Getting lost may be earliest sign of Alzheimer's disease

It is hoped that spotting the earliest signs of dementia could help to limit progression of the neurological disease and could even prevent some of the more devastating symptoms. However, a significant problem in dementia care is that many people don't experience problems until they have issues with their memory, which usually means damage has already been done to the brain.

A new study could provide valuable insight into how to identify the earliest signs of the condition, potentially offering a better prognosis for future sufferers.

The research, conducted by a team at Washington University, St Louis, found that getting lost may be one of the earliest signs of Alzheimer's disease.

Published in the Journal of Alzheimer's Disease, the study revealed that having trouble building cognitive maps of new surroundings could lead to the eventual onset of the disorder.

Denise Head, senior author of the study and associate professor of psychological and brain sciences in Arts & Sciences at Washington University, said the findings suggest that navigational tasks to assess cognitive mapping strategy could be a powerful new tool for spotting the earliest signs of Alzheimer's disease-related changes.

Previous research has suggested that problems with navigation problems are related to the early stages of Alzheimer's disease and it is thought that this may be the result of amyloid plaques build up, which affects the brain's memory and long-term recognition.

However, the new study suggests a way that this preclinical damage could be measured and assessed. It is also some of the first to look at healthy patients who may be at a high risk of developing the disorder, instead of analysing people who have already been diagnosed with the condition.

The hippocampus, which is linked with long-term memory, recognising new places and creating cognitive maps, is often damaged in the early signs of Alzheimer's disease.

In this study, researchers used a virtual maze navigation experiment to see whether specific problems with route learning and cognitive map building, which involve the hippocampus, could be found in preclinical Alzheimer's.

All 72 participants were divided into three groups based on their test results of brain and spinal fluids, which detect biomarkers that can predict future development of Alzheimer's-related brain damage.

Those who were otherwise healthy but had these markers were considered to have preclinical Alzheimer's disease. Overall, the study involved 42 clinically normal individuals who didn't have the markers, 13 clinically normal individuals who were positive for these markers and were diagnosed with preclinical Alzheimer's, and 16 individuals with documented behavioural symptoms of early-stage Alzheimer's.

They were all tested on how well they could learn and follow a pre-set route, and how well they could create and use a cognitive map of the environment. All participants were given 20 minutes to either learn a specified route, or to study and explore the maze. They were then tested on their ability to recreate it.

According to the study, those with the markers of preclinical Alzheimer's recorded lower scores on their ability to learn the locations of objects in the environment. However, they eventually managed to overcome these problems, performing almost as well as cognitively normal participants during further navigation tasks.

Professor Head said: "While they may require additional training to learn new environments, the good news here is that they seem to retain sufficient information to use a cognitive map almost as well as their cognitively normal counterparts."

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