Visual signs and symptoms in patients with the visual variant of Alzheimer disease

Abstract

BackgroundProminent visual symptoms can present in the visual variant of Alzheimer’s disease (VVAD). Ophthalmologists have a significant role to play in the early diagnosis of VVAD.MethodsWe retrospectively reviewed the files of ten consecutive patients diagnosed with VVAD. All patients had a full neuro-ophthalmologic examination, a formal neurological and neuro-psychological testing, and cerebral MRI to confirm diagnosis. In addition, functional neuroimaging was obtained in seven patients.ResultsThe common primary symptom at presentation with all patients was difficulty with near vision (reading difficulty n = 8, “visual blur” in near vision n = 2), and difficulty writing (n = 3). Following assessment, impaired reading and writing skills were evident in 9/10 and 8/10 patients respectively. Median distance visual acuity was 20/25 and at near the median visual acuity was J6. Partial homonymous visual field defect was detected in 80 % (8/10) of the patients. Color vision was impaired in all patients when tested with Ishihara pseudoisochromatic plates, but simple color naming was normal in 8/9 tested patients. Simultanagnosia was present in 8/10 patients. Vision dysfunction corresponded with cerebral MRI findings where parieto-occipital cortical atrophy was observed in all patients. PET scan (5 patients) or SPECT (2 patients) revealed parieto-occipital dysfunction (hypometabolism or hypoperfusion) in all 7 tested patientsConclusionsVisual difficulties are prominent in VVAD. Dyslexia, incomplete homonymous hemianopia, preserved color identification with abnormal color vision on Ishihara, and simultanagnosia were all symptoms observed frequently in this patient series. Ophthalmologists should be aware of the possibility of neurodegenerative disorders such as VVAD in patients with unexplained visual complaints, in particular reading difficulties.

The Eye As a Biomarker for Alzheimer's Disease

“…In addition, a visual variant of AD (VVAD) affecting relatively younger persons has been identified, though it is important to distinguish this as a separate pathophysiological entity known as posterior cortical atrophy. Patients suffering from VVAD typically first present with visual symptoms in the fifth or sixth decade of life and eventually the cognitive decline follows the course more typically seen in AD (Levine et al, 1993; Lee and Martin, 2004; Kaeser et al, 2015). In addition to potentially important early visual changes, the eye is very accessible and the retina can be easily imaged, thus making ocular biomarkers attractive.…”

Ocular and Visual Manifestation of Alzheimer’s Disease: A Literature Review II Part: Clinical Studies

“…In rare cases, the authors detected a complete Balint's syndrome (simultanagnosia, oculomotor apraxia and optic ataxia) (6). The MRI showed atrophy in the parieto-occipital regions and the single-photon emission computed tomography (SPECT) and PET decreased metabolism or hypoperfusion in the same regions (3,9). However, in the classical form, AD disturbances of the visual pathway were documented.…”

“…The retina is part of the CNS and is easy to study. On the other hand, visual disturbances are frequent in AD patients (2) and sometimes AD begins with visual symptoms (3). Therefore, many researchers have examined the eyes and mainly the retina in order to confirm the diagnosis, to monitor the development of the disease or the response to drugs.…”

Data-driven detection of latent atrophy factors related to phenotypical variants of posterior cortical atrophy

“…While multiple pathologies may underlie the posterior cortical atrophy syndrome, the most common biological substrate is Alzheimer's disease, accounting for ~80% of the cases (Renner et al, 2004;Tang-Wai et al, 2004;Montembeault et al, 2018). Posterior cortical atrophy has been coined the "visual variant of Alzheimer's disease" (Kaeser et al, 2015) and is the most common non-amnestic variant of Alzheimer's disease, afflicting ~5% of all patients diagnosed in a memory clinic setting (Snowden et al, 2007). Posterior cortical atrophy manifests at a relatively young age compared to amnestic-predominant Alzheimer's disease (Mendez et al, 2002;Schott et al, 2016).…”