* * *
When my paediatric colleague told Vincent and his mother what the diagnosis was, there were mixed emotions. Vincent recalls feeling quite overwhelmed. ‘It’s a difficult concept that it’s a chronic disorder, where no matter what happens you’ve got it for the rest of your life. That’s quite a hard thing to get into your head.’ But there was also a clear sense of relief. ‘Before that [the diagnosis], I couldn’t really be sure. Some people thought it might be psychosomatic.’
Dahlia tells me something very similar. She was expecting it. ‘In my heart I knew. But when the diagnosis came, it was a relief too, because at least you know Vincent was not making it up. Vincent is not lazy. He was doing his very best. But on the other hand of course it’s sad because it is something he has to cope with.’
The diagnosis has clearly had some benefits. Despite dropping out of school, Vincent has gone on to achieve excellent grades in his exams at secondary school. With a medical diagnosis in hand, he started at a school for children with special needs, and the flexibility has allowed him to achieve something close to his full potential. Vincent now attends a boxing academy, where he studies alongside training.
The diagnosis has also permitted treatment to commence.
For patients with delayed or advanced sleep phase syndrome, extreme ‘evening owls’ or ‘morning larks’ respectively, apart from trying to keep a strict sleeping regime, there are two major forms of treatment.
As well as being the chemical cue that the pineal gland churns out to signal the chiming of the circadian clock, melatonin also directly influences that clock. Melatonin feeds back on the suprachiasmatic nucleus as well, and so is in itself a Zeitgeber. By giving people melatonin, the clock can also be shifted forward or back.
The other option is to manipulate light. Exposing people to very bright light, in the form of a lightbox, can also cause a shift. These lightboxes simulate natural sunlight, and are very rich in blue light, which seems to have the biggest effect on the retinal ganglion cells.
The timing of melatonin and light in relation to the underlying circadian clock is crucial, however. Depending on when in the circadian cycle melatonin or light is delivered, it can have very opposite effects. Exposing someone to bright light for an hour in the hour or two before natural bedtime can delay their bedtime by up to two hours; expose them to the same bright light in the morning after waking, and the bedtime will shift forward by about thirty minutes. Similarly, give someone melatonin in the early evening and they will go to sleep earlier; taken in the morning it will push bedtime back. In practice, we rarely give morning melatonin as it also potentially makes people drowsy, though there is some evidence that even small doses can cause a shift in the circadian clock without causing significant drowsiness.
Of course, for Vincent and others like him, there is no fixed rhythm that we can tailor melatonin and light timings to. But we can use these treatments to anchor his circadian rhythm. By giving his suprachiasmatic nucleus a regular evening dose of melatonin, and his retinal ganglion cells a dose of daytime bright light, his circadian rhythm is cajoled into staying a little more in sync with the outside world. And this regime, while not perfect, has made a significant improvement. Vincent still drifts a bit, particularly in the winter months, but treatment has made a big difference to his life.
‘At the moment, I’m attending college and, so far, I am able to attend most of the time. And it’s going okay. But I don’t always feel 100 per cent.’ Vincent tells me that he is currently managing to sleep at about 11 p.m. and get up at 6.30 a.m., and this cycle is fairly static. He has only missed a couple of days of school in the past few weeks. Every so often, however, despite our strategy to keep his rhythm regular, it still drifts. ‘When my sleeping pattern goes off track and it’s hard to bring it back, I’ll stay awake for the next day and just not sleep at night. Then I’ll fall asleep at a normal time again. That helps get me back into a pattern a bit quicker than waiting for several weeks. But it doesn’t always work 100 per cent.’
I ask him about his boxing. ‘I can be pretty inconsistent with my performance. So sometimes I can be much slower, or my reactions aren’t quite so good [when I am out of sync]. I try to compensate by being faster and more powerful. But sometimes it’s hard.’
We chat about what he thinks his future holds, what career he sees before him. ‘I don’t know. It’s definitely going to be very difficult to fit in properly. There’s not too much choice. Maybe self-employment or something like that. Something where I’m able to work on my own.’
