Neurological complications of covid-19 and possible neuroinvasion pathways: A systematic review

The Coronavirus Disease 2019 (COVID-19) outbreak has shocked the whole world with its unexpected rapid spread. The virus responsible for the disease, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), enters host cells by means of the envelope spike protein, which binds to angiotensin-converting enzyme 2 receptors. These receptors are highly expressed in heart, lungs, respiratory tract epithelium, endothelial cells and brain. Since an increasing body of significant evidence is highlighting a possible neuroinvasion related to SARS-CoV-2, a state of the art on the neurological complications is needed. To identify suitable publications, our systematic review was carried out by searching relevant studies on PubMed and Scopus databases. We included studies investigating neurologic manifestations of SARS-CoV-2 in patients over 18. According to the analyzed studies, the most frequent disorders affecting central nervous system (CNS) seem to be the following: olfactory and taste disorders, ischemic/hemorrhagic stroke, meningoencephalitis and encephalopathy, including acute necrotizing encephalopathy, a rare type of encephalopathy. As regards the peripheral nervous system (PNS), Guillain-Barré and Miller Fisher syndromes are the most frequent manifestations reported in the literature. Important clinical information on the neurological manifestations of SARS-CoV-2 would help clinicians raise awareness and simultaneously improve the prognosis of critically ill patients

Correlati psicofisiologici dei meccanismi attentivi stimulus-driven e goal-directed: uno studio multi-parametrico

Stato dell’arte: I meccanismi attentivi stimulus-driven/bottom-up e goal-directed/top-down sono sottesi da circuiterie cerebrali distinte che coinvolgono rispettivamente giunzione temporo-parietale e corteccia frontale ventrale per il primo, che si attiva in risposta a stimoli salienti inaspettati, e principalmente corteccia prefrontale dorsolaterale, corteccia cingolata anteriore, corteccia orbitofrontale, solco intraparietale e lobulo parietale superiore per il secondo, che si attiva in risposta a stimoli target attesi. Tali meccanismi di regolazione dell’attenzione sono mediati dalla transizione da uno stato di allerta tonica ad uno stato di allerta fasica; in particolare, sembra che la corteccia cingolata anteriore e la corteccia orbitofrontale abbiano la funzione di regolazione della suddetta transizione attraverso un meccanismo di feedback sul Locus Coeruleus, la struttura cardine del sistema noradrenergico. Studi elettrofisiologici hanno riportato la correlazione tra attività del suddetto nucleo e la manifestazione della P300, le cui componenti P3a e P3b rifletterebbero a livello neurale i meccanismi attentivi bottom-up e top-down; infatti, la P3a viene generata a seguito della presentazione di stimoli infrequenti e inaspettati (stimoli distrattori o non-target), mentre la manifestazione della P3b segue la presentazione di stimoli infrequenti ma attesi (stimoli target). Inoltre, numerosi studi hanno dimostrato l’attendibilità della dilatazione del diametro pupillare come misura indiretta dell’attivazione del Locus Coeruleus; tale correlazione è stata osservata anche parallelamente alla manifestazione della P300 in un paradigma oddball, durante il quale è stata osservata anche una significativa desincronizzazione della banda di frequenza beta a seguito della presentazione degli stimoli non-target e target, la quale però non si verificava per la condizione standard. Razionale: La letteratura esistente non fornisce dati coerenti riguardo ai correlati neurofisiologici specifici delle componenti P3a e P3b; in particolare, alcuni studi evidenziano un ruolo specifico del Locus Coeruleus nella generazione della P3a, e quindi un ruolo specifico di tale nucleo nei meccanismi bottom-up, mentre altri studi riportano una correlazione specifica tra l’attivazione del Locus Coeruleus e la manifestazione della P3b, e di conseguenza una più specifica funzione di questa struttura nella modulazione dei meccanismi top-down. Tali discrepanze hanno fornito una valida motivazione ad analizzare più dettagliamente le suddette correlazioni. Obiettivi: Il presente studio si prefigge di indagare, all’interno del paradigma oddball, la correlazione specifica tra l’attività del Locus Coeruleus, rilevata indirettamente tramite la misurazione della risposta pupillare, e le componenti ERP P3a e P3b, correlati elettrofisiologici rispettivamente dei processi attentivi stimulus-driven e goal-directed. Materiali e metodi: Un paradigma oddball a tre stimoli (target, non-target, standard) è stato fatto eseguire ad un gruppo di ventisei soggetti giovani adulti sani, contemporaneamente all’esecuzione della pupillometria e dell’elettroencefalogramma. Prima della sessione sperimentale ai partecipanti sono stati somministrati alcuni test psicometrici per rilevare l’eventuale presenza di disagio psichico e per valutare le capacità attentive. Risultati: Sono state rilevate significative correlazioni negative rispettivamente tra P3b e risposta pupillare e tra P3b e sincronizzazione del ritmo beta; per contro, sono state ottenute correlazioni positive rispettivamente tra dilatazione del diametro pupillare e sincronizzazione del ritmo beta e tra P3a e STAI 1 e tra P3a e sezione A del Trail Making Test. Discussione: Le correlazione negativa tra P3b e risposta pupillare, e di conseguenza attivazione del Locus Coerules, suggeriscono l’alternanza di IPSP e EPSP tra Locus Coeruleus e corteccia; in particolare la minore attività di scarica del Locus Coeruleus, a cui si interpone la desincronizzazione dell’attività beta, corrisponderebbe ad una maggiore sincronizzazione corticale necessaria per la generazione di un’ampia componente P3b. Conclusioni: I risultati ottenuti suggeriscono la natura multicomponenziale dei correlati psicofisiologici del meccanismo di regolazione top-down dell’attenzione, che sembrano essere costituiti da una catena di eventi neurofisiologici che coinvolgono la manifestazione della P3b, la desincronizzazione del ritmo beta e il declino della frequenza di oscillazione pupillare. Resta ancora aperta la questione relativa ai correlati neurofisiologici della componente P3a, e di conseguenza dei meccanismi di regolazione bottom-up dell’attenzione

