A research paper by the principal investigators referenced in the NYT article cited in the blog post above that may be of interest. It includes a questionnaire on mental visualization on which persons self-identifying as aphantasiacs generally score poorly. Poor autobiographical memory appears to be not unusual among the very small non-random study population.

http://www.eugencpopa.ro/wp-content/uploads/Afantazia-.pdf

I wonder if the deficit has anything to do with retrieval inefficiencies (cued vs uncued recall). Quite a number of the (very small) study population reported involuntary mental visualizations.

...pronounced like the long vowel and first letter of the alphabet...