The social isolation and reduction in physical activity caused by COVID-19 lockdowns appear to have negatively impacted brain metabolism, according to new neuroimaging research from France. The study has been published in the scientific journal Human Brain Mapping.
“I’m a physician, specializing in molecular neuroimaging, with a strong interest in neurological and psychiatric diseases without obvious brain morphological/structural lesions, and my research team and I have been investigating therapeutic interventions that could modulate these brain dysfunctions. In this line of research, we are looking at the impact of physical activity on neuroprotection and brain plasticity,” said study author Eric Guedj, a professor of biophysics and nuclear medicine at Timone Hospital and Aix-Marseille University.
“With the lockdown, it was interesting to investigate whether sedentary lifestyle along with social isolation may have a negative impact on brain functioning. Moreover, we are currently working on the brain substrate of long COVID, and some colleagues link the condition to the psychological/physiological effects of lockdown. If we consider that the lockdown has protected people from the outbreak spread, it has also been associated with obvious psychological and physical side-effects. The issue was to specify if long COVID is also a consequence of these functional impairments due to societal measures or more directly a consequence of the virus itself.”
“On this second hypothesis, we could consider that the lockdown has prevented infections, and thus long COVID in many patients,” Guedj explained. “The point is also particularly complex because many patients with long COVID have post-exertional malaise. It was thus important to clearly distinguish the brain profile of patients with physical deconditioning (linked to the lockdown) from those of long COVID.”
The researchers compared position emission tomography (PET) brain scans from adult patients before, during, and after the COVID-19 lockdown in France. The sample included 212 patients who underwent brain scans between March 17 and May 11, 2019, 95 patients who underwent brain scans between March 17 and May 11, 2020, and 188 patients underwent brain scans after May 11, 2020.
Compared to patients who received brain scans before the lockdown, patients who received brain scans during the lockdown tended to exhibit reduced metabolism in the left precentral gyrus, sensorimotor network, and left amygdala. The researchers also observed reduced metabolism in the left primary motor cortex during lockdown. Metabolism in the left primary motor cortex was heightened during the post-lockdown deconfinement period, but still reduced compared to the pre-lockdown period in 2019.
In contrast, Guedj and his colleagues have found that long COVID is associated with metabolic abnormalities in olfactory regions, the right temporal lobe, the brainstem, and cerebellum.
“Lockdown is associated with functional impairment of brain motor and emotion networks, with a major impact on younger adults (probably because it was a break from a previous mode of functioning), and only partial reversibility during the deconfinement,” Guedj told PsyPost. “We estimate that deconfinement has to be twice as long as confinement to regain the level of previous brain functioning. This profile of brain dysfunction is distinct from those reported in long COVID, even if the two conditions can be associated in some patients.”
The researchers examined brain imaging data that had been acquired in clinical settings from patients experiencing conditions such as cognitive impairment, glioma, and epilepsy.
“The study has been performed in patients with neurological diseases, so theoretically we cannot directly extend these results to healthy subjects,” Guedj explained. “The study is by definition retrospective, but it will difficult to ethically reproduce this design, prospectively, in healthy subjects with an unjustified lockdown of two months.”
The study, “The impact of COVID-19 lockdown on brain metabolism“, was authored by Eric Guedj, Jacques-Yves Campion, Tatiana Horowitz, Fanny Barthelemy, Serge Cammilleri, and Mathieu Ceccaldi.
