Brain Metabolic Correlates of Decision Making in Amnestic Mild Cognitive Impairment

Abstract

Persons with amnestic mild cognitive impairment (MCI) have subtle impairments in medical decision-making capacity (MDC). We examined the relationship between proton magnetic resonance spectroscopy (MRS) and MDC in MCI. Twenty-nine MCI patients and 42 controls underwent MRS to obtain ratios of N-acetylaspartate (NAA)/Creatine (Cr), Choline (Cho)/Cr, and myo-Inositol (mI)/Cr of the posterior cingulate. They also completed the Capacity to Consent to Treatment Instrument (CCTI), a vignette-based instrument measuring decisional standards of expressing choice, appreciating consequences of choice, providing rational reasons for choice, and understanding treatment choices. Patients showed abnormal MRS ratios of mI/Cr and Cho/Cr compared to controls, and impairments on the CCTI understanding and reasoning Standards. Performance on the Reasoning Standard of the CCTI was correlated with NAA/Cr (r = 0.46, p < 0.05). The relationship of NAA/Cr with decision-making suggests a role for posterior cortical neuronal functioning in performance of complex IADLs in MCI.

Decreased Glutamate Levels in Patients with Amnestic Mild Cognitive Impairment: An sLASER Proton MR Spectroscopy and PiB‐PET Study

“…Earlier 1 H‐MRS studies in patients with aMCI, conducted using the conventional protocols, such as PRESS, showed that the 1 H‐MRS abnormalities identified in patients with aMCI were similar, but only milder compared to the abnormalities identified in patients with AD dementia . In patients with aMCI, the elevation in the myo ‐inositol level was shown to precede the decrease in the NAA level .…”

The heritability of brain metabolites on proton magnetic resonance spectroscopy in older individuals

“…Particularly, the high heritability of NAA:W is of interest as this could function as an endophenotype of aging. Examining the interaction of the genetic and environmental factors can also help in understanding the pathophysiology of brain diseases, since several environmental factors, including toxic chemicals (Weiss and Landrigan, 2000), stress, subclinical cerebrovascular events (Raz and Rodrigue, 2006), temperature, oxygenation (KatzBrull et al, 2006), some medicines such as cholinesterase inhibitor (Griffith et al, 2010), and even laboratory conditions can show influences on brain metabolite concentrations.…”

Imaging the Alzheimer Brain

“…One good example of a likely candidate for this use comes from the difficult clinical decision as to whether patients can manage their own financial affairs. This capacity in MCI patients has been related to angular gyrus volume, measured by MRI, a region previously demonstrated to be important in math ability [194], and neuronal volume in the posterior cingulate cortex, measured by MRS [195]. This brain-behavior association may someday be usedinthe context of an early warning such that patients with a faster rate of change in this region may need special protections and monitoring to avoid financial predators who seek to exploit a developing vulnerability.…”