Hemispatial Neglect
One sunny day, in Milan.
He woke up as the light broke through his window in the early morning. The blinds had recently been removed and a replacement was yet to arrive. He was now accustomed to waking up naturally with the sunrise and going about his morning routine. He had barely finished getting dressed when two men in white knocked on the door. He opened. They seemed peculiar to him, these scientists, always on edge, as if some discovery was always on the cusp of happening. He had recently fallen and damaged his skull, likely the result of a small stroke. The doctors told him his posterior parietal lobe had been damaged… He did not quite understand what this was but he felt happy to be alive. Yet, his perception of the world was quite different. The scientists were sent to check on him and he asked them to explain more about what had happened. “What is the parietal lobe? Will I be okay? Why are you here?”.
One of them was kind enough to explain, albeit in a slightly gory manner. “Let’s start from your first question, sir. Imagine if you took a blade and horizontally sliced through the middle of your forehead. Easy to picture right? - the man’s smile troubled him slightly - we use the word anterior to refer to the front part of that ‘slice’, essentially where your nose is. Posterior, refers to the back part, towards the back of your head.” They lay a drawing on the table to clarify. Something along the lines of this:
“In anatomy, you can use the terms anterior and posterior to mean the front or the back part of something, respectively. Lastly, your parietal lobe is just a specific area of your brain, right above your ears. We do not know the extent of the damage yet, but that’s what we are here to investigate. We think it may have affected the way you perceive space”. He was completely puzzled by all this but some remaining pain on the right side of his head was enough for him to pinpoint this parietal lobe.
The word “damage” did not seem to linger in his mind. He felt tired and in deep need of energy. Showing his best hospitality skills, he began to brew some coffee for himself and his peculiar guests. The smell of coffee quickly filled the room; the Italian espresso, dark with no sugar, a drink he had favoured for many years… They sat down at the table. He did not know what to expect but the two men said they had a few “tests” they wanted to run by him. He was told it would help clarify his condition, and he acceded without complaint. “We know the parietal lobe has a role to play in spatial recognition and we’d like to confirm our hypothesis”.
It started with a very simple task. He always had an analog clock in his home, a loyal companion, a constant reminder of the human condition. The task was to simply draw this clock on paper. “That’s easy enough!” - he thought. And, without hesitation, he began to draw. The semi-circle on the right, then on the left, then the handles of the clock and lastly, the numbers… Once finished, he handed the drawing over to the scientists. He felt the drawing was imperfect and it quickly became clear that the entire left side of the clock was missing. The numbers on the right were stacked very close to one another. 12 was in its correct position, but on the opposite side there was 11, with 6 now slotted around 3 o’clock. He did not understand it… But such was his perception.
“Sir, we believe you are afflicted with what we call hemispatial neglect. You seem to be unable to recall the details in your egocentric space”. This sequence of words made no sense to him… He had some knowledge of Latin, so he could guess some of the meanings. Ego, I, centric, center… The scientists continued - “Egocentric space refers to the world as we perceive it around ourselves; it would be easy to convince anyone that the world seems to turn solely around them from this perspective. I know we tend to get very fancy in Science with these terms…”. “Are there other types of space?” - he asked. “Yes indeed, there is also what we call allocentric space; this refers to the space around objects and their relationship to one another.” - the scientist smiled slightly as he developed on the technicalities.
“It seems that you are unable to pay attention to what is on the left side of your egocentric space, this is what we call hemispatial neglect. Hemi, from the Ancient Greek, “half”, means that it only one side is affected. It is possible that this condition may be affecting your memory of certain locations too, we will do another quick test for that”.
They asked him to recall the Piazza del Duomo, in his hometown of Milan, a square he had known his whole life. “Place yourself with your back to the entrance of the Duomo” - he had always loved the imposing facade of the Gothic cathedral. “Now, imagine the main landmarks on the left and on the right and simply list them for us”. Could the task have been easier? - he thought again albeit slowly filling up with doubt. He proceeded to list all the landmarks he could remember, mentally walking through the Piazza, picturing it all in his “mind’s eye”. “Once you get to the other side of the square, turn around and walk back towards the Duomo, and again, tell us the landmarks on either side”. And so he did, but something seemed to be off. He did not notice immediately but the list was entirely different. How could this have happened? Half of the city simply seemed to have vanished from his mind. “That will be enough for today.” - said the scientist. He then turned to his colleague: “Again, we seem to confirm that neglect also affects spatial memory, we will have to record these findings”.
As they signed him up for further tests in the future they told him that this condition was extremely rare and that his parietal lobule (a specific sub-region) of the parietal lobe was indeed damaged. He sunk down as they left, still in slight disbelief at the fact that his brain now ignored half of the world…
Neglect is a condition that affects people’s lives in ways that are difficult to explain. Just like many unusual neurological conditions they are a reminder of the uniqueness of humans and the seemingly invisible hardship that some people face.
Some references and other cool resources on the topic are below for those that want to delve deeper into the Science. These, alongside my old neuroscience notes, were extremely helpful in putting this small piece together.
- Milan experiment: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3707912/
- Spatial neglect (literature review): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4602245/
This is my first attempt at publishing something slightly more long-form. Would absolutely love feedback (especially criticism). Thanks for reading.
Feel free to get in touch for more resources and references on the topic.