ISLAMABAD, Jan 26 (Online): Researchers estimateTrusted Source that about 32 million people have a type of dementia called Alzheimer\u2019s disease, with another 69 million at the prodromal stageTrusted Source, which is defined as having mild cognitive impairment.
\nIt\u2019s well understood that Alzheimer\u2019s impacts brain functions such as memory, spatial awareness, speaking, and writing, but lesser known are the changes to the brain associated with the condition that may also impact the eyesTrusted Source.<\/p>\n
Previous studiesTrusted Source show that changes that occur in the brain with Alzheimer\u2019s may also happen in the retina of the eye. Researchers have also noted eye changes with Alzheimer\u2019s, including contrast sensitivityTrusted Source required for reading, color visionTrusted Source, and visual field lossTrusted Source.
\nIn a new study, researchers from the University of California \u2014 San Francisco examined how Alzheimer\u2019s affects the eye by identifying the effects of a rare eye condition known as posterior cortical atrophyTrusted Source or Benson\u2019s syndrome.
\nScientists reported that about 94% of people with posterior cortical atrophy also had Alzheimer\u2019s disease pathology.
\nBased on their findings, researchers urged the need for more clinical awareness of posterior cortical atrophy for earlier diagnosis of Alzheimer\u2019s disease.<\/p>\n
The results were published in the journal The Lancet NeurologyTrusted Source.
\nWhat is Benson\u2019s syndrome?
\nPosterior cortical atrophy \u2014 also known as Benson\u2019s syndrome \u2014 is a rare neurodegenerative disorderTrusted Source affecting vision.
\nThe disease causes brain cells to die in the back portion of the brain responsible for managing what a person sees.
\n\u201cPosterior cortical atrophy is a progressive brain disorder that affects visual regions in the brain,\u201d Dr. Gil Rabinovici, neurologist and director of the Alzheimer\u2019s Disease Research Center at the University of California \u2014 San Francisco and senior author of this study, explained to Medical News Today.<\/p>\n
\u201cOver time, visual loss can progress to the point of functional blindness.\u201d
\nThe first symptoms of posterior cortical atrophy normally occur between the ages of 50 and 65. Symptoms can vary between individuals but normally include:
\n\u2022\tvision issues
\n\u2022\tdifficulty recognizing people, places, and\/or objects
\n\u2022\treading difficulties with words and\/or numbers
\n\u2022\tinability to judge distances correctly
\n\u2022\tbumping into doorways and furniture when moving
\n\u2022\tproblems driving
\n\u2022\tunable to identify left from right
\n\u2022\tanxiety
\n\u2022\tconfusion
\n\u2022\tbehavioral changes<\/p>\n
Rare eye condition linked to Alzheimer\u2019s pathology
\nAlthough previous studies have found posterior cortical atrophy is most commonly associatedTrusted Source with Alzheimer\u2019s disease pathology, the prevalence of the condition is still unknown.
\nResearchers estimate that between 5\u201315% of people diagnosed with Alzheimer\u2019s disease may also have posterior cortical atrophy.
\n\u201cFrom a clinical point of view, posterior cortical atrophy is probably the second most common clinical presentation of Alzheimer\u2019s disease after memory loss, yet it is under-recognized, and patients can go undiagnosed or misdiagnosed for years,\u201d Dr. Rabinovici said.
\n\u201cThere has been a major need in the field for a large, international multi-site study that comprehensively characterizes the syndrome and raises awareness amongst clinicians.\u201d<\/p>\n
\u201cAlzheimer\u2019s disease is defined biologically by the presence of toxic proteins called plaques and tangles in the brain, causing brain dysfunction and brain tissue loss. In most patients, these proteins affect memory regions in the brain early on, but in posterior cortical atrophy, for reasons that we don\u2019t really understand, these proteins accumulate early on in visual areas that are located in the back (posterior) parts of the brain.\u201d<\/p>\n
\u2014 Dr. Gil Rabinovici, neurologist
\nAlzheimer\u2019s prevalent in 94% with Benson\u2019s syndrome
\nFor this study, Dr. Rabinovici and his team analyzed data from more than 1,000 people with posterior cortical atrophy at 36 medical research centers in 16 countries.
