A study published in the European Archives of Psychiatry and Clinical Neuroscience showed that patients with the most severe post-COVID smell and taste disorders were likely to perform worst in cognitive tests, especially when the test involved memory.

According to the study, the most common sensory complication was a moderate or severe reduction in sense of taste (20%), followed by a moderate or severe olfactory deficit (18%), a moderate or severe deficit of both smell and taste (11%), and parosmia or distortion of olfactory perception (9%).

Dr. Rodolfo Damiano, a doctoral candidate from the University of Sao Paulo′s Medical School (FM-USP) in Brazil, stated that they did not find any psychiatric symptoms (such as anxiety or depression) to be associated with loss of smell and taste, but they observed that attention and episodic memory were more impaired in patients with more chemosensory alterations. The research team added that COVID-related loss of smell derives from the inflammation triggered by SARS-CoV-2 in the olfactory mucosa. Dr. Orestes Forlenza, Professor in FM-USP′s Psychiatry Department, explained that the cognitive losses observed in Alzheimer′s and post-Covid syndromes derive from different pathogenic processes, but these may overlap, particularly in the case of older people who already have primary cognitive symptoms and have contracted Covid. 

(Source: https://www.daijiworld.com/news/newsDisplay?newsID=990648 )