October 26, 2006

The therapeutic power of rhyme

Two days ago, Scott Adams, author of Dilbert, reported some extraordinary news on his blog. Poetry has cured him. Not just any poetry, either, but rhymed and metered verse. Well, specifically, a nursery rhyme:

Jack be nimble, Jack be quick.
Jack jump over the candlestick.

Fans will be glad to know that those trochees haven't cured Scott's dyspeptic reaction to modern management, office politics, and the eternal cycle of suckers and cynics. Today's strip:

Rather, Adams was cured of an incurable disease: spasmodic dysphonia.

Here's Wikipedia on the syndrome:

Spasmodic dysphonia (or laryngeal dystonia) is a voice disorder characterized by involuntary movements of one or more muscles of the larynx ... during speech. Individuals who have spasmodic dysphonia may have occasional difficulty saying a word or two or they may experience sufficient difficulty to interfere with communication. Spasmodic dysphonia causes the voice to break or to have a tight, strained or strangled quality.

S.D. Schaefer, "Neuropathology of spasmodic dysphonia", Laryngoscope 93(9) 1183-204 (1983) describes it as "a devastating voice disorder of unknown etiology, with a variable clinical presentation and response to treatment", and suggests that is is "one of several spasmodic brain stem disorders with variable presentation which are known by the cranial nerve nuclei or pathways of major clinical involvement". T. Finitzo et al., "Spasmodic Dysphonia, Whether and Where", JSHR, 32 541-555 (1989), could identify no brain lesions in 16% of patients, with "isolated, multifocal, cortical lesions" in over 50%, "mixed subcortical and cortical pathology" in 25%, and only subcortical lesions in 7%. K.D. Pool et al., "Heterogeneity in spasmodic dysphonia", Archives of Neurology, 48(3) (1991) conclude that "spasmodic dysphonia is a manifestation of disordered motor control involving systems of neurons rather than single anatomical sites".

Adams explains that in some cases, including his, the symptoms depend on the type of speech and the context of speaking:

The weirdest part of this phenomenon is that speech is processed in different parts of the brain depending on the context. So people with this problem can often sing but they can’t talk. In my case I could do my normal professional speaking to large crowds but I could barely whisper and grunt off stage. And most people with this condition report they have the most trouble talking on the telephone or when there is background noise. I can speak normally alone, but not around others. That makes it sound like a social anxiety problem, but it’s really just a different context, because I could easily sing to those same people. [...]

The commonest therapy for spasmodic dysphonia is to paralyze the affected muscles with botulinum toxin, as Adams explains:

While there’s no cure, painful Botox injections through the front of the neck and into the vocal cords can stop the spasms for a few months. That weakens the muscles that otherwise spasm, but your voice is breathy and weak. [...]

I stopped getting the Botox shots because although they allowed me to talk for a few weeks, my voice was too weak for public speaking. So at least until the fall speaking season ended, I chose to maximize my onstage voice at the expense of being able to speak in person.

And here's how the poetry worked:

The day before yesterday, while helping on a homework assignment, I noticed I could speak perfectly in rhyme. Rhyme was a context I hadn’t considered. A poem isn’t singing and it isn’t regular talking. But for some reason the context is just different enough from normal speech that my brain handled it fine.

Jack be nimble, Jack be quick.
Jack jumped over the candlestick.

I repeated it dozens of times, partly because I could. It was effortless, even though it was similar to regular speech. I enjoyed repeating it, hearing the sound of my own voice working almost flawlessly. I longed for that sound, and the memory of normal speech. Perhaps the rhyme took me back to my own childhood too. Or maybe it’s just plain catchy. I enjoyed repeating it more than I should have. Then something happened.

My brain remapped.

My speech returned.

Not 100%, but close, like a car starting up on a cold winter night. And so I talked that night. A lot. And all the next day. A few times I felt my voice slipping away, so I repeated the nursery rhyme and tuned it back in. By the following night my voice was almost completely normal.

When I say my brain remapped, that’s the best description I have. During the worst of my voice problems, I would know in advance that I couldn’t get a word out. It was if I could feel the lack of connection between my brain and my vocal cords. But suddenly, yesterday, I felt the connection again. It wasn’t just being able to speak, it was KNOWING how. The knowing returned.
I still don’t know if this is permanent. But I do know that for one day I got to speak normally. And this is one of the happiest days of my life.

It's always inspiring to hear good news, and this story has a bunch of extra feel-good dimensions: persistence in the face of adversity, curing the incurable by the power of poetry, creating new brain pathways by reactivating old memories, magical invocation of verses learned in childhood.

Adams' experience reminds me of a treatment for aphasia invented in the 1970s, "melodic intonation therapy".

Neurological researchers Sparks, Helm , and Albert developed melodic intonation therapy in 1973 while working with adults in the Aphasia Research Unit at the Boston VA Hospital (Marshal and Holtzapple 1976). MIT is based on the hypothesis of these researchers that “increased use of the right hemisphere dominance for the melodic aspect of speech increases the role of that hemisphere in inter-hemispheric control of language, possibly diminishing the language dominance of the damaged left hemisphere” (Marshal and Holtzapple 1976:115). In order to do this common words and phrases are turned into melodic phrases emulating typical speech intonation and rhythmic patterns (Davis et al. 1999, Marshal and Holtzapple 1976, and Carroll 1996). One study using PET (positron emission tomography) scans found that areas controlling speech in the left hemisphere were “reactivated” by the end of MIT.

That's P. Berlin et al., "Recovery from nonfluent aphasia after melodic intonation therapy: a PET study:", Neurology 47(6) 1504-1511 (1996):

Without MIT, language tasks abnormally activated right hemisphere regions, homotopic to those activated in the normal subject, and deactivated left hemisphere language zones. In contrast, repeating words with MIT reactivated Broca's area and the left prefrontal cortex, while deactivating the counterpart of Wernicke's area in the right hemisphere. The recovery process induced by MIT in these patients probably coincides with this reactivation of left prefrontal structures.

At the time MIT (= "melodic intonation therapy") was being developed at the Boston VA, I was a few miles away at MIT (= "Massachusetts Institute of Technology"), working on models of the rhythms and pitch contours of normal speech (The Intonational System of English, MIT dissertation, 1975). So when MIT failed to become a very widely used therapy, because it doesn't help all or even most aphasic patients, I was disappointed. Nevertheless, MIT sometimes produces remarkable results. (This is true under both interpretations.)

Perhaps whatever Melodic Intonation Therapy is doing, in the cases where it works, is similar to what Scott Adams accomplished for himself with his nursery rhyme. The usual way of reciting such poems is similar to the way that MIT turns "common words and phrases ... into melodic phrases emulating typical speech intonation and rhythmic patterns".

Posted by Mark Liberman at October 26, 2006 07:31 AM