Wednesday, March 28, 2012

The girl who feels no pain: 3 fascinating neurological disorders

This post is the first in a short series on “What I learned in my undergrad neuroscience classes.” Today, I describe a few fascinating neurological disorders.

Have you watched episodes of medical shows like Grey’s Anatomy or House and wondered where they come up with some of their disorders? Are there really people out there who feel no pain, or who only have half a brain? There are. In undergrad I took a few neuroscience classes and learned fascinating details about neurological disorders. It seems that if you want to understand how the brain works, one of the best approaches is look at what happens when parts of the brain malfunction. Although I’ve forgotten 85% of what I learned, some of the more unbelievable details have stuck with me, and I thought I’d share a few of them with you today. So without further ado, here are some of the neurological disorders that I can’t get out of my head:

Clock drawn by hemineglect patient
Hemineglect. Take a look at the world around you, do you see both hands sitting on your keyboard, are you able to see your entire computer screen? What is sitting to your left? To your right? For people with hemineglect, the answers to these questions aren’t so simple. This is a condition following brain damage (typically to the right hemisphere) in which people fail to be aware of items on the side of their visual field that is opposite to where the damage was done. In short, people with this condition just stop seeing things that are on one side of a space. So give a person with hemineglect a plate of food and they will only eat things on the right side. Give them a piece of paper, and they will only draw on one side of it. If you see a person who has only one side of his face shaved or only half his hair brushed that person may be suffering from hemineglect.  In extreme cases, people with hemineglect may not see large objects, such as a person, standing on their neglected side. 

Prosopagnosia
Prosopagnosia. Humans have an innate ability to recognize faces as, well, faces. We know when we are looking at a person as opposed to an object, and we are able to differentiate one face from another. However, it turns out that not everyone has this ability. Prosopagnosia, also known as "face blindness" can be something someone is born with, or can occur as a result of brain damage. Depending on the degree of severity, prosopagnosiacs may have trouble recognizing a familiar face, be unable to differentiate between unknown faces, or even be unable to differentiate a face from an object. In some cases, patients may not even be able to recognize their own face in the mirror. However, give them non-facial clues, such as clothing, hairstyle, or voice, and they can recognize people and distinguish between them. Faces provide us with so much information about a person, can you imagine what it must be like to find a distinctive pair of earrings more recognizable than a face?

Does this hurt?
Congenital insensitivity to pain. Some people are born without the ability to experience pain. When I learned about this disorder, my first response was a twinge of jealousy. No pain? Childbirth, here I come! But it turns out that I’m probably better off with my capacity to feel pain. How do you know to take your hand away from the fire if it doesn’t start to hurt? What keeps you from pushing yourself too hard if your body isn’t fighting back? Walk on a broken ankle? Why not! Children with this condition often suffer from serious problems because they are unaware that anything is wrong with them. So perhaps I should reappraise my pain as good and consider myself lucky.

There is also disorder in which people do not feel something if they are not looking at it. So if a man picks up a briefcase while looking at it, he is fine, but as soon as he glances away, he will drop the briefcase. This has something to do with our haptic perception but I cannot find the name of it. If you know the name, tell me in the comments!

All of these examples of what can happen when parts of our brain stop working remind me how much I take for granted… I walk, talk, see, hear, taste, touch, all without a thought about what my body and brain are able to do. Today, I think, I will focus on being appreciative that I can see both hands on my keyboard as I type. 

Do you find these disorders as fascinating as I do? Do you find one particularly intriguing or unbelievable? Have you learned about other disorders you think I’d want to know about? 

Further Reading 
  • Kerkhoff, G. (2001). Spatial hemineglect in humans Progress in Neurobiology, 63 (1), 1-27 DOI: 10.1016/S0301-0082(00)00028-9
  • McNeil, J., & Warrington, E. (1993). Prosopagnosia: A face-specific disorder The Quarterly Journal of Experimental Psychology Section A, 46 (1), 1-10 DOI: 10.1080/14640749308401064

15 comments:

  1. "So if a man picks up a briefcase while looking at it, he is fine, but as soon as he glances away, he will drop the briefcase." - the name escapes me too! This is bugging me. I thought a quick google for "lack of proprioception" would do the job. Wikipedia suggests "sensory ataxia", but that's a new term for me

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    1. Thanks for your google attempts Chris! I also looked up lack of proprioception, haptic input problems, and other similar terms and had no luck. Sensory ataxia seems close but not quite right (seems like its more about coordination than lack of feeling).

