When the brain breaks. What happens when neurological errors change our life forever?

Our brains are amazing, but sometimes they make very strange “errors” that change how people see the world, feel their bodies, or recognize others.  

You probably already know about Alzheimer's disease or Schizophrenia, but did you know that there is a neurological error when you stop seeing any faces? The writer and neurologist Oliver Sacks recounts the story of a man who "mistook his wife for a hat." “He suffered from a condition where he couldn't recognize faces, known as prosopagnosia, or face blindness.” (“Bizarre Brain Disorders - Business Insider”) People with prosopagnosia cannot recognize faces, even of friends or family, and may rely on voices, hairstyles, or clothing instead. Some people with prosopagnosia can't even recognize their own face. This can happen after a brain injury, but it can also be present from birth, making social life and school interactions more challenging. For individuals with prosopagnosia, the challenge is not in the basic visual processing of faces; they can see and often describe facial features. “However, the brain’s ability to integrate these features into a recognizable whole face is impaired.” (“Prosopagnosia: Mayo Clinic study sheds new light on "face ... - PsyPost”) “The Intake and Referral Center at the Mayo Clinic identified 487 patients with possible prosopagnosia, of which 336 met study criteria for probable or definite prosopagnosia.” (“Prosopagnosia: face blindness and its association with ... - PubMed”) The condition is usually caused by stroke, but as many as 2.5% of people may be born with it. This is a neurological error that makes people struggle with everyday tasks and makes social life difficult. It can either affect the identification of facial features difficulties, or it can lead to difficulties with associating faces and features to individuals. 

Another fascinating example of neurological error is Hemi-spatial Neglect: Half the World Disappears. In hemi-spatial neglect, often after a stroke, a person may ignore one side of space and even one side of their own body, such as shaving only half their face or eating only half of the food on their plate. Their eyes can see normally, but attention systems in damaged brain regions fail to process one side of the world. The interhemispheric imbalance causes one side of hemisphere to become more active after the other hemisphere, which results in attention diversion and eye movements towards this side. (“Spatial Neglect - PubMed”) In experiments where people with this dissociation were asked to draw a picture of normal daily objects, patients often only drew half of a face or a house or placed all the numbers in clocks only on one side. They also often only shave half of their beard or draw makeup only on half of their face. This dissociation is certainly a difficulty in daily life as it cuts off half of the world. The overall incidence of hemineglect disorder is up to 82% in post-stroke patients. A case study reported that many patients of neglect were above 65 years of age, and fewer patients of neglect were below the age of 65 years. 

Alien Hand Syndrome: A Hand With “Its Own Mind”. In alien hand syndrome, a person’s hand performs actions that do not match the intended action, such as buttoning a shirt while the other hand is trying to unbutton. Damage to areas that coordinate voluntary movement, and conscious control appears to let automatic movement patterns escape normal supervision by the rest of the brain. Your hand may lift and levitate. It may grab objects and not let them go. “Your hand can undo previously completed actions, like untying your shoes after you just finished tying them.” (“Alien Hand Syndrome: What It Is, Symptoms & Treatment - Wockr”) Your leg may move or step.  

• Dyspraxia. One of your hands acts independently. 

• Alien hand sign. You believe that your hand isn’t your own. 

• Anarchic hand syndrome. Your hand performs a task that you have no control over. 

• Supernumerary hand. You feel like you have an extra limb. 

• Levitating hand. Your hand raises on its own. 

Alien Hand Syndrome is caused by damage or a disconnection in the brain, often due to a stroke, brain tumours, aneurysm, or neurodegenerative disease like Parkinson's or Alzheimer's. Certain brain damages are associated with: 

• Left medial frontal lobe: Right hand 

• Corpus callosum: Left hand 

• Right parietal lobe: Left hand 

All these neurological errors are certainly a struggle for people with it, so not only do they have social struggles, but also, they cannot function properly. Even though these neurological errors are incredibly rare and extra hard to treat, that doesn’t mean they don’t deserve help and recognition. The best way to help people with these syndromes is through understanding and inclusion. Listen patiently, help when needed, and raise awareness about how brain injuries or neurological disorders affect everyday life. Brain error research can not only help people with it but also help discover a lot of information about the brain in general, as it is the most fragile and one of the most important parts of us, which can also make mistakes. 

You can find more information and research here, Remember to stay curious, because the brain is still being studied and many conclusions are still being questioned and refined. 

Prosopagnosia (face blindness) 

Josephs, Keith A., et al. “Prosopagnosia: Face Blindness and Its Association with Neurological Disorders.” Journal of Clinical Neuroscience, vol. 119, 2024, pp. 1–9. PubMed, https://pubmed.ncbi.nlm.nih.gov/38419734/.  

Palermo, Romina, and Elinor McKone. “Is It Just Face Blindness? Exploring Developmental Prosopagnosia.” The Quarterly Journal of Experimental Psychology, vol. 75, no. 2, 2022, pp. 282–301. PubMed Central, https://pmc.ncbi.nlm.nih.gov/articles/PMC8870183/.  

Rubin, Scott. “Bizarre Brain Disorders.” Business Insider, 31 Aug. 2015, https://www.businessinsider.com/bizarre-brain-disorders-2015-8.  

Stokes, Marek, et al. “What Is the Prevalence of Developmental Prosopagnosia? An Empirical Assessment of Different Diagnostic Cutoffs.” Cortex, vol. 164, 2023, pp. 40–55. ScienceDirect, https://www.sciencedirect.com/science/article/abs/pii/S0010945223000138.  

“Developmental Prosopagnosia: Even ‘Mild’ Face Blindness Can Severely Disrupt Daily Life.” PsyPost, 3 June 2025, https://www.psypost.org/developmental-prosopagnosia-even-mild-face-blindness-can-severely-disrupt-daily-life/.  

Hemispatial neglect 

Sarwar, Adeel, and Nasir Bhatti. “Spatial Neglect.” StatPearls, StatPearls Publishing, 13 Aug. 2023, https://www.ncbi.nlm.nih.gov/books/NBK562184/.  

Appelros, Peter, et al. “Prevalence of Spatial Neglect Post-Stroke: A Systematic Review.” Annals of Physical and Rehabilitation Medicine, vol. 64, no. 5, 2021, 101548. PubMed, https://pubmed.ncbi.nlm.nih.gov/33246185/.  

Alien Hand Syndrome and brain regions 

“Alien Hand Syndrome.” Ausmed, 10 June 2025, https://www.ausmed.com/learn/articles/alien-hand-syndrome.  

“Frontal Lobe.” Cleveland Clinic, https://my.clevelandclinic.org/health/body/24501-frontal-lobe.  

“Parietal Lobe.” Cleveland Clinic, https://my.clevelandclinic.org/health/body/24628-parietal-lobe.  

“Corpus Callosum.” Cleveland Clinic, https://my.clevelandclinic.org/health/body/corpus-callosum.