Testing

Researchers hope that a simple retina scan may prove to be a useful tool to diagnose Alzheimer’s disease (AD).  The scan, optical coherence tomography angiography (OCTA), is a non-invasive test which may also be used as a screening tool to identify patients at risk who are not yet showing symptoms of Alzheimer’s disease.

Atrophy or shrinking of the  hippocampus, a portion of the brain integral to memory, is often found in patients with early signs of AD.  

The retina scan is based upon the correlation between thinning of the retina and the shrinking portion of the brain.  Using a patient's own red blood cells instead of an injected dye, the OCTA can measure minute changes in the thickness of the retina.

Symptoms of Alzheimer’s Disease

Alzheimer’s disease, also called senile dementia, primarily causes memory loss and confusion.   I should stress that there are many other diseases which share the symptoms listed below and proper diagnosis can only be made with a thorough medical exam.

Symptoms of AD include:

• Memory loss, e.g. difficulty remembering events
• Inability to concentrate, planning and problem solving are difficult
• Difficulty completing routine tasks at home/work
• Confusion with respect to location or passage of time
• Getting lost - not understanding driving distances, misplacing items
• Jumbled language and using words
• Poor judgement and decision making

Diagnosis of Alzheimer’s Disease

There is no single test to diagnose Alzheimer’s disease.  The diagnosis is made only after a complete medical history, a thorough medical exam and ancillary testing.

Your doctor will use a multifaceted approach to make the diagnosis of AD and to insure that there are no other medical diseases which can mimic the symptoms of AD.

Additional testing may include:

• Blood tests - while there is no diagnostic blood test for Alzheimer’s, but testing may rule out other diseases
• Brain imaging may help support the diagnosis of AD and rule out other causes such as bleeding, tumors or stroke
• Brain scans
  • MRI - magnetic resonance imaging
  • CT - computerized tomography
  • PET scan - positron emission tomography

Presently, the diagnosis of AD is not made easily.  The diagnosis requires individualized evaluation and use of expensive ancillary testing and scanning.

There is no screening test of those at risk for developing Alzheimer’s disease.  Identifying individuals at risk for developing the disease will allow early institution of treatment and future planning.  

The OCTA retina scan may indeed become an inexpensive, yet specific, method for screening and making the diagnosis of Alzheimer’s disease.

Randall V. Wong, M.D.
Retina Specialist
Virginia and Washington, D.C.