Selective impairment in musical chord Reading in posterior cortical atrophy: A case study of integrative visual agnosia.

Background: Posterior cortical atrophy (PCA) is a rare neurodegenerative disorder characterized by visuospatial and/or visuoperceptual deficits, resulting from atrophy in the occipitoparietal and/or occipitotemporal cortices. Among reported cases, visuoperceptual deficits are less commonly described compared to visuospatial impairments. Objective: To address this gap, we present a qualitative behavioral observation of an individual with PCA in which visuoperceptual deficits manifested as symbolically intuitive symptoms. Methods: This case study examines a 58-year-old female with PCA whose primary symptom was difficulty reading chords on musical scores, despite being able to perceive their overall shape and having no difficulty reading individual notes or other musical symbols such as flats (♭) and sharps (♯). Her challenges are discussed within the framework of integrative visual agnosia, a condition involving the inability to synthesize partial visual inputs into cohesive wholes. A comprehensive neuropsychological evaluation was performed, and brain imaging-including positron emission tomography (PET)-was used to explore underlying pathology. Results: Neuropsychological testing revealed severe alexia, characterized by word-by-word reading, and visual object agnosia with minimal visuospatial deficits. These visuoperceptual impairments were marked by fragmented perception of objects and failure to integrate parts as object complexity increased. Imaging showed left-dominant occipitotemporal abnormalities consistent with Alzheimer's disease pathology, confirmed by amyloid-β and tau PET findings. Conclusions: This case highlights the diagnostic challenges clinicians face in recognizing visuoperceptual deficits in PCA. The individual's integrative visual agnosia, exemplified by her difficulty interpreting musical chords, offers valuable insight into how such deficits manifest in daily activities.