1996 - The Island of the Colorblind

by Oliver Sacks

  ‘There is one more fern, over here,’ said Lynn, ‘you’ll want to see. Take a look at this fellow, with its two different types of leaves. The divided fronds are the fertile ones; the spearlike ones are sterile. Its name is Humata heterophylla, and it is named after Umatac (or Humatag) where it was found in the 1790s, by the first botanical expedition to Guam – you might call it the national fern of Guam.’

  John and I made some more housecalls in the afternoon. We drove to the village of Yona, and stopped at the first house, where John’s patient, Jesus, was sitting on the porch; now that he had become almost petrified with the bodig, this was where he loved, above all, to sit all day. I was told he had ‘man-man’ – the Chamorro word for staring blankly into space – though this was not a blank staring, a staring at nothing, but an almost painfully engrossed, wistful staring, staring out at the children who played in the road, staring at the occasional passing cars and carts, staring at the neighbors leaving for work each morning, and returning late in the day. Jesus sat on his porch, unblinking, unmoving, motionless as a tortoise, from sunrise till midnight (except on the rare days when high winds or rain lashed across it), forever gazing at a constantly varying spectacle of life before him, an enraptured spectator, no longer able to take part.68 I was reminded of a description of the aged Ibsen after his stroke, aphasic, partly paralyzed, no longer able to go out or write or talk – but insistent, always, that he be allowed to stand by the tall windows in his room, looking out on the harbor, the streets, the vivid spectacle of the city. ‘I see everything,’ he had once murmured, years before, to a young colleague; and there was still this passion to see, to be an observer, when all else was gone. So it was, it seemed to me, with old Jesus on his porch.

  When John and I greeted Jesus, he answered in a small, flat voice, devoid of inflection or intonation, but his answers were precise and full of detail. He spoke of Agana, where he had been born in 1913, and how pleasant and tranquil it was then (‘Not like now – it’s completely changed since the war’), of coming to Umatac with his parents when he was eight, and of a long life devoted to fishing and farming. He spoke of his wife, who had been half Japanese and half Chamorro; she had died of bodig fifteen years ago. Many people in her family had lytico or bodig; but his own children and grandchildren, fortunately, seemed free of it.

  We had been told that Jesus might pass the whole day with scarcely a word. And yet he spoke well, even volubly, when we engaged him in conversation; though, it soon became apparent, he waited for our questions. He could respond quite readily, but could not initiate a sentence. Nor, it seemed, a movement either – he might sit totally motionless for hours, unless something or someone called him to move. I was again strongly reminded of my post-encephalitic patients and how they were crucially dependent on the initiative of others, calling them to speech or action. I tore a page out of my notebook, balled it up, and threw the balled paper at Jesus. He had been sitting, seemingly incapable of movement, but now his arm shot up in a flash, and he caught the paper ball precisely. One of his little grandsons was standing by, and his eyes widened with astonishment when he saw this. I continued playing ball, and then asked Jesus to throw the ball at his grandson, and then to another child, and another. Soon we had the entire family playing ball, and akinetic Jesus, no longer akinetic, kept it going between us all. The children had not realized that their ‘paralyzed’ grandfather could move by himself at all, much less that he could catch a ball, aim it accurately, bluff, throw it in different styles and directions, and improvise a fast ball game among them.

  For his grandchildren it was a discovery, and one, I thought, which might transform his relationship with them – but this calling-into-action was well known to his old friends in the community. Once a week, he would go to the senior center – he would have to be picked up and lifted (‘like a corpse,’ he said) into the car; but once there, and seated at a card table, he could play a fast and hard game of gin rummy. He could not start the play – someone else had to do this – but once the first card was slapped down, he would suddenly come to life, respond, pick up another card, and continue the game. The people of Umatac, Merizo, Dededo, and Santa Rita may have little scientific knowledge of parkinsonism, but they have a great deal of informal knowledge, a folk neurology based on decades of close observation of the bodig in their midst. They know well how to unfreeze or unlock patients if they get frozen, by initiating speech or action for them – this may require another person walking with the patient or the rhythmic pulse of music. They know how patterns on the floor or the ground can help the parkinsonian to organize his walking; how patients scarcely able to walk on a flat surface can negotiate complex obstacles, rough terrain, easily (and indeed, fare oddly well with these); how the mute and motionless parkinsonian can respond beautifully to music, singing and dancing, when speech and motion had previously seemed impossible.