* * *
For anyone who has done shift work, or is a regular traveller, Vincent’s experiences will ring true. The disruption of your circadian cycle is disconcerting. I recall the drives into hospital at 3 a.m. on a Monday morning as a registrar, being called in to see someone with a stroke, feeling groggy and slightly nauseated, not thinking totally clearly. And even though I was passing through the streets of central London, one of the busiest cities on earth, I distinctly remember the feeling of being largely on my own – a strong sense of isolation; that I was not at one with the world. While the rest of the city was almost entirely tucked up in bed, here I was transgressing into a time of day that I had no business being awake in.
Ultimately, we are social beings. Although our circadian rhythms originated from our bacterial ancestors and have evolved to keep us awake in the sunlight and asleep in the dark, what I find remarkable is the importance they play in synchronising us as a social group, enabling people to live with similar rhythms: to eat at the same time; work at the same time; play at the same time; sleep at the same time.
This circadian clock knits our lives together as a species and as a society. And when one loses this clock, it sets us apart from the world around us; disconnects us from our family, friends and colleagues.
In Vincent’s case, however, he cannot simply quit his job, or fly around the world a little less. For him, this is a constant and natural state of being. I am struck by the sense that it is this apartness without an end in sight, more than any other aspect of his condition, that is the most distressing. The loneliness of living one’s life on a different rhythm to everyone else.
2
IN THE STILL OF THE NIGHT
Jackie is a grey-haired woman in her seventies, softly spoken, with a ready laugh. She speaks with what I take to be a gentle West Country burr, but which I later discover is a relic of her upbringing in Canada. She tells me of a time she went for a night-time ride on her motorbike.
She herself has no recollection of this moonlit ride, however, because she was asleep at the time. As well as her motorbike, she has also driven her car in her sleep. Without witnesses, she would be none the wiser to the fact that she is doing all this – managing to get dressed; ride or drive several miles; get undressed; and get back into bed – all without the slightest awareness that she has even left her bed. Disconcerting to the extreme, and almost implausible. Her doctor’s response when she reported these events was to suggest admission to an in-patient psychiatric secure unit – not an appealing option for Jackie. And it is for that reason she finds herself sitting in my clinic.
Her letter of referral, from another sleep physician, was somewhat routine. ‘Dear Guy,’ it read. ‘I would be grateful if you could see this lady, who was originally seen with a main complaint of sleepwalking, which she seems to be coping with quite reasonably, but it has been quite extreme.’ There were some concerns about her breathing overnight, and some possible brainwave abnormalities on her sleep study, performed in her local hospital. But certainly nothing prepared me for the ‘quite extreme’ sleepwalking she went on to describe.
At first, I was incredulous. Many of the patients I have seen with this degree of ‘sleepwalking’ turned out to have a psychiatric or psychological root to their problems, like the woman I saw a few years ago who slit her throat and wrists with a kitchen knife, apparently in her sleep, or a young woman from Ireland who had been found eight miles away fro
m home with her handbag and keys, having walked this distance without shoes. Jackie’s rather matter-of-fact delivery of her tale, and initial apparent lack of concern over the degree of her night-time behaviour, did nothing to quell my cynicism. But, as I heard more about the background to her problems, I became more and more convinced about the nature of her sleep-motorbiking and sleep-driving.
Jackie’s problems started decades before I met her. Born in the UK, she was brought up in Canada, and it was there that her sleepwalking first became apparent. ‘I used to walk down the stairs to the lounge, open the door and stand in the doorway where my parents were,’ she says, explaining her actions in the middle of the night. ‘Well, it freaked Mother out, but Father just took my hand, took me back upstairs and put me to bed and that was it. But I’ve been doing it virtually since I could walk.’
