Part 4 (1/2)

Thus, Dr Jonathan Cole, a former student of mine and now a spinal neurophysiologist, describes how in a woman with persistent phantom leg pain, anaesthesia of the spinous ligament with Lig-nocaine caused the phantom to be anaesthetized (indeed to disappear) briefly; but that electrical stimulation of the spinal roots produced a sharp tingling pain in the phantom quite different from the dull one which was usually present; whilst stimulation of the spinal cord higher up reduced the phantom pain (personal communication). Dr Cole has also presented detailed electrophysiological studies of a patient with a sensory polyneuropathy of fourteen years' duration, very similar in many respects to Christina, the ”Disembodied Lady” (see Proceedings of the Physiological Society, February 1986, p. 5IP).

7.

On the Level It is nine years now since I met Mr MacGregor, in the neurology clinic of St. Dunstan's, an old-people's home where I once worked, but I remember him-I see him-as if it were yesterday.

'What's the problem?' I asked, as he tilted in.

'Problem? No problem-none that I know of . . . But others keep telling me I lean to the side: ”You're like the Leaning Tower of Pisa,” they say. ”A bit more tilt, and you'll topple right over.” '

'But you don't feel any tilt?'

'I feel fine. I don't know what they mean. How could I be tilted without knowing I was?'

'It sounds a queer business,' I agreed. 'Let's have a look. I'd like to see you stand and take a little stroll-just from here to that wall and back. I want to see for myself, and 1 want you to see too. We'll take a videotape of you walking and play it right back.'

'Suits me, Doc,' he said, and, after a couple of lunges, stood up. What a fine old chap, I thought. Ninety-three-and he doesn't look a day past seventy. Alert, bright as a b.u.t.ton. Good for a hundred. And strong as a coal-heaver, even if he does have Parkinson's disease. He was walking, now, confidently, swiftly, but canted over, improbably, a good twenty degrees, his centre of gravity way off to the left, maintaining his balance by the narrowest possible margin.

'There!' he said with a pleased smile. 'See! No problems-I walked straight as a die.'

'Did you, indeed, Mr MacGregor?' I asked. 'I want you to judge for yourself.'

I rewound the tape and played it back. He was profoundly shocked when he saw himself on the screen. His eyes bulged, his jaw dropped, and he muttered, 'I'll be d.a.m.ned!' And then, 'They're right, I am over to one side. I see it here clear enough, but I've no sense of it. I don't feel it.'

'That's it,' I said. 'That's the heart of the problem.'

We have five senses in which we glory and which we recognise and celebrate, senses thar const.i.tute the sensible world for us. But there are other senses-secret senses, sixth senses, if you will- equally vital, but unrecognised, and unlauded. These senses, unconscious, automatic, had to be discovered. Historically, indeed, their discovery came lare: what the Victorians vaguely called 'muscle sense'-the awareness of the relative position of trunk and limbs, derived from receptors in the joints and tendons-was only really defined (and named 'proprioception') in the 1890s. And the complex mechanisms and controls by which our bodies are properly aligned and balanced in s.p.a.ce-these have only been defined in our own century, and still hold many mysteries. Perhaps it will only be in this s.p.a.ce age, with the paradoxical license and hazards of gravity-free life, that we will truly appreciate our inner ears, our vestibules and all the other obscure receptors and reflexes that govern our body orientation. For normal man, in normal situations, they simply do not exist.

Yet their absence can be quite conspicuous. If there is defective (or distorted) sensation in our overlooked secret senses, what we then experience is profoundly strange, an almost incommunicable equivalent to being blind or being deaf. If proprioception is completely knocked out, the body becomes, so to speak, blind and deaf to itself-and (as the meaning of the Latin root proprius hints) ceases to 'own' itself, to feel itself as itself (see Chapter Three, 'The Disembodied Lady').

