The first is that people with a genetic predisposition to sleepwalking might be partially woken by events that for a non-sleepwalker would have little bearing on their sleep. Their deep sleep may be inherently less deep or less stable. I have certainly seen patients in whom sleepwalking has been triggered by noises like a squeaking bed, a plane flying overhead or the rumble of a distant lorry. Perhaps a vibrating phone on the bedside cabinet when a text comes through in the middle of the night.
Daytime stress may cause night-time sleep to be less deep, too. Alcohol is generally considered a sedative, but actually may have precisely the reverse effect. It makes sleep more fragmented, and a full bladder can certainly wake people up – as can the snoring associated with a skinful of beer. Equally, all of us are aware of the effects of daytime stresses on sleep, making it more broken. Thus, in some people, anything that causes an arousal – a small shift out of deep sleep – may make a sleepwalking event more likely to occur.
The second possibility is almost the opposite explanation – that sleepwalkers sleep more soundly than non-sleepwalkers, and what would normally wake people up completely from deep sleep only succeeds in partially waking the brain of sleepwalkers, resulting in these events. Sleep deprivation is a potent way of making deep sleep even deeper, and some drugs commonly used as sleeping aids can certainly trigger sleepwalking events, sometimes even in people who have never sleepwalked. The most dramatic case of this I have seen is a woman in her seventies who began to sleep-bathe in the middle of the night (she was discovered chin-deep in bubble bath) after being prescribed a sleeping tablet.
The reality is that both explanations are probably valid. For children, in whom sleepwalking and other non-REM parasomnias are so common, deep sleep is incredibly stable, as any parent who has picked up their child in the middle of the night will testify, and this may well be why so many children exhibit these behaviours. In adults, the disruption of deep sleep by a variety of factors may well be a more significant explanation, on a background of an underlying genetic susceptibility. In fact, targeting these factors is often a successful way of treating non-REM parasomnias in adults. Cutting down on alcohol, reducing daytime stress, avoiding loud noises and an uncomfortable bed may help. Regular sleep patterns and avoidance of sleep deprivation may also be useful, as this reduces excessive deep sleep, from which people might have difficulty fully waking. Treatment of snoring is often a useful technique. For some people, however, particularly if you have types of behaviour that put yourself or others at risk, medication may be the only option.
So what have Jackie and Alex done to treat their parasomnias? To my surprise, Jackie has never really wanted any treatment for her sleep-driving. She wanted an explanation for why she does the things she does, but has worked out her own ways of keeping herself and the other road-users of Seaford out of danger. In many ways, this is perhaps one of the most convincing aspects of her sleepwalking for me.
Until recently, she has never really sought medical help for her events, but has always seen this as part and parcel of who she is. She has absolutely nothing to gain from this, and is somewhat taken aback by my interest in her condition. She tells few people about her nocturnal life, and has not really let it impact on her daytimes. Her primary concern is her and others’ safety. Having been diagnosed with mild sleep apnoea as well, previous attempts at treatment have been focused on this aspect of her sleep, on the basis that occasionally stopping breathing might be precipitating her events.
She has been trialled on a treatment called CPAP, whereby a mask that is strapped to the face delivers pressurised air to prevent her airway collapsing. This treatment is intrusive and can be difficult to tolerate, as Jackie has discovered. She just didn’t get on with it. An alternative would be an oral device, a little like a boxer’s mouthguard, to push the lower jaw forward and create more space at the back of the throat. For the moment, Jackie has not pursued this, nor is she keen to take any medication for her sleepwalking. From her perspective, using her time-locked safe has resolved the issues that cause her concern.
For the most part, Alex finds his sleepwalking episodes amusing and is generally relaxed about the sleep terrors. In recent months, his nights have been a little more peaceful, for some unknown reason. Perhaps he is one of those individuals who is slowly ‘growing out’ of his non-REM parasomnias, albeit a little later on in life than most. He is rather phlegmatic about his sleep issues. ‘I’ve had it all my life, so it’s one of those things I’ve just lived with,’ Alex says. ‘I don’t know anything different. Whenever there’s a party and someone has to say something weird about themselves, then I usually have one of those stories.’
