The findings of a Canadian study indicate that elderly patients with mild cognitive impairment (MCI) may be able to get some early insight into the possibility that their disease will progress to dementia, specifically to Alzheimer's disease.

The study enrolled 45 elderly adults who met the criteria for MCI, as determined through several clinical tests and assessments, and 20 healthy volunteers used as controls. All subjects underwent magnetic resonance imaging (MRI) and completed a series of neuropsychological tests at the start of the study. The baseline MRI measured hippocampal volume, cortical thickness, and white matter hyperintensities. The neuropsychological tests evaluated the subject's abilities to perform tasks related to verbal and episodic memory and executive control processes. The researchers monitored the subjects yearly for two years to assess which patients' MCI had progressed to dementia and whose had remained stable.

Five of the 45 MCI patients were lost to follow-up. Among the remaining 40 patients, 18 (45%) had progressed to dementia over the two-year follow-up and 22 (55%) remained stable. Fifteen of the affected 18 patients were diagnosed with probable Alzheimer's disease and three with mixed dementia.

Comparisons between the patients with MCI progression and those with stable MCI showed that those whose impairment progressed had worse results at baseline on the episodic memory tests. Specifically, the areas of free recall and recognition were strong predictors of the development of dementia. Review of the baseline MRIs revealed that cortical thickness was significantly reduced in the patients with progression to dementia compared with those with stable MCI.

When the MRI results and the results of neuropsychological testing were taken together, the combination of cortical thinning in the right anterior cingulate gyrus along with controlled recollection and familiarity-based recognition deficiencies had an overall predictive accuracy of 87.5%, compared with 82.5% for MRI and 75% for neuropsychological tests alone. These findings demonstrated that the two-pronged diagnostic approach was more effective in detecting preclinical Alzheimer's disease and could give clinicians a head start on its prevention and treatment.

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