There’s a common misconception that dementia is a disease, but it’s actually collection of symptoms. Dementia symptoms affect a person’s memory and sometimes other faculties, like reasoning and judgment. These impairments of a person's mental ability are significant enough to disrupt daily life.
So what symptoms make for a diagnosis of dementia? The first criterion for dementia is memory impairment, but others must occur at the same time.
There are many different types of memory, including long- and short-term memory. Verbal memory involves a person’s ability to recall things like names and events. Motor memory refers to retention of the ability to carry out tasks and activities requiring motor skills, such as riding a bicycle.
In addition to memory impairment, one of the following dementia symptoms must be present:
- Executive function impairment
Aphasia is speech impairment that causes people to struggle to speak despite having intact verbal mental “hardware.” Patients have trouble speaking, but not because their tongue or the muscles in their larynx don’t work.
Most commonly, doctors observe what are called “expressive aphasias,” meaning cases in which a patient struggles to get the right words out. A doctor might show a patient a pen, for example, and then ask: “What is this?” Instead of identifying it as a “pen,” a person with aphasia might say: “It's one of those things that you write with.” They might also use the wrong word for an object or be unable to use the same words in a different context.
Apraxia is a condition in which a person has impaired motor abilities despite having intact motor hardware. To test someone’s motor abilities, a doctor might say, “Take this piece of paper in your left hand, fold it in half and put it on the floor.” The patient with apraxia will take it, but they might take it with both hands or the wrong hand, and then struggle to fold it. They might drop it. They are just not able to manipulate the object like they once were.
Agnosia is a loss of sensory functioning, which means a person loses their sensory abilities despite having intact sensory hardware. It affects the five senses.
To test for agnosia, a doctor might put a paper clip or coin in the hands of a patient while their eyes are closed. A person with agnosia would struggle to identify the object. They can feel but not identify the object.
Executive Function Impairment
Executive function impairment is, perhaps, the most critical cognitive loss, because it affects a person’s ability to plan, organize, sequence, monitor and complete complex, goal-directed behaviors.
Executive function is the set of cognitive processes that allows you to behave independently from your environment instead of having the environment mediate your behaviors. It affects the brain’s frontal lobe functioning, making performing complex tasks — such as driving a car — difficult.
People with executive function impairment become dependent on routine. When something in their environment changes, they cannot adjust. Judgement and insight become impaired. For example, someone who is cooking a familiar dish might get interrupted by a telephone call. When they return to the task, they’ve forgotten how to make the recipe.
Other symptoms of dementia may include functional impairmen, which occurs when a patient is no longer able to perform self-care activities and meet self-care needs. These might include tasks like using the telephone, managing money or medications and driving or arranging transportation. It may also include more basic functional loss like walking, toileting, grooming and bathing.
Have you observed any of these dementia symptoms in someone in your care? Talk to a health care professional about how to cope. You can also download our free ebook "Most Common Types of Dementia: A Caregiver’s Guide to Alzheimer’s Disease, Vascular Dementia, Lewy Body Dementia and More."If you're looking for a comprehensive resource for family caregivers, check out our online Family Caregiver Guide.