  But what was it that had caused the lytico-bodig, what was it that had come and gone? There had been a sort of conceptual vacuum, John said, when the cycad hypothesis had collapsed in the early seventies. The disease continued to claim more Chamorros, and patients were treated, when possible, for their symptoms – but there was a marked lull in research for a while, at least in Guam.

  And yet in the seventies there was a discovery of great importance. Two pathologists, Frank Anderson and Leung Chen, performed autopsies on two hundred Chamorros, many of whom had died suddenly in traffic accidents. (Agana had been a small, slow-moving town before the war, and transport was leisurely – usually by carts pulled by the big-horned carabao, along the rutted and frequently flooded roads. But following the war, there was a sudden increase in population, especially American military, who brought along with them fast roads and cars; this caused a sudden rise in traffic fatalities among the Chamorros, who were wholly unused to this rapid pace.) None of these people had ever shown any neurological symptoms; yet seventy percent of those born before 1940 showed clear pathological changes in the nervous system similar to the neurofibrillary tangles which Hirano had found in patients with lytico-bodig. The occurrence of these neurofibrillary tangles fell off sharply in those born in the 1940s, and they were not seen at all in anyone born after 1952. This extraordinary finding suggested that the lytico-bodig might have been almost universal among the Chamorros at one time – even though only a small proportion went on to develop overt neurological symptoms. It suggested, moreover, that the risk of contracting the disease was now very much reduced – and that even though cases continued to occur, these had probably been contracted many years before, and were only now becoming symptomatic. ‘What we are now seeing, Oliver,’ said John, pounding the steering wheel for emphasis, ‘are the late effects of something that happened long ago.’69

  When Yoshiro Yase, an ardent sport-fisherman as well as a neurologist, went to study the newly identified disease focus on the Kii Peninsula, he was told there were scarcely any fish in the local rivers, and this prompted him – memories of the Minamata tragedy still being vivid – to analyze their waters. Though these were free of infectious agents or toxins, they were oddly low in calcium and magnesium. Could this, he wondered, be the cause of the disease?

  Gajdusek was fascinated by Yase’s findings, the more so as he had been struck by the red soil, rich in iron and bauxite, in the swamp lands around the Auyu and Jakai villages. When he was able to return in 1974 – Western New Guinea having become Irian Jaya in the intervening upheavals – he now tested the water from the shallow wells which the villagers dug in the red soil, and found unusually low levels of calcium and magnesium, as well as elevated levels of iron, aluminum, and other metals.

  At this point, Kurland moved to the Mayo Clinic to pursue other research, feeling that the cycad hypothesis, though valid, could not be proven. His place at the NIH was taken by Gajdusek, who was now intrigued and excited at the notion of a mineral etiology of the Western Pacific disease. Gajdusek enlisted Yase, and together they examined well water from Guam and found that this too
was low in calcium and magnesium. This triple coincidence seemed definitive:

  Comparison of the Western New Guinea focus with the foci of ALS and Parkinson’s disease on Guam and the Kii Peninsula of Japan is inescapable [Gajdusek wrote], and the close association of parkinsonism and motor neuron symptoms in yet another non-Chamorro population group should not only dispel most doubts about the probably close relationship between the two syndromes, but also point to an aetiologic role of some unknown environmental factor.

  The unknown environmental factor, it seemed likely, had to do with low calcium and magnesium levels in the drinking water, and the consequences of these on the nervous system. Such low levels, he speculated, might trigger a compensatory reaction in the parathyroid glands, leading in turn to excessive absorption of calcium, aluminum, and manganese ions. The deposition of these in the nervous system, he felt, might result in the premature neuronal aging and death seen with the lytico-bodig.

