Myo-inositol in geriatric patients with cognitive impairment

Background & Objective: Cognitive impairment, in geriatric population, is reported in patients with depression, mild cognitive impairment (MCI), and dementia. MCI is the transitional stage before dementia, with annual conversion rate to dementia of about 20%. Early diagnosis of the underlying cause of cognitive impairment in geriatric patients is crucial for proper management. This could be achieved through proton magnetic resonance spectroscopy. We aimed to study the difference of frontal, posterior cingulate gyrus, and occipital myo-inositol (MI), and myo-inositol/creatine (MI/Cr) ratio between patients with MCI, and cognitive impairment associated with geriatric depression; and study if these metabolites could differentiate between MCI and cognitive impairment associated with geriatric depression. Methods: Geriatric patients with MCI, and elderly patients with depression associated with cognitive impairment, along with sex and age matched healthy control were evaluated clinically and underwent neuropsychological testing, laboratory tests as well as brain MRI and proton magnetic resonance spectroscopy at baseline. Patients were reevaluated clinically, and neuropsychologically at 12, and 24 months from baseline. Results: The present study included 62 subjects. Patients with MCI had significantly higher posterior cingulate gyrus, occipital MI/Cr ratio, and frontal MI and MI/Cr ratio than normal controls. No differences were seen between geriatric patients with cognitive impairment associated with depression and those with MCI and healthy control in any of the studied metabolites in the studied brain regions. Conclusion: Elevated posterior cingulate gyrus, occipital, and frontal MI/Cr ratio, and frontal MI level could help to identify patients with MCI from healthy control, but could not differentiate between MCI and cognitive impairment associated with depression.