Does progressive aphantasia exist? The hypothetical role of aphantasia in the diagnosis of neurodegenerative diseases.

Aphantasia is a heterogeneous neuropsychological syndrome consisting of the inability to create mental images. We argue that its progressive form may be a harbinger of dementia. Aphantasia may manifest as the inability to create any mental images or to create complex scenes, inability to spontaneously initiate generation of mental images, and/or inability to visualize a sequence of events.