Alzheimer’s Disease and Parkinson’s Disease may appear first in the eye, possibly years before the first clear symptoms of the either disease appear. This offers hope of detecting two devastating and common diseases in their earliest stages. Damage from these brain and central nervous system diseases may prove very difficult to reverse. Detecting these illnesses, which impact mostly the elderly, as early as possible could mean treatments that slow the diseases’ progress and preserve functioning. Several recent studies on the eye hold promise of reliable early detection, routine screening and therefore, early intervention.
Alzheimer’s Disease and the Eyes
A form of dementia, Alzheimer’s disease gradually diminishes quality of life. Therefore, any progress in early diagnosis will have an impact on patients, as well as their caregivers. Currently, there is no definitive test for Alzheimer’s disease; on death, an autopsy will reveal plaques and tangles in the brain. The doctor makes a diagnosis based on medical history and by ruling out other potential causes of the symptoms. For example, certain nutritional deficiencies can mimic Alzheimer’s.
The damaging plaque in the brain is made mostly of a protein called beta-amyloid. These build up in the brain for many years before clear symptoms of Alzheimer’s disease appear. Initial systems include short-term memory loss, which may be easily written off as a natural part of the aging process. As the disease progresses, other symptoms appear, including short attention span, problems with language, poor judgment, disorientation, loss of motivation, moodiness, behavioral problems, misplacing items, paranoia, hostility, poor self-care and depression. Eventually, bodily functions fail, leading to death.
Currently, treatments for this brain disorder are sub-par. Some drug treatments have limited effect.
Hope lies in early detection. The sooner Alzheimer’s Disease is diagnosed, the sooner new interventions and not-yet-developed treatments can begin. The theory is that slowing down the progression of the illness can preserve brain functioning, allowing the patient to lead a healthier, full-length life.
The eyes may ultimately provide reliable means for detecting Alzheimer’s disease in its earliest stages. Researchers were able to see signs of Alzheimer’s disease in mice by looking at the patterns of light reflected from the retina. 1 Distinct patterns indicated a diagnosis of Alzheimer’s before signs of beta amyloid plaque had appeared in the brain. This research is likely to apply to humans, which may make early, reliable screening possible.
At AAIC 2014, Shaun Frost of the CSIRO (Commonwealth Scientific and Industrial Research Organization, Australia) and colleagues reported preliminary results of a study of volunteers who took a proprietary supplement containing curcumin. Curcumin, which is made from the bright yellow spice turmeric, binds to beta-amyloid with high affinity. This harmless compound has fluorescent properties that allow amyloid plaques to be detected in the eye using a novel system from NeuroVision Imaging, LLC, and a technique called retinal amyloid imaging (RAI). This allows doctors to find the plaque by examining the eyes using retinal amyloid imaging. Volunteers also underwent brain amyloid PET imaging to correlate the retina and brain amyloid accumulation.2
Another potential screening tool is the Self-Administered Gerocognitive Examination. It was developed at Ohio State University Wexner Medical Center. This simple written test can be scored by a physician.
Approximately 70% of the risk of Alzheimer’s is believed to be a complex combination of genetics. Other causes may include insufficient deep sleep, chronic inflammation, homocysteine levels, cerebrovascular disease, head injury, pollutants, or possibly a virus. The disease may be triggered by several factors that are different in each person.
Regardless of how the genetic deck is stacked, a healthy lifestyle can head off many diseases. Keeping the mind and body active throughout life reduces your risk. Eating a nutritious diet is also helpful for heading off disease as we age. Certain supplements and a special diet have been helpful for supporting Alzheimer’s Disease.
The eyes may also be key to future Alzheimer’s treatments. Dr Li-Huei Tsai and colleagues at the Massachusetts Institute of Technology have found that exposing the eyes flashing light reduced amyloid plaque in rodents. The light activated protective cells that cancelled out the protein. This is yet to be tested in humans. 3
Note: Patients with Alzheimer’s disease are more likely to develop glaucoma.
Parkinson’s Disease and Detection
Typically starting as a small tremor, Parkinson’s Disease affects movement. This disease of the central nervous system progresses over time, potentially reducing the quality of life. It is rare in young people and usually hits around age 60 or older. Other symptoms include stiffness and slowness of movement. Facial expression may be blank, and arms may not swing when walking. Speech may become slurred or soft. Posture and balance can be impaired. Therefore, patients may need help with daily tasks. In later stages, dementia, sleeping disorders, depression and anxiety may develop. World-wide, 1% of people over age 65 have this disease.
Nerve cells in the brain are gradually breaking down and dying in patients with Parkinson’s disease. Neurons that produce dopamine die, resulting in the symptoms. The cause is unclear; genetics may play a role, especially if many close family members are affected. This disease occurs in men more frequently than women.
There is no clear test for diagnosing Parkinson’s Disease. Imaging technology and blood work may be used to rule out other diseases. A Parkinson’s drug such as carbidopa-levodopa may be tried for a time to see if it provides significant relief. If they do, a diagnosis of Parkinson’s may be made.
While there is no cure, drugs are available to control symptoms; however, they have side-effects and may have diminished impact over time. Pollution and exposure to pesticides may increase the risk of developing this disease.
Researchers used a pesticide to induce Parkinson’s in rodents. They closely monitored the animals’ retinas. Early on, they could detect swelling and other specific changes in the retina. Later, the animals developed the disease.4 If this research applies to people, doctors may be able to reliably detect Parkinson’s Disease in its earliest stages.
Just like early detection is important, early prevention is also crucial. Regular exercise, daily mental challenges and proper nutrition are well-researched ways of preventing a host of diseases. The Standard American Diet (SAD) is less nutritious than needed and contains pesticide residue. Take extra effort to eat a wide variety of organic fruits and vegetables. Walk or bike instead of driving. Work out at a fitness center three times a week and drink plenty of water. Also, stay mentally active with crossword puzzles, reading, going to lectures, socializing and playing brain-stimulating games.
Up Next: See our page on Alzheimer’s Disease Nutrition and learn more about Alzheimer’s Disease.
- Swati S. More, et al, Early Detection of Amyloidopathy in Alzheimer’s Mice by Hyperspectral Endoscopy, Investigative Opthalmology & Visual Science, June, 2016. ↩
- PUBLIC RELEASE: 13-JUL-2014. Smell and eye tests show potential to detect Alzheimer’s early. New Alzheimer’s biomarker results reported at Alzheimer’s Association International Conference 2014. ALZHEIMER’S ASSOCIATION ↩
- https://www.bbc.com/news/health-38220670 ↩
- “The retina as an early biomarker of neurodegeneration in a rotenone-induced model of Parkinson’s disease: evidence for a neuroprotective effect of rosiglitazone in the eye and brain.” Eduardo Maria Normando et. al. Acta Neuropathologica Communications. Neuroscience of Disease, August, 2016 ↩