Can you remember the last time that you confused left and right?
Most healthy people have no issues telling left from right, but for some people (about 15 percent), left-right confusion is a somewhat common experience in their everyday lives. Common situations in which people confuse left and right every now and then include giving instructions about directions to somebody else who is driving a car, moving the wrong foot during dancing, or taking the wrong direction when hiking. However, some psychiatric and neurological disorders lead to a marked increase in left-right confusion. Studying patients with these disorders may help in understanding why left-right confusion occurs, but so far, there has been no systematic investigation about which exact diseases and disorders are linked to an increase in left-right confusion.
A new review study on left-right confusion
A new study, now published in the neuroscientific journal Brain Research Bulletin (Thaler and Ocklenburg, 2025), focused on systematically assessing the scientific literature on left-right confusion in psychiatric, neurodevelopmental, and neurological diseases and disorders (Disclaimer: I am one of the authors of the publication). The study was a so-called systematic review, a specific type of scientific article in which published research studies relevant to answering a question are identified using clearly defined search criteria for scientific databases. In the study, data from 20 original research studies were analyzed and integrated.
What were the results of the study?
- The first main results of the study were that especially patients with brain damage (e.g., due to a stroke) in the parietal lobe of the brain experienced an increase in left-right confusion. The parietal lobe is located in the upper part of the brain towards the back, and it is important for visuo-spatial processing, among other things. Thus, it makes sense that damage to this part of the brain leads to problems with distinguishing left and right, which is a spatial task.
- Patients with Alzheimer’s disease also showed an increase in left-right confusion. As Alzheimer’s disease is linked to a shrinking of the brain, which also includes the parietal lobe of the brain, this finding is in line with the first result.
- People with dyslexia also show an increase in left-right confusion, with about twice as many people with dyslexia reporting problems with left-right confusion as people without dyslexia. In contrast to the first two groups of people, this increase is due not to brain damage but probably to problems with linking the words left and right to their spatial directions in the real world.
For other investigated disorders, such as schizophrenia or prosopagnosia, the results on left-right confusion were less clear than for those three groups.
Takeaway
The study shows that different groups of people have problems with left-right confusion due to different reasons. One reason for left-right confusion is that the functioning of the parietal lobe, which is central for spatial abilities, is impaired. Another reason is problems linking words and directions. Clearly, more research on left-right confusion is needed to understand this fascinating problem.
