Applied Evidence

What’s causing my older patient’s cognitive decline?

J Fam Pract. 2017 November;66(11):670-676

From The Journal of Family Practice | 2017;66(11):670-676.

References

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Other causes of reversible dementia

A meta-analysis performed in 1988 found that 11% of cases of dementia were reversible.³³ However, an update using the same methodology in 2003 revealed the number had dropped to less than 1%.³⁴ In the latest meta-analysis, one of the authors’ leading hypotheses for the dramatic decline in apparent prevalence was a significant shift in the study population from the inpatient to outpatient setting. In studies of community-based populations used in the re-analysis, the reported prevalence of reversibility was near zero.³⁴

Metabolic abnormalities—most often B₁₂ deficiency and hypothyroidism—are commonly cited as potential causes of dementia. Four systematic reviews, including one conducted by the Cochrane Collaborative, concluded there is a lack of evidence that treating low vitamin B₁₂ in individuals with dementia improves cognition.^35,36 There is some evidence, though, of a time-limited window for successful treatment within 12 months of the onset of symptoms.^37,38 A study reviewing causes of dementia in nearly 3000 individuals found one case of reversible dementia attributable to hypothyroidism.³⁹ A subsequent review reached similar conclusions about the lack of data to support the notion that treatment of hypothyroidism reverses dementia.⁴⁰

Similarly, imaging for cerebral tumors, subdural hematomas, or normal-pressure hydrocephalus rarely identifies these as a cause of dementia.⁴¹ This is particularly true of unselected community-based populations, as there are typically signs or symptoms suggesting an intracranial pathology.

Numerous medications have been implicated in causing acute confusional states, and there is some evidence for their role in chronic confusion (TABLE 3).^42,43In my experience, many who experience adverse effects on cognition with medications will also have an underlying neurodegenerative process, and symptoms do not completely resolve with withdrawal of the offending agent.

CASE

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Further assessment of the patient yielded a score of 29/30 on the Montreal Cognitive Assessment* and a zero on the Patient Health Questionnaire-2. Careful review of her daily function revealed no significant deficits in ADL or IADL performance, and her daughter confirmed that she had not observed any significant decline in her mother’s function. There was no significant family history of dementia. The patient was reassured that her cognitive changes were normal and age related.

Unfortunately, few data support specific interventions to reduce this patient’s risk of developing dementia. She was commended for keeping her blood pressure and blood sugar levels under control, thereby reducing her risk of vascular disease.

She and her daughter were directed to the Alzheimer’s Association Web site (alz.org) as a resource for information about signs and symptoms to watch for and for caregiving resources, should they be needed. She was briefly counseled to eliminate distractions to improve her ability to complete tasks and improve recall along with rehearsing or writing down information that she wished to retain.

Finally, she was counseled to remain physically, cognitively, and socially active as these are factors generally associated with healthy aging, have some evidence to support efficacy in reducing the risk of cognitive decline,^44,45 and are unlikely to be of harm.

*The Montreal Cognitive Assessment is a validated office-based tool for the evaluation of cognitive impairment that is highly sensitive for the detection of mild cognitive impairment.

CORRESPONDENCE
Ian M. Deutchki, MD, Professor of Family Medicine and Geriatrics, University of Rochester Medical Center, 777 S. Clinton Avenue, Rochester, NY 14620; Ian_Deutchki@URMC.Rochester.edu.