Clearing Up Some Confusing Terms

What are amnesia, aphasia, anomia, alexia, agraphia, acalculia, (relatively commonly used terms) and agnosia, apraxia, anosagnosia, anosadiaphoria (relatively uncommonly used terms)?  Wow, I have been doing behavioral neurology for over 25 years and I know I missed a few of the “a” words here....In numerous previous blogs I have frequently referred to disorders of thinking and memory and occasionally I have used the term cognition.  I have also briefly mentioned some of the terms above, such as aphasia.  I believe it is time to be a little more specific about what some of these terms mean. I will try in this blog to describe some specific terms that are commonly used in discussing Alzheimer’s disease and related disorders.

In the previous blog this month, I tried to describe the common brain imaging tests that may be associated with an evaluation of a patient with Alzheimer’s disease.  As the evaluation progresses and the patient is seen by a psychiatrist, neurologist, neuropsychologist, psychologist or other health care professional, one or more of the “a”  terms or related terms may be used.  They are convenient shorthand for conveying an accurate description of a patient’s ability of disability.  As indicated some of these terms are commonly used and some are uncommonly used.  We will review the common terms.

Thinking and Memory: These two words may be loosely translated into “cognition.”

Cognition: Cognition is a term that includes the various brain abilities that enable a person to perform complex interactions with the environment (including other people).  It includes all of and more than the terms that will be discussed below. 

Amnesia: This is an impairment of the cognitive function memory.  In clinical neuroscience (neurology, psychiatry, psychology etc), when the letter “a” is applied to the front of a word or term, the “a” indicates an impairment of that ability.  Amnesia may be applied to any type of memory loss, including loss of language related information (verbal amnesia) or spatial information (spatial amnesia).  When patients with Alzheimer’s disease cannot remember what day it is, where they are, who is President, or where the closest drug store is, they are demonstrating amnesia.

Aphasia: This is an impairment of language, especially spoken language.  It includes the ability to speak with the appropriate words and grammar, understand spoken language, repeat spoken language and say names of objects or people.  When patients with Alzheimer’s disease cannot speak in grammatically correct sentences, convey accurate information, name objects or people or understand what is being said to them, they are demonstrating aphasia.

Anomia: This is an impairment in the ability to accurately say the name of something.  It is not because the patient cannot recognize the item but because something disrupts the brain’s ability to produce the correct word.  When patients with Alzheimer’s disease say the wrong name (calling a “penguin” a “parrot”), they are demonstrating anomia.