Alex is keen to try non-drug-based treatments in the first instance. One of his acquaintances has suggested hypnotherapy, which Alex is going to pursue. We have agreed that if this does not help, the next steps would be to start medication. Initially, I have suggested melatonin, a tablet version of the hormone produced by the brain as a signal to sleep – what we term a sleep promoter. In many countries around the world, this drug is seen as a health supplement, and can be bought off the shelf in supermarkets and pharmacies, although in the UK it is only available on prescription.
If he is still putting himself at risk, then other options would include antidepressant drugs or benzodiazepines, neither of which are without issues. The decision to use these drugs needs to be weighed up carefully. We do not fully understand how these drugs work, and the evidence for drug treatment in non-REM parasomnias is for the most part limited, due to lack of research. Any treatment needs to be supplemented with avoidance of potential triggers such as noise and sleep deprivation, and practical measures such as door alarms and locks on the windows.
When pressed as to why he thinks he might be having sleep terrors, he says: ‘A lot of people have given me their theories on it – they think that I’ve been bottling up stress and anxiety and then letting it out when I’m asleep – but I’m not really sure.’
To my mind, Alex is one of the most relaxed people I have met in my clinic, and seems largely unruffled by most things. Katie, his ex-girlfriend, confirms my view: ‘I don’t think I’ve ever seen him anxious about anything. In the six years I’ve known him, I’ve never known him really to repress anything. He’s always been quite open about any issues that he’s having.’
‘I guess it helps me with stressful situations in real life,’ Alex muses. ‘I know that if one day I do wake up and there is a man in the room with a knife, I’ll be more relaxed about it and hopefully have a clearer head and deal with the situation. So I guess it’s sort of preparing me for that . . .’
* * *
Our previous binary view of brain states, either awake or asleep, really does not represent the truth. Rather than black and white, it appears that there are infinite shades of grey – and Jackie, Alex and many others like them occupy this grey zone in the middle of the night.
3
DISNEY WAS RIGHT
In my childhood, I must have seen the Disney film Cinderella several times. I have vague memories of a scene in which Cinderella is dancing, and her animal companions help her to make a dress. Birds clutch a ribbon between them as the mice busily stitch it together. Some thirty years later, however, watching the film with my two young daughters, I was suddenly struck by something in the film.
If you have exceptional recall, or have young children too, you may remember two scenes. In one, Bruno the dog is sleeping on a rug on the stone floor of the kitchen. As he does so, he growls and his legs move, as if he is running or chasing something. He is dreaming of chasing his arch-enemy Lucifer, the stepmother’s evil cat, and he suddenly leaps up, bites the rug he is lying on, before waking up, startled. Cinderella pets his head as he calms down. In another scene, the King, obsessed with marrying off his son, Prince Charming, lies asleep in the centre of his vast bed, which has an ornate baroque golden headboard and royal red bedcovers. Lying on his side, with his head on the pillow, he laughs and chuckles
as he dreams that his imaginary grandchildren are riding on his back. His dream-grandson, clutching a golden sceptre or rattle, begins to bang him repeatedly on the head. The King wakes with a start and tumbles out of bed, caught up in the bedcovers.
* * *
A couple of years ago, I had received an email from a psychiatrist colleague about a patient. ‘He is eighty years old. The main issue is what he calls “violent night terrors”, occurring between 2 and 4 a.m. over the past six months. He sleeps with his wife who he says has osteoporosis, and has been so concerned he has been thinking of moving into a separate bedroom. There is a background of some mild “difficulty with sleep” of a longer duration than six months.’
