Every human experience is stored inside the brain. Thoughts, feelings, perceptions, sights, and sounds can all be reduced to electrical impulses that fire back and forth between synapses. All this in a little organ protected by only a few inches of bone.
Brains are remarkable, but they aren't immune to injury or degradation. Every year, millions of people injure themselves in accidents, develop diseases, or succumb to old age. The brain is incredibly resilient, however, and some parts can be independently damaged without affecting other areas.
The opposite is also true; one damaged area can impede the normal functions of all the other parts. Scientists and medical professionals have been studying the brain for more than a century, but there's still a lot that's not known - for a small organ, it's extraordinarily complex.
New brain disorders are still being discovered today, some of which are particularly disturbing and can lead to tragic results for the sufferers. The following brain disorders and neurological diseases still baffle many scientists who, despite numerous studies, have been unable to develop long-lasting cures. Some of the disorders are extremely rare, so rare that they barely exist, but are well documented nonetheless.
15 Frontotemporal Dementia
The frontal and temporal lobes of the brain control things like judgment, speaking, emotions, speech, and movement. Those who suffer from frontotemporal dementia (FTD) experience cell degeneration and tissue shrinkage in these parts of the brain. The symptoms vary in severity from person to person.
The basic symptoms change a person’s behavior slightly, resembling the common psychological disorder of depression. The most severe symptom is the inability to use accurate or descriptive language, despite being able to speak freely.
Another severe symptom is involuntary muscle movement. This means that a person suffering from FTD may not be able to communicate or move freely as they once did. It’s important to remember that FTD is different from Alzheimer's, as FTD can develop at a much younger age and more quickly.
14 Huntington’s Disease
Scientists have discovered that Huntington’s disease (HD) is a genetically inherited brain disorder. A child born from a parent with HD has a 50% chance of developing the disorder themselves. HD occurs when certain brain cells responsible for movement and emotions die to the point where sufferers can no longer live a normal life.
Not only do people with HD become depressed and apathetic; they also have difficulty focusing or recalling memories. In later stages, they often need professional care as their body begins to deteriorate. Death usually follows about 25 years after first diagnosis.
13 Moebius Syndrome
Moebius syndrome (MS) is a genetic brain disorder which inhibits muscular movements. The affected areas are the face, including eye movement, and the disorder usually manifests itself from birth. Infants and youth with MS experience a paralysis of facial movements and cannot perform simple expressions such as smiling, frowning, or raising their eyebrows.
The syndrome is very rare, affecting only 1 in 50,000 to 1 in 500,000 newborns. It has also been linked to autism. However, autism is extremely difficult to diagnose in people with MS. The lack of facial expressions from MS can be confused with impaired social interaction, which is common in autism.
Picking up fallen objects like a spoon or even swallowing are simple physical tasks we rarely consciously think about. But with ataxia, doing even these everyday things is extremely difficult and sometimes impossible.
Epilepsy is a very common neurological disorder compared to the others on this list. According to the Epilepsy Foundation, it's a spectrum chronic disorder characterized by uncontrollable seizures, uncontrollable muscle spasms, and many other symptoms.
People are diagnosed as epileptic if they experience more than two seizures that are not caused by a medical condition, like low blood sugar. Epilepsy is disturbing because the seizures associated with it are very unpredictable and can be violent. The disorder is manageable when properly treated but can still adversely affect the sufferer's personal and professional life.
10 Visual Agnosia
With visual agnosia (VA), a person may be able to think, speak, and socially interact ostensibly normally, but can’t recognize common objects, people, or places.
A sufferer of VA may be able to analyze in detail the hidden meanings of a Shakespeare play or solve complex math equations. But if you placed an object like a nail clipper in front of them, they would not be able to name it or describe how it is used.
This disorder is commonly caused by an injury to the parietal and temporal lobes of the brains from strokes or trauma. Beyond visual agnosia, there is also auditory and tactile agnosia.
The brain has developed special functions over millions of years of evolution. For example, hearing a loud bang for the first time will generate a fearful or excited emotional and physical state. This is to protect the body from potential harm. However, if the bang happens again, the emotional and physical response will be less intense if you've registered that the sound isn't associated with harm.
But this isn't the case for sufferers of misophonia, a brain disorder where people are extremely sensitive to specific sounds which act like triggers. Particular sounds that other people barely notice cause extreme negative emotional reactions in people who suffer from misophonia. They can angrily act out because of the great distress caused by the sound triggers.