  It was John’s hope, in 1983, that he might join Gajdusek’s team and help crack the disease at last. But Gajdusek told him he was too late – the cause of the lytico-bodig had now been established, and in any case the disease had almost vanished, because of the shift to a Western diet, which was high in calcium – there was not much left to do, and his team would be pulling out of there soon. John was surprised to hear Gajdusek express himself so forcefully, he told me, and disappointed, because he had hoped to work with him. But he decided to come to Guam nonetheless, if only to take care of patients as a physician, and not as an investigator.

  But the very day after John arrived on Guam, he had an experience comparable to Zimmerman’s nearly forty years before: working in the naval hospital in Agana, he saw a dozen patients with the lytico-bodig in his first clinic. And one of them also had a supranuclear palsy – a complex disturbance of gaze, in which the patient can look sideways, but not up or down. This had never previously been reported in lytico-bodig, but it was the hallmark of the syndrome John and his Toronto colleagues had delineated nearly twenty years before. This convinced him that lytico-bodig was neither extinct nor comprehensively described, and that there was still time and opportunity for its further investigation.

  Guam had superb medical facilities on the naval base, but in the outlying villages, basic medical care was very inadequate, and neurological care scarce – there was only one overworked neurologist, Dr. Kwang-Ming Chen, to care for 50,000 Chamor-ros, and 100,000 other residents of the island as well. Not only were there still many hundreds of Chamorro people with lytico-bodig, Chen told John, but new cases kept appearing – several dozen a year, he thought, and these new cases sometimes took forms different from either the classic lytico or bodig; the man with supranuclear palsy was a case in point.

  In particular, John observed, he began to see increasing numbers of elderly people, women especially, who had severe memory disturbances, amnesic syndromes, without any dementia; catatonia without parkinsonism (like Estella); dementia without parkinsonism (like her sister-in-law); arousal disorders (like Euphrasia); or unclassifiable syndromes (like Juan’s), novel forms of the disease never described before.

  John was still excited by the mineral hypothesis, and he wanted to pursue it, to gather more conclusive evidence. He invited an old friend and colleague from Toronto, Donald Crapper McLachlan (a neurologist and chemist who had shown elevated levels of aluminum in Alzheimer’s brains as far back as 1973), to join him on Guam, and working with colleagues from the University of Guam, they compared soil samples from Umatac with soil from fifty-five other sites on Guam and reexamined mineral levels in samples of well water all over the island.

  Their results, to their surprise, differed greatly from Gaj-dusek and Yase’s – indeed it seemed that the one water source in Umatac, the Piga spring, which the early investigators had found to have low calcium, was quite atypical. Every other water source and all the soils they sampled had high levels of calcium, as might be expected on a limestone island. Further analysis of the soils and of vegetables grown in them found adequate levels of calcium and magnesium and normal levels of aluminum, which seemed to shake the notion of a mineral deficiency or aluminum excess as the cause of lytico-bodig (without, however, excluding it completely).

  John is of a passionate disposition and tends to get strongly invested in theories and ideas. He had a huge respect for Gaj-dusek’s intuition, and was greatly taken by the mineral hypothesis; John had hoped to confirm, and perhaps elucidate, this with his own investigations. He had been elated by these hopes, and the promise of Gajdusek and Yase’s hypothesis – and now, suddenly, all this had collapsed. He was back to where Kurland had been a decade earlier, in a conceptual void.

  Then, in 1986, his eye was caught by a letter in the Lancet which resurrected the cycad hypothesis. Peter Spencer, a neurotoxicologist, using a purified form of the amino acid BMAA from cycad seeds, found that it could induce a neurological syndrome in monkeys, conceivably analogous to human lytico.