Is it possible to identify chronic fatigue syndrome via machine learning techniques?

Background: Chronic fatigue syndrome (CFS) is characterized by persistent exhaustion lasting at least six months, post-exercise malaise, discomfort, and neurological and autonomic symptoms. Numerous efforts to formulate a standardized definition for CFS have been made and the most extensive diagnostic tools are Fukuda criteria and Canadian Consensus Document. Since CFS symptoms overlap other disorders, identifying CFS has proven difficult. Therefore, the development of accurate diagnostic tools, such as Machine Learning (ML) techniques, is necessary. Neuroimaging and psychometric testing may be augmented using ML in different fields such as malingering, and clinical medicine. ML employs algorithms and statistical models to draw inferences from patterns in data. Herein, we provide an overview of the state of the art on the current ML protocols used to diagnose CFS. Methods: We conducted a literature search of available sources on ML protocols to diagnose CFS. Results: Watson and colleagues demonstrated that DePaul Symptom Questionnaire (DSQ) data in combination of ML techniques can provide accurate basis for diagnosing CFS; furthermore, Provenzano and colleagues implemented a ML predictive model to diagnose CFS by basing on magnetic resonance imaging structural and functional data. Conclusion: ML models have shown promising advantages in solving classification problems, addressing clinical questions such as identifying predictors that distinguish patients from healthy controls, thus allowing to make inferences at group and individual level. Future research is needed to substantiate the aforementioned findings, and to develop models able to perform differential diagnosis by identifying key pathognomonic cluster of neuroimaging, immunological and behavioral characteristics of CFS

Lavender aromatherapy: a systematic review from essential oil extraction and administration to cognitive enhancing effects.

Modern society is reviving the practice of aromatherapy, and lavender is reported to be the most worldwide purchased plant for essential oils (EO) extraction. Since odors can modulate cognitive functions acting through specific neuroanatomical pathways, lavender EO inhalation can enhance cognition. Taking into account EO quality and diffusion devices, we conducted a systematic review on the effects of lavender EO inhalation on arousal, attention and memory in healthy subjects. Starting from this new multidisciplinary perspective, cognitive effects were revised to link outcomes to effective and reproducible aromatherapy protocols. A systematic search on MEDLINE database using Cognitive Atlas and plant authenticity-related keywords was performed. Among the 806 articles yielded, 11 articles met eligibility criteria. Subjects administered with lavender EO displayed arousal decrease and sustained attention increase. Puzzling results were obtained regarding memory. Lack of EO quality assessment and high heterogeneity in inhalation protocols did not allow assessing whether different EO composition differently modulates cognition and whether placebo or expectancy effect can be discerned from EO effect itself. However, GABAergic pathway modulation exerted by linalool, a major lavender EO constituent, explains arousal reduction and sustained attention enhancement. In conclusion, aromatherapy can be an innovative, practical and non-invasive tool to prevent cognitive lapses

Lavender aromatherapy: a systematic review from essential oil extraction and administration to cognitive enhancing effects.

