Foreign accent syndrome (FAS) is a rare condition which causes affected patients to suddenly speak their native language in a foreign accent.
Cases of FAS were reported as early as 1900. However, one of the best known historical cases is “Astrid L”, a Norwegian woman who suffered a traumatic brain injury from shrapnel during a WW2 air raid in 1941. She survived, but found herself mispronouncing vowels in such a way that she seemed to have a German accent, leading to social isolation and stigmatization for the remainder of the war.
Since then, there have been about another 60 FAS cases reported in the literature and media, mostly in patients who have suffered acute neurologic events such as strokes, multiple sclerosis and head injury.
Unlike most neurologic syndromes, FAS has not been localized to a lesion in a particular brain area.
The only thing that can be said is that most affected patients have lesions affecting the dominant hemisphere in or around known language areas.
Brain imaging studies from a FAS patient: The MRI (left) shows enlargement of the Sylvian fissure from atrophy of the left temporal lobe. The PET scan (right) shows focal hypometabolism in the left temporal lobe.
Many affected patients were initially mute, then developed FAS as they recovered from a non-fluent aphasia:
There are also some cases of FAS that have developed after minor neurologic events, or even without any clearly identifiable neurological cause at all. Some of these patients have had normal brain imaging, suggesting that the problem can be functional or psychogenic.
This is all further complicated by the fact that different listeners can perceive different accents in a single speaker.
The video clip is a patent with FAS syndrome after brain injury from hemiplegic migraine. She is said to have a Chinese accent. Does it sound Chinese or just slurred to you?
The table below is from a FAS case report, where the affected patient’s “foreign accent” was obviously described very differently by observers.
This suggests that FAS may not be a true syndrome after all, but simply a listener-bound epiphenomenon.
What does this mean?
Well, we have already explained that most FAS patients have some kind of speech or language problem that changed how they speak. That explains the association with lesions in the dominant hemisphere. However the “foreign accent” may actually just something perceived by the listener – the variability of perceived accents is explained by the fact that listeners have different experiences with languages other than their own.
In other words FAS may not be a true syndrome, but simply an epiphenomenon that exists only in the ears of the beholder.