Abstract
Prior proton magnetic resonance spectroscopy (MRS) studies have consistently reported decreased brain n-acetyl aspartate (NAA) levels and increased myo-inositol (mI) levels in subjects with Alzheimer's disease (AD) relative to healthy comparison subjects. These studies have usually been conducted in small and homogeneous populations of patients with established Alzheimer's disease. Few studies have tested the usefulness of this finding in a general population seeking evaluation for memory loss and other cognitive declines. We designed a study to evaluate the significance of single-voxel proton MRS findings in these patients with memory loss and other cognitive declines. Thirty-five subjects with a primary complaint of memory loss and other cognitive declines were consecutively referred over a period of 13 months to a specialty clinic. Patients with a diagnosis of mild to moderate probable Alzheimer's disease (N=22), non-Alzheimer's dementia (depression, multiinfarct dementia, Parkinson's Disease, Korsakoff's Psychosis, and bipolar disorder; N=13), and healthy comparison subjects (N=18) were examined with respect to possible differences in metabolites using proton MRS in a 3.4-ml anterior temporal lobe voxel. The Alzheimer's disease group had 10.7% lower NAA/creatine (Cr) ratios relative to the healthy comparison group and 9.4% lower NAA/creatine relative to the non-Alzheimer's dementia group (15.0% lower NAA/creatine relative to the depression subgroup of the non-Alzheimer's dementia group). There were no significant differences in choline (Cho) or myo-inositol ratios among the groups. There were significant correlations between NAA/creatine ratios and mini-mental status exam (MMSE) scores in subjects with Alzheimer's disease (t=2.41, p=0.032) but not in subjects with non-Alzheimer's dementia or in its depression subgroup. This study found a reduction in the neuronal marker NAA in the anterior temporal lobe of patients diagnosed with probable Alzheimer's disease, using a short add-on proton MRS exam. This change was not observed in patients whose memory loss and other cognitive declines were not attributed to Alzheimer's disease, suggesting that it may aid in the diagnosis or detection of Alzheimer's disease.
| Original language | English |
|---|---|
| Pages (from-to) | 1313-1322 |
| Number of pages | 10 |
| Journal | Progress in Neuro-Psychopharmacology and Biological Psychiatry |
| Volume | 28 |
| Issue number | 8 |
| DOIs | |
| State | Published - Dec 2004 |
Bibliographical note
Funding Information:This work has been supported in part by the Alzheimer's Association/Improved Order of Red Men and Degree of Pocahontas Pilot Research Grant (PRG-94-145), the Brudnick Foundation, DA14013 (B.D.F.), and the NARSAD and Harvard-MIT Clinical Investigator Training Award (I.K.L.). The authors would like to thank Anne Smith and Eileen Connoly for performing MR scans.
Keywords
- Alzheimer's disease
- Magnetic resonance spectroscopy
- Temporal lobe
- n-acetyl aspartate