A recent study conducted by scientists at the Johns Hopkins Bloomberg School of Public Health suggests that a wrist-worn device could potentially aid in the early detection of Alzheimer's disease, allowing for prompt intervention and support. With around six million adults affected by Alzheimer's in the United States alone, accurate diagnosis plays a crucial role in providing appropriate treatment and care.

Actigraphs, watch-like devices that monitor daily activity patterns, were utilized in the study to analyze the movements of 82 cognitively healthy older adults. Each participant, with an average age of 76, wore the device continuously for a week and underwent a PET scan. The scan revealed that 25 individuals exhibited a buildup of the protein amyloid beta in their brains, a known indicator of Alzheimer's disease.

Findings from the analysis of activity patterns highlighted significant differences between those with amyloid buildup and those without. Notably, adults with amyloid-positive results tended to be more active in the afternoon compared to their amyloid-negative counterparts. These results lend support to a previous study, suggesting that actigraphs could be an effective tool for detecting early signs of Alzheimer's before significant cognitive decline occurs.

The researchers propose that these watch-like devices could potentially be worn by individuals to monitor their sleep and wake activity. Abnormal patterns could then prompt individuals to seek consultation with their doctors for comprehensive Alzheimer's screening. However, the findings need to be replicated in larger studies to further validate their effectiveness.

Adam Spira, a study author and professor in the department of Mental Health at the Bloomberg School, emphasized the need for further research, stating, "We need to replicate these findings in larger studies, but it is interesting that we've now seen a similar difference between amyloid-positive and amyloid-negative older adults in two independent studies."

The reasons behind the specific activity patterns observed in individuals with amyloid buildup are not yet understood. However, the phenomenon of "sundowning," where agitation increases in the afternoon and early evening, is well-documented among individuals with Alzheimer's. This could be attributed to poor sleep, as abnormal sleep patterns are considered potential early indicators of the disease. It is possible that Alzheimer's-related brain changes affect a person's circadian rhythm, altering their sleep-wake cycle. Additionally, sleep loss may contribute to the buildup of amyloid plaques, creating a vicious cycle.

Spira suggested that the higher afternoon activity observed in the study could be a signal of "preclinical sundowning." Nevertheless, it's important to note that the findings represent averages among a small sample of older individuals over a short period of time. Thus, individuals who exhibit high activity in the afternoon should not be alarmed, as it is not possible to predict the development of amyloid plaques solely based on activity timing.

While further research is needed to fully comprehend the development of Alzheimer's disease, studies indicate that amyloid plaques and tangles begin accumulating in the brain one to two decades before diagnosis. Early intervention and treatments have been found to be more effective in slowing the progression of the disease.

The potential of the wrist-worn actigraph devices in detecting the early warning signs of Alzheimer's presents a promising avenue for advancing disease management and providing timely support to individuals affected by this debilitating condition.