Case study results show patient has brain connectivity similar to healthy individuals, pointing to positive prognosis possibilities.
The neurological outcomes for COVID-19 patients who are unresponsive might not be as bleak as previously thought.
According to a case study, published by investigators at Massachusetts General Hospital (MGH) last week in the Annals of Neurology, it is possible these patients have a better shot at functional recovery than standard imaging alone would indicate.
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By using resting-state functional magnetic resonance imaging (rs-fMRI), the team, led by Brian Edlow, M.D., director of the Laboratory for NeuroImaging of Coma and Consciousness and associate director of the Center for Neurotechnology and Neurorecovery at MGH, discovered that an unconscious COVID-19-positive patient had “robust functional connectivity” in the default mode network (DMN), a brain network that is believed to be involved in human consciousness.
"Because there are so many unanswered questions about the potential for recovery in unresponsive patients who have survived severe COVID-19, any available data that could inform prognosis are critical," Edlow said. "Our unexpected observations do not prove that functional MRI predicts outcomes in these patients, but they suggest that clinicians should consider the possibility that unresponsive survivors of severe COVID-19 may have intact brain networks. We should, thus, exercise caution before presuming a poor neurologic outcome based on our conventional tests."
Having a greater understanding -- and being able to provide some neurological context around possible prognosis -- could be helpful for patients' families as they are trying to make healthcare decisions for a loved one, added lead author David Fischer, M.D., neurocritical care fellow at MGH.
The Case Study
The patient, a 47-year-old man with hypertension and asthma, presented to the hospital with fever and shortness of breath. He was placed on a ventilator, and for roughly 60 days, he floated in and out of a coma and a minimally conscious state. On the 40th day of his hospitalization, he underwent both 3T structural and functional MRI scans.
The structural scan revealed substantial damage that is often associated with hypoxic-ischemic brain injury – symmetric T2 hyperintensity of the bilateral basal ganglia, medial thalami, and parahippocampal gyri, and diffusion restriction of the basal ganglia. However, the rs-fMRI revealed a different picture. It showed his DMN connectivity was comparable to healthy patients, pointing to his potential for recovery, the team said.
Those positive outcomes began to emerge 20 days later, the team reported, as the patient began to follow commands, such as blinking his eyes and opening his mouth upon instruction, intermittently over a week timespan. By day 66, he could follow four out of four vocalization commands and could successfully complete gaze tracking to visual and auditory stimuli.
Ultimately, the team said, these results indicate that further investigation is needed into how the virus impacts unresponsive patients.
“The long-term outcomes for patients with disorders of consciousness following severe COVID-19…are unknown,” the team said. “Longitudinal cohort studies in this population will be crucial for understanding their disease course and developing prognostic biomarkers. Therefore, any available data that may inform prognosis in this novel disease are critical.”