key: cord-0865296-4i5hwml5
authors: Goyal, Abhishek; Kar, Avishek; Saxena, Khushboo
title: COVID Eyes: REM in COVID-19 Survivors
date: 2021-01-11
journal: Sleep Vigil
DOI: 10.1007/s41782-020-00124-2
sha: f87042f0b3a16fb5cbc8aa61c3092b7e2074f10a
doc_id: 865296
cord_uid: 4i5hwml5

Increased REM density and alpha intrusion are routinely seen in COVID-19 patient. These findings may correlate with unstable sleep pattern in COVID-19 survivors and therefore, sleep hygiene and proper counselling should be emphasized upon. Clinicians and technicians should be aware of these EEG changes with reference to COVID-19 survivors in interpreting polysomnography.

A 58-year-old male, known case of hypertension, diabetes mellitus was admitted with COVID-19 ARDS in ICU. Patient denied any history of depression or insomnia before contracting COVID-19 infection. After one month of discharge from ward, he underwent level I polysomnography ( Excessive REM density (characterised by increased REM movements) and increased REM amplitude (up to 300 μV) were seen (Fig. 1) .

REM density is usually defined by number of rapid eye movements per epoch of REM sleep. Average REM density seen in normal healthy subjects was 2.9-8.86 per minute in our lab (unpublished data). Increased REM density has been reported in patients with depression. Increased REM density has also been associated with poor prognosis in various psychiatric disorders like suicidality in schizophrenia, relapse in recovering alcoholics, and poor response to antidepressant in depression [1] . In this case, patient screened negative for insomnia (Insomnia Severity Index Score-6/28) and depression (Patient Health Questionnaire-4 for Anxiety and Depression score of 0/12) on the day of sleep study.

Alpha intrusion was seen in non-rapid eye movement (NREM) as well as REM stages in this patient. Alpha intrusion has been reported in psychiatric disorders like fibromyalgia, depression, chronic fatigue syndrome, anxiety disorder, and primary sleep disorders like psychophysiological insomnia, obstructive sleep apnea, circadian disorders and narcolepsy. REM alpha bursts (alpha activity lasting at least 3 s without an increase in EMG amplitude) may represent microarousals (Fig. 2) [2, 3] .

It would be too early to conclude that these changes are primarily due to viral infection. Effect of viral infection on human sleep has not been widely studied. However, few studies have noted that effect of viruses on REM stage is variable. Intranasal inoculation with influenza virus in mice has been shown to enhance NREM and decrease REM [4] . Sleep study in patients with HIV virus has shown normal REM density and reduced REM time [5, 6] . Patients of poliovirus develop obstructive sleep apnoea later in their lives due to involvement of upper airway muscles.

We are currently doing polysomnography in COVID-19 survivors (after 4 weeks of discharge) who were admitted in our hospital as part of research study. In our experience, increased REM density and REM alpha intrusion are routinely seen in COVID-19 patients. Whether these changes 

Conflict of interest no conflict of interest. 

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