Queen Square Institute of Neurology, University College London, London, UK.
Institute of Ophthalmology, University College London, London, UK.
Behav Res Methods. 2024 Oct;56(7):7748-7760. doi: 10.3758/s13428-024-02448-7. Epub 2024 Jun 18.
Impairments of object recognition are core features of neurodegenerative syndromes, in particular posterior cortical atrophy (PCA; the 'visual-variant Alzheimer's disease'). These impairments arise from damage to higher-level cortical visual regions and are often missed or misattributed to common ophthalmological conditions. Consequently, diagnosis can be delayed for years with considerable implications for patients. We report a new test for the rapid measurement of cortical visual loss - the Graded Incomplete Letters Test (GILT). The GILT is an optimised psychophysical variation of a test used to diagnose cortical visual impairment, which measures thresholds for recognising letters under levels of increasing visual degradation (decreasing "completeness") in a similar fashion to ophthalmic tests. The GILT was administered to UK Biobank participants (total n=2,359) and participants with neurodegenerative conditions characterised by initial cortical visual (PCA, n=18) or memory loss (typical Alzheimer's disease, n=9). UK Biobank participants, including both typical adults and those with ophthalmological conditions, were able to recognise letters under low levels of completeness. In contrast, participants with PCA consistently made errors with only modest decreases in completeness. GILT sensitivity to PCA was 83.3% for participants reaching the 80% accuracy cut-off, increasing to 88.9% using alternative cut-offs (60% or 100% accuracy). Specificity values were consistently over 94% when compared to UK Biobank participants without or with documented visual conditions, regardless of accuracy cut-off. These first-release UK Biobank and clinical verification data suggest the GILT has utility in both rapidly detecting visual perceptual losses following posterior cortical damage and differentiating perceptual losses from common eye-related conditions.
物体识别障碍是神经退行性综合征的核心特征，尤其是后部皮质萎缩（PCA；“视觉变异型阿尔茨海默病”）。这些损伤源自于高级皮质视觉区域的损伤，且经常被忽视或归因于常见的眼科疾病。因此，诊断可能会延迟数年，这对患者有重大影响。我们报告了一种新的皮质视觉损失快速测量测试——分级不完全字母测试（GILT）。GILT 是一种用于诊断皮质视觉障碍的测试的优化心理物理变体，它以类似于眼科测试的方式测量在视觉退化（字母“完整性”下降）水平不断增加的情况下识别字母的阈值。GILT 被用于英国生物库参与者（总 n=2359）和以初始皮质视觉（PCA，n=18）或记忆丧失（典型阿尔茨海默病，n=9）为特征的神经退行性疾病患者。英国生物库参与者，包括典型成年人和有眼科疾病的人，都能够在低完整性水平下识别字母。相比之下，PCA 患者在完整性仅有适度下降的情况下始终会出错。对于达到 80%准确率截止值的参与者，GILT 对 PCA 的灵敏度为 83.3%，使用替代截止值（60%或 100%准确率）时，灵敏度增加到 88.9%。与没有或有记录的视觉疾病的英国生物库参与者相比，特异性值始终超过 94%，无论准确率截止值如何。这些首次发布的英国生物库和临床验证数据表明，GILT 在快速检测后部皮质损伤后出现的视觉感知损失以及区分感知损失与常见与眼睛相关的疾病方面具有实用性。
