A U.S. project is using in-home monitoring devices to observe subtle behaviour changes in elderly participants, hoping to find clues to early diagnosis of the degenerative brain disease

"Big brother is watching" -- but this time it's a good thing.

In George Orwell's fictional dystopian world of 1984, that phrase took on sinister overtones. But in 2007 Oregon, a real-life "big brother" with modern spy technology is watching in a much more benevolent manner.

In a $7-million (U.S.) federally funded project, Oregon Health and Science University is placing monitoring devices such as motion sensors attached to walls and doorways in the homes of 300 octogenarians to track their movements and daily activities in hopes of spotting subtle behaviour changes that may signal impending Alzheimer disease.

"Now, it takes years to determine if someone's developing dementia," says Dr. Jeffrey Kaye of the Oregon university.

During routine check-ups, even doctors may miss signs. "If you only assess patients every once-in-a-blue-moon, you really are at a loss to know what they are like on a typical day," Kaye says. But monitoring how they fare at home, on bad days as well as good ones and not just when they're on their best behaviour at the doctor's office, may spot changes that provide clues that someone is at risk.

Early predictors may be as simple as variations in the speed of walking down a hallway, or getting slower at dressing or typing.

The theory is that as Alzheimer's begins destroying brain cells, the signals to the nerves may become inconsistent. One day the signals to walk fire fine but the next those signals are fuzzy and people hesitate, creating wildly varying activity patterns.

The project is based on a pilot study, tracking 14 participants in their upper 80s for almost a year, that showed that half had mild cognitive impairment, a precursor of Alzheimer's. Impaired participants showed a much greater variation in daily activities such as walking speed, especially in the afternoons.

Also under study are in-home interactive kiosks that administer monthly memory and cognition tests, computer keyboards bugged to track typing speed, and pill boxes that record when seniors forget to take, or are late taking, their medications.