Memory loss due to Alzheimer's disease is distressing both for the person with the condition and for those close around them.
Kelly Gunderson is just one of many who has to cope with the pain of seeing a family member suffer from dementia. Yet she filmed the amazing moment her 87-year-old mother with Alzheimer's briefly recognised her daughter.
Gunderson captured a conversation with her mother in a hospital bed.
Gunderson's mother at first appears to not know she is lying next to her daughter. So Gunderson asks, "Do you think I would just lay here with just anybody?"
Her mother replies: "No. I think you want to have to love them if they want to."
Gunderson then asks whether her mother knows who she is and she says she does and that her daughter's name is Kelly.
The look of shock and surprise on Gunderson's face says it all. She is overjoyed that her mother has remembered her, even if it is just for a brief moment.
"Well I love Kelly. And I didn't I name you Kelly? Well I love you Kelly," her mother says.
"A while ago you didn't know who I was," Kelly responds. On her YouTube page, Gunderson wrote: "My 87 year old mother with Alzheimer's knew who I was, even if just for a moment."
Alzheimer's disease is the most common form of dementia, a set of symptoms that include memory loss and difficulties with thinking, problem-solving and language.
As the video draws to a close with Gunderson revelling in her mother's brief remembrance of who her daughter is, the mother simply cries, "Oh, isn't it wonderful?"