Blog | Thursday, October 24, 2013

QD: News Every Day--Brief screening for cognitive impairment may not affect outcomes

Brief screening instruments can detect cognitive impairment, but the results may not have an effect on clinical care, according to a new study.

Researchers performed a systematic review for the U.S. Preventive Services Task Force to examine whether brief cognitive screening instruments were diagnostically accurate and to investigate the benefits and harms of interventions for early cognitive impairment. Five key questions were addressed:

1. Does screening for cognitive impairment in community-dwelling older adults in primary care-relevant settings improve decision-making, patient, family or caregiver, or societal outcomes?
2. What is the test performance of screening instruments to detect cognitive impairment in elderly, community-dwelling primary care patients?
3. What are the harms of screening for cognitive impairment?
4. Do interventions for MCI or mild to moderate dementia in older adults improve decision-making, patient, family or caregiver, or societal outcomes?
5. What are the harms of interventions for cognitive impairment?

The study was funded by the Agency for Healthcare Research and Quality and was published online by Annals of Internal Medicine on Oct. 22.

The study authors found that the Mini-Mental State Examination is the most thoroughly studied instrument for detecting dementia but pointed out that it can't be used without cost. Publicly available instruments that performed adequately included the Clock Drawing Test, Mini-Cog, Memory Impairment Screen, Abbreviated Mental Test, Short Portable Mental Status Questionnaire, Free and Cued Selective Reminding Test, 7-Minute Screen, and Informant Questionnaire on Cognitive Decline in the Elderly. The review also found that FDA-approved medications for Alzheimer's disease and caregiver interventions yielded only small benefit of uncertain clinical importance. Evidence was also limited for cognitive stimulation and exercise in patients with mild to moderate dementia or mild cognitive impairment.

The authors noted that their review had a narrow scope and didn't address comparative performance of screening instruments or the possibility of combining screening instruments, among other factors. However, they concluded that although brief screening instruments can detect cognitive impairment, it is not confirmed whether screening and early diagnosis improve decision making or outcomes.

"Despite a large body of evidence spanning decades of research, it is still unclear whether FDA-approved medications, caregiver interventions, cognitive interventions, or exercise interventions in persons with earlier detected cognitive impairment have a clinically significant effect," the authors wrote. "How best to identify persons with cognitive impairment and understanding how and whether early identification affects important decision making is much needed to address this common, growing, and costly health condition."