New research out of Canada shows that near-infrared biospectroscopy – a scientific technique around for decades – may provide early diagnosis of Alzheimer's disease and other neurodegenerative disorders.
With 5.3 million people in the U.S. living with Alzheimer's disease – and many more expected given the aging population – healthcare providers are still looking for a means to provide early diagnosis, even if there isn't a cure.
The Alzheimer's Association (Chicago) points out that an early diagnostic offers a better chance of benefiting from available therapies, time to make choices that maximize quality of life, reduced anxieties about unknown problems and more time to plan for the future.
Near-infrared biospectroscopy measures the wavelength and intensity of the absorption of near-infrared light by a sample.
"In 2003 we published a paper showing there are changes in the blood of Alzheimer's disease patients," Hyman Schipper, MD, lead author of the study and professor of neurology and medicine at McGill University (Montreal) told Medical Device Daily. "There are reactive oxygen species present in the brains of people with Alzheimer's that may be causing some of the damage in the brains and that's been known for 20 years. What's apparent recently is these modifications are happening in the blood."
Once these chemicals are modified, the spectroscope can detect the modification.
"We don't know exactly what chemical is being modified, but this is a top-down approach," Schipper said. "When we started to look at blood samples from people with Alzheimer's disease, we found consistent and good sensitivity and specificity changes between Alzheimer's and normal samples using this instrument. It can detect modification of some unknown chemical constituents, probably a protein."
A study published in the June 2009 Journal of Alzheimer's Disease, included blood plasma samples taken from 63 subjects, 19 who had Alzheimer's disease, 27 with mild cognitive impairment (which is a frequent indication of Alzheimer's disease) and 17 normal elderly people. They measured the oxidative stress in the plasma. Oxidative stress is usually caused by a chemical imbalance that can damage cells and biofluids, including proteins, lipids and DNA. Researchers already knew that oxidative stress is somehow involved in neurological diseases.
Near-infrared biospectroscopy achieved a sensitivity of 80% and specificity of 77% when differentiating the Alzheimer's patients from the normal elderly control group.
"This was very consistent across the 63 samples," Schipper said. "Twenty seven had mild cognitive impairment (some memory loss but not enough to fulfill criteria for Alzheimer's). We do know that mild cognitive impairment is the preclinical state of Alzheimer's, so any test that can detect a change in mild cognitive impairment may allow you to intervene pharmacologically. We don't need a test for late in the disease. These results demonstrate the potential for near-infrared biospectroscopy to differentiate mild, and possibly preclinical Alzheimer's disease from normal aging with high accuracy."
Schipper said the technology has been licensed to a company that he founded, Molecular Biometrics (Norwood, Massachusetts).
"The company's first product is using the same platform for in vitro fertilization," he said. "That's what's very close to entering the market. The second product would be for neurodegenerative diseases. We published another paper showing this was good at differentiating Parkinson's disease from normal. The spectrum is different from Alzheimer's and the Parkinson's work is further ahead than Alzheimer's. We're engaging 35 centers in the U.S. in a new study funded by the Michael J Fox Foundation [New York] looking at Parkinson's patients and an equal number of normal patients to validate the test for a Parkinson's application."
If that works, Molecular Biometrics would be very close to moving the Parkinson's test into the market.
"Alzheimer's disease is a little behind that, but if things go well and large-scale studies go well, it's possible the Parkinson's product could enter the market in two to three years," he said. "The Alzheimer's disease product would come in three to five years."
Schipper pointed out that the technology is relatively easy to use compared with most diagnostics that are in vogue today and only a very small sample of blood is needed. The device being developed by his company would provide a simple series of numbers after analyzing the blood sample. The higher the number, the higher the likelihood that it's Parkinson's or Alzheimer's.
"There is a phenomenal need in neurology to have a blood test for diseases like Alzheimer's. It would be a major breakthrough to diagnose the patient without interviewing the patient in some cases," he said. "People need to know if the person is demented or not to determine the level of care, particularly for comatose patients. We see people with severe memory loss and depression. We're shocked that they have to go to a psychiatrist, get therapy to reduce the depression and then a test to determine if it's Alzheimer's."
Schipper said the pharmaceutical industry would also be able to make use of an Alzheimer's diagnostic for more targeted drug trials.
"They will need to accrue fewer patients to run their trials," he said.