Alzheimer Disease: Stoub TR

deToledo-Morrell L, Stoub TR, Wang C. · Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA. · Prog Brain Res. · Pubmed #17765748 No free full text.

Abstract: Quantitative imaging techniques allow the in vivo investigation of age and disease related changes in the brain and their relation to cognitive function. In this chapter we review imaging evidence indicating that the entorhinal cortex and hippocampus show atrophy very early in Alzheimer's disease (AD) and in individuals who are at risk of developing AD compared to age appropriate controls. Furthermore, the extent and rate of atrophy of the entorhinal cortex, a brain region pathologically involved very early in the disease process, can predict who among the elderly will develop AD. Techniques that assess the integrity of white matter further demonstrate that alterations in the parahippocampal white matter in the region that includes the perforant path could partially disconnect the dentate gyrus and other hippocampal subfields from incoming sensory information. Such partial disconnection and degradation in transmission of sensory information in people at risk of AD and in patients with very mild AD could contribute to the memory dysfunction associated with the early stages of the disease.

Stoub TR, deToledo-Morrell L, Stebbins GT, Leurgans S, Bennett DA, Shah RC. · Department of Neurological Sciences, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA. · Proc Natl Acad Sci U S A. · Pubmed #16785436 links to  free full text

Abstract: The concept of amnestic mild cognitive impairment (MCI) describes older people who show a decline predominantly in memory function, but who do not meet criteria for dementia. Because such individuals are at high risk for developing Alzheimer's disease, they are of great interest for understanding the prodromal stages of the disease process. The mechanism underlying memory dysfunction in people with MCI is not fully understood. The present study uses quantitative, high-resolution structural MRI techniques to investigate, in vivo, the anatomical substrate of memory dysfunction associated with MCI. Changes in brain structures were assessed with two imaging techniques: (i) whole-brain, voxel-based morphometry to determine regions of reduced white matter volume and (ii) sensitive volumetric segmentation of the entorhinal cortex and hippocampus, gray matter regions that are critically important for memory function. In participants with amnestic MCI, compared with age-matched controls, results showed a significant decrease in white matter volume in the region of the parahippocampal gyrus that includes the perforant path. There was also significant atrophy in both the entorhinal cortex and the hippocampus. Regression models demonstrated that both hippocampal volume and parahippocampal white matter volume were significant predictors of declarative memory performance. These results suggest that, in addition to hippocampal atrophy, disruption of parahippocampal white matter fibers contributes to memory decline in elderly individuals with MCI by partially disconnecting the hippocampus from incoming sensory information.

Stoub TR, Bulgakova M, Leurgans S, Bennett DA, Fleischman D, Turner DA, deToledo-Morrell L. · Department of Neurologic Sciences, Rush University Medical Center, Chicago, IL, USA. · Neurology. · Pubmed #15883311 No free full text.

Abstract: OBJECTIVE: To determine if baseline entorhinal and hippocampal volumes and their rate of atrophy could predict the risk of incident Alzheimer disease (AD). METHODS: The authors used proportional odds models to assess the relationship between entorhinal and hippocampal size and risk of incident AD among 58 nondemented elderly people. All participants were followed with annual clinical evaluations and structural MRI scans for up to 5 years (baseline and 5 years of follow-up). At baseline, 23 of 58 participants received a diagnosis of amnestic mild cognitive impairment (MCI) and 35 of 58 were healthy control subjects with no cognitive impairment. Structural MRI scans were acquired with a T1-weighted three-dimensional spoiled gradient-recalled echo pulse sequence in a 1.5 T scanner. Entorhinal and hippocampal volumes were derived from 1.6-mm gapless coronal images reformatted to be perpendicular to the long axis of the hippocampus and were normalized by dividing with intracranial volume. RESULTS: Fourteen of 58 nondemented participants developed AD during the follow-up period. Initial diagnosis of MCI was a significant predictor of incident AD. In addition, both baseline entorhinal volume and its slope of decline were independent predictors of incident AD, but initial hippocampal size and its rate of decline were not, after controlling for entorhinal volume. CONCLUSION: In nondemented individuals, entorhinal cortex atrophy is associated with risk of Alzheimer disease.

deToledo-Morrell L, Stoub TR, Bulgakova M, Wilson RS, Bennett DA, Leurgans S, Wuu J, Turner DA. · Department of Neurological Sciences, Rush University, Chicago, IL 60612, USA. · Neurobiol Aging. · Pubmed #15312965 No free full text.

Abstract: With high-resolution quantitative magnetic resonance imaging (MRI) techniques, it is possible to examine alterations in brain anatomy in vivo and to identify regions affected in the earliest stages of Alzheimer's disease (AD). In the present study, 27 patients diagnosed with mild cognitive impairment (MCI) received a high-resolution MRI scan at baseline and were followed with yearly clinical evaluations. Ten of the 27 patients converted to AD during a 36-month period following the baseline clinical evaluation. Hippocampal and entorhinal cortex volumes derived from the baseline scan were compared to determine which of these two regions, known to be pathologically involved very early in the course of AD, could best differentiate MCI converters from non-converters. Although both entorhinal and hippocampal volumes were found to be independent predictors of the likelihood of conversion to AD, it was the right hemisphere entorhinal volume that best predicted conversion with a concordance rate of 93.5%.

Goncharova II, Dickerson BC, Stoub TR, deToledo-Morrell L. · Department of Neurological Sciences, Rush University, 1653 W. Congress Parkway, Chicago, IL 60612, USA. · Neurobiol Aging. · Pubmed #11705633 No free full text.

Abstract: A new protocol for measuring the volume of the entorhinal cortex (EC) from magnetic resonance images (MRI) was developed specifically to measure the EC from oblique coronal sections used in hippocampal volumetric studies. The relative positions of the anatomic landmarks demarcating EC boundaries were transposed from standard coronal sections to oblique ones. The lateral EC border, which is the most controversial among anatomists, was defined in a standard and conservative manner at the medial edge of the collateral sulcus. Two raters measured the EC twice for 78 subjects (healthy aged individuals, very mild AD patients, and elderly patients who did not meet criteria for dementia) to study intra- and inter-rater reproducibility and reliability of measurements. The level of accuracy achieved (coefficients of reproducibility of 1.40-3.86%) and reliability of measurements (intraclass correlation coefficients of 0.959-0.997) indicated that this method provides a feasible tool for measuring the volume of the EC in vivo.