Dementia: A brief overview

Author: Renee Flores, MD & Naysia Ahmed, MD

Key Points

Dementia describes a syndrome caused by chronic and/or progressive brain disease affecting higher cortical function.

It is estimated that the prevalence of Alzheimer's disease will triple by 2050.

Mild cognitive impairment (MCI) may be described as a transition phase between cognitive changes from normal aging and dementia.



Dementia is an umbrella term that includes:

Risk factors include: 



Assess for delirium before dementia. The CAM is a recommended screening tool:

Some comparative facts include

Comparing Dementia and Delirium
Dementia Delirium
Onset Insidious, with an uncertain starting point Rapid, usually with a certain starting point
Main symptom Loss of memory, particularly for a recent event(s) Inattention
Cause May be related to an underlying brain disorder, such as Alzheimer disease, vascular dementia, or Lewy body dementia Nearly always related to underlying acute change, such as dehydration, infection, or starting or stopping medications
Orientation Impaired Fluctuates
Level of consciousness May be normal until advanced stages Fluctuates from being lethargic to hyperalert
Language May be problematic with word choices Slowed or rapid speech, frequently with incoherent and/or inappropriate language
Progression Slowly progresses, gradually but eventually greatly impairing all mental functions Causes variations in mental function- people are alert one moment and sluggish and drowsy the next
Development Often permanent Fluctuates; days to weeks to months
Treatment Needed but less urgently; slows progression but does not cure Immediate; usually reversible

Once delirium is ruled out, the next steps are:





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American Medical Association (2013). Dementia. Retrieved from Accessed November 1, 2013. 

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U.S. Preventive Services Task Force (2003). Screening for dementia: recommendations and rationale. Annals of Internal Medicine; 138: 925-926. http://www.preventive