Modern society is reviving the practice of aromatherapy, and lavender is reported being the most worldwide purchased plant for essential oil (EO) extraction. Since recent studies reported cognitive enhancing effects of lavender besides the hypno-inducing effects, a literature review is needed. Considering EO quality and diffusion devices, we conducted a systematic review on the effects of lavender EO inhalation on arousal, attention and memory in healthy subjects. Starting from this new multidisciplinary perspective, cognitive effects were reviewed to link outcomes to effective and reproducible protocols. A systematic search on MEDLINE, ERIC, PsycInfo, Google Scholar, and Scopus databases using Cognitive Atlas and plant-related keywords was conducted. Among the 1,203 articles yielded, 11 met eligibility criteria. Subjects administered with lavender EO displayed arousal decrease and sustained attention increase. Controversial results emerged regarding memory. Lack of EO quality assessment and protoco

The effects of Transcranial Direct Current Stimulation on food craving and food intake in individuals affected by obesity and overweight: a mini review of the magnitude of the effects

Obesity represents one of the wellness diseases concurring to increase the incidence of diabetes, cardiovascular diseases, and cancer. One of the main perpetuating factors of obesity is food craving, which is characterized by an urgent desire to eat a large and various amount of food, regardless of calories requirement or satiety signals, and it might be addressed to the alteration of the dorsolateral prefrontal cortex (DLPFC) activity. Despite most of the gold-standard therapies focus on symptom treatment only, non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) could help treat overeating by modulating specific neural pathways. The current systematic review was conducted to identify whether convergent evidence supporting the usefulness of tDCS to deal with food craving are present in the literature. The review was conducted by searching articles published up to January 1st 2022 on MEDLINE, Scopus and PsycInfo databases. We included studies investigating the effects of tDCS on food craving in subjects affected by overweight and obesity. According to eligibility criteria, 5 articles were included. Results showed that tDCS targeting left DLPFC with unipolar montage induced ameliorating effects on food craving. Controversial results were shown for the other studies, that might be ascribable to the use of bipolar montage, and the choice of other target areas. Further investigations including expectancy effect control, larger sample sizes and follow-up are needed to support more robust conclusions. To conclude, tDCS combined with the use of psychoeducative intervention, diet and physical activity, might represents a potential to manage food craving in individuals with overweight and obesity

Psycho-cognitive individual resources of Liver Pre-Transplant Candidates pave the way for identifying an adherence core: A Retrospective Pilot Study

Background: Patients’ adherence to medical prescription during pre- and post- liver transplant phases is crucial to prevent treatment inefficacy. Literature has highlighted the urge of performing a psychological characterization to prevent post-intervention relapses and to impede treatment non-adherence behavior. The aim of this study is to define an “adherence core” by investigating personality traits, cognitive functions, and affective symptoms of patients waiting for liver transplant to enhance treatment effectiveness. We hypothesize a negative correlation between depressive and anxious symptoms and cognitive abilities and a positive association between some personality traits (Open-mindedness, Conscientiousness and Extraversion) and cognitive functions. Materials and methods: Forty-six candidates (23 females, mean age: 56.02±7.81 years, range: 39-76) for liver transplantation were assessed utilizing the following psychometric tools: State-Trait Anxiety Inventory Form Y1 and Form Y2, Big Five Questionnaire and Beck Depression Inventory 2. Cognitive assessment included: Coloured Progressive Matrices, Rey's 15-word list, Semantic Incidental Memory Test for Adults, Attentional Matrices Test and Corsi Block-tapping Test. Results: The findings showed that education level negatively correlated with trait anxiety and positively correlated with Open-mindedness and Emotional Stability. Coloured Progressive Matrices negatively correlated with trait anxiety and depressive symptoms and positively correlated with Emotional Stability and Open-mindedness. Significant correlations were also shown between cognitive tests. Rey Immediate Recall scores showed positive correlation with: Rey Delayed Recall, Semantic Incidental Memory, and Attentional Matrices. Moreover, the findings demonstrated a positive correlation between trait anxiety and depressive symptoms, as well as a negative correlation between trait anxiety and Emotional Stability. Additionally, state anxiety was found to be positively correlated with depressive symptoms and negatively correlated with Energy and Open-mindedness. Discussion: Higher fluid abilities, with lower degree of depression state, less pronounced anxious trait, and more open-minded personality can potentially aid patients in managing the distress associated with pre- and post-transplantation, ultimately resulting in optimal adherence. Furthermore, the positive association observed between the attention and memory domains might suggest their significant involvement in predicting adherence trajectories. In line with literature highlighting the paramount role of psychological factors in recovering from organ transplant, this study paves the road for the potentiation of individual resources and weaknesses identification to reduce relapses and healthcare costs. However, small sample size and lack of causality direction of results prevent robust conclusions