Alzheimer's early detection in post-acute COVID-19 syndrome: a systematic review and expert consensus on preclinical assessments

Abstract

IntroductionThe risk of developing Alzheimer's disease (AD) in older adults increasingly is being discussed in the literature on Post-Acute COVID-19 Syndrome (PACS). Remote digital Assessments for Preclinical AD (RAPAs) are becoming more important in screening for early AD, and should always be available for PACS patients, especially for patients at risk of AD. This systematic review examines the potential for using RAPA to identify impairments in PACS patients, scrutinizes the supporting evidence, and describes the recommendations of experts regarding their use.MethodsWe conducted a thorough search using the PubMed and Embase databases. Systematic reviews (with or without meta-analysis), narrative reviews, and observational studies that assessed patients with PACS on specific RAPAs were included. The RAPAs that were identified looked for impairments in olfactory, eye-tracking, graphical, speech and language, central auditory, or spatial navigation abilities. The recommendations' final grades were determined by evaluating the strength of the evidence and by having a consensus discussion about the results of the Delphi rounds among an international Delphi consensus panel called IMPACT, sponsored by the French National Research Agency. The consensus panel included 11 international experts from France, Switzerland, and Canada.ResultsBased on the available evidence, olfaction is the most long-lasting impairment found in PACS patients. However, while olfaction is the most prevalent impairment, expert consensus statements recommend that AD olfactory screening should not be used on patients with a history of PACS at this point in time. Experts recommend that olfactory screenings can only be recommended once those under study have reported full recovery. This is particularly important for the deployment of the olfactory identification subdimension. The expert assessment that more long-term studies are needed after a period of full recovery, suggests that this consensus statement requires an update in a few years.ConclusionBased on available evidence, olfaction could be long-lasting in PACS patients. However, according to expert consensus statements, AD olfactory screening is not recommended for patients with a history of PACS until complete recovery has been confirmed in the literature, particularly for the identification sub-dimension. This consensus statement may require an update in a few years.

COVID-19 and Alzheimer’s Disease Share Common Neurological and Ophthalmological Manifestations: A Bidirectional Risk in the Post-Pandemic Future

“…Clinical follow-up studies with the intent of evaluating the extent and the duration of cognitive impairment in large cohorts of COVID-19 patients along with further experimental investigations on SARS-CoV-2-infected human brain organoids possibly recapitulating the phenotypic expression of key AD hallmarks are still needed. From a translational point of view, the concerted effort from clinicians, researchers, patients, caregivers and health and social care agencies, in association with a deep understanding of the biological aspects linking COVD-19 and AD physiopathologies, will help in designing specific diagnostic/therapeutic strategies [274,275], in order to mitigate the impact of long-lasting neurological and ophthalmological COVID-19 complications in the aging population.…”

A Decision-Making Algorithm for Remote Digital Assessments of Alzheimer’s Disease

“…Available RDA include digital tasks and games, voice recording, video and motor sensors, olfactory screenings, as well as hearing and vision screenings [2]. During the CO-VID-19 pandemic, RDA became increasingly used in daily clinical practice, and evidence rapidly accumulated on their feasibility, acceptability, and efficacy [3,4]. For instance, a recent review showed that digital cognitive biomarkers achieved comparable or even better diagnostic performance than traditional paper-and-pencil tests [5].…”