Tip of the tongue and “senior moments”: the truths behind dementia

Tip of the tongue and “senior moments”: the truths behind dementia

Nitin K Sethi, MD


        Comprehensive Epilepsy Center, Department of Neurology, NYP-Weill Cornell Medical Center, New York, NY (U.S.A.)


Address for Correspondence:

NK Sethi, MD

Comprehensive Epilepsy Center

Department of Neurology

NYP-Weill Cornell Medical Center

525 East 68th Street, York Avenue

New York, NY 10021

Fax: 212-746-8984

Email: sethinitinmd@hotmail.com

I read an interesting article in the Wall Street Journal by Melinda Beck titled ” The science behind senior moments”. In it she talks about “senior moments”-episodes where-in you are temporarily unable to recall a name, forget a number (like the telephone number of a close friend or a relative) or enter a room and forget what you were supposed to do. Just what do these “senior moments” represent-are they just signs of normal aging process or are they a warning sign of impending dementia?

Let me give you an example. Let us assume you are watching a movie starring Cary Grant. You see Cary Grant on the screen, you know who he is but for the life of you, you cannot recall his name. we call this the “tip of the tongue” syndrome. You have the name on the tip of your tongue but are unable to get it out. We all have older family members and friends. We notice that at times they are more forgetful. They forget their keys, forget names: are these “senior moments” or are they signs of dementia? Is there anything called senile dementia? (that is dementia occuring due to old age itself, not due to a neurodegenerative condition like Alzheimer’s disease).

Before we discuss this further, we should try to understand how memories are formed and stored in the brain. In simple terms we first register and encode memory, then this is stored and finally it is retrieved. What do i mean by this? Well the first thing which occurs is registration and encoding. For one to retain memory, one must first register what one is trying to remember. Let me explain this with an example. Lets assume you are reading a book. At the same time you are watching the TV and talking to your friend on the phone (that is you are multi-tasking). Now if I ask you to recall what you just read, it is possible that you shall not be able to do so well. Why? This is because your attention was divided and hence you never really registered what you were reading in the first place. If you did not register, you did not commit it to your memory and hence you cannot recall it. So first lession is that when you are trying to memorize something, make sure you pay attention.

Then comes consolidation and storage of memory, the process by which the brain stores the memory. Memory is usually stored in the temporal lobes and the hippocampus. This is a complex process and a lot is still not known how exactly are these memory programs laid down in the brain. Consolidation and storage of memory ensures that the memories become more permanent. There is some data to suggest that consolidation and storage of memory occurs at night while we are asleep. Maybe there is some truth to grandma’s saying of getting a good night sleep before a big examination.

Finally is the process of retrieval. This is the process by which we are able to recall an old memory. One can have a problem at any step of this memory process. Patient’s with Alzheimer’s dementia usually have a problem with both consolidation and retreival. Someone who is intoxicated but does not have Alzhemier’s dementia like an alcoholic shall have problems with encoding as he is delirious.

Now that we know how memory is formed, I want to stress that the tip of the tongue syndrome occurs in many healthy people. Why does it occur? Why is there a temporary memory block which then clears by itself and we are able to remember everything? No one quite knows the answers to these questions.

Senior moments though (especially if they are occuring in the senior population above the age of 65) deserve a more closer look. Is the problem episodic (comes and goes) or is it constant (always present)? Is is static and stable or is it progressive? Does it involve just one domain of memory (like names) or is it more widespread involving multiple domains (not just names but things like forgetting how to drive a car, problems with calculations and abstract thinking etc).

If the above are present, then it is not senior moments and is more likely to be dementia. Some neurologists doubt if something like senile dementia actually exists. We all have met some elderly people with razor sharp memory.

That in essence is the truth behind senior moments and the tip of the tongue syndrome.