The Memory Stress Test

Excerpted from
Age-Proof Your Mind; Detect, Delay and Prevent Memory Loss Before It's Too Late
By Zaldy S. Tan M.D., MPH

On the first day of anatomy class back when I was in medical school, I remember standing at the back of a long hallway with my classmates, listening to an elderly professor as she read our group assignments from a piece of paper. One by one, she called out our names and assigned us to random groups of four students each. We did our best to focus our attention on what she was saying, but it wasn't easy. Lined up in neat rows in front of us were cadavers whose outlines we could barely make out under the thick green tarp. When she finished reading our group assignments, the professor told us that over the course of the year, we would get well acquainted with our cadavers. She said that we were about to meet the best teacher we would encounter in medical school.

The dissection of the cadaver was the culmination of our anatomy class. The dead brought new life to the pictures and diagrams we had been studying in our books. The caretakers of the cadavers kept them from decaying in the midst of the course by injecting them with formaldehyde. This provided us with ample time to sequentially dissect the heart, the lungs, the stomach and intestines, the reproductive organs, and the muscles and nerves. Out of respect for the cadaver, we exposed only the part of the body we were studying at the moment, leaving everything else covered. As the end of the year drew closer, curiosity got the best of my group and we decided to sneak a peek at our cadavers head when the professor wasn't looking. To our surprise, we saw that its skull had been opened and the brain was mysteriously missing. We later learned that the delicate brain had been removed because it could not be preserved inside the skull. The handlers had extracted it soon after death and kept it in preservative-filled jars. There it remained until we were ready to tackle the anatomy of the nervous system.

Having a strong interest in the brain as a medical student, I eagerly awaited the day we were scheduled to study it. When we finally plucked out the three-pound fatty mass from its chemical bath, I was impressed by how remarkably fresh it looked considering that it had been more than six months since its owner died. With scalpels in gloved hands, each member of our group took a turn cutting the brain in the precise fashion dictated by our professor, careful not to accidentally cut a delicate nerve or sever a small artery. With some awe and a lot of confusion, we identified each part of the brain and the function that it controlled. One by one, we examined the brain areas that controlled voluntary movement, those that sensed visual stimuli, and even the horseshoe-shaped mound responsible for short-term memory, the hippocampus. Although the exercise was very informative, I found myself somewhat dissatisfied at the end of it. I had expected that in the process of dissecting the brain we would be able to identify the part that was responsible for some of the human mind's most important functions, such as logical thought, judgment, and emotions. These are the capacities of the mind that distinguish humans from the other animals I had dissected in biology class. But after I had a chance to think it over, my initial bout of disappointment was replaced by a newfound respect for the complexity of the human mind.

Unlike other organs such as the heart, which has a corresponding structure responsible for each function, many of the functions of the mind cannot be explained by simply dissecting the brain. The mind is an entity whose inner workings remains a mystery to us up to this day. For years, researchers have struggled to find a way to separate the worried well from those who are truly in the very early stages of dementia. While there is no single blood test, brain scan, or memory test that will confirm the presence or absence of incipient Alzheimer's disease, it is possible to make the diagnosis through a combination of subjective memory complaints and a battery of objective memory tests. In this chapter, I will help you to "dissect" the mind into some of the cognitive domains discussed in chapter 2, as well as the mind's other abilities:

1. Attention and concentration
2. Language
3. Memory
4. Executive function
5. Abstract thinking
6. Calculation

I will begin by presenting some of the tests I use in my clinic to test for memory and other cognitive domains. I invite you to take these tests and get better acquainted with your mind.