Locked in with the bitter taste of lemon

This week’s New Scientist has a number of interesting mind and brain articles. The most striking is on locked-in syndrome, where people are completely paralysed despite having intact minds.

The article is by author Laura Spinney who wrote a novel based on locked-in syndrome called The Quick (ISBN 0007240503).

One of the challenges is to find a route for affected patients to communicate with the ‘outside world’. Sometimes eye movements are spared, which famously allowed Jean-Dominique Bauby to write the profoundly beautiful book The Diving Bell and the Butterfly (ISBN 0007139845).

She notes one case where all other routes had failed, so a rather unorthodox approach was tried with initial success, only to slip frustratingly away.

Despite the technology, communication is still a considerable challenge for these people. To operate the TTD [Thought Translation Device - converts movements into words] requires months of arduous training, and the failure rate is high. Last year, in the journal Neurology, Birbaumer and colleagues described a particularly tragic case of failure (vol 67, p 534). A 46-year-old German woman who had been diagnosed with the degenerative disease amyotrophic lateral sclerosis [ALS], also known as motor neuron disease, had made it clear that she desperately wanted to live. By the time she came to Birbaumer’s attention, she had already been locked in for a year. After trying in vain to train her to use the TTD, they decided her chances might improve if they implanted the electrodes in her brain rather than sticking them to her scalp. For this, they needed her consent, which she clearly couldn’t give. Impasse.

Then, walking past an electronics store one day, Birbaumer’s colleague Barbara Wilhelm spotted a medical device for measuring the pH of saliva, and had an idea. They trained the woman to change the acidity of her spit by imagining either the taste of lemon, or the taste of milk. She learned to push the pH one way to say “yes”, the other to say “no”. When they asked her if she agreed to them implanting the electrodes, she replied yes, repeatedly; three hours later, however, she lost control of her salivary pH. The electrodes were implanted, but she hasn’t achieved any control over her brain activity. Birbaumer is still trying to tap into other potential channels of communication, but he fears that after a certain time locked-in patients may lose the capacity to control anything voluntarily.

The issue also has a cover story on whether conscious beings could spontaneously arise from the universe, and another on the effect of breakfast on mental performance.

As New Scientist is still a little bit backward none of the articles have been made freely available (ever wondered why Scientific American gets more coverage on the net?), so you’ll need to find a copy at your local newsagent or library to have a look.

Link to table of contents.

2 Comments

  1. Posted August 15, 2007 at 10:27 pm | Permalink

    Interesting information. However, your site is rather let down by the lack of self-awareness shown by your statement:
    As New Scientist is still a little bit backward none of the articles have been made freely available (ever wondered why Scientific American gets more coverage on the net?)
    Hello?! Do I HAVE to register to comment here? And what’s with the sneaky “leave the last box ticked saying he’d like bucket loads of spam – he’ll never notice?”

  2. Posted August 16, 2007 at 8:48 am | Permalink

    Typekey is an anti-spam measure. You will not get any spam from signing in using Typekey. Typekey allows us to prevent spammers from filling up our blog with adverts.
    Mindhacks.com is daily and free to everyone to read – i’d say that’s pretty good. If you have to sign in to post comments then blame comment spammers.


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