Imagine leaving your bedroom for the kitchen, only to find that you suddenly cannot tell which way to go.
For most people, being lost means taking a wrong turning in an unfamiliar city or momentarily losing their sense of direction after a phone battery runs flat. Spotting a recognisable landmark will usually be enough to get them oriented again.
For others, however, their sense of direction has never functioned in this conventional way. They may recognise the buildings and landmarks around them, and otherwise have typical cognitive abilities, but still lose their way in places they have known for years. In serious cases, this can happen even within their own home.
What is developmental topographical disorientation?
This condition is called developmental topographical disorientation, or DTD. In contrast with navigation difficulties that arise following a brain injury or neurological disease, DTD is present throughout life and has no acquired brain injury to account for the problem.
The first case to be described with the term DTD was published in 2009 by neuroscientist Giuseppe Iaria and colleagues at the University of British Columbia in Canada.
The woman in their study had experienced navigation problems for her entire life, despite having intact sensory and intellectual abilities in other respects. Tests conducted in both real-world and virtual settings indicated a highly specific difficulty: she struggled to build a mental representation of her surroundings, which researchers describe as a cognitive map.
Brain scans provided a further indication. As she attempted to create a cognitive map, regions involved in memory and spatial navigation did not produce the usual activity pattern seen in control participants completing the same task.
Why cognitive maps matter for navigation
A cognitive map is not like viewing Google Maps in your mind. Instead, it is an internal understanding of the relationships between different locations.
You may know that your home is close to a railway station, that the supermarket is several streets past your home, and that the park is in a different direction. Understanding these relationships lets you take shortcuts, reach a familiar place from another direction, or regain your bearings after a wrong turn.
For some people with DTD, forming this wider representation of space seems especially challenging.
A systematic review of 15 empirical studies of DTD concluded that navigation difficulties were mainly linked to problems with the quality of these mental maps. By comparison, people generally retained the ability to recognise landmarks.
This accounts for one of the condition's most notable features: a person might identify a building without difficulty, yet be unable to locate it accurately in relation to the surrounding streets and places.
The difficulty may even affect the home. In severe cases, people with DTD asked to draw maps of their homes could recall the order of the rooms, but found it hard to represent their shapes, sizes and locations accurately.
As a result, a well-known route may be manageable provided everything unfolds as expected. A road closure, an alternative entrance or a wrong turning, however, can interrupt the chain of cues on which a person depends and make finding another route far more difficult.
That is why DTD can have much greater consequences than merely being "bad with directions".
How DTD affects daily life
Researchers investigating the condition generally seek severe navigation difficulties that have existed since childhood. These include repeatedly becoming lost in extremely familiar locations, with no other cognitive or neurological condition that sufficiently accounts for them.
The consequences can extend into everyday life. Research indicates that DTD may limit independent mobility and may even shape education and career decisions. Some people manage by learning particular routes by heart, depending on other people or using navigation technology.
GPS can therefore offer important independence. Yet readily available navigation technology could also conceal severe problems: a person who habitually follows instructions on their phone may seldom find out how hard it would be to navigate without it.
Much remains unknown to researchers. Studies have applied varying definitions and assessment approaches, and no standardised diagnostic tool exists for DTD.
Related: Trichotillomania: New Study Explains Why People Feel Compelled to Pull Out Their Own Hair
Researchers are seeking clearer methods for separating the condition from the broad range of navigation abilities found across the general population.
Even so, DTD already demonstrates something striking about a skill most of us scarcely register. Every journey through a neighbourhood - or even between rooms - relies on the brain connecting locations, memories, directions and distances into a coherent awareness of where we are.
For most people, this process is so automatic that it is rarely given any thought. DTD illustrates how much unseen work the brain performs to prevent us from losing our way.
This article was fact-checked by Rachel Garner and edited by Clare Watson. While we take pride in our process, we are only human. If you notice an error, please let us know.
Comments
No comments yet. Be the first to comment!
Leave a Comment