Хөгжлийн явцад үүсдэг топографийн чиг баримжаа алдагдах эмгэг нь мэдрэлийн гэмтэлгүй хүмүүст насан туршид нь тохиолддог орон зайн баримжаалах чадварын хомсдол юм.
Топографийн чиг баримжаа алдагдах (DTD) эмгэгийг анх 2009 онд University of British Columbia-ийн судлаач Жузеппе Иариа болон түүний баг тодорхойлжээ. Энэхүү эмгэгтэй хүмүүс танил орчин, тэр ч байтугай өөрийн гэртээ ч төөрөх тохиолдол гардаг бөгөөд энэ нь тархины гэмтэл эсвэл бусад мэдрэлийн өвчнөөр тайлбарлагдах боломжгүй байдаг. Судалгаагаар, тэдний тархинд орон зайг дүрслэн бодох буюу “танин мэдэхүйн зураглал” үүсгэх үйл явц хэвийн бус ажилладаг болохыг тархины дүрс оношилгоогоор тогтоосон байна.
DTD-тэй хүмүүс тухайн газрын тэмдэг, барилга байгууламжийг таньдаг ч тэдгээрийн хоорондын байрлал, зай хэмжээг нэгдсэн зураглалд буулгахдаа бэрхшээлтэй байдаг нь 15 эмпирик судалгааг нэгтгэсэн системчилсэн тоймоор нотлогджээ. Энэхүү чадвар дутагдсанаас болж тэд танил маршрутаасаа бага зэрэг хазайхад л эргэж олохдоо хүндрэлтэй тулгардаг. Уг эмгэг нь хүний бие даасан байдал, боловсрол, ажил мэргэжлийн сонголтод сөргөөр нөлөөлж болзошгүй юм.
Одоогийн байдлаар DTD-ийг оношлох стандарт аргачлал байхгүй бөгөөд судлаачид уг эмгэгийг хүн амын ерөнхий төөрөх хандлагаас ялгах судалгааг үргэлжлүүлж байна. Олон хүн GPS болон навигацийн технологийн тусламжтайгаар өдөр тутмын амьдралдаа зохицдог ч технологид хэт найдах нь уг эмгэгийн шинж тэмдгийг бүрхэгдүүлэх эрсдэлтэй гэж үздэг. Хэдийгээр тархины энэхүү нарийн төвөгтэй үйл ажиллагааг бид анзаардаггүй ч DTD нь бидний орон зайд баримжаалах чадвар ямар чухал болохыг харуулж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Imagine walking from your bedroom to the kitchen and suddenly not knowing which way to turn.
For most of us, getting lost means taking a wrong turn in an unfamiliar city or briefly losing our bearings when our phone battery dies. A familiar landmark is usually enough to put us back on track.
But for some people, that sense of direction has never worked in the usual way.
They can recognize buildings and landmarks around them and have otherwise typical cognitive abilities, yet still become lost in places they have known for years.
In severe cases, that can include their own home.
The condition is known asdevelopmental topographical disorientation, or DTD. Unlike navigation problems that can emerge after brain injury or neurological disease, DTD is lifelong and occurs without an acquired brain injury that would explain the difficulty.
Thefirst case described using the term DTD was reported in 2009by neuroscientist Giuseppe Iaria and colleagues at the University of British Columbia in Canada.
The woman they studied had struggled with navigation throughout her life despite otherwise intact sensory and intellectual abilities.
Tests in real and virtual environments pointed to a remarkably specific problem: she had difficulty constructing a mental representation of her surroundings – what researchers call acognitive map.
Brain imaging offered another clue. When she tried to form a cognitive map, brain regions involved in memory and spatial navigation did not show the typical pattern of activity seen in control participants performing the same task.
A cognitive map doesn’t mean seeing something like Google Maps inside your head. It is a mental representation of how different places relate to one another.
You might know that your home is near a train station, that the supermarket is several streets beyond your home, and that the park lies in another direction. Those relationships allow you to find shortcuts, approach a familiar destination from a different direction, or recover after making a wrong turn.
In some people with DTD, building this broader spatial representation appears to be particularly difficult.
A systematic review of 15 empirical studies on DTDfound that navigation difficulties were largely associated with problems in the quality of these mental maps. Landmark recognition, by contrast, was generally preserved.
That helps explain one of the condition’s most striking features. Someone may recognize a building perfectly well without being able to place it correctly in relation to the streets and places around it.
The problem can extend even to the home. In severe cases, when people with DTD have been asked to draw maps of their homes, they could remember the sequence of rooms while struggling to represent their shapes, sizes, and positions accurately.
A familiar route can therefore work as long as everything happens as expected. But a road closure, a different entrance, or a wrong turn may disrupt the sequence of cues a person relies on, making it much harder to find an alternative route.
This is why DTD can be far more consequential than simply being “bad with directions”.
Researchers studying the condition generally look for severe navigation problems that have been present since childhood, including repeatedly becoming lost in highly familiar places, without another cognitive or neurological condition that adequately explains them.
The effects can reach into everyday life.Researchsuggests DTD can restrict independent mobility and even influence educational and career choices. Some people cope by memorizing specific routes, relying on other people, or using navigation technology.
GPS can therefore provide valuable independence. At the same time, easy access to navigation technology may make severe difficulties less visible: someone who routinely follows directions on a phone may rarely discover how difficult navigating without it would be.
There is still much that researchers do not know. Studies have used different definitions and assessment methods, and there is no standardized diagnostic tool for DTD.
Related: Trichotillomania: New Study Explains Why People Feel Compelled to Pull Out Their Own Hair
Researchers are working toward clearer ways of distinguishing the condition from the wide range of navigational ability seen in the general population.
But DTD already reveals something remarkable about an ability most of us barely notice.
Every trip through a neighborhood – or even from one room to another – depends on the brain linking places, memories, directions, and distances into a coherent sense of where we are.
For most of us, that happens so automatically that we rarely think about it.
DTD shows just how much work the brain is quietly doing to keep us from getting lost.
This article was fact-checked by Rachel Garner and edited by Clare Watson. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.
