New diagnostic biomarkers offer ray of hope for Alzheimer's disease

August 30, 2012

Alzheimer's disease (AD) is one of the most common brain disorders, with an estimated 35 million people affected worldwide. In the last decade, research has advanced our understanding of how AD affects the brain. However, diagnosis continues to rely primarily on neuropsychological tests which can only detect the disease after clinical symptoms begin. In a supplement to the Journal of Alzheimer's Disease, investigators report on the development of imaging-based biomarkers that will have an impact on diagnosis before the disease process is set in motion.

"There is an urgent need for the development of reliable diagnostic that can detect AD pathology at an incipient phase," says Guest Editor Dr. Pravat Mandal, Adjunct Associate Professor of the Department of Radiology, Johns Hopkins Medicine, Baltimore, MD and Additional Professor, National Brain Research Center, India. "This special issue focuses on the latest strides made in identifying diagnostic biomarkers using state-of-the-art imaging modalities."

The issue looks at the application of various (MRI) technologies for diagnosing AD and monitoring the progression of the disease. For example, Brian T. Gold and colleagues report on the use of diffusion tension imaging (DTI) to identify changes in the white matter of patients with amnestic (MCI), an early symptom of AD. Charles D. Smith and colleagues describe MRI-based detection of key structural alterations in cognitively normal subjects that can serve as a predictor of .

While MRI provides information about the anatomy of the brain, functional MRI (fMRI) provides crucial information about the regions involved during specific tasks. The issue explores how fMRI can detect changes in functional activation and connectivity in AD patients. Monitoring alterations in functional related to visual processing deficits in AD has immense potential as an early diagnostic biomarker, according to a review by Dr. Mandal and colleagues. By using fMRI to study normal older individuals, patients with MCI, and those with AD as they perform cognitive tasks and at rest, Jasmeer P. Chhatwal and Reisa Sperling reveal the functional alterations associated with healthy aging as well as MCI and AD.

Magnetic resonance spectroscopy (MRS) is a powerful non-invasive imaging technique that can provide crucial information about neurochemical changes in AD. Dr. Mandal and colleagues report that the identification of neurochemical changes in the brains of MCI and AD patients may provide a "signature" of early AD pathology, and may aid in diagnosing patients who are moving from MCI to more advanced AD.

Imaging is also used to examine the molecular and therapeutic effects of potential AD treatments. Liam Zaidel and colleagues found that patients treated with donepezil for mild cognitive symptoms had a significant increase in interhemispheric functional connectivity of the left and right dorsolateral prefrontal cortices. Giulia Liberati and colleagues describe a non-invasive brain-computer interface that can detect a patient's emotional and cognitive state. It could provide vital information on the effect of clinical drugs on brain function and cognition in patients with AD.

The issue also includes a thought-provoking argument from Edo Richard and colleagues calling for a paradigm shift in dementia research and biomarker development. Current biomarker research focuses on correlates of plaques and tangles, which are poor markers in older dementia subjects. The authors suggest that the acknowledgement that dementia in older subjects is different from dementia at a young age will lead to new approaches in biomarker development and research.

"Research is needed to understand which molecular, structural, and functional changes are causally related to the onset of AD," says Dr. Mandal. "This special issue aims to conceptualize more effective and reliable biomarkers for AD."

George Perry, PhD, Editor-in-Chief, Journal of , and Dean and Professor, College of Sciences, University of Texas at San Antonio, says, "The development of biomarkers to aid in early detection of the onset of AD is critical. This special issue will spur research into multi-model imaging based biomarker development for AD."

Explore further: Scientists reveal early diagnostic clues for AD using advanced brain imaging technology

More information: "Biomarkers for Alzheimer's Disease Using Multi-Model Imaging Research," Guest Edited by Pravat K. Mandal. Journal of Alzheimer's Disease, Volume 31 (2012), Supplement 3.

Related Stories

Scientists reveal early diagnostic clues for AD using advanced brain imaging technology

May 2, 2012
Alzheimer's disease (AD) is a major neurodegenerative disorder that affects millions of people worldwide. New and accurate techniques for early diagnosis are critical. Pravat K. Mandal, PhD, and his colleagues have developed ...

Revised criteria could reclassify many with mild Alzheimer dementia

February 6, 2012
Many patients currently diagnosed with very mild or mild Alzheimer disease dementia could potentially be reclassified as having mild cognitive impairment (MCI) under revised criteria for that condition, according to a report ...

Changes seen in cerebrospinal fluid levels before onset of Alzheimer dementia

January 2, 2012
Cerebrospinal fluid levels of Aβ42 appear to be decreased at least five to 10 years before some patients with mild cognitive impairment develop Alzheimer disease (AD) dementia whereas other spinal fluid levels seem to ...

Recommended for you

Multi-gene test predicts Alzheimer's better than APOE E4 alone

September 22, 2017
A new test that combines the effects of more than two dozen genetic variants, most associated by themselves with only a small risk of Alzheimer's disease, does a better job of predicting which cognitively normal older adults ...

Personality changes don't precede clinical onset of Alzheimer's, study shows

September 21, 2017
For years, scientists and physicians have been debating whether personality and behavior changes might appear prior to the onset of Alzheimer's disease and related dementias.

Newly ID'd role of major Alzheimer's gene suggests possible therapeutic target

September 20, 2017
Nearly a quarter century ago, a genetic variant known as ApoE4 was identified as a major risk factor for Alzheimer's disease—one that increases a person's chances of developing the neurodegenerative disease by up to 12 ...

Is the Alzheimer's gene the ring leader or the sidekick?

September 15, 2017
The notorious genetic marker of Alzheimer's disease and other forms of dementia, ApoE4, may not be a lone wolf.

Potential noninvasive test for Alzheimer's disease

September 6, 2017
In the largest and most conclusive study of its kind, researchers have analysed blood samples to create a novel and non-invasive way of helping to diagnose Alzheimer's disease and distinguishing between different types of ...

Researchers unlock the molecular origins of Alzheimer's disease

September 6, 2017
A "twist of fate" that is minuscule even on the molecular level may cause the development of Alzheimer's disease, VCU researchers have found.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.