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Neurodegenerative diseases are characterised by neuronal loss and abnormal deposition of pathological proteins in the nervous system. Among the most common neurodegenerative diseases are Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease and transmissible spongiform encephalopathies (TSEs). Sleep and circadian rhythm disturbances are one of the most common symptoms in patients with neurodegenerative diseases. Currently, one of the main objectives in the study of TSEs is to try to establish an early diagnosis, as clinical signs do not appear until the damage to the central nervous system is very advanced, which prevents any therapeutic approach. In this paper, we provide the first description of sleep disturbance caused by classical scrapie in clinical and preclinical sheep using polysomnography compared to healthy controls. Fifteen sheep classified into three groups, clinical, preclinical and negative control, were analysed. The results show a decrease in total sleep time as the disease progresses, with significant changes between control, clinical and pre-clinical animals. The results also show an increase in sleep fragmentation in clinical animals compared to preclinical and control animals. In addition, sheep with clinical scrapie show a total loss of Rapid Eye Movement sleep (REM) and alterations in Non Rapid Eyes Movement sleep (NREM) compared to control sheep, demonstrating more shallow sleep. Although further research is needed, these results suggest that prion diseases also produce sleep disturbances in animals and that polysomnography could be a diagnostic tool of interest in clinical and preclinical cases of prion diseases.

Guillain-Barré syndrome (GBS) is a well-established complication of infectious disease. So it is not surprising that several cases have been described during the actual SARS-CoV-2 infection pandemic. Most of the descriptions are patients suffering a severe GBS in the setting of a severe SARS-CoV-2 infection. We described five patients with mild forms of COVID-19. After 2-4 weeks, these patients develop mild neurological symptoms. The clinical and neurophysiological studies supported a diagnosis of an acute polyneuropathy. Symptoms resolved without specific treatment and primary care physicians managed all patients outpatiently. Mild SARS-CoV-2 infection could associate mild neurological complications too. So patients complaining about mild neurological symptoms, a SARS-CoV-2 infection may be excluded., Supplementary Information: The online version contains supplementary material available at 10.1007/s42399-021-00855-x., Competing Interests: Conflict of InterestThe authors declare no competing interests., (© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2021.)