Alzheimer’s disease is usually diagnosed when someone begins showing signs of memory loss. But the damage to the brain from Alzheimer’s disease starts a decade or more before the onset of symptoms. Researchers are working on a method, using optical coherence tomography (OCT), that is already routinely used by many eye doctors and retina specialists.
Having a way to detect the beginning of Alzheimer’s disease, before symptoms show up, could mean that treatments can be started early, and the progress of those treatments monitored.
Early detection could mean that neurotransmitter medication that can slow progression could be started sooner. The effectiveness of early treatments could be monitored with eye scans.
In Alzheimer’s disease, the communication among neurons is disrupted. Neurons are specialized cells that process and transmit information by electrical and chemical signals. They do that by communicating to each other through neurotransmitters. One neurotransmitter that is affected by the disease is acetylcholine.
Researchers think that reduced levels of acetylcholine cause some of the symptoms of Alzheimer’s disease. Medications that inhibit the breakdown rate of acetylcholine are prescribed to afflicted patients to strengthen the cell-to-cell communication that continually gets damaged in Alzheimer’s disease.
OCT Scan Detects Early Signs of Alzheimer’s
Researchers at Duke University and at Washington University School of Medicine in St. Louis have found evidence that Optical Coherence Tomography (OCT) scans can detect the changes in the tiny capillaries and the thinning of the retinal layers in the eye that signal the beginnings of Alzheimer’s disease.
There is a dense web of microscopic blood vessels inside the retina. In Alzheimer’s patients, researchers using OCT scans noted that the web of blood vessels was less dense. The retinal nerve fiber layer was also thinner in patients without Alzheimer’s disease.
What is OCT?
Optical coherence tomography is an imaging modality that uses light waves to take cross-section images of the retina. An OCT shows each of the distinctive layers of the retina and the thickness of nerve fibers.
The images from an OCT scan are high-quality, extremely sharp images because they use light, rather than sound or radio frequency that are used in other medical imaging modalities.