The old man suddenly became intent, his brows knitted, his lips pursed. He stood motionless, in deep thought, presenting the picture that I love to see: a patient in the actual moment of discovery-half-appalled, half-amused-seeing for the first time exactly what is wrong and, in the same moment, exactly what there is to be done. This is the therapeutic moment.

'Let me think, let me think,' he murmured, half to himself, drawing his s.h.a.ggy white brows down over his eyes and emphasising each point with his powerful, gnarled hands. 'Let me think. You think with me-there must be an answer! I tilt to one side, and I can't tell it, right? There should be some feeling, a clear signal, but it's not there, right?' He paused. 'I used to be a carpenter,' he said, his face lighting up. 'We would always use a spirit level to tell whether a surface was level or not, or whether it was tilted from the vertical or not. Is there a sort of spirit level in the brain?'

I nodded.

'Can it be knocked out by Parkinson's disease?'

I nodded again.

'Is this what has happened with me?'

I nodded a third time and said, 'Yes. Yes. Yes.'

In speaking of such a spirit level, Mr MacGregor had hit on a fundamental a.n.a.logy, a metaphor for an essential control system in the brain. Parts of the inner ear are indeed physically-literally-like levels; the labyrinth consists of semicircular ca.n.a.ls containing liquid whose motion is continually monitored. But it was not these, as such, that were essentially at fault; rather, it was his ability to use his balance organs, in conjunction with the body's sense of itself and with its visual picture of the world. Mr MacGregor's homely symbol applies not just to the labyrinth but also to the complex integration of the three secret senses: the labyrinthine, the proprioceptive, and the visual. It is this synthesis that is impaired in Parkinsonism.

The most profound (and most practical) studies of such integrations-and of their singular disintegrations in Parkinsonism- were made by the late, great Purdon Martin and are to be found in his remarkable book The Basal Ganglia and Posture (originally published in 1967, but continually revised and expanded in the ensuing years; he was just completing a new edition when he died recently). Speaking of this integration, this integrator, in the brain, Purdon Martin writes 'There must be some centre or ”higher authority” in the brain . . . some ”controller” we may say. This controller or higher authority must be informed of the state of stability or instability of the body.'

In the section on 'tilting reactions' Purdon Martin emphasises the threefold contribution to the maintenance of a stable and upright posture, and he notes how commonly its subtle balance is upset in Parkinsonism-how, in particular, 'it is usual for the labyrinthine element to be lost before the proprioceptive and the visual'. This triple control system, he implies, is such that one sense, one control, can compensate for the others-not wholly (since the senses differ in their capabilities) but in part, at least, and to a useful degree. Visual reflexes and controls are perhaps the least important-normally. So long as our vestibular and proprioceptive systems are intact, we are perfectly stable with our eyes closed. We do not tilt or lean or fall over the moment we close our eyes. But the precariously balanced Parkinsonian may do so. (One often sees Parkinsonian patients sitting in the most grossly tilted positions, with no awareness that this is the case. But let a mirror be provided, so they can see their positions, and they instantly straighten up.) Proprioception, to a considerable extent, can compensate for defects in the inner ears. Thus patients who have been surgically deprived of their labyrinths (as is sometimes done to relieve the intolerable, crippling vertigo of severe Meniere's disease), while at first unable to stand upright or take a single step, may learn to employ and to enhance their proprioception quite wonderfully; in particular, to use the sensors in the vast latissimus dorsi muscles of the back-the greatest, most mobile muscular expanse in the body-as an accessory and novel balance organ, a pair of vast, winglike proprioceptors. As the patients become practised, as this becomes second-nature, they are able to stand and walk-not perfectly, but with safety, a.s.surance, and ease.

Purdon Martin was endlessly thoughtful and ingenious in designing a variety of mechanisms and methods that made it possible for even severely disabled Parkinsonians to achieve an artificial normality of gait and posture-lines painted on the floor, counterweights in the belt, loudly ticking pacemakers-to set the cadence for walking. In this he always learned from his patients (to whom, indeed, his great book is dedicated). He was a deeply human pioneer, and in his medicine understanding and collaborating were central: patient and physician were coequals, on the same level, each learning from and helping the other and between them arriving at new insights and treatment. But he had not, to my knowledge, devised a prosthesis for the correction of impaired tilting and higher vestibular reflexes, the problem that afflicted Mr MacGregor.