      Hopefully someone can point us in the right direction!

      Amie

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    2. Cognitive Dysfunction?


      And i have Cognitive insensitivity to pain

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  2. Have you read "The Man Who Mistook His Wife for a Hat"? It's full of these fascinating cases of neurological mysteries.

    Great post!

    Thanks,

    D

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    1. Great to have you back, D! I haven't read the whole book, but I saw something on it the other day and that is partly what inspired this post. I also recently learned that Oliver Sacks himself suffered from prosopagnosia!

      Thanks for reading,
      Amie

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  3. I've been fascinated lately by aphasia, specifically the story of Sarah Scott. She had a stroke at age 18 and had to basically relearn how to speak--documented in a series of short videos, starting here: http://www.youtube.com/watch?v=1aplTvEQ6ew

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    1. Aphasia is another really interesting disorder that is often taught in neuroscience classes! What I find particularly fascinating is the distinction between two types of aphasia: broca's aphasia and wernicke's aphasia. Sarah Scott has broca's aphasia, where she knows what she wants to say, but has difficulty getting the words out. Typically with broca's aphasia, the patient uses halting language and loses his or her ability to speak in grammatically correct sentences. In contrast, when someone suffers from wernicke's aphasia, they have fluent speech that is grammatically correct but meaningless. I've heard it referred to as "word salad." All the nouns and verbs are in the right places, but the words are nonsensical or made up. They also are unable to understand what others are saying to them.

      This distinction between types of aphasia suggests that we have different areas of our brain that control what we want to say and how we want to say it. So interesting.

      Thanks for reading!
      Amie

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  4. I think I'ld hate it if I could not feel pain. I mean during the birth of my daughter I'ld like it if I did not feel it yet I wouldnt be able to of experience the whole thing. I get hurt alot and I mean alot so this article was very interesting to me. I have Von Willie Brands Disease which is a blood disorder. So if I didnt feel any pain along with having VWB and was shocked when the doctors on House did a few scenes of mine :) I felt special for that show.

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    1. YOU WANT TO FEEL PAIN!!!! Not feeling pain is horrble i dont feel pain but have gotten hurt so many times and ended up in a Intensive care unit for hours

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  5. Hi Amie,
    I work in a research lab and am personally interested in the disorder of prosopagnosia. The description that you provided is a little bit off. Typically, the types of prosopagnosia are divided into Acquired Prosopagnosia (AP) and Developmental Prosopagnosia (DP). AP happens because of an injury or trauma to the brain- specifically the fusiform face area- and individuals with DP are born with the disorder. Prosopagnosia is sometimes referred to as Face Blindness and leaves people unable to recognize others by their faces. It occurs in varying degrees; those with the most sever cases won't recognize their own face or those of close family members. Most individuals with prosopagnosia don't have trouble identifying the emotion or age of a face though.

    Thanks for spreading the word about prosopagnosia! You can find more information at faceblind.org.
    Misty

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    1. Hi Misty,

      Thanks for the clarifying comments about prosopagnosia! I want to make sure my post reflects the current consensus on the topic, so I did a little more research and made some changes to the post. I see that some information websites distinguish between apperceptive and associative prosopagnosia, and others do not. Is this a common distinction in prosopagnosia research, or something that only a subsection of researchers focus on?

      Thanks for reading!
      Amie

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  6. Hello! It's Sarah's mum here, I just came across your blog and noticed you mentioned her - we'll be uploading a new video in May to show Sarah's progress. She has been involved in a research project using Transcranial Magnetic Stimulation, that has been quite effective.

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  8. NO PAIN = horrible

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  9. I have Cognitive insensitivity to pain ive fallen on my head and not felt a thing an didnt even no until my friend screamed at me and other times ive put a hot iron away and didnt know it was on my skin was red and stuff but it didnt bother me. Ive gotten punched and just stared at the person it didnt hurt. ive cut myself with a knife while cutting fruit and didnt know... you think you would notice but you dont and anyone who says "IT WOULD BE GREAT TO NOT FEEL PAIN" my thought is it would be great to be in a Intensive care unit for hours or days...

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