When Mrs. B was admitted to the hospital in March 2002, her doctors diagnosed limbic encephalitis, a brain infection that left her autobiographical memory in tatters. As a result, she can only recall around 2 percent of events that happened the previous week, and she often forgets who people are. But a simple device called SenseCam, a small digital camera developed by Microsoft Research, in Cambridge, U.K., dramatically improved her memory: she could recall 80 percent of events six weeks after they happened, according to the results of a recent study.

"Not only does SenseCam allow people to recall memories while they are looking at the images, which in itself is wonderful, but after an initial period of consolidation, it appears to lead to long-term retention of memories over many months, without the need to view the images repeatedly," says Emma Berry, a neuropsychologist who works as a consultant to Microsoft.

SenseCam is worn around the neck and automatically takes a wide-angle, low-resolution photograph every 30 seconds. It contains an accelerometer to stabilize the image and reduce blurriness, and it can be configured to take pictures in response to changes in movement, temperature, or lighting. "Because it has a wide-angle lens, you don't have to point it at anything--it just happens to capture pretty much everything that the wearer can see," says Steve Hodges, the manager of the Sensor and Devices Group at Microsoft Research, U.K.

An entire day's events can be captured digitally on a memory card and downloaded onto a PC for subsequent viewing. Using specially designed software, the Microsoft researchers can convert the pictures into a short movie that displays the images at up to 10 frames per second, allowing a day's events to be viewed in a few minutes.

SenseCam was originally developed as a memory aid for healthy people, but it is now in clinical testing for those with memory impairment, such as dementia. Narinder Kapur, head of the Neuropsychology Department at Addenbrooke's Hospital, Cambridge, U.K., and leader of the eight-patient study, recently published an initial case report of one patient in the journal Neuropsychological Rehabilitation. Kapur and his colleagues found that Mrs. B could remember most nontrivial events after she had spent around one hour reviewing the SenseCam images with her husband every two days for a two-week period.

The device might help patients with mild forms of Alzheimer's disease, says Giovanni Frisoni, a neurologist at a clinical research institute in Brescia, Italy, who is not involved in the research. He is skeptical, however, about whether SenseCam could be used by patients with Alzheimer's disease without assistance from their caregivers. Still, "it might have a beneficial effect on soothing the patients' anxiety," he says. "All Alzheimer's patients have a deep anguish due to their perceived, although usually not confessed, inability to remember their recent past. Being able to go through the recent events may have a reassuring effect. Reassurance is what Alzheimer's patients want but, unfortunately, [is] what they are often denied."