When I first meet John* and his wife Liz*, it is quite clear they are both traumatised by their recent experiences. John is in his eighties, but looks much younger. I envy him his full head of grey hair. He is still actively working and is incredibly successful in his professional life. He is tall and slim and wears fashionable round glasses with thick, dark-brown frames. He tells me his story in a soft, deliberate manner, despite the obvious angst this causes him. Liz sits next to him, elegant and equally gentle, trying to communicate her concern and the shock of what has been going on, mindful of upsetting John. She explains the final straw that caused them to seek medical help.
‘This time he’d actually come all the way over to my side of the bed and grabbed me on my arm, and it scared me so much when the nails went in. I was out of bed before I knew it, screaming my head off – and I’m not a screamer. And I was shaking and crying, just saying, “We can’t do this any more.” That was the final one, when I realised it was too much.’
John had managed to draw blood. It was at this point that they had moved into separate beds.
But this episode was not the first. John has been having these ‘night terrors’ for a couple of years now, rather than for the six months mentioned in the referral letter. ‘I think there has been a leading-up to this for years,’ Liz explains. ‘Before the actual physical violence, there would be this very weird sound coming from John, almost from the depths.’ Over the months, John’s episodes intensified.
Liz tells me: ‘Occasionally, he would kick me, but it would be with such ferocity that it would be as if you were walking behind a horse or a donkey and they lashed out and kicked you. And it would be so unlike John. That was the freaky thing, because it was almost like the day person was completely different to the night person, so that added to the weirdness of it all.’
John shifts uncomfortably and grimaces on hearing what he has put his wife through. Liz continues, talking about the strange sounds John would make: ‘And it would be like a crescendo, and it was always scary. What was he going to do once he’d got to the top, you know, with the crescendo? Was he going to lash out or what was going to happen?’
These events were happening every week or two. Even after moving into separate beds, Liz could still hear John thrashing about in bed.
John tells me: ‘Although I knew that I was having dreams about things, I didn’t realise that they were manifesting themselves in such obvious ways – thrashing about, leaping out of bed, calling out in a very strange voice and all of that kind of thing – until Liz pointed it out.’
I ask him about the content of his dreams.
It’s the kind of traditional nightmare, like suddenly finding yourself in a large wood with a tiger. What happens is that I’m doing something perfectly routine, something perfectly normal – there was no reason I shouldn’t be in a wood, and I was often in a wood, you know – but then suddenly you’re aware of a presence that you weren’t expecting and then it becomes sinister and you get fearful. It could be other animals, or the sort of things that frighten people like snakes and anything like that. Things that eat you and bite you. The typical experience is that at that moment when you expect their jaws to close on you, that’s when you wake up.
According to Liz, John sometimes lets out what she describes as a disembodied howl as he lashes or kicks out. ‘I’m kicking at some object, usually an animal, to get something away.’
Liz’s initial fear was that John was suffering from epilepsy, and John really didn’t know what to think. ‘I’m always embarrassed by them now. Since my wife started to point out that I was having these things and being violent in the process, I’ve rather dreaded them.’
On listening to their story, however, it is quite clear to me that they are describing John acting out his vivid dreams or nightmares. He experiences dreams of a narrative structure, a story evolving like the plot of a film or book, which suddenly turns nasty. The fear or strong emotion triggers the kicking or lashing out – a natural response to what is going on in John’s mind.
Their first thought had been to seek psychological help. John explains: ‘At one stage I went to a therapist that Liz recommended through a friend of hers.’ The therapist was obviously taking the Freudian view that dreams are a window into the subconscious, and perhaps represent repressed thoughts or psychological trauma. ‘I had several sessions with him [the therapist], which was all about going into tigers and what tigers meant and stuff, a great deal of detail. But it didn’t do anything for me, I’m afraid.’
* * *
If the psychological explanation for John’s nocturnal problems is insufficient, could there be a neurological explanation? As discussed in the previous chapter, most of our dreaming, particularly these dreams with narrative content, arise in a stage of sleep termed REM sleep. The discovery of this stage of sleep was, as is often the case, rather serendipitous.
