algoritmo HVG-TE (Horizontal Visibility Graph – Transfer Entropy).
Dopo la ricostruzione delle sorgenti corticali e l’estrazione delle serie temporali per ciascuna regione di interesse (ROI), sono stati costruiti i grafi HVG relativi a ogni ROI, ottenendo una rappresentazione topologica delle dinamiche temporali dei segnali. Le serie HVG sono state successivamente analizzate tramite Effective Transfer Entropy, in ambiente R. Per ogni soggetto e condizione sperimentale sono state ottenute matrici di entropia di trasferimento normalizzate. Dalle matrici, sono stati calcolati gli indici di In-Flow e Out-Flow e, per ogni compito motorio, sono state calcolate le mappe di connettività medie.
I risultati evidenziano un ruolo centrale del lobo temporale, probabilmente per la sua funzione di integrazione delle informazioni visive e propriocettive. La configurazione della connettività varia con la disponibilità dell’informazione visiva: con gli occhi aperti prevale l’attivazione frontale, mentre con gli occhi chiusi aumenta il coinvolgimento delle aree occipitali. Nelle condizioni posturali più instabili la connettività direzionale diventa più diffusa, suggerendo una rete più ampia per compensare la complessità del compito. Nel complesso, questi risultati supportano l’ipotesi che l’AIS possa includere specifiche modalità di integrazione sensoriale e riorganizzazione corticale per compensare eventuali deficit propriocettivi.
Nonostante i limiti metodologici e la numerosità ridotta del campione, l’approccio HVG-TE si è dimostrato efficace nel descrivere la direzionalità della connettività cerebrale durante semplici compiti posturali.
La tesi riporta nel primo capitolo la motivazione fisiopatologica, nel secondo capitolo descrive la pipeline per il calcolo del HVG-TE, nel terzo capitolo i risultati e nel quarto capitolo una possibile interpretazione clinico-neuroscientifica, offrendo una visione integrata delle evidenze emerse e delle prospettive future nello studio della connettività cerebrale nell’AIS
Spikes analysis before and after stimulation of the vagus nerve: a case study.
No full textembargoed_20261017Epilepsy is one of the most common and serious neurological conditions worldwide. It affects people of all ages, genders and backgrounds. Thirty-five percent of patients with epilepsy are drug-resistant, meaning they do not fully respond to medication. For selected patients, epilepsy surgery — involving either resective procedures or the implantation of neurostimulators — represents a valid therapeutic option. Neuromodulatory approaches involving direct or induced electrical currents have been developed to reduce seizure frequency and duration. One such approach is vagus nerve stimulation (VNS), which sends regular, mild electrical pulses to the brain via the vagus nerve to prevent or reduce seizures. Once the electrical charge reaches the brainstem, it is discharged to different areas of the brain, modulating neural networks. This thesis reports a case study of a pediatric patient with drug-resistant epilepsy undergoing VNS therapy, with high-density EEG recordings collected before implantation and four months after. The aim was to provide neurologists with further quantitative information to support the interpretation of EEG signals, identification of epileptic foci and evaluation of treatment efficacy. Epileptiform discharges were annotated by a neurologist. Spikes were processed using an automated algorithm to extract morphology, duration, amplitude and sharpness and to estimate the presumptive onset channel. Moreover, scalp topographies and spectral analysis were performed to investigate both spatial distribution and background rhythms.
Results showed a marked reduction in spike frequency after VNS (from ~15 to ~3 events per minute), particularly during wakefulness, with residual discharges more focal and spatially restricted. Morphological analysis indicated that post-VNS spikes during wakefulness had shorter duration and higher sharpness, whereas during sleep amplitudes and sharpness decreased, with more stable temporal features. Topographical maps confirmed a shift from diffuse frontal–central activity to more localized frontal discharges. Spectral analysis demonstrated a reduction of pathological delta activity during wakefulness and a shift of rhythms to the expected distribution during wakefulness and sleep.
These findings suggest that VNS modulates both quantitative and qualitative aspects of epileptiform discharges and background activity, supporting its role as an effective neuromodulatory treatment. Despite the limitations of a single-case design, this study highlights methodological strategies and provides evidence of VNS-induced electrophysiological improvements in a pediatric drug-resistant epileptic patient.Epilepsy is one of the most common and serious neurological conditions worldwide. It affects people of all ages, genders and backgrounds. Thirty-five percent of patients with epilepsy are drug-resistant, meaning they do not fully respond to medication. For selected patients, epilepsy surgery — involving either resective procedures or the implantation of neurostimulators — represents a valid therapeutic option. Neuromodulatory approaches involving direct or induced electrical currents have been developed to reduce seizure frequency and duration. One such approach is vagus nerve stimulation (VNS), which sends regular, mild electrical pulses to the brain via the vagus nerve to prevent or reduce seizures. Once the electrical charge reaches the brainstem, it is discharged to different areas of the brain, modulating neural networks. This thesis reports a case study of a pediatric patient with drug-resistant epilepsy undergoing VNS therapy, with high-density EEG recordings collected before implantation and four months after. The aim was to provide neurologists with further quantitative information to support the interpretation of EEG signals, identification of epileptic foci and evaluation of treatment efficacy. Epileptiform discharges were annotated by a neurologist. Spikes were processed using an automated algorithm to extract morphology, duration, amplitude and sharpness and to estimate the presumptive onset channel. Moreover, scalp topographies and spectral analysis were performed to investigate both spatial distribution and background rhythms.
Results showed a marked reduction in spike frequency after VNS (from ~15 to ~3 events per minute), particularly during wakefulness, with residual discharges more focal and spatially restricted. Morphological analysis indicated that post-VNS spikes during wakefulness had shorter duration and higher sharpness, whereas during sleep amplitudes and sharpness decreased, with more stable temporal features. Topographical maps confirmed a shift from diffuse frontal–central activity to more localized frontal discharges. Spectral analysis demonstrated a reduction of pathological delta activity during wakefulness and a shift of rhythms to the expected distribution during wakefulness and sleep.
These findings suggest that VNS modulates both quantitative and qualitative aspects of epileptiform discharges and background activity, supporting its role as an effective neuromodulatory treatment. Despite the limitations of a single-case design, this study highlights methodological strategies and provides evidence of VNS-induced electrophysiological improvements in a pediatric drug-resistant epileptic patient
High-density EEG sleep correlates of cognitive and affective impairment at 12-month follow-up after COVID-19
Full text linkObjective
To disentangle the pathophysiology of cognitive/affective impairment in Coronavirus Disease-2019 (COVID-19), we studied long-term cognitive and affective sequelae and sleep high-density electroencephalography (EEG) at 12-month follow-up in people with a previous hospital admission for acute COVID-19.
Methods
People discharged from an intensive care unit (ICU) and a sub-intensive ward (nonICU) between March and May 2020 were contacted between March and June 2021. Participants underwent cognitive, psychological, and sleep assessment. High-density EEG recording was acquired during a nap. Slow and fast spindles density/amplitude/frequency and source reconstruction in brain gray matter were extracted. The relationship between psychological and cognitive findings was explored with Pearson correlation.
Results
We enrolled 33 participants ( 17 nonICU) and 12 controls. We observed a lower Physical Quality of Life index, higher post-traumatic stress disorder (PTSD) score, and a worse executive function performance in nonICU participants. Higher PTSD and Beck Depression Inventory scores correlated with lower executive performance. The same group showed a reorganization of spindle cortical generators.
Conclusions
Our results show executive and psycho-affective deficits and spindle alterations in COVID-19 survivors – especially in nonICU participants – after 12 months from discharge
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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