'So that's it, is it?' asked Mr MacGregor. 'I can't use the spirit level inside my head. I can't use my ears, but I can use my eyes. Quizzically, experimentally, he tilted his head to one side: ”Things look the same now-the world doesn't tilt.” Then he asked for a mirror, and I had a long one wheeled before him. 'Now I see myself tilting,' he said. 'Now I can straighten up-maybe I could stay straight. . . But I can't live among mirrors, or carry one round with me.'

He thought again deeply, frowning in concentration-then suddenly his face cleared, and lit up with a smile. 'I've got it!' he exclaimed. 'Yeah, Doc, I've got it! I don't need a mirror-I just need a level. I can't use the spirit levels inside my head, but why couldn't I use levels outside my head-levels I could see, I could use with my eyes?' He took off his gla.s.ses, fingering them thoughtfully, his smile slowly broadening.

'Here, for example, in the rim of my gla.s.ses . . . This could tell me, tell my eyes, if I was tilting. I'd keep an eye on it at first; it would be a real strain. But then it might become second-nature, automatic. Okay, Doc, so what do you think?'

'I think it's a brilliant idea, Mr MacGregor. Let's give it a try.'

The principle was clear, the mechanics a bit tricky. We first experimented with a sort of pendulum, a weighted thread hung from the rims, but this was too close to the eyes, and scarcely seen at all. Then, with the help of our optometrist and workshop, we made a clip extending two nose-lengths forward from the bridge of the spectacles, with a miniature horizontal level fixed to each side. We fiddled with various designs, all tested and modified by Mr MacGregor. In a couple of weeks we had completed a prototype, a pair of somewhat Heath Robinsonish spirit spectacles: 'The world's first pair!' said Mr MacGregor, in glee and triumph. He donned them. They looked a bit c.u.mbersome and odd, but scarcely more so than the bulky hearing-aid spectacles that were coming in at the time. And now a strange sight was to be seen in our Home-Mr MacGregor in the spirit spectacles he had invented and made, his gaze intensely fixed, like a steersman eyeing the binnacle of his s.h.i.+p. This worked, in a fas.h.i.+on-at least he stopped tilting: but it was a continuous, exhausting exercise. And then, over the ensuing weeks, it got easier and easier; keeping an eye on his 'instruments' became unconscious, like keeping an eye on the instrument panel of one's car while being free to think, chat, and do other things.

Mr MacGregor's spectacles became the rage of St. Dunstan's. We had several other patients with Parkinsonism who also suffered from impairment of tilting reactions and postural reflexes-a problem not only hazardous but also notoriously resistant to treatment. Soon a second patient, then a third, were wearing Mr MacGregor's spirit spectacles, and now, like him, could walk upright, on the level.

8.

Eyes Right!

Mrs S., an intelligent woman in her sixties, has suffered a ma.s.sive stroke, affecting the deeper and back portions of her right cerebral hemisphere. She has perfectly preserved intelligence-and humour.

She sometimes complains to the nurses that tney have not put dessert or coffee on her tray. When they say, 'But, Mrs S., it is right there, on the left', she seems not to understand what they say, and does not look to the left. If her head is gently turned, so that the dessert comes into sight, in the preserved right half of her visual field, she says, 'Oh, there is it-it wasn't there before'. She has totally lost the idea of 'left', with regard to both the world and her own body. Sometimes she complains that her portions are too small, but this is because she only eats from the right half of the plate-it does not occur to her that it has a left half as well. Sometimes, she will put on lipstick, and make up the right half of her face, leaving the left half completely neglected: it is almost impossible to treat these things, because her attention cannot be drawn to them ('hemi-inattention'-see Battersby 1956) and she has no conception that they are wrong. She knows it intellectually, and can understand, and laugh; but it is impossible for her to know it directly.

