Multimodal approaches supporting the diagnosis, prognosis and investigation of neural correlates of disorders of consciousness: A systematic review.

The limits of the standard, behaviour-based clinical assessment of patients with disorders of consciousness (DoC) prompted the employment of functional neuroimaging, neurometabolic, neurophysiological and neurostimulation techniques, to detect brain-based covert markers of awareness. However, uni-modal approaches, consisting in employing just one of those techniques, are usually not sufficient to provide an exhaustive exploration of the neural underpinnings of residual awareness. This systematic review aimed at collecting the evidence from studies employing a multimodal approach, that is, combining more instruments to complement DoC diagnosis, prognosis and better investigating their neural correlates. Following the PRISMA guidelines, records from PubMed, EMBASE and Scopus were screened to select peer-review original articles in which a multi-modal approach was used for the assessment of adult patients with a diagnosis of DoC. Ninety-two observational studies and 32 case reports or case series met the inclusion criteria. Results highlighted a diagnostic and prognostic advantage of multi-modal approaches that involve electroencephalography-based (EEG-based) measurements together with neuroimaging or neurometabolic data or with neurostimulation. Multimodal assessment deepened the knowledge on the neural networks underlying consciousness, by showing correlations between the integrity of the default mode network and the different clinical diagnosis of DoC. However, except for studies using transcranial magnetic stimulation combined with electroencephalography, the integration of more than one technique in most of the cases occurs without an a priori-designed multi-modal diagnostic approach. Our review supports the feasibility and underlines the advantages of a multimodal approach for the diagnosis, prognosis and for the investigation of neural correlates of DoCs.

Neurological complications of SARS-CoV-2 infection among solid organ transplanted patients: does immunosuppression matter?

Introduction: SARS-CoV-2 infection can lead to a broad range of neurological manifestations such as olfactory and gustative disorders, myalgias, headache, and fatigue but also more rare and severe neurological pictures such seizures, encephalitis, and cerebrovascular diseases. It is still unknown if the underlying pathophysiological mechanism is the direct cytotoxic effect of the virus on central nervous system or if the related systemic inflammation leads to cerebral suffering and neurological symptoms. Studying neurological manifestations of SARS-CoV-2 infection among solid organ transplant recipients, who take immunosuppressive drugs, may help to shed light on this topic. Methods: We enrolled a total of 73 solid organ transplantation recipients (kidney, liver, lung, heart and combined) with a history of SARS-CoV-2 infection (in the period between July 2020 and June 2021). We collected all demographic and clinical general information and, through phone interviews, we registered retrospectively the occurrence of neurological symptoms during the acute phase of infection and within the next 6 months. Results: Approximately 27.4% (20/73) of patients needed hospitalization during the infection, 25.3% (18/73) were treated with oxygen therapy, and only one patient was admitted to the Intensive Care Unit for mechanical ventilation. Almost 74% (54/73) of patients reported at least one neurological symptom/disease. The most frequent neurological complications were myalgia (57.5%), headache (37%), and hyposmia/hypogeusia (37%). Need of oxygen therapy during the SARS-CoV-2 infection was statistically significantly associated to neurological complications (p= 0.0344). Pre-infection neurological comorbidities and immunosuppression levels (higher levels of tacrolimus and also being on steroids) did not modify the probability to have neurological manifestations. Discussion: Frequency of headache was comparable with the same self-reported symptom in the general population, while hyposmia/hypogeusia was more frequent in our cohort of transplant recipients. Higher level of tacrolimus as well as being on steroids did not result protective against neurological manifestation. Lastly neurological symptoms occurred more frequent in more severe cases of infection.