Let’s assume that you have already diagnosed a patient with Alzheimer’s Disease (AD). Your patient has received a full workup to rule out medical causes, and has had a full battery of neuropsychological tests. (See this month’s interview with Dr. Small for guidance on this initial workup.) Let’s further assume that you have started a standard cocktail of whichever cholinesterase inhibitor you prefer, plus memantine (Namenda).
Actually, that was the easy part. Now, you have to figure out if the medications are working. You’re dissatisfied with the old fashioned method of simply asking the patient and the family if there has been any improvement or decline in functioning, because it is too subjective. You’d like to be able to get a number to write in the chart so that you can convincingly demonstrate that treatment is working (or not).
The standard research instrument used for monitoring treatment outcomes in dementia is the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog) (Rosen WG et al., Am J Psychiatry 1984;141(11):1356–64). While it is useful in research, the ADASCog takes 30 minutes to administer and is thus too time consuming for the average busy clinician.
Two common alternatives that have been brought over from the bench to the bedside are the Mini Mental State Exam (MMSE) (Folstein MF et al., J Psychiatr Res 1975;12:189–198) and the Clock Drawing Test (Sunderland T et al., J Am Geriatr Soc 1989;37(8):725-729). The MMSE is quick—usually completed in less than 10 minutes—and effective at identifying and monitoring moderate to severe dementia. Studies have documented a typical decline of two to four points over 12 months if dementia is untreated. For patients who have been treated, the decline in scores is generally no more than one point (Winblad B et al., Neurology 2001;57:489–495; Courtney C et al., Lancet 2004;363:2105–2115). Keep in mind, however, that the test is not sensitive for mild cognitive impairment (MCI) or mild AD (Ihl R et al., Psychiatry Res 1992;44:93–106; Tombaugh TN et al., J Am Geriatr Soc 1992;40: 922–935), or for detecting impairment in patients who are well-educated and intelligent (Crum RM et al., JAMA 1993;269:2386–2391).
A relatively new test, called the Mini-Cog (Borson J et al., J Am Geriatr Soc 2003;51(10):1451–1454), is a combination of the MMSE’s three item recall question and the Clock Drawing Test. The Mini-Cog is administered in two steps. First, you ask your patient to repeat and memorize three simple words (the specific words are up to you). Then you give him a paper and pen, and ask him to draw a clock with the hands pointing to “11:10.” Once the clock is drawn, ask him to repeat your three words. The Mini-Cog is faster to administer than the MMSE, and studies have shown no significant differences in sensitivity or specificity between the two.
In measuring cognition on the milder end of the spectrum (MCI and mild AD), a potential alternative to the MMSE and the Mini-Cog is the Montreal Cognitive Assessment (MoCA). The MoCA emphasizes language and executive skills, takes about 10 minutes to conduct, and is very effective for identifying MCI (Nasreddine ZS et al., J Am Geriatr Soc 2005;53:695–699). The MoCA test and instructions are available for free at www.mocatest.org. (For TCPR’s take on the MoCA, see “The MoCA: A Better MMSE?” TCPR May 2008.)
While these instruments are effective in assessing cognition, they neglect some important aspects of treatment outcome in dementia, particularly caregiver burden and quality of life. Caregiver burden refers to the challenges faced by family members of patients with dementia, and can lead to significant problems with burnout and depression in those who care for such patients (Black W et al., Int Psychogeriatr 2004;16(3):295–315). To assess this, we recommend the shortened 7-item Screen For Caregiver Burden available in Appendix 1 at the end of the developer’s article (Hirschman KE et al., J Am Geriatr Soc 2004;52(10):1724–1729).
To assess your patients’ quality of life and functional abilities, we recommend the Quality of Life in Alzheimer’s Disease scale (QOL-AD) (Logsdon RG et al., Psychosomatic Medicine 2002:64:510–519), which takes about 10 minutes to administer and is available online with instructions at http://bit.ly/9RjySn.