Alzheimer’s ABC’s: Cognitive Changes (Depression and AD)

Depression and Alzheimer’s
In the first three posts (1, 2, 3) of this series we explored how to identify and understand many symptoms of early Alzheimer’s disease (AD), as well as how to use them to build a historical timeline.  These posts provide a good foundation for moving forward in our basic understanding of AD.

In this post we move into the topic of cognitive changes associated with early AD, and include an exercise you can try with your loved ones at home.

Early Alzheimer’s or Depression?
Twenty percent of people with Alzheimer’s disease (AD) also develop depression, so it is not uncommon for a person with AD to also be depressed. However, I see a number of patients who present with symptoms of AD, when the patient is simply depressed with no real sign of AD. So an individual could show apparent symptoms of AD and be in one of following groups: 1. they actually have AD, 2. they have both AD and are depressed or 3. they are experiencing pure depression with no associated AD.

Since people with depression sometimes complain very bitterly of memory difficulties, it’s very important from a clinical standpoint to distinguish between early AD and pure depression.

This is a crucial distinction, offered here to help you better understand the basic concepts. If symptoms are present it is important to have a physician conduct a full evaluation, since making the clinical determination can be tricky.  (You can also access our clinical, early warning screening test online by visiting our website.)

One unique way we can address this challenge is through associated memory. Here’s something you can try at home: ask the individual to remember 3 words (example: telephone, police, river). Have them repeat the words aloud to you and then go back to whatever they were doing.  Wait 10 minutes before asking them to repeat the words.

This is free recall – asking them to repeat the words with no help from you.  If they cannot remember all 3 words then give them a clue or a bit of information to help them identify the category, without giving away the word.  For example, if they miss the word “phone” you might say: one word I asked you to remember is a means of communication.

A patient who is depressed will find the clues very helpful and be able to recall all three words.  This associated recall will not, however, help a person with AD. The words will be irretrievably lost.  The defect here is in the hippocampus and temporal lobe, which prevented the individual from laying down the new memories when they heard the words initially.

With pure depression, the memory is laid down but the depression itself causes an attentional defect.  The inability to pay proper attention initially interferes with memory of the words during free recall.  Since the memory was initially laid down however, the clues will help depressed individuals to retrieve the words.

This is another example why taking a thorough history can be very helpful at distinguishing early Alzheimer’s disease from other problems which may present with similar symptoms. You may access our early warning screening test for Alzheimer’s online by visiting:

I wish you very good health.

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