Features of FAS:
(1) There is a major and permanent change in the nature of the person's speech.
(2) The new speech is not under the patient's conscious control.
(3) The new speech sounds different from the person's native language.
(4) The speech is perceived as foreign by listeners and by the patient.
Conditions associated with FAS:
(1) stroke
(2) head injury
(3) intracranial hemorrhage
(4) multiple sclerosis
(5) bipolar disorder or psychosis
(6) neurodegeneration
Brain imaging may show subcortical injury to language centers in the left brain (left anterior temporal cortex, left internal capsule, other).
Theories for occurrence:
(1) unlocking of a learned speech pattern that has been suppressed
(2) a change in how phonemes are generated which is interpreted as "foreign" by a listener