Eugene Aserinsky, one of the discoverers of REM sleep, recalls meeting Nathaniel Kleitman – at the time already one of the most prominent sleep researchers in the world – in his small office at the University of Chicago in the early 1950s. Aserinsky was a graduate student searching for a research project. He self-effacingly recalls:
After satisfying himself that my mind was a clean slate devoid of any self-generated ideas, Kleitman related a story. He had read in Nature [one of the most highly regarded scientific journals to this day] an article by a physicist called Lawson, who claimed that, while riding in a railroad compartment, he was able to distinguish sleep onset through observing the blinking rates of fellow passengers. What disturbed Kleitman was the allegation by Lawson that the blinking stopped abruptly with sleep onset rather than stopping gradually.
Aserinsky was more disturbed by the fact that Nature had bothered to even publish such an un-noteworthy observation.
Nevertheless, he was tasked with reading all that had been published on the subject of blinking – thus becoming ‘the premier savant in that narrow field’ – and testing Lawson’s hypothesis. Over several weeks, Aserinsky tried fruitlessly to build a machine to record eyelid movements, eventually admitting defeat. Instead, Kleitman suggested that the young researcher spend some time observing babies as they slept. (Kleitman was already involved in a study involving recording body movements in sleep in infants, using kit that was attached to their cribs.) A short while later, Aserinsky had to return to his mentor, his tail between his legs, admitting defeat yet again. He had noted that babies’ eyelids quivered in their sleep even with their eyes closed. Did this represent a true blink?
Aserinsky writes with a lovely turn of phrase: ‘I plodded along for months attempting to draw blood from this research turnip . . . but painstaking, diligent exploration of minutiae will frequently lead to the “golden manure” phenomenon whereby there is a rewarding result.’ After several months of observations, he noted that roughly every hour or so, infants had a period of about twenty minutes during which their eyes would stop moving. It was some time later, having had help in building an eye movement recording device, that he began to successfully measure eye movements in sleeping adults.
He started to witness vigorous jerky eye movements in subjects who appeared to be deep asleep, and that these periods were also episodic throughout the night. On one occasion, he recorded a subject who appe
ared to be having a nightmare during one of these stages of sleep characterised by these eye movements, with him moaning or talking in a slurred way. On waking the subject, and hearing the description of his nightmare, Aserinsky assumed the speech and his nightmare were clearly related, and began to wonder if the eye movements related to visual imagery while dreaming.
Over the next few years, he went on to perform countless experiments, some in conjunction with William Dement, one of the other grandfathers of sleep research, including at one point a televised sleep session using his son as the subject, and found that subjects would frequently report dreaming if woken from REM sleep.
Aserinsky moved away from the field of sleep research for about a decade, but his interest was reignited when he witnessed his St Bernard dog, coincidentally, just like Cinderella’s companion, also called Bruno, going into what was by this stage called REM sleep, exhibiting regular muscle twitching. He assumed that Bruno was repeatedly dreaming the same dream, and that there was some association between his muscle activity and the content of Bruno’s dreams. And so Aserinsky’s research into REM sleep was driven on by his dog doing much the same thing as John.
* * *
Listening to John recount his dreams, I know they are typical of those arising from REM sleep. But the type of dreams he is having will sound familiar to everyone, so why don’t we all act out our dreams? REM sleep has subsequently been the subject of a huge amount of research, but some sixty-five years later, the function of REM sleep remains a mystery (see Chapter 13). However, we do know that during this stage of sleep, which occurs about four or five times per night, our brainwaves look like we are almost awake, and there are changes to how our blood pressure, heart rate and breathing are regulated. But, despite our brains appearing to be so active during REM sleep, our bodies are largely paralysed. All muscles, with the exception of the muscles of the eyes, the diaphragm (the large muscle that is responsible for most breathing movements) and sphincters at the top and bottom of the gastrointestinal tract, develop complete weakness. The muscles essentially shut down. This is such a strong feature of REM sleep that in the practical setting of the sleep lab, we use the drop-out of electrical signals from the jaw or limbs to help define it.
The Nocturnal Brain Page 6