When a deaf man has Tourette’s

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Yesterday, I mentioned that I’d considered calling this blog “Coprolalia,” after the term for those involuntary utterances made by some people with Tourette’s Syndrome. Coprolalia has been on my mind because I recently came across a fascinating case study. It is both straightforward and profound, equally suited to be a topic of discussion at a serious scientific conference or an impromptu cocktail party. It is, in short, just plain cool.

Communicating using American Sign Language. (These signers are not affiliated with the study in question.)

The case study, which appeared in the journal Movement Disorders in 2000, concerned a 29-year-old man who had been deaf since infancy. We’ll call him Signing Sal. Sal, as it happens, also had Tourette’s. In most people, coprolalia involves randomly blurting out obscenities. Sal, however, wasn’t shouting out obscenities—he was signing them. The researchers—led by Andrew J. Lees at the National Hospital for Neurology and Neurosurgery in London—note that Sal was particularly fond of making sexual signs when talking to women. He was also known, as part of his tic, to spell out expletives, letter by letter, in sign language.

The implications are fascinating to consider. Sal’s case illustrates that coprolalia is a lot more than some mere muscular misfire, more than some vocal cords twitching like a bad leg. The fact that Sal’s utterances were in a language that uses hands, not voiceboxes, means that coprolalia isn’t a compulsion of vocalization, per se–it’s a compulsion of expression. That suggests that the outbursts contain some legitimate, meaningful content.

So let’s look at the content. There have been many theories about why coprolalia usually involves profanity, rather than other kinds of words. Some have speculated that expletives may be commonly uttered because of some inherent phonetic quality they share. Among other things, many expletives tend to contain “fricative” sounds, produced when we push air out of a small opening, as we do when pronouncing words that begin with f or s. Perhaps something about these sounds makes them easier to access during a tic?

But, as the researchers point out in this case study, there aren’t fundamental distinctions between how obscene and non-obscene signs are made. (It’s not the case, for instance, that expletives are made extra forcefully or with a different kind of motion than other words.) And still, Sal’s tics involved expletives, not other random signs. What’s more, the authors write, “Further evidence for a semantic basis for tics is provided by … the occurrence of finger-spelled obscenities, an act equivalent to writing or spelling words out, and therefore divorced from phonologic content. This suggests that the idea underlying coprolalia is more important than the phonology of the utterance.”

The authors provide one more salient point that underscores how much content matters. When Sal was in cooking class, rather than signing expletives, he tended to display the sign for “vomit.” In some ways, in that particular context, with classmates eagerly preparing their dishes, the word vomit is even more subversive than an obscenity would be.

What the authors conclude from this accumulated evidence is that coprolalia, then, comes from some sort of urge to disrupt or disturb others. In fact, they say, coprolalia is a kind of linguistic aggression: “The utterance of obscenities is a form of aggressive behavior, and there may be failure in the control of these brief aggressive impulses in Gilles de la Tourette syndrome.” That’s an entirely different dysfunction—and, in my mind, a far more interesting one–than some twitchy vocal cords.

Reference: Morris, H. R., Thacker, A. J., Newman, P. K. and Lees, A. J. (2000), Sign language tics in a prelingually deaf man. Movement Disorders, 15: 318–320. DOI: 10.1002/1531-8257(200003)15:2<318::AID-MDS1018>3.0.CO;2-H

(Photo by David Fulmer)

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