An elderly patient presents brought by family for confusion. After a full but negative workup, you wonder whether this could represent dementia.
The main differential for confusion in this age group is delirium vs dementia.
Is the problem chronically progressive?
Dementia should have been slowly developing for months or years. If the problem is acute, consider delirium. The family states they are not sure about the time course, though you note that sometimes respect for the elderly expresses itself in overlooking the minor infirmities of aging.
Is the patient attentive?
Inattention is the hallmark of delirium. Have them count months backward to demonstrate attentiveness. If they can’t do that, they may be in a delirium and further testing for dementia is not valid. She can count months backward.
The definition of dementia according to DSM-IV is a chronic deficit in memory plus one more cognitive domain (mainly language, praxis, and executive function) not explainable by another condition.
A bedside examination can quickly assess this using 3 item recall at 5 minutes as well as clock-drawing. Patients with dementia usually have impairment in both modalities. When this examination is formalized as the “mini-Cog” it has been shown to have good sensitivity and specificity. It tests short-term memory and executive function as well as spatial awareness. I like to additionally test long-term memory, usually by asking about the previous three presidents.
She recalls one item at 5 minutes and can not draw a legible clock. She is able to describe but not name the current president. You suspect dementia and refer her to a neurologist for futher evaluation.
Take Home Points:
-Diagnosing dementia is invalid in delirium (acute, inattentive)
-Dementia: deficits in memory and at least one other cognitive domain
-3-item recall and clock-drawing assesses memory and executive/spatial functioning