CAM - Confusion Assessment Method

Observations by the Interviewer



Delirium (acute confusional state) is a common, serious, and potentially preventable source of morbidity and mortality for older hospitalized patients. Delirium has assumed particular importance because patients over 65 years currently account for more than 48% of all days of hospital care. Currently, delirium occurs in 25-60% of older hospitalized patients, with associated mortality rates of 25-33%. Based on 1994 U.S. vital health statistics, each year delirium complicates hospital stays for over 2.3 million older persons, involving over 17.5 million inpatient days, and accounting for 8 billion dollars of Medicare expenditures. Substantial additional costs accrue following hospital discharge because of the increased need for institutionalization, rehabilitation, and home care.

The Confusion Assessment Method (CAM) was originally developed in 1988-1990, to improve the identification and recognition of delirium. CAM was intended to provide a new standardized method to enable non-psychiatrically trained clinicians to identify delirium quickly and accurately in both clinical and research settings.
Since its development, the Confusion Assessment Method has become the most widely used instrument for detection of delirium world-wide, because of both its strong validation results as well as its ease of use. The CAM instrument has been used in over 250 original articles to date, as either a process or outcome measure, and has been translated into over six languages world-wide. When validated against the reference standard ratings of geriatric psychiatrists based on comprehensive psychiatric assessment, the CAM had a sensitivity of 94-100%, specificity of 90-95%, and high inter- observer reliability in the original study of 50 patients (Inouye, 1990). More recently this work has been extended (Wei, 2008), and in 7 high-quality validation studies on over 1,000 subjects, the CAM had a sensitivity of 94% (95% CI 91-97%) and specificity of 89% (95% CI 85-94%).
The CAM is usually rated by a clinical or trained lay interviewer on the basis of an interview with the patient that includes at least a brief cognitive assessment. The Mini- Mental State Examination was used in the original validation, but its use is now restricted by copyright law. A more brief assessment, the Modified Mini-Cog Test (Pg. 25) is recommended for quick screening. Generally, the entire CAM rating takes 5-10 minutes to complete.
Adapted from: Inouye SK, vanDyck CH, Alessi CA, Balkin S, Siegal AP, Horwitz RI. Clarifying confusion: The Confusion Assessment Method. A new method for detection of delirium. Ann Intern Med. 1990; 113: 941-948. Confusion Assessment Method: Training Manual and Coding Guide, Copyright 2003, Hospital Elder Life Program, LLC.
Interviewer: Immediately after completing the interview, please answer the following questions based on what you observed during the interview, Modified Mini-Cog Test, and Digit Span Test.


There are 34 questions in this survey.
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