Knowing it intellectually, knowing it inferentially, she has worked out strategies for dealing with her imperception. She cannot look left, directly, she cannot turn left, so what she does is to turn right-and right through a circle. Thus she requested, and was given, a rotating wheelchair. And now if she cannot find something which she knows should be there, she swivels to the right, through a circle, until it comes into view. She finds this signally successful if she cannot find her coffee or dessert. If her portions seem too small, she will swivel to the right, keeping her eyes to the right, until the previously missed half now comes into view; she will eat this, or rather half of this, and feel less hungry than before. But if she is still hungry, or if she thinks on the matter, and realises that she may have perceived only half of the missing half, she will make a second rotation till the remaining quarter comes into view, and, in turn, bisect this yet again. This usually suffices-after all, she has now eaten seven-eighths of the portion-but she may, if she is feeling particularly hungry or obsessive, make a third turn, and secure another sixteenth of her portion (leaving, of course, the remaining sixteenth, the left sixteenth, on her plate). 'It's absurd,' she says. 'I feel like Zeno's arrow-I never get there. It may look funny, but under the circ.u.mstances what else can I do?'

It would seem far simpler for her to rotate the plate than rotate herself. She agrees, and has tried this-or at least tried to try it. But it is oddly difficult, it does not come naturally, whereas whizzing round in her chair does, because her looking, her attention, her spontaneous movements and impulses, are all now exclusively and instinctively to the right.

Especially distressing to her was the derision which greeted her when she appeared only half made-up, the left side of her face absurdly void of lipstick and rouge. 'I look in the mirror,' she said, 'and do all I see.' Would it be possible, we wondered, for her to have a 'mirror' such that she would see the left side of her face on the right? That is, as someone else, facing her, would see her. We tried a video system, with camera and monitor facing her, and the results were startling, and bizarre. For now, using the video screen as a 'mirror', she did see the left side of her face to her right, an experience confounding even to a normal person (as anyone knows who has tried to shave using a video screen), and doubly confounding, uncanny, for her, because the left side of her face and body, which she now saw, had no feeling, no existence, for her, in consequence of her stroke. 'Take it away!' she cried, in distress and bewilderment, so we did not explore the matter further. This is a pity because, as R. L. Gregory also wonders, there might be much promise in such forms of video feedback for such patients with hemi-inattention and left hemi-field extinction. The matter is so physically, indeed metaphysically, confusing that only experiment can decide.

Postscript Computers and computer games (not available in 1976, when I saw Mrs S.) may also be invaluable to patients with unilateral neglect in monitoring the 'missing' half, or teaching them to do this themselves; I have recently (1986) made a short film of this. I could not make reference, in the original edition of this book, to a very important book which came out almost simultaneously: Principles of Behavioral Neurology (Philadelphia: 1985), edited by M. Ma.r.s.el Mesulam. I cannot forbear quoting Mesulam's eloquent formulation of 'neglect': When the neglect is severe, the patient may behave almost as if one half of the universe had abruptly ceased to exist in any meaningful form. . . . Patients with unilateral neglect behave not only as if nothing were actually happening in the left hem-is.p.a.ce, but also as if nothing of any importance could be expected to occur there.

9.

The President's Speech What was going on? A roar of laughter from the aphasia ward, just as the President's speech was coming on, and they had all been so eager to hear the President speaking . . .

There he was, the old Charmer, the Actor, with his practised rhetoric, his histrionisms, his emotional appeal-and all the patients were convulsed with laughter. Well, not all: some looked bewildered, some looked outraged, one or two looked apprehensive, but most looked amused. The President was, as always, moving-but he was moving them, apparently, mainly to laughter. What could they be thinking? Were they failing to understand him? Or did they, perhaps, understand him all too well?