"Sweet 16" Cognitive Assessment Tool Promising in Older Adults

Megan Brooks

November 10, 2010

November 10, 2010 — Researchers from Boston, Massachusetts, have developed and validated a 16-item cognitive assessment tool known as the "Sweet 16" that can identify problems in thinking, learning, and memory among older adults.

The Sweet 16 tool grew out of a need to have an instrument that would be quick to administer and free to use, Tamara G. Fong, MD, PhD, assistant professor of neurology at Harvard Medical School and staff neurologist at Beth Israel Deaconess Medical Center, Boston, explained in an email to Medscape Medical News.

"There are a lot of other brief cognitive tests available," she noted, "but these often required pen and paper or other props such as special forms to administer, or the instruments weren't well validated, or they took too long," she noted. "The copyright on the Mini-Mental State Examination [MMSE], with its fee per usage, was another challenge. Thus, we decided to develop a new test that would improve on what was currently available."

Their report was published online November 8 in the Archives of Internal Medicine.

To develop the Sweet 16, Dr. Fong and colleagues used information from 774 patients aged 65 years and older who completed the MMSE before being admitted to a skilled nursing facility directly from an acute medical or surgical hospitalization. The Sweet 16 performance characteristics were then independently validated in 709 participants in the Aging, Demographics, and Memory Study using clinical consensus diagnosis and 2 different dementia and cognitive decline rating scales.

Table 1. Description of Sweet 16 Items

Item No. Item Description Cognitive Domain Points
1 – 8 Orientation to time and place Temporal/spatial orientation 8
9 – 11 Immediate repetition (3 items) Registration 3
12 – 13 Digit spans backward Sustained attention 2
14 – 16 Recall (3 items) Short-term memory 3

 

In the development cohort, the Sweet 16 correlated highly with the MMSE (P < .001). There was significant (P < .001) overall agreement between the 2 instruments at "clinically relevant thresholds (< 14 for Sweet 16 and < 24 for MMSE)," the investigators report.

Validated against the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), the area under the curve was 0.84 for the Sweet 16 and 0.81 for the MMSE (P = .06), they further report.

The results, Dr. Fong told Medscape Medical News, "actually exceeded our expectations for how well the Sweet 16 instrument performed in comparison to the MMSE. As a screening instrument, it had better sensitivity and was much quicker to administer (2 minutes compared to a minimum of 10 minutes for the MMSE)."

Table 2. Performance of the Sweet 16 and MMSE Compared With IQCODE and Clinical Diagnosis

Measure Sweet 16 Score <14, % (95% CI) MMSE Score <24, % (95% CI)
IQCODE    
 Sensitivity 80 (67 – 91) 64 (51 – 77)
 Specificity 70 (65 – 91) 86 (83 – 89)
Clinical diagnosis    
 Sensitivity 99 (97 – 100) 87 (78 – 95)
 Specificity 72 (68 – 77) 89 (86 – 92)

CI = confidence interval; IQCODE = Informant Questionnaire on Cognitive Decline in the Elderly; MMSE = Mini-Mental State Examination

An IQCODE score higher than 3.5 and a clinical diagnosis were used as reference standards to compare with both the MMSE score lower than 24 and the Sweet 16 score lower than 14.

"This instrument could be used in the research setting for study eligibility screening, to measure risk, and as an outcome measure," Dr. Fong said. "For the clinician, the Sweet 16 could be used to screen patients in a primary care setting who complain about memory problems, or in the hospital to determine if someone might have some cognitive impairment that puts them at a higher risk for complications such as delirium."

Dr. Fong emphasized that the Sweet 16 is only a screening test for cognitive impairment and is not intended to replace more sensitive and comprehensive tests of cognitive function.

"The Sweet 16 on its own is not intended to be a definitive test to diagnose dementia but, rather, to identify patients who might need further evaluation by a neurologist or other specialist," she said.

The Sweet 16 instrument, training materials, and equivalency scores are available online.

Clear Need for Better Assessment Tools

Reached for comment on the Sweet 16, James Galvin, MD, MPH, clinical professor of neurology and psychiatry at NYU Langone Medical Center and clinical director of the Pearl Barlow Center for Memory Evaluation and Treatment in New York City, said, "There is a clear need and a push by many investigators, including myself, to develop tools to assist primary care providers in detecting cognitive impairment in older adults." Dr. Galvin is the developer of the AD8 dementia screening test.

"This attempt at developing a very, very brief performance measure is admirable," Dr. Galvin added. However, he said, "it's unclear from the study whether the Sweet 16 would assist doctors in defining the very earliest signs of dementia, which are diagnostically the most challenging.

"There are people in the validation sample that have severe dementia, which is not a diagnostic dilemma," he points out. "I think it would have been more useful to only do the study comparing healthy older adults vs people with the very mildest signs of dementia because that is the challenge — including mild cognitive impairment, which is even more of a diagnostic challenge."

Development of simple and effective cognitive assessment tools for primary care is "timely," Dr. Galvin noted, given the requirement in the health reform bill that primary care physicians assess for cognitive impairment as part of the annual wellness visit for Medicare beneficiaries.

Dr. Fong and colleagues have disclosed no relevant financial relationships. Dr. Galvin is developer of the AD8 dementia screening test but has disclosed no other relevant financial relationships.

Arch Intern Med. Published online November 8, 2010.

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