Semantic memory refers to the general world knowledge we've accumulated throughout our lives. This general knowledge such as facts, ideas, meaning and concepts is intertwined in experience and dependent on culture. Together, these shape our view of the world and ourselves.

But, to put it in simpler terms, our semantic memory is our store of factual knowledge of the world and the meaning of words. And as these definitions infer, semantic memory is critical to our survival.

Semantic memory is distinct from episodic memory, which is our memory of experiences and specific events that occur during our lives. But these two types of memories must work together for you to keep your semantic memory sharp. To form new semantic memories, we need to use our episodic memories to learn new information.

We need to constantly form new semantic memories because of the threat of dementia. And we also need to do this to ward off "semantic dementia."

People with some types of dementia have a deterioration of the anterior temporal lobe. This leads to difficulties understanding what words mean. People with Alzheimer’s most commonly exhibit this abnormality, which is most prominent in a type of aphasia known as semantic dementia.

Semantic dementia is a degenerative disorder that causes a progressive loss of semantic knowledge. It affects both verbal and nonverbal domains. Aphasia is an impairment of language, affecting the production or comprehension of speech and the ability to read or write.

People with semantic dementia don't know what certain words mean. For example, they can't tell the difference between “medicine” or “shoe."

In the words of one study conducted in 2010, "Semantic dementia (SD) designates a progressive cognitive and language deficit, primarily involving comprehension of words and related semantic processing. These patients lose the meaning of words, usually nouns, but retain fluency, phonology, and syntax."

Memory Storage
The brain recalls information from the brain efficiently, but unlike a computer. Photo courtesy of Pixabay, public domain

And which parts of the brain stores semantic memory? Semantic memory is normally linked to the left temporal lobe. On the other hand, the right temporal lobe has been linked to knowledge of nonverbal information and facial recognition. Other parts of the brain also participate in semantic memory.

Improving your semantic memory can be as easy as doing a crossword puzzle. That's because semantic memory stores the meaning of words and nonverbal concepts. It also stores the relationships within and between words and concepts.

The good news is research suggests semantic memory doesn't decline in normal aging. Your vocabulary and your ability to solve crossword puzzles may actually improve with age since you continue to learn new information throughout your life.