Poor Sense Of Direction? It Could Be Alzheimer’s…

We’ve told you before how a waning sense of direction could be one of the earliest indicators of Alzheimer’s disease. It’s true. While memory problems are the best-known symptom of Alzheimer’s disease, there are many others. One of the earliest to appear can be difficulties with navigation, where someone can get lost in their own neighborhood or when driving a familiar route.

Picking up early, subtle signs of navigation problems during a routine checkup would be a major diagnostic advance in detecting and treating early Alzheimer’s disease. Thanks to neuroscientists in the United Kingdom, this may not be far away.

Navigational problems are a common early sign of Alzheimer's disease seen in 40 percent to 54 percent of patients. Sufferers can get lost in familiar surroundings and become disorientated when out of well-known territory.

Failure to Identify Familiar Landmarks

As researchers from Taiwan wrote in 2012, Alzheimer’s patients “are prone to make incorrect turns while driving, failing to identify familiar landmarks or scenes, or failing to access their stored allocentric spatial memory,” the type of memory that relies on recalling and recognizing landmarks.

The researchers developed a questionnaire to evaluate the likelihood of patients with mild to moderate Alzheimer’s disease getting lost. This tool is feasible, valid, and reliable, however, the tool has its limitations and is only used when patients have already received a diagnosis of Alzheimer’s. This doesn’t help folks who have not yet been diagnosed or who may be at risk. What’s more urgently needed is a robust tool that can identify spatial navigation problems in the very earliest stages of the disease, before symptoms appear, so doctors can recommend appropriate action to delay or even prevent the condition.

And that’s just what neuroscientists at University College London have come up with. They started with the most common navigational error seen in early Alzheimer’s disease.

At Risk Patients Overestimate Turns

The London team developed a process using a virtual reality headset combined with a computational model to explore in detail the navigational errors Alzheimer’s patients make when walking.

To put it through its paces, they enrolled 110 adults, 31 of whom were young and healthy, 36 were older and cognitively healthy, and 43 were diagnosed with mild cognitive impairment (MCI). Those with MCI had their cerebrospinal fluid (CSF) tapped to look for biomarkers suggesting that Alzheimer’s is likely to develop. Eleven volunteers tested positive for these biomarkers.

In the next part of the study, participants had to put on the virtual reality headsets and complete a task that involved walking along a guided route with two straight lines connected by a turn and then return to their starting position using their memory alone. They repeated this pattern several times with different backgrounds and landmarks to test their navigational skills.

The findings, published in the journal Current Biology in October, showed those with both MCI and the biomarkers consistently overestimated the turns on the route. For instance, they thought they had turned 160 degrees when they had only completed 100 degrees. They also showed increased variability in their sense of direction. Neither problem was seen in cognitively healthy older participants or those with MCI without Alzheimer’s biomarkers.

Of course, the model needs testing on a much larger cohort but based on this trial it was a tremendous success because it was able to detect navigational errors specific to Alzheimer’s disease, not errors arising from normal aging or general cognitive decline.

Practical Tests in The Making

Joint first author, Dr. Andrea Castegnaro explained, saying, “Our findings offer a new avenue for the early diagnosis of Alzheimer’s disease by focusing on specific navigational errors.

“We aim to develop practical tests that can be easily integrated into clinical settings. We are designing these tests to be both quick and comprehensive, aiming to collect sufficient data for a reliable diagnosis in a time-efficient manner, thereby increasing the likelihood of their widespread adoption.

“Cognitive assessments are still needed to understand when the first cognitive impairments develop, and when it comes to existing spatial memory tests used in clinics, those often rely on verbal competence. Our tests aim to offer a more practical tool that doesn't rely on language or cultural background.”

Our Takeaway

The science shows that memory loss makes it hard to drive safely. Last year we reported on one study that found folks with Alzheimer’s had more than double the car wrecks per year as healthy people of the same age – 0.09 crashes per year compared with 0.04 crashes.

Another study showed that people with mild cognitive impairment and very mild dementia were impaired while driving to the same level as 16- to 20-year-old drivers.

The reality is if you or someone you love starts making errors while driving—errors turning or otherwise—it’s a good idea to get cognitive function checked. It’s also a good idea to keep a log of any repeated memory lapses, small changes in driving ability or other errors in cognitive function to share with a doctor.