This supplementary appendix provides additional information about the study "Prospective memory assessment before and after Covid-19" published in the New England Journal of Medicine. The study aimed to assess prospective memory (the ability to remember to perform a task at a future time) before and after SARS-CoV-2 infection. The study was conducted as a population-based, open cohort study in Norway, involving participants aged 18-96 years. Participants were recruited through social media and nationwide media coverage, and completed a baseline questionnaire and five follow-ups. The study included the Everyday Memory Questionnaire (EMQ), a 13-item questionnaire used to assess prospective memory. The EMQ scores were analyzed using a linear mixed effects model, which accounts for the correlation between measurements from the same participant. The study found that SARS-CoV-2 infection was associated with a decline in prospective memory, with the effect being more pronounced in those who had more severe symptoms. The study also found that the effect of SARS-CoV-2 infection on prospective memory was more pronounced in those who had been bedridden for longer periods. The study had several limitations, including a lower response rate for the second EMQ questionnaire and potential self-report bias. The study also included sensitivity analyses to account for missing data and to ensure the validity of the results. The results of the study suggest that SARS-CoV-2 infection may have a lasting impact on prospective memory, and further research is needed to understand the mechanisms behind this effect.This supplementary appendix provides additional information about the study "Prospective memory assessment before and after Covid-19" published in the New England Journal of Medicine. The study aimed to assess prospective memory (the ability to remember to perform a task at a future time) before and after SARS-CoV-2 infection. The study was conducted as a population-based, open cohort study in Norway, involving participants aged 18-96 years. Participants were recruited through social media and nationwide media coverage, and completed a baseline questionnaire and five follow-ups. The study included the Everyday Memory Questionnaire (EMQ), a 13-item questionnaire used to assess prospective memory. The EMQ scores were analyzed using a linear mixed effects model, which accounts for the correlation between measurements from the same participant. The study found that SARS-CoV-2 infection was associated with a decline in prospective memory, with the effect being more pronounced in those who had more severe symptoms. The study also found that the effect of SARS-CoV-2 infection on prospective memory was more pronounced in those who had been bedridden for longer periods. The study had several limitations, including a lower response rate for the second EMQ questionnaire and potential self-report bias. The study also included sensitivity analyses to account for missing data and to ensure the validity of the results. The results of the study suggest that SARS-CoV-2 infection may have a lasting impact on prospective memory, and further research is needed to understand the mechanisms behind this effect.