One of the biggest mysteries of medicine is why medical students choose to study anything besides the brain. Here are some of the most fascinating neurological syndromes:
- Neglect syndrome is due to large right-sided injuries, almost always a stroke. These patients are paralyzed on the left side and blind to the left side of the world. Moreover, they are often unaware of their deficits (anosognosia), and some patients can even be completely unaware the left side of the world even exists. One patient of mine was completely confident in her ability to clap, though she could not move her left side. Even after her right hand met only air in response, she insisted she was able to clap, but simply did not “want to”. You could put her left arm in front of her face and she would insist it belonged to someone else. As her condition improved, she gained intellectual awareness of her inability to move her left side, but described it as a “bother” rather than the tragedy it was (anosodiaphoria). These patients also lack prosody, which refers to the pitch and tone of a sentence. Their speech may sound very robotic, without any feeling.
- Patients with apraxia lose learned motor skills. These patients have intact strength, sensation, and coordination, yet they may have trouble with simple tasks such as dressing themselves. They approach everyday items the way I’d approach an airplane’s cockpit. I could physically turn all the knobs, but I wouldn’t know where to begin.
- Alien limb syndrome is a rare condition, a patient’s limb may take on a life of its own. One woman, with a parietal lobe stroke, said her arm moved a plate across her table for no reason. As I was speaking to her, her hand constantly picked at her blanket without her intending to do this. She felt like her arm didn’t belong to her.
- Patients with Wernicke’s aphasia can speak in sentences that are grammatically correct, but are utterly devoid of meaning. For example they may say, “He went to the thing there that they were all going to do about it after the thing.” To anyone who doesn’t speak English, they sound completely normal, and patients have no insight into their deficit. They can’t understand anything you say, nor can they understand why you can’t understand them. Since they are unaware of their own deficits, they can become frustrated when no one understands them, and they may try to leave the hospital. They may have limited deficits otherwise, and I’ve seen at least several patients be admitted to a psychiatric ward.
- Broca’s aphasia is essentially the inverse of Wernicke’s aphasia. These patients can understand language quite well, but have deficits in speech production. These patients are aware of their deficits, and it’s awful to watch their suffering. They are almost always weak on the right-side of their body.
- Patients alexia without agraphia are unable to read (alexia), but they are able to write (without agraphia). This occurs due to an injury to the occipital (visual) cortex on the left hemisphere, which contains the language areas for most people. Patients can speak and write just fine, however their visual cortex on the left is functionally blind. When they look at a words, only their right brain perceives it. Since this part of the brain has no language, they can’t read what they just wrote. These patients are also blind to the right-half of the world.
- Patients with injuries to both occipital lobes are blind, but can be unaware of it (Anton’s syndrome). The last patient I met with this was admitted to the trauma service after she fell down a flight of stairs. It took several days before someone noticed she couldn’t see. She didn’t complain about it to anyone and denied it when asked.
- Patients with masses in their occipital lobes can have interesting hallucinations. One woman with a tumor of her right occipital lobe reported seeing “fields of checkerboards” and brilliant flashing colors on the left side of her world. Another man with a similar tumor described seeing all sorts of animals on the left.
- Prosopagnosia is a more subtle visual deficit, where patients lose the ability to recognize faces. One woman I met went to lunch with friends and was convinced a stranger sat down when her friend returned from the bathroom. Later, she described calling out to a woman on the street, who she thought was her cousin. These sorts of problems with facial recognition can also be seen in psychiatric disorders, where patients are convinced a loved one is an imposter (Capras delusion) or that a stranger is someone close to them (Fregoli delusion).
- Patients with simultanagnosia can only view one object in their visual field at a time. If you saw the letter H made up of a bunch of small Ts, you’d be able to see both the big and small letters. These patients will see just a few scattered Ts, but can’t see the overall picture. It is due to lesions of both parietal lobes.
- I’ve met patients with transient global amnesia. As the name implies, these patients have an episode, less than 24 hours, where they are unable to remember anything. This usually occurs in older people, sometimes during strenuous activities. They may ask you why they are in the ER a dozen times, as they are unable to remember your answer. Patients are usually better by the next day, though they don’t remember what happened the day before. The condition rarely recurs.
- I’ve met patients with limbic encephalitis, who may also have profound memory deficits, combined with severe psychosis, agitation, and seizures. This condition most often occurs in young women, often with ovarian teratomas. I’ve seen perfectly healthy women develop severe delusions over the course of a few days. These patients can be admitted to psychiatric units before their disease is properly diagnosed. Alternatively, they can be ill enough to need mechanical ventilation in an ICU. If the tumor is removed early enough and patients are given immunotherapy, the eventual outcome can be good.
- I’ve seen patients with frontal lobe injuries who can walk and talk perfectly fine. They seem mostly normal in formal neurological tests. Yet, they just can’t make good decisions in the real world, navigating the hundreds of small social encounters we all have daily. They can be short-tempered and inappropriate, or inappropriately jocular. They have no boundaries or filters and can get in big trouble. Their deficits may be hard to pinpoint during a conversation, but they can’t function well in the world.
Having said all this, it’s important to remember these patients are not there for our fascination. Nearly all of them had devastating brain injuries, some of which we are currently powerless to treat. Multiple branches of neurology, such as stroke, MS, and migraines have had significant advances over the past decade. Yet, significant progress for other conditions remains stubbornly out of reach, and it’s no secret what’s happening to medical research today.