\nThe researchers found that about 94% of study participants with posterior cortical atrophy also had Alzheimer\u2019s disease pathology, while the remaining 6% had other dementia conditions including Lewy body disease and frontotemporal lobar degeneration.
\nScientists also reported at the time of participants\u2019 diagnosis:<\/p>\n
\u2022\t61% had constructional dyspraxia (inability to build a simple structure with blocks or copy a drawing)
\n\u2022\t49% had space perception deficitTrusted Source (problem with moving through an environment or properly gauging distance between themselves and an object)
\n\u2022\t48% had simultanagnosiaTrusted Source (inability to see more than one object at a time)
\n\u2022\t47% had newly developed challenges with basic math calculations
\n\u2022\t43% had new issues with reading
\nEarlier identification of Benson\u2019s syndrome needed
\nDr. Rabinovici said their findings should encourage neurologists and eye care professionals to consider posterior cortical atrophy in people with slowly progressive visual loss not explained by primary eye disease.
\n\u201cEarly brain scans such as MRI can clarify that the problem is in the brain, not the eyes, since tissue loss in the visual areas of the brain can be profound,\u201d he continued.<\/p>\n
\u201cFurther tests like PET scans, spinal fluid, or blood tests for Alzheimer\u2019s disease proteins can seal the diagnosis of posterior cortical atrophy due to Alzheimer\u2019s disease.
\nAnd Dr. Rabinovici said that earlier identification of posterior cortical atrophy can allow people to access established treatments for Alzheimer\u2019s, as well as new treatments like the antibodiesTrusted Source that remove amyloid from the brain.
\n\u201cThese treatments are more effective the earlier in the disease course they are started,\u201d he explained. \u201cAn early and accurate diagnosis can facilitate care planning for patients and their families.\u201d<\/p>\n
\u201cFurthermore, patients can avoid unnecessary and unhelpful procedures such as constantly trying new eyeglasses or even undergoing surgery for early cataracts that are not actually the cause of vision loss,\u201d Dr. Rabinovici added.
\nImpetus for more posterior cortical atrophy screenings
\nMNT also spoke with Dr. Alexander Solomon, a surgical neuro-ophthalmologist and strabismus surgeon at Pacific Neuroscience Institute in Santa Monica, CA, about this study.
\nDr. Solomon commented that it is extremely useful to see such a large and thoroughly evaluated data set on the strong connection between Alzheimer\u2019s and posterior cortical atrophy, but as a clinician who treats these patients, it is hardly surprising given the disease is sometimes known as the visual variant of Alzheimer\u2019s.<\/p>\n
\u201cIt is good to see more attention being brought to the disease, which I think (is) more awareness from neurologists than your average eye care professional. I think it can serve as an impetus to start screening patients complaining about difficulty with visual processing early for evidence of underlying posterior cortical atrophy by referring them appropriately to a neurologist, neuropsychologist, or neuro-ophthalmologist more familiar with diagnosing the condition.\u201d<\/p>\n
\u2014 Dr. Alexander Solomon, surgical neuro-ophthalmologist
\nDr. Solomon said this study would be a good springboard to help develop prospective studies on how best to screen and diagnose patients presenting with some of the symptoms of posterior cortical atrophy to help achieve better and earlier diagnostic certainty and to see how many of these correlations hold up.
\n\u201c(The researchers) alluded to the fact that one weakness here is that diagnosis was made by individual practitioners with varying diagnostic criteria with almost no limit to how long ago this diagnosis was made, and thoughts\/attitudes\/criteria have shifted over time which could affect results,\u201d he explained.
\n\u201cI\u2019d also be really interested to see the efficacy of some of the clinical tests for Alzheimer\u2019s as screening tools for the disease, as this may encourage more widespread and earlier use of these tests if appropriate.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"
ISLAMABAD, Jan 26 (Online): Researchers estimateTrusted Source that about 32 million people have a type of dementia called Alzheimer\u2019s disease, with another 69 million at the prodromal stageTrusted Source, which is defined as having mild cognitive impairment. It\u2019s well understood that Alzheimer\u2019s impacts brain functions […]<\/p>\n
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