Aug 26 2010

Foreign Accent Syndrome

Via YouTube, we can see another case of “foreign accent syndrome (FAS).” This is a rare condition in which a person appears to speak with a foreign accent following a stroke or other brain damage. In this case a woman from Devon who naturally speaks with a “west country lilt” now is said to speak with a Chinese accent. Take a look at the video and decide for yourself.

Essentially this woman has had a migraine stroke – which is the most common cause of stroke in in younger adults. This may have damaged either her language area (specifically Broca’s area or a nearby region that would affect Broca’s function, causing a form of aphasia) or it is also possible that she has damage in another part of the brain causing weakness of certain muscles involved in speech, in which case we would term what she has a dysarthria. I think the former is more likely just from how she sounds, but cannot say definitively without more information.

In any case, the damage has altered her speech, making it more difficult for her to pronounce certain words and also appears to affect the prosody of her speech – her inflection and rhythm. The result is only vaguely reminiscent of a Chinese accent, in my opinion. And you can still hear a bit of her native accent underneath. This is actually an excellent example of what foreign accent syndrome is (as the expert on the video correctly points out) – it is just a coincidence and a heavy helping of pattern recognition that the resulting speech abnormality reminds us of one of the many accents in the world – in this case, Chinese.

There are a number of case reports of FAS in the literature, with many different types of accents resulting from mostly strokes but also tumors, bleeds, and multiple sclerosis lesions. In one case the lesion was located in the dominant anterior parietal lobe, in the sensory cortex. In another case there was a stroke in the “left internal capsule, basal ganglia and frontal corona radiata.” A lesion there would cause mainly weakness in the muscles of speech, rather than an impairment of language itself. Yet another case involved a lesion in Broca’s area (language cortex responsible for speech output) – in this case the resulting accent was identified by different blinded examiners as being from various different countries, or even as just being “strange”. The authors concluded:

These findings suggest that FAS is not due to the acquisition of a specific foreign accent, but to impairment of the suprasegmental linguistic abilities (tone, accent, pauses, rhythm, and vocal stress) that make it possible to distinguish native language.

The anatomy of FAS is poorly understood because there are few cases and they probably represent a diverse collection of specific lesions – those that just happen to produce the impression of  one kind of accent or another. There are three basic types of localizations that are plausible: Lesions might affect primary language cortex – that part of the brain that is dedicated to understanding language and producing speech. There is also a separate region of cortex in the opposite hemisphere that provides the prosody of speech – inflection and rhythm that both produces and interprets meaning and emotion (for example, understanding that someone is asking a question or using sarcasm from inflection). Also, any part of the motor system that affects the muscles used in speech could affect the ability to pronounce words, perhaps causing certain consonants to be dropped which could resemble a dialect that also drops those consonants.

Case reports generally agree that in FAS the foreign accent is perception only, not reality. In one detailed analysis the researchers showed that the subject continue to display typical linguistic features of their native tongue, but had altered prosody of speech that created the impression of a foreign accent. In other words – the appearance of an accent was superficial, but if you look closely at the details of speech they were consistent with the original native language.

Most reported cases involve a stroke or brain damage with a documented lesion. There are some cases, however, without a known brain lesion. In these cases the question arises – is this particular example of FAS psychogenic, meaning it is psychological rather than neurological. Cases which strongly suggest a psychogenic cause are ones in which there is no lesion, but also the apparent accent seems to be more of an affectation than a deficit. For example, taking on a refined British-sounding accent without any hint of dysarthria or speech deficit is suspect. In one reported case a patient with schizophrenia spoke with a British accent during psychotic episodes, and a detailed neurological evaluation revealed no brain dysfunction or language defect. This accent resolved when the psychotic episodes resolved.

Conclusion

FAS is a rare and interesting syndrome resulting from damage to a part of the brain responsible for or contributing to various aspects of speech. There is general agreement that these lesions do not result in the acquisition of a real and specific foreign accent, but simply deficits of either pronunciation or the “tone, accent, pauses, rhythm, and vocal stress” of speech that are simply suggestive of a foreign accent.

In addition there are foreign accent-like syndromes in which subjects without a focal brain lesion affect a specific foreign accent. These cases are likely psychogenic, and there are reports of  this occurring in psychiatric illnesses during psychotic episodes.

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