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Tests detect dementia in older people; cognitive stimulation or some drugs may slightly improve cognitive function

Lin JS, O’Connor E, Rossom RC, et al. Screening for cognitive impairment in older adults: A systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2013;159:601-12.

Review questions

In older people, do screening tests detect cognitive impairment or dementia?

In older people with cognitive impairment or dementia, can treatments improve cognitive function?

Background

Mild cognitive impairment includes problems with thinking, memory, language and judgment that are noticeable but don’t much affect daily living. Dementia is cognitive impairment that is serious enough to interfere with daily living.

Doctors may not know if their patients have early cognitive impairment without doing tests. It may seem logical that if detected early, people may be able to get treatments to improve their cognitive function. However, we are not sure which treatments, if any, help to improve cognitive function in people with cognitive impairment or dementia.

How the review was done

The researchers did a systematic review, searching for studies that were published up to December 2012.

They found 46 studies on screening tests for dementia. The studies included mostly women (average age 69 to 95 years).

They found 174 randomized controlled trials on the effects of different treatments on cognitive impairment.

What the researchers found

The quality of evidence was rated as fair.

Screening tests

The Mini-Mental State Examination or MMSE was the screening test most studied. It detected about 88% of people with dementia. In people who did not have dementia, the MMSE falsely indicated that 14% had dementia (“false-positives”).

Treatment

Treatments that improved cognitive function

Compared with control, cognitive function:

  • improved by a small amount with cholinesterase inhibitors, including donepezil (Aricept®), galantamine (Razadyne®) and rivastigmine (Exelon®);
  • improved by a small amount with memantine (Namenda®); and
  • improved by a medium amount with cognitive stimulation, which involves a wide range of activities, usually done in a small group, to stimulate thinking and memory (e.g., talking about past and current events, puzzles, music, gardening).

People sometimes stopped taking cholinesterase inhibitors because of side-effects. This was not a problem with memantine and was not reported with cognitive stimulation.

 

Compared with control, cognitive function did not differ with:

  • aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil®), naproxen (Aleve®), indomethacin (Indocin®) and celecoxib (Celebrex®);
  • dietary supplements (multivitamins, B vitamins, vitamin E with or without vitamin C, and omega-3 fatty acids);
  • steroids (estrogen with or without progesterone, and testosterone); and
  • non-drug treatments other than cognitive stimulation (exercise and education).

Conclusion

The Mini-Mental State Examination detected most people with dementia among older people but falsely labelled some as having dementia. Cholinesterase inhibitors (including donepezil, galantamine and rivastigmine), memantine and cognitive stimulation may improve cognitive outcomes in older people with cognitive impairment or dementia, but improvements are generally small.


Effective treatments for mild cognitive impairment or dementia*

Treatments

Number of trials and people

Effect on cognitive function

Side-effects

Cholinesterase inhibitors (donepezil, galantamine and rivastigmine)

48 trials (18,390 people)

Small improvement, which may not be noticeable, at 6 months, mostly in people with moderate dementia or Alzheimer disease

More people stopped taking the drug because of side-effects, but there was no increase in serious side-effects

Memantine

10 trials (3,476 people)

Small improvement, which may not be noticeable, at 6 months, mostly in people with moderate dementia or Alzheimer disease

No difference in number of people who stopped taking the drug because of side-effects

Cognitive stimulation

6 trials (513 people)

Medium improvement at 6 to 12 months in people with mild cognitive impairment or mild dementia

Not reported

*Treatments were usually compared with placebo.




Glossary

Cognitive function
Mental processes, including thinking, learning and remembering.
Cognitive impairment
Trouble remembering, learning new things, concentrating, or making decisions that affect everyday life.
False-positive
A test result that suggests the presence of a disease which turns out not to be there.
Placebo
A harmless, inactive, and simulated treatment.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

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