This paper is pointing to the inconsistencies and lack of differentiation in detecting the differences among vascular dementia, dementia, and Alzheimer lesions. There is still need for a clear differential diagnosis of early onset Alzheimer’s independent of dementia.

One promising finding is reported by Shepherd et al. (2007) and contributes toward differential diagnosis between early-onset AD and late-onset AD. Using neuronal cell loss counts, they showed that those with early-onset AD have more neuronal cell loss in the superior frontal cortex than those with sporadic AD (i.e., independent of the inflammatory plaque factor being present).

Another differentiation was made by Giannakopoulos at al. (2007) using stereological measures of neuronal numbers, total neurofibrillary tangles (NFT), total amyloid volume, and neuropil thread (NT) length in the hippocampus and entorhinal cortex. They report that of the above measures, NT formation in the hippocampal area and entorhinal cortex is found in the early stages of AD, not present in severe dementia.

Another area of...  Read more

This paper is pointing to the inconsistencies and lack of differentiation in detecting the differences among vascular dementia, dementia, and Alzheimer lesions. There is still need for a clear differential diagnosis of early onset Alzheimer’s independent of dementia.

One promising finding is reported by Shepherd et al. (2007) and contributes toward differential diagnosis between early-onset AD and late-onset AD. Using neuronal cell loss counts, they showed that those with early-onset AD have more neuronal cell loss in the superior frontal cortex than those with sporadic AD (i.e., independent of the inflammatory plaque factor being present).

Another differentiation was made by Giannakopoulos at al. (2007) using stereological measures of neuronal numbers, total neurofibrillary tangles (NFT), total amyloid volume, and neuropil thread (NT) length in the hippocampus and entorhinal cortex. They report that of the above measures, NT formation in the hippocampal area and entorhinal cortex is found in the early stages of AD, not present in severe dementia.

Another area of study that may contribute to differential diagnosis is knowing the difference between dementia with Lewy bodies and Alzheimer's in those already diagnosed at old age. Ishii at al. (2007) studied the different brain regions of 74-year-olds with mild dementia compared to those with Alzheimer's and healthy controls using glucose uptake/PET and eco MRI.

MRI and glucose metabolism results were compared for the whole brain, hippocampal, occipital, and striatal volumes. The dementia with Lewy body patients had significantly less volume in the striatum using MRI, but PET showed significantly less glucose metabolic reductions in the temporal, parietal, and frontal areas—including in the occipital lobe. In AD patients, the hippocampal volume and its glucose metabolism decreased significantly, but the occipital volume and metabolism remained.

Thus, the differential diagnosis between dementia and Alzheimer's rests in volumetric and metabolic changes in medial temporal lobes—occipital lobe versus that of hippocampus.

Based on these three reports, the prospective areas to study for differential diagnosis of early Alzheimer's independent of dementia can be as follows: a) neuronal cell loss in the superior frontal cortex, b) neuropil thread formation in certain areas of hippocampus and entorhinal cortex, and c) early-onset hippocampal volume and glucose metabolism reduction.

References:
Shepherd CE, Grace EM, Mann DM, Halliday GM. Relationship between neuronal loss and 'inflammatory plaques' in early onset Alzheimer's disease. Neuropathol Appl Neurobiol. 2007 Jun;33(3):328-33. Abstract

Giannakopoulos P, von Gunten A, Kovari E, Gold G, Herrmann FR, Hof PR, Bouras C. Stereological analysis of neuropil threads in the hippocampal formation: relationships with Alzheimer's disease neuronal pathology and cognition. Neuropathol Appl Neurobiol. 2007 Jun;33(3):334-43. Epub 2007 Apr 18. Abstract

Ishii K, Soma T, Kono AK, Sofue K, Miyamoto N, Yoshikawa T, Mori E, Murase K. Comparison of regional brain volume and glucose metabolism between patients with mild dementia with lewy bodies and those with mild Alzheimer's disease. J Nucl Med. 2007 May;48(5):704-11. Abstract

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