Rapid Eye Clinic Screening Battery for Visual Cortical Dysfunction (VisCorD) & Visual Field Perimetry

The VisCorD screening battery is designed for use in eye clinics along with the Visual Field Perimetry to identify potential posterior cortical visual dysfunction in patients who have unexplained visual complaints following a comprehensive eye exam* see disclaimer.

Click here to take the survey to help the designers know more about who is utilizing this screening assessment. This information will only be accessible by the team base at University of Colorado School of Medicine.DV

Background

This screening tool was initially recommended in 2023 by the Posterior Cortical Atrophy (PCA) Assessment Working Party, part of the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) Atypical Alzheimer's Disease (AD) Professional Interest Area (PIA)¹. Members of this Working Party developed the VisCorD based on survey data collected from Atypical AD PIA members about their approaches to assessing core features of PCA—an atypical Alzheimer's disease phenotype characterized by cortical visual dysfunction with relative preservation of memory and other cognitive functions².

The Working Party's consensus recommendations addressed the assessment of core PCA features across three settings:

the outpatient clinic
formal neuropsychological evaluation
research

They also proposed the VisCorD as a rapid eye clinic screening battery for identifying cortical visual dysfunction within eye clinics.

Interpretation of Results

If the patient has evidence of a homonymous visual field defect without an imaging finding to account for the visual field defect and/or fails one of the six test items, then referral to a behavioral neurologist and/or neuropsychologist is indicated. However, the sensitivity and specificity of the six items are only known for the CPC-Q; thus, the false positive and false negative rates for the other five items are unknown.

*Disclaimer: The items in the battery are recommended to help screen for visual brain dysfunction (aka visual cortical dysfunction). The battery should not be used to diagnose visual cortical dysfunction. Patients with poor performance should be referred to a behavioral neurologist for further assessment. For patients with ocular diseases that result in loss of visual acuity and/or visual field, test results should be interpreted with extreme caution as the tests may be difficult to perform in the setting of vision loss due to eye diseases.

References:

Pelak VS, Tang-Wai DF, Boeve BF, Bouwman FH, et al. Consensus recommendations for clinical assessment tools for the diagnosis of posterior cortical atrophy syndrome from the Atypical AD PIA of ISTAART. Alzheimers Dement (Amst). 2023 Sep 20;15(3):e12474. doi: 10.1002/dad2.12474. PMID: 39329067; PMCID: PMC11425198.
Crutch SJ, Schott JM, Rabinovici GD, Murray M, Snowden JS, et al. Alzheimer's Association ISTAART Atypical Alzheimer's Disease and Associated Syndromes Professional Interest Area. Consensus classification of posterior cortical atrophy. Alzheimers Dement. 2017 Aug;13(8):870-884. doi: 10.1016/j.jalz.2017.01.014. Epub 2017 Mar 2. PMID: 28259709; PMCID: PMC5788455.