A new study sheds light on a powerful tool that may detect signs of Alzheimer’s disease before patients show any symptoms of cognitive decline: the home computer.
An early online version of this paper detailing the findings has been published and is scheduled for publication in the Journal of Alzheimer’s Disease (volume 52, issue 2).
OHSU researchers have found a significant correlation between infrequent daily computer use and brain imaging signs commonly seen in early-stage Alzheimer’s patients.
Using an MRI scan, the researchers measured the volume of the hippocampus - a brain region integral to memory function - in adults aged 65 years and older who were cognitively intact and dementia-free.
Diminished hippocampal volume is a well-known sign, or biomarker, of Alzheimer’s disease and the eventual development of dementia.
In Alzheimer’s disease, there is an overall shrinkage of brain tissue. The grooves or furrows in the brain, called sulci (plural of sulcus), are noticeably widened and there is shrinkage of the gyri (plural of gyrus), the well-developed folds of the brain’s outer layer. In addition, the ventricles, or chambers within the brain that contain cerebrospinal fluid, are noticeably enlarged. In the early stages of Alzheimer’s disease, short-term memory begins to fade (see box labeled ‘memory’) when the cells in the hippocampus, which is part of the limbic system, degenerate.
The ability to perform routine tasks also declines. As Alzheimer’s disease spreads through the cerebral cortex (the outer layer of the brain), judgment declines, emotional outbursts may occur and language is impaired. As the disease progresses, more nerve cells die, leading to changes in behavior, such as wandering and agitation. In the final stages of the disease, people may lose the ability to recognize faces and communicate; they normally cannot control bodily functions and require constant care. On average, the disease lasts for 8 to 10 years, but individuals with Alzheimer’s can live for up to 20 years.
The study, led by Lisa Silbert, M.D., with the OHSU Layton Center for Aging & Alzheimer’s Disease, found that an additional hour of computer use a day was associated with a .025 percent larger hippocampal volume. A smaller hippocampal volume is an indicator of increased risk for developing Alzheimer’s disease. The researchers will continue to follow these participants to see if their smaller hippocampal volume and decreased computer use predict future cognitive decline.
Silbert and colleagues hypothesize that the reason that patients with smaller hippocampal volumes may spend less time using their home computer is it requires the use of multiple cognitive domains, including executive function, attention and memory.
Hippocampal volumes and memory performance
Although there is currently no effective treatment for the disease, there is increasing interest in identifying the disease at its earliest stages, as early intervention may be most effective in combatting it.
Given their increased risk of developing dementia, individuals with MCI have been studied extensively and can shed light on processes that may occur prior to disease onset.
Identification of assessment techniques for use in clinical trials of Alzheimer’s therapies is, therefore, essential. Use of disease markers, such as hippocampal volumes and memory performance, is also useful in diagnosis and treatment planning.
Mild Cognitive Impairment (MCI) represents a pre-dementia state, in which an individual shows changes in memory or other thinking skills but continues to function fairly normally in daily life. Given their increased risk of developing dementia, individuals with MCI have been studied extensively and can shed light on processes that may occur prior to disease onset.
In our study, we examined the relationship between the size of the hippocampus and measures of both verbal memory (such as learning and recalling a list of words) and non-verbal memory (such as learning and recalling geometric shapes) in a large sample of patients in our memory clinic, including a group of individuals diagnosed with MCI. Our goal was to determine whether the memory measures were closely related to the size of the hippocampus.
The researchers have been following a group of volunteers in Portland for nine years through a suite of embedded technology in their homes. These tools allow the researchers to assess their mobility, sleep, socialization, computer use and medication intake. The purpose of this monitoring is to identify meaningful changes in everyday life that don’t involve the participants taking tests or going to doctor appointments.