Case Discussion: “Vision” Loss Diagnosis

The correct diagnosis in the case of “vision” loss (JW Neurol Nov 22 2011) is migraine aura presenting as alexia without agraphia. Most respondents to our poll chose this diagnosis; a few chose focal seizure or disconnection syndrome.

Neurological phenomena in migraine usually precede the headache. In most instances, the underlying cause is believed to be a form of spreading cortical depression. The symptoms may build up and then recede over a period of 20 minutes or more. In this case, the area of cortex likely to be affected is that responsible for symbolic language: Wernicke area, in the posterior left hemisphere. In the usual case of alexia without agraphia, there is a right homonymous hemianopia, which this patient did not have, and a l…