It was when she joined the Brownies that her night-time antics became a problem. Needless to say, Jackie was definitely not the most popular girl to share a tent with. In the middle of the Canadian wilderness, her sleep activities were particularly unfortunate. ‘I used to make this sort of growling,’ she says. ‘But it wasn’t a quiet sort of growl. I think they thought a bear was coming after them. I growled so much and so loud that it frightened them, so they wouldn’t have me around.’ She was also a handful for the adults supervising the trips. ‘I’d get up in the middle of the night and I’d walk down to the river. I’d walk into the woods. They couldn’t cope with me, so I had to be picked up and taken back home again.’ She laughs as she tells me these stories, but I imagine that the impact of this on her as a child was terrible, and perhaps caused her to be a little socially isolated.
For anyone who is a parent, some of Jackie’s nocturnal behaviours will sound very familiar. Sleepwalking and related issues are incredibly common in childhood. Most traumatising, for parents rather than the children, are sleep terrors, when children will scream and cry inconsolably in the middle of the night and then go back to sleep, subsequently waking without any recollection. These conditions are termed non-REM parasomnias, as they arise from non-dreaming, very deep sleep. Trying to wake a child from deep sleep is highly likely to generate some sleep-talking or even sleepwalking.
What is less common is the persistence of sleepwalking into adulthood, which occurs in about 1–2 per cent of people. Jackie is one of these people. Her episodes persisted through to early adulthood, after her move back to the UK. It was shortly after her return that her sleepwalking took a twist. She was lodging with an elderly woman when one morning she came down for breakfast. Her landlady greeted her with a confusing question. ‘She said, “Where did you go last night?’ ” Jackie tells me. She denied having gone anywhere. ‘Well, you went out on your motorbike,’ her landlady replied. Jackie recalls being completely shocked, and initially perplexed. It is easy to imagine her incomprehension at what she had just been told. From her perspective, she had simply gone to bed that night as usual, and had woken up as usual. She immediately asked if she had been wearing her helmet. ‘Oh, yes, you clomped down the stairs and you had your helmet and you went out,’ her landlady said, adding that she had been gone for about twenty minutes. There were no other clues, as she had returned the motorbike to exactly the same place she had left it.
After a few more night rides, Jackie gave her motorbike keys to her landlady for safekeeping, and later sold it. She still misses her BSA 250. ‘Brilliant bike! You can hear that coming for miles.’ I tell her it is surprising that it did not wake her up. ‘It is, isn’t it?’ she says.
* * *
So how does medical science explain what is happening in Jackie’s case, these complex behaviours such as walking, growling or even motorbiking in deep sleep? We have known for years that certain animals like dolphins, seals and birds can sleep with one half of their brain at a time, allowing them to swim or fly while sleeping, what is termed ‘uni-hemispheric sleep’. Aquatic mammals obviously need to be able to swim and surface to breathe, but like us they must also sleep, so this neat evolutionary trick prevents them from drowning while carrying out these necessary functions. It also stresses the importance of deep sleep from an evolutionary perspective: if deep sleep served little useful purpose, why would this uni-hemispheric sleep be necessary?
In humans, however, uni-hemispheric sleep does not exist. We used to think of sleep being an ‘on’ or ‘off’ brain state: either you are awake or you are asleep; there is nothing in between. But, in recent years, we have learned that this is not the case. Deep sleep and full wakefulness lie at the extremes of a spectrum, and, implausible as it may sound, it is possible for us to be in both states at the same time.
When monitoring brainwaves using electrodes attached to the scalp, as we do when we undertake sleep studies on patients, the hallmark of deep, non-REM sleep is of synchronous electrical activity throughout the brain – slow waves of high amplitude termed ‘delta’ waves. But in these sleepwalking events, the picture can be very different. Mixed in with these slow waves, sometimes we see brainwave activity that looks very much like the activity of a brain that is wide awake, suggesting that wake and sleep are occurring at the same time. Using scalp electrodes really only gives us a limited glimpse of what is happening within the brain, though, like looking into a room through a keyhole. It is impossible to get the whole picture. This technique only provides information about what is happening close to the surface of the brain; nothing about what is happening in the brain’s core.
