The man who mistook his wife for a hat by Oliver Sacks, Оливер Сакс Page A

Simon as well. Within a year he had become very 'handy' in all ways, and particularly enjoyed simple carpentry, shaping plywood and wooden blocks, and assembling them into simple wooden toys. He had no impulse to sculpt, to make reproductions-he was not a natural artist like Madeleine. But still, after a half-century spent virtually without hands, he enjoyed their use in all sorts of ways.
       This is the more remarkable, perhaps, because he is mildly retarded, an amiable simpleton, in contrast to the passionate and highly gifted Madeleine J. It might be said that she is extraordinary, a Helen Keller, a woman in a million-but nothing like this could possibly be said of simple Simon. And yet the essential achievement-the achievement of hands-proved wholly as possible for him as for her. It seems clear that intelligence, as such, plays no part in the matter-that the sole and essential thing is use.
       Such cases of developmental agnosia may be rare, but one commonly sees cases of acquired agnosia, which illustrate the same fundamental principle of use. Thus I frequently see patients with a severe 'glove-and-stocking' neuropathy, so-called, due to diabetes. If the neuropathy is sufficiently severe, patients go beyond feelings of numbness (the 'glove-and-stocking' feeling), to a feeling of complete nothingness or de-realisation. They may feel (as one patient put it) 'like a basket-case', with hands and feet completely 'missing'. Sometimes they feel their arms and legs end in stumps,
       with lumps of 'dough' or 'plaster' somehow 'stuck on'. Typically this feeling of de-realisation, if it occurs, is absolutely sudden . . . and the return of reality, if it occurs, is equally sudden. There is, as it were, a critical (functional and ontological) threshold. It is crucial to get such patients to use their hands and feet-even, if necessary, to 'trick' them into so doing. With this there is apt to occur a sudden re-realisation-a sudden leap back into subjective reality and 'life' . . . provided there is sufficient physiological potential (if the neuropathy is total, if the distal parts of the nerves are quite dead, no such re-realisation is possible).
       For patients with a severe but sub-total neuropathy, a modicum of use is literally vital, and makes all the difference between being a 'basket-case' and reasonably functional (with excessive use, there may be fatigue of the limited nerve function, and sudden de-realisation again).
       It should be added that these subjective feelings have precise objective correlates: one finds 'electrical silence', locally, in the muscles of the hands and feet; and, on the sensory side, a complete absence of any 'evoked potentials', at every level up to the sensory cortex. As soon as the hands and feet are re-realised, with use, there is a complete reversal of the physiological picture.
       A similar feeling of deadness and unrealness is described above in Chapter Three, 'The Disembodied Lady'.
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        Phantoms
       A 'phantom', in the sense that neurologists use, is a persistent image or memory of part of the body, usually a limb, for months or years after its loss. Known in antiquity, phantoms were described and explored in great detail by the great American neurologist Silas Weir Mitchell, during and following the Civil War.
       Weir Mitchell described several sorts of phantom-some strangely ghost-like and unreal (these were the ones he called 'sensory ghosts'); some compellingly, even dangerously, life-like and real; some intensely painful, others (most) quite painless; some photographically exact, like replicas or facsimiles of the lost limb, others grotesquely foreshortened or distorted … as well as 'negative phantoms', or 'phantoms of absence'. He also indicated, clearly, that such 'body-image' disorders-the term was only introduced (by Henry Head) fifty years later-might be influenced by either central factors (stimulation or damage to the sensory cortex,