3 ms·

To be honest, counting down from 100 by subtracting 7 every time is not easy for me. Am I the only one here?

• biofox 12y ago
  Thank you! I also find this task difficult. Knowing I'm not the only one is reassuring.
• miketuritzin 12y ago
  Yeah, and it's also something that most people have probably never tried to do before in their entire lives. It strikes me as an odd choice to test for dementia.
  • bunderbunder 12y ago
    Loss of executive function is a common symptom of dementia. It seems entirely plausible to me that a good way to test for that is to ask someone to solve a relatively simple problem that they've nonetheless probably never been asked to solve before. Especially one that involves applying some iterative process.
  • bsder 12y ago
    No, the fact that people haven't done it before is exactly why it's a good test. Many people have memorized things like count up by 3, 5, etc. so they're not good tests of cognition. The point isn't to do it fast. It's to do it at all. Another test for dementia is to draw an old-school analog clock with a specific time on it. Being unable to draw the time, or even the clock (it will look like Salvador Dali) is a sign something is wrong.
• fragsworth 12y ago
  I think the idea is that it's not supposed to be easy, but you should at least be able to do it with effort, even if it takes you a while. Being totally unable to figure out how to do it (in your head) indicates something is wrong.
• Cass 12y ago
  This might actually be partly generational, if you, like me, grew up using a calculator. I must've done that test with probably about a hundred patients by now, and I have to tell you, the average halfway mentally competent seventy year old can do it faster than me. It's particularly embarrassing when they make a mistake early on, and then I can't just look down at the test sheet in my hand for the correct answers to see if the rest of the numbers are correct. That said, like other commenters have said, it's supposed to be a little bit hard. This exercise is part of the mini mental state examination [1], which is intended to be a screening test for the early stages of dementia, so you want to challenge people a little. The math part is actually the second-hardest task - the most difficult part for people with even very mild cognitive problems seems to be drawing the two interlocking pentagons. 1: http://en.wikipedia.org/wiki/Mini%E2%80%93mental_state_examination http://en.wikipedia.org/wiki/Mini%E2%80%93mental_state_exami...
  • simoncion 12y ago
    When asked to draw the interlocking pentagons, is one shown the picture beforehand, or is one supposed to conjure up the arrangement based solely on a description? If the former, do we have any idea as to why this is difficult?
• robrenaud 12y ago
  Well, if you do it a little, the obvious pattern emerges. You see that either: - There is no need for a carry, and then you just need to remember the previous 10s digit and subtract 7 from the ones place [tiny bit of memory work, single digit subtraction by 7]. - There is a need for a carry, the 10s place goes down by 1, the ones place goes up by 3 [a little extra strain on memory, single digit addition by 3]. Dispatching between those operations is easy. Is the ones place greater than or equal to 7?
  • MaysonL 12y ago
    I found it easier, for some reason, to just subtract 7, 14, 21, 28… from 100.