But there are other ways of looking at the brain. In 2000, Swiss researchers managed to capture brain activity during sleepwalking using a technique called SPECT. This involves the injection of a radionuclide, a radioactively labelled chemical, and rather than telling us about the structure of an organ, it tells us about its activity. This ‘dye’, the injected radionuclide, concentrates in areas where the blood flow is greatest, which equates to areas of greatest metabolic activity, i.e. those tissues with the highest demand for oxygen. In a feat of timing, these researchers managed to inject the radionuclide within twenty-four seconds of a sleepwalking event starting, in a sixteen-year-old boy who was known to sleepwalk several times a week. Even more impressively, they managed to do all this with him lying in a SPECT scanner, to detect where in the brain the radioactive substance was most concentrated. By comparing this scan to a scan performed in deep sleep, what they found was remarkable. During the sleepwalking episode, a deep area of the brain called the posterior cingulate cortex was found to be very active, while another area, the frontoparietal cortex, showed significantly reduced activity compared to wakefulness. Essentially, what they found was that small areas of the brain were awake, while other areas of the brain remained asleep. Those areas with increased activity, the cingulate cortex in particular, are involved in the control of behaviour associated with strong emotions. In contrast, the frontoparietal cortices, especially an area called the prefrontal cortex, where there was reduced activity, are involved in planning, rational thinking and personality. This pattern in sleepwalking, particularly in the sixteen-year-old, in whom sleepwalking often had elements of fear associated with it, makes perfect sense. During these events, the part of his brain involved in strong emotion was in overdrive, almost awake, while the part of his brain involved in logic, in personality, in planning his actions, remained deep asleep. It seems that this dual brain state of simultaneous wake and sleep explains these phenomena of complex activities: the ability to interact with the world around you, without the ability to think rationally, as you would when you are awake.
Serendipitously, an Italian group also captured sleepwalking in a twenty-year-old man, this time with electrodes implanted into the brain during monitoring for possible surgery for epilepsy. For patients suffering from epilepsy that does not respond to medication, surgical removal of the area of the brain triggering seizures can sometimes be an option, but relies upon the accurate identification of precisely where the seizures are coming from. Because of the limitations of recording electrical acti
vity from the scalp, small wires are inserted into the skull, usually over the surface of the brain but sometimes with electrodes inserted deep into the brain substance. In this case, the poor young man had suffered from epileptic seizures since the age of seven, having had meningitis as an infant. Unfortunately for him, although fortunately from our perspective, he had also experienced sleepwalking since even before his meningitis diagnosis, and during the course of his study, the patient experienced both seizures and sleepwalking. With electrodes recording directly from within the brain itself, on one occasion during deep sleep he turned in his bed, extended his arms as if to embrace someone, gave a kiss, and muttered a few words before going back to sleep. During this sleep-kissing episode, electrical activity in motor and cingulate areas once again showed waking activity, while other areas remained in very deep sleep. This study would appear to confirm the conclusions of the SPECT study performed a few years earlier, proving that those earlier imaging findings were truly a reflection of sleep state rather than simply a result of blood-flow changes in the brain.
So it seems that sleep, rather than being a global phenomenon affecting the whole brain, is a local occurrence. The brain does not act as a whole, and in these unusual cases, different parts of the brain can simultaneously exist in different states of wakefulness or sleep. In a similar way to a dolphin sleeping with only one hemisphere, it appears that this can happen in the human brain, albeit on a more local level.
* * *
Alex is another of my patients, now in his twenties, but a regular sleepwalker since childhood. He is tall, well-spoken, with long hair and an earring. He lives in a shared house in a rapidly gentrifying area of south London. He is working for a charity at present, but intends to travel the world. When I first meet him, he attends clinic with his mother. The referral letter states: ‘He is already taking common-sense steps to do with his parasomnia, but if anything things are becoming more frequent, and the risk of him getting into trouble is increasing. I would therefore be grateful if you could arrange to see him before he succumbs to some unfortunate mishap.’
The Nocturnal Brain Page 4