Association between chemosensory impairment with neuropsychiatric morbidity in post-acute COVID-19 syndrome: results from a multidisciplinary cohort study

Abstract

Preliminary methodologically limited studies suggested that taste and smell known as chemosensory impairments and neuropsychiatric symptoms are associated in post-COVID-19. The objective of this study is to evaluate whether chemosensory dysfunction and neuropsychiatric impairments in a well-characterized post-COVID-19 sample. This is a cohort study assessing adult patients hospitalized due to moderate or severe forms of COVID-19 between March and August 2020. Baseline information includes several clinical and hospitalization data. Further evaluations were made using several different reliable instruments designed to assess taste and smell functions, parosmia, and neuropsychiatric disorders (using standardized psychiatric and cognitive measures). Out of 1800 eligible individuals, 701 volunteers were assessed on this study. After multivariate analysis, patients reporting parosmia had a worse perception of memory performance ( p < 0.001). Moderate/severe hypogeusia was significantly associated with a worse performance on the word list memory task ( p = 0.012); Concomitant moderate/severe olfactory and gustatory loss during the acute phase of COVID-19 was also significantly associated with episodic memory impairment ( p = 0.006). We found a positive association between reported chemosensory (taste and olfaction) abnormalities and cognition dysfunction in post-COVID-19 patients. These findings may help us identify potential mechanisms linking these two neurobiological functions, and also support the speculation on a possible route through which SARS-CoV-2 may reach the central nervous system. Supplementary Information The online version contains supplementary material available at 10.1007/s00406-022-01427-3.

Anosmia in COVID-19 could be associated with long-term deficits in the consolidation of procedural and verbal declarative memories

“…Studies assessing olfactory function in long-COVID have found that reported mental clouding was associated with more severe olfactory loss (Di Stadio et al, 2022). In addition, as in our study, olfactory loss was associated with cognitive impairment objectively assessed with neuropsychological tests of declarative memory (Damiano et al, 2022;Delgado-Alonso et al, 2022;Fiorentino et al, 2022).…”

“…However, this memory might be supported by other brain regions of the limbic system over time. Anosmia as a symptom in the long-COVID syndrome is frequently associated with the limbic system, both functionally (Damiano et al, 2022;Delgado-Alonso et al, 2022;Kay, 2022;Voruz et al, 2022;Yus et al, 2022) and structurally (Douaud et al, 2022;Morbelli et al, 2022). Therefore, a specific alteration of consolidation of procedural memory in long-COVID patients suffering from olfactory dysfunction is plausible.…”

“…Olfactory bulb dysfunction may extend to connected and proximal regions of the limbic systems that support memory (Kay, 2022). Studies that analyze the associations between symptoms and memory performance have found that olfactory dysfunction in long-COVID patients is frequently related to lower scores in tests assessing declarative memory (Damiano et al, 2022;Delgado-Alonso et al, 2022).…”

Association between olfactory dysfunction and mood disturbances with objective and subjective cognitive deficits in long-COVID

“…In this way, declarative verbal memory, a memory system mainly supported by the medial temporal lobe including the hippocampus and other limbic system structures ( Catani et al, 2013 ), could be more impaired in long-COVID patients than other memory systems non-related to the limbic system function, such as procedural memory ( Llana et al, 2022a ). Olfactory dysfunction was associated not only with subjective memory complaints but also with objective verbal ( Damiano et al, 2022 ) and episodic ( Delgado-Alonso et al, 2022 ) memory performance, as well as with executive dysfunction and anxiety, but not depression ( Delgado-Alonso et al, 2022 ). Specifically, the study of Cecchetti et al (2022) found an association between dysgeusia and hyposmia during acute COVID-19 and increased vulneravility in declarative memory over time.…”

Neurological Consequences, Mental Health, Physical Care, and Appropriate Nutrition in Long-COVID-19

“…Furlan Damiano and Collaborators found a positive correlation between chemosensory problems (hypogeusia and parosmia) and cognitive dysfunction performing a neurobiological study on a statistical sample composed by 700 hospitalized mild-to-severe COVID-19 patients. The latter authors hypothesized that upon reaching the CNS, SARS-CoV-2 induces molecular and cellular cascade processes similar to those occurring in neurodegenerative diseases (Furlan Damiano et al 2022 ).…”