At the bottom of this post is an excerpt from a YouTube Psychology Vidcast by Dr. Ross Avilla.
In this video he discusses a woman a known as BT who was thought to have lost her sight from brain damage.
BT also has Dissociative Identity Disorder.
The video implies that she developed DID as an adult, which is not likely.
According to the Washington Post:
German psychologists Hans Strasburger and Bruno Waldvogel, went all the way back to her initial diagnosis of cortical blindness. Her health records from the time show that she was subjected to a series of vision tests — involving lasers, special glasses, lights shined across a room — all of which demonstrated her apparent blindness. Since there was no damage to her eyes themselves, it was assumed that B.T.’s vision problems must have come from brain damage caused by her accident (the report does not say what exactly happened in the accident).
Waldvogel had no reason to doubt that diagnosis when B.T. was referred to him 13 years later for treatment for dissociative identity disorder, once called multiple personality disorder. B.T. exhibited more than 10 personalities, each of them varying in age, gender, habits and temperament. They even spoke different languages: some communicated only in English, others only in German, some in both (B.T. had spent time in an English-speaking country as a child but lived in Germany)….
Then, four years into psychotherapy, something strange happened: Just after ending a therapy session, while in one of her adolescent male states, B.T. saw a word on the cover of a magazine. It was the first word she had read visually in 17 years.
…Strasburger and Waldvogel say their finding is evidence that DID can unfold at a very basic, biological level. After all, it was not just high-level cognitive functions, like reading, that were affected by B.T.’s condition — even basic things like depth perception were difficult for her. And B.T.’s doctors could see all that playing out in her brain right in front of them on the EEG.
The case study shows that DID “is a legitimate psycho-physiologically based syndrome of psychological distress,” Dr. Richard P. Kluft, a clinical professor of psychiatry at Temple University School of Medicine not associated with the study, told Brain Decoder. The condition is not just a product of culture and psychiatrists’ suggestions, he said; as in B.T.’s case, it “represents the mind’s attempt to compartmentalize its pain.”