The mental disruption that comes with being hospitalized can cause temporary memory loss for up to a month for seniors who are sick, according to new research.

This is imperative for caregivers to realize, said investigators at Northwestern University’s Feinberg School of Medicine. Hospital-induced memory loss could affect how they remember discharge instructions and other critical information, they note.

The researchers studied 200 seniors over the age of 70 who had not been diagnosed with dementia or cognition problems prior to being admitted to the hospital and participating in the study. Upon their date of discharge, investigators administered cognition tests to evaluate the patients’ mental status. One-third of participants displayed scores that “were not previously recognized” and on the lower end. One month later scores had improved.

“When the senior is no longer sick enough to be in the hospital, it doesn’t mean they’re 100 percent ready to be on their own,” said researcher Lee Lindquist, M.D. “It’s a critical time and they need extra support and understanding from healthcare professionals and family.”

The study was published online in the Journal of Internal Medicine.