Clinical Exams Diagnose Alzheimer’s Best

There’s been a rash of reports of blood or spinal fluid analyses that are claimed to predict the likelihood of Alzheimer’s in people with mild cognitive impairment (MCI).  However, a recent study shows that cognitive testing, done correctly, is a better way to go.  The study comes from Spanish Alzheimer specialists, and is published in the Archives of General Psychiatry.

The researchers compared the ability of spinal fluid analyses, brain volumes (determined by magnetic resonance imaging, or MRI), and cognitive tests to predict the occurrence of Alzheimer’s disease in MCI subjects.  The Alzheimer’s Disease Neuroimaging Initiative database was used to study 116 MCI patients who converted to Alzheimer’s within two years, and 204 who did not; an additional 197 age-matched people without cognitive impairment served as a control group. Twenty-five different factors from the spinal fluid, MRI, and cognitive tests were analyzed in a stepwise logistic regression fashion, to determine those factors that showed a statistically- significant predictive ability.

Three significant predictors were identified with this methodology;

1. A decline in time (over 2 years) on the Functional Assessment Questionnaire.
2. A decline in scores of Part B of the Trail Making Test
3. Reduced thickness of the cortex of the middle temporal lobe of the brain on MRI 

The analyses in this study show that three significant predictors of development are simple and do not involve complicated, expensive, or invasive procedures.  Other tests show more modest changes in those with Alzheimer’s, and are less useful for diagnosis.  Of course, a more specific blood test may emerge in the future.  Until then, we can rely on the three methods listed above.