Design of roads, intersections contributes to disorientation in people with dementia

December 17, 2020

A roundabout in the city of Sheffield, England. (Photo by Benjamin Elliott on Unsplash)

Dense or otherwise complicated road networks are connected to missing-person incidents involving people with dementia, according to a recent study, shining light on the role the disease plays in spatial awareness and other cognitive processes.

The study, published in Scientific Reports in late October, examined more than 200 police records from January 2014 through December 2017 regarding missing individuals with dementia in Norfolk County in the United Kingdom. Its findings suggested that the design of the road networks, including the complexity of intersections, in the areas where dementia patients went missing contributed to them becoming lost, underscoring an important environmental risk factor in light of previous reports that approximately 70% of dementia patients may go missing at least once during the course of the disease.

The researchers noted that in the U.K. alone, approximately 40,000 individuals with dementia go missing for the first time every year, and that number is likely to see growth in line with the projected worldwide increase of people with the disease.

Michael Hornberger, a professor at the University of East Anglia and an author of the study, said that while people tend to think of dementia as causing memory-related problems, spatial disorientation — an impaired ability to navigate an environment — is also a common early symptom of the disease.

“If you have potential spatial disorientation because of your dementia, then we wanted to investigate whether the road structure makes a difference in how likely you’re getting lost,” Hornberger said. “Each crossing or intersection in road structure is a spatial decision point where people have to make a decision, or are more likely to get lost.”

The researchers found that areas that featured more complicated intersections along with less-structured road layouts provided a bigger problem for individuals with dementia, as they can create a larger sense of spatial disorientation. These types of road layouts can be found in urban, suburban and rural areas, Hornberger said, and that in general where people live does not matter with respect to their likelihood of becoming lost. 

People with dementia become lost or have trouble navigating complex intersections due to how intersections create “multiple decision points that people have to make when navigating through the environment, so it makes them more lost,” he said.

Hornberger said that there are four main scenarios in which those people become lost. In addition to the less common situations, such as a person choosing to leave their home at night or suddenly becoming agitated and leaving, the two scenarios that the researchers primarily focused on were when a person with dementia is alone on routine outings or when they are left waiting in place.

A person with dementia may be alone on a routine trip away from home for a simple task such as taking their dog for a walk or taking a short trip to a local store, Hornberger said, which is something that they may be able to do early on in the development of the disease.

Waiting in place may become a trigger for a missing-person incident when an individual with dementia is with someone else, such as a family member or caretaker, and is told to wait somewhere while the other person handles an errand, Hornberger said. The person with dementia may then forget why they were waiting, leading them to wander off and become lost.

Hornberger stressed that the research shows that in general, more awareness of spatial disorientation as an early symptom of dementia is needed.

“People are still so unaware of that, and the first episode really happens, very often, completely out of the blue,” he said, adding that it’s important to make “people aware that this is a potential predictor of this disease.”

Individuals who are at risk of dementia or who are showing symptoms of the disease should make sure that they are choosing routes that are highly familiar to them when they are venturing out, which Hornberger said should make them less likely to become lost. He added that another potential countermeasure for the issue would be the use of a location device, such as a GPS app on a phone, to track where a dementia patient is. While using such an application generally allows for the person’s caretakers to find them quickly without needing to involve law enforcement, it does raise privacy concerns, Hornberger noted.

The next step in this research will be looking into how people with potential early dementia symptoms are able to handle driving, which Hornberger said is in the early stages and is recruiting participants from throughout the U.K.

He said that the research will hopefully allow for a greater understanding of how dementia can influence spatial awareness, and provide the ability for people with the disease to continue to lead active lives.

“We should not underestimate how the environment is really shaping us, and how potentially a disease can impact how we move through this environment,” Hornberger said, referring to the area in which we live. “We want to encourage people with dementia to stay as active as long as possible, so we don’t want them to just stay at home, but be out there doing things and being active, but in a safe way.”

The study, “Impact of road network structure on dementia-related missing incidents: a spatial buffer approach,” was published on Oct. 29 in Scientific Reports. It was authored by Vaisakh Puthusseryppady, Martyn Patel and Michael Hornberger, all of the Norwich Medical School at University of East Anglia, and Ed Manley of the Centre for Advanced Spatial Analysis at University College London.

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