  Spencer’s work in this realm went back to the 1970s, when, with his colleague Herb Schaumburg, he had travelled to India to investigate the neurolathyrism there. It had been known for centuries that a spastic paralysis of the legs could follow continued eating of the chickling pea; that this was due to the neurotoxic amino acid BOAA, which damaged the cortical motor cells and their descending connections in the spinal cord, had been known since the 1960s. Spencer’s new studies made clear how BOAA heightened sensitivity to glutamate, one of the neurotransmitters involved in the motor system, and simulated its action as well. BOAA intoxication, therefore, could push the glutamate receptor cells into a sort of overdrive, until they literally died of overexcitation and exhaustion. BOAA was an ex-citotoxin – this was the new term. Could BMAA, he wondered, so similar in structure to BOAA, also act as an excitotoxin and produce a disorder like lytico?

  There had been attempts to induce such disorders in animal experiments during the sixties, but the results were inconclusive, and this line of research had been dropped. Now, using cynomolgus monkeys and repeated administrations of BMAA, Spencer succeeded, after eight weeks, in inducing ‘a degenerative motor system disease’ associated with damage to the motor cells in the cerebral cortex and spinal cord.70 He further observed that BMAA might have two distinct effects: given in high doses, it caused an ALS-like condition to develop rapidly; but smaller doses seemed to cause, after a considerably longer period, a parkinsonian condition – a double action reminiscent of the Guam disease.

  These results seemed to refute the first criticism made in the 1960s of the cycad hypothesis – that there existed no animal model. Now Spencer, with a characteristic burst of energy, set about refuting the other, seemingly lethal criticism of the cycad hypothesis – that there were no cycads in the Kii Peninsula or Irian Jaya. Like Gajdusek had before him, he trekked into the jungles of Irian Jaya with his colleague Valerie Palmer – and they discovered that there were cycads here (though they seemed to be a different species from the Guam one). They found, moreover, that cycads were treated as veritable medicine cabinets by the local people, who used raw seeds (like the Chamorros) as poultices on open wounds. On the Kii peninsula, they went on to discover, cycads were also used medicinally, as tonics. With these two discoveries, in the lab and the field, the cycad hypothesis, discarded fifteen years earlier, was now revivified.

  John could not contain his excitement at these new thoughts and findings – everything seemed to fit together perfectly. He would phone Spencer in New York, and the two would have excited conversations for hours, sometimes nightly, discussing clinical data, and bringing out more and more ‘coincidences’ of cycads and disease in the Marianas. With his colleague Tomasa Guzman, John now embarked on reexamining the whole question of cycad distribution and use in the Marianas. They observed that while lytico-bodig was common among the Chamorros on Guam and Rota, where cycads were plentiful, there was no lytico-bodig reported on the island of Saipan (at least none in the previous seventy years – it remained uncerta
in whether the Saipanese Chamorros had been prone to it before this).71 But they pointed out that the cycad forests of Saipan had been cut down by the Japanese in 1914, to clear land for sugar cane, and that the use of fadang had ceased soon after this. And that on lytico-bodig – free Tinian, where there were forests of cycads, the Chamorros had never made use of them. They proposed that the family clusters of disease found on Guam, which did not follow any known genetic distribution, could be related to differences in the way each family prepared their fadang – some family recipes involved soaking the seeds overnight, some for three weeks; some would use seawater, some fresh; some would shorten the washing process so that the flour would have a stronger taste. Steele and Guzman ended their paper with some striking accounts of people who had developed lytico-bodig as long as twenty years after a single exposure to fadang.

  But many researchers felt, after the first flush of enthusiasm, that the amounts of BMAA Spencer was feeding his monkeys were completely unphysiological – more than the most devoted fadang eater could consume in a lifetime. Indeed, Gajdusek calculated, to reproduce Spencer’s experiment in a human being, the subject would have to eat a ton and a half of unprocessed cycad seeds in twelve weeks. This in itself was not an annihilating criticism – experimental toxicology often uses massive doses of materials in its initial experiments in order to increase the chance of getting results within a reasonable time. But now John, knowing how meticulously the seeds were detoxified before the production of fadang, set about measuring the amount of BMAA the flour actually contained; he started sending samples out for analysis, and was surprised to find that many of these had very low levels of BMAA, and some almost none at all. With this he turned against the cycad hypothesis, which had so exercised him for more than three years – turned against it with the vehemence with which he had once espoused it.