Smith, Glenn E.

ABSTRACTBACKGROUND AND PURPOSEMild cognitive impairment (MCI) precedes both Alzheimer's disease (AD) dementia and with Lewy bodies (DLB). We investigated proton magnetic resonance spectroscopy (MRS) characteristics of MCI patients who progressed to DLB compared to those who progressed to AD dementia or remained stable.METHODSConsecutive MCI patients who underwent single voxel MRS at baseline and progressed to DLB (n = 10) were identified during a median follow‐up period of 18 months. From the same cohort, we identified age‐ and sex‐matched MCI patients who progressed to AD dementia (n = 27) or remained stable (n = 20) during a similar follow‐up period. This study was approved by the Institutional Review Board and informed consent was from every subject.RESULTSMCI patients who progressed to AD dementia were characterized by lower N‐acetylaspartate (NAA)/Cr ratio in the posterior cingulate voxel compared to those who progressed to DLB (P = .001). Decreased NAA/Cr in the posterior cingulate voxel differentiated MCI patients who progressed to DLB from those who progressed to AD with an area under the receiver operating characteristic curve of .85 (P < .001) on logistic regression analysis.CONCLUSIONSMRS may be useful in differentiating MCI patients with prodromal AD dementia from those with prodromal DLB for early disease‐specific interventions.