8 Exploding Head Syndrome
Exploding head syndrome (EHS) is a form of parasomnia, a sleep disorder. People who suffer from EHS experience sudden, extreme loud noises just before falling asleep. These cause deep fear and distress because they come from an unknown source.
People have reported the loud sounds may resemble cymbals crashing or a bomb exploding. Others have reported that the sounds may be accompanied by a blinding flash of light. EHS is painless, but is incredibly disturbing for people without a psychiatric disorder who experience the sounds frequently.
7 Phantom Limb Syndrome
Phantom limb syndrome (PLS) is perhaps one the most well known yet mysterious brain disorders. It occurs in amputees who feel chronic pain or sensations from a part of the body that is no longer there.
For example, a person who loses their arm may feel as if their missing limb is being crushed. This is because the brain still receives impulses from the original nerves. The brain needs time to adapt to changes in the body and rewrite how it perceives impulses from a limb that no longer sends information. PLS can be extremely uncomfortable for those who suffer from it, but new biofeedback techniques have helped reduce the painful symptoms.
There are many dissociative disorders where people don’t feel like they inhabit their bodies. But nothing is quite as disturbing as somatoparaphrenia (SP), a delusion where people “disown” certain limbs or one half of their bodies. People with SP don’t understand how their limbs or other parts have become attached to them, and believe they don't actually belong to their bodies.
Neurologists who have studied SP believe that this delusion is caused by damage of the cerebral regions of the brain by strokes. Not only do people with SP refuse to believe their body parts are actually theirs; they may also think that a limb, commonly the left arm, is actually the limb of another person.
5 Developmental Topographical Disorientation
It’s easy for people with normal brain functions to know where they're going and how to get there. For example, getting from the living room to the kitchen is as simple as getting up and walking because the locations and routes are hard-wired into your brain. But this is not possible with developmental topographical disorientation (DTD).
The disorder is caused by focal brain damage, where the brain can no longer process spatial information, environments, or landmarks in any given surrounding. As a result, people with DTD easily get lost even in places they have been many times before. Their inability to generate cognitive maps can cause massive confusion. They often have no idea where they are even in neighborhoods they grew up in.
Prosopagnosia (PG) is also known as “face blindness”. It is the complete inability to fully perceive or recognize faces, even those of people that sufferers have known for years, including family members. The disorder may be so severe that sufferers are unable to recognize other objects like cars or animals.
A sufferer can look at a person and perceive everything about them except their detailed facial features. The disorder makes normal nonverbal communication virtually impossible because sufferers cannot read or understand facial gestures and queues.
The most common causes of PG is a stroke or head injury which damages a certain part of the brain responsible for facial processing.
Synesthesia may sound like science fiction but it's a very real brain disorder where senses like taste, smell, touch, and hearing become intertwined. For example, a person who suffers from synesthesia may have the very rare ability to see sound and taste, or to hear colours.
One example is Ingrid Casey, a woman who perceives the letter “N” as sienna brown, “J” as light green, and the number “8” as the color orange. She also perceives pain as a colour. She told Livescience that a shin splint throbs in hues of orange and yellow.
The disorder was once considered a psychological illness until scientists developed a neurological cause for the syndrome. One cause is believed to be the building of new neural connections that leads to a “breakdown of the boundaries that normally exist between the senses.”
2 Fregoli Syndrome
The fregoli delusion (FD) gives a whole new meaning to paranoia. Caused by brain lesions, there is a neurological foundation for this delusion occurring in people of relatively normal psychological health.
Also known as “the delusion of doubles”, people with FD believe that a single person has changed their appearance to resemble a number of different people. For example, if the sufferer is a patient in a hospital, they might come to believe without a doubt that both the doctor and the nurse are actually one person wearing disguises.
People who suffer a brain injury to the right frontal areas can develop this disorder. However, if neurological damage or deficiencies are ruled out, it may be a form of paranoid psychosis.
1 Cotard’s Syndrome
Cotard’s syndrome (CS), also known as “walking corpse syndrome”, is an extremely rare disorder that causes people to think they are physically dead even though they are very much alive. Some sufferers believe that some of their body parts like arms or legs don’t actually exist.
The Daily Mail reported on a teenager who suffered from CS. It was found that the teenager, named Haley, experienced a malfunction in her fusiform gyrus, a part of the brain that recognizes faces.
The malfunction creates a distorted reality, causing people to vehemently believe that, for example, they stink like rotting fish because their flesh is decomposing. Sufferers can go about their normal daily activities, all the while convinced they are a corpse rather than a living person.