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Friday, June 10, 2011

Is It Memory Loss or Dementia?

A VIEW FROM THE OFFICE



Am I Just Forgetful or Am I Getting Dementia?

     This is a question that worries many of us as we creep above the age of 50. For some people it starts even younger. It is my personal observation that we have more brain fatigue in our population than ever in the history of the world just because we have so much information and media to digest and because we tend to be multi-tasking all the time and wired all the time. I can't believe this hyperarousal for the ordinary business of life is any good for us.
     So how many of you out there have had the experience of trying to pull up a word from your vocabulary for a common object, something you absolutely know you know, but you can't come up with it? How many of you have stepped into another room to get something and have forgotten what you were looking for before you even get half way into the room? How many of you when taking pills at night can remember whether you have already taken you vitamin pill?  How many of you have worried about an important lunch date for weeks then forgot all about it when the time came? How many of you have drawn a total blank on the PIN number for your ATM card and had to go home cashless?  These minor humiliations are happening all the time to more and more of us. It is also true that there are more cases of Alzheimer's disease in the general population than there ever has been before--most of this due just to the fact that we are living much longer than we used to.
     Generally, as soon as a middle aged person has repeated bouts of memory lapses of the kind described above they start to worry, "Could I have Alzheimer's?"
     The good news is that, if you have the presence of mind to ask yourself this question, you probably do not have Alzheimer's disease.  The other good news is that even if you did, it's not as bad as it once was. It is now possible to live 20 or more years of completely function life after the initial diagnosis of mild Alzheimer's.
     The New England Journal of Medicine has just published an article on "Mild Cognitive Impairment," which is the term for this kind of repetitive memory loss that is not Alzheimer's disease. (Petersen RC. Mild Cognitive Impairment. NEJM 2011; 364: 2227-34)
I thought it might be a worthwhile endeavor to illustrate the range of cognitive function between normal and full-blown Alzheimer's disease. Here the authors identify their subject, mild cognitive impairment, as "an intermediate state of cognitive function between the changes seen in aging and those fulfilling the criteria for dementia and often Alzheimer's disease. Most people undergo a gradual cognitive decline, typically with regard to memory, over their life span; the decline is usually minor, and although it may be a nuisance, it does not compromise the ability to function." Only about 1 in 100 people go through an entire lifespan with no signs of cognitive impairment. Currently it is estimated that the prevalence of mild cognitive impairment in population-based studies ranges from 10 to 20% among persons older than 65 years of age. In the US the incidence of dementia is 1-2% per year.
     The authors divide cognitive impairment into two categories:
     1. Amnestic mild cognitive impairment: "Typically, these patients and their families are aware of the increasing forgetfulness. However, other cognitive capacities, such as executive , use of language, and visuospatial skills, are relatively preserved, and functional activities are intact, except perhaps for some mild inefficiencies."
     2. "Non-amnestic mild cognitive impairment is characterized by a subtle decline in function not related to memory, affecting attention, use of language, or visuospatial skills." 

     The distinction between these two types of memory function is subtle and somewhat difficult. The memory loss is more severe in patients with the amnestic type. "Typically, they start to forget important information that they previously would have remembered easily  such as appointments, telephone conversations, or recent events that would normally interest them (e.g., for a sports fan, outcomes of sport events). However, virtually all other aspects of function are preserved. The forgetfulness is generally apparent to those close to the person but not to the casual observer." The big difference in dementia is that in dementia the cognitive deficits are affecting daily functioning to the extent that there is loss of independence in the community.
     What most people with mild cognitive impairment are worried about is whether it will progress to actual dementia. In reality, such progression occurs in only 10% of patients.

     If a diagnosis of "mild cognitive impairment" is made there is not much to do. While there are some fancy imaging techniques that are being use in research, they will not help an individual patient, particularly as there is no specific treatment for this condition. While medications offer no benefit as yet, there is some evidence of potential benefit from cognitive rehabilitation, including the use of mnemonics, association strategies, and computer-assisted training programs. One of the most important points for evaluation is to rule out the possibility of depression (from loss of significant others or diminished circumstances or chronic disease), as depression clearly causes major impairment of memory. For the purposes of prevention, traditional cardiac risk factors appear to be markers for a higher risk of this condition. Thus the most effective primary prevention is likely to be, as I have said so many times before, a healthy lifestyle. You know: 0 - 5 - 10 - 30 - 150. (0 cigarettes, 5 servings of fruits and vegetables daily, 10 minutes of relaxation daily, a BMI < 30, and 150 minutes of exercise each week)
     For the most part mild memory loss is a normal aspect of aging to which the kindly grace of age helps us to adjust.
     I do not expect you to remember any of this article.

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