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The science of sleep

Michelle Zhu
Michelle Zhu • 11 min read
The science of sleep
Dr Kenny Pang, an ear, nose and throat specialist who runs a private practice at Paragon, shares some of the discoveries he has made during his decades-long fascination with sleep
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Dr Kenny Pang, an ear, nose and throat specialist who runs a private practice at Paragon, shares some of the discoveries he has made during his decades-long fascination with sleep

SINGAPORE (Apr 1): Singaporeans are the world’s worst sleepers, according to a recent global sleep survey conducted by Philips. Out of the 12 countries surveyed by the Dutch lighting and health technology firm, the city state ranks among the least-rested, with just 6.3 hours of sleep over the weekdays and 6.7 hours on weekends — significantly under the global averages of 6.8 and 7.8 hours respectively.

Based on the annual survey’s findings, stress was the No 1 reason Singaporeans were losing sleep at night, followed by other factors such as their sleeping environment and distraction from entertainment such as TV and social media.

These issues all fall under the generic umbrella subject of sleep hygiene, a term used to describe a set of recommended habits one should practice regularly to get a good night’s sleep. Common rules include having a relatively consistent sleep schedule; limiting blue light exposure from devices such as smartphones and tablets before turning in for bed; and avoiding stimulants such as caffeine and alcohol.

Sometimes, however, consecutive nights of restless sleep may also be caused — or exacerbated by — physical conditions such as obesity, sinusitis or simply one’s facial structure, says Dr Kenny Pang, founder and clinical medical director of Asia Sleep Centre.

Options is speaking to the ear, nose and throat (ENT) specialist at his clinic at Paragon Medical Centre on the eve of World Sleep Day, which fell on March 15. The annual event aims to champion awareness of the importance of sleep, although it is not particularly well known, nor widely celebrated, in Singapore. At just 48, Pang has already spent more than 20 years of his life studying, researching and treating sleep disorders of every imaginable kind — especially insomnia, sleep apnea and snoring. He has yet to tire of the subject, pausing only periodically during this interview to catch his breath as he offers up nuggets of his medical findings and did-you-knows.

“We often take sleep for granted even though we spend about a third of our lives sleeping. That means if one lives up to the average age of 88, that’s 27 years dedicated to sleeping alone. Twenty to thirty per cent of that time is spent on dreaming — dream sleep is one of the most rejuvenating types of sleep that one can have. People generally think that the more you dream, the more tired you are but that is just a myth; it’s actually the opposite,” shares the doctor.

After graduating from the Faculty of Medicine at the National University of Singapore in 1994, Pang attained his fellowship from the Royal College of Surgeons in Edinburgh and Ireland in 1999 and 2002 respectively. He obtained his Master of Medicine in ENT in 2001, and was accredited as an ENT surgeon in 2004 after six cumulative years of ENT surgical training.

“The head and neck are some of the most complex parts of the human anatomy, which makes ENT surgery very difficult to master. I’m the sort of person who likes a challenge, that’s why I took it up. I also wanted to focus on sleep because there are so many aspects and facets to learn about, some which we have yet to understand,” says Pang, who also undertook a sleep surgery and sleep medicine fellowship at the Medical College of Georgia in the US, and is trained in robotic surgery.

Back in Singapore, he worked at Tan Tock Seng Hospital for 13 years before eventually starting his private practice, Asia Sleep Centre, in 2006, where he continues to treat all forms of sleep disorders. Consultations are held at the main clinic located on the 18th floor of Paragon Medical, with a dedicated operating theatre just two storeys above for him to perform nose and throat surgeries with the aim of helping his patients sleep better.

No rest for the breathless

Obstructive sleep apnea, the condition that causes periodic cessations in breathing because of the blockage of a sleeping individual’s airways, is one of the main causes of loud, regular snoring as well as poor sleep patterns. Pang observes that among his patients suffering from OSA, the highest proportion comprises men aged 30 to 50, as they “tend to work very hard and are very driven, don’t exercise and put on weight, and some of them also pick up habits such as smoking and drinking” at this stage of their lives.

Men and women with narrow chins, or what Pang terms “Southern Chinese chins”, are especially prone to OSA as well. The doctor illustrates this propensity by referring to one’s facial bone structure as a container, and the volume, such as skin and soft tissues, to its contents.

“It’s a balance between the box, or the container, and its contents. If the container is big like mine, I won’t snore if I put on weight because I have a wider jaw,” says Pang, gesturing to the lower end of his face.

“But, for those with narrow chins, once they put on weight they will start snoring and possibly choking at night because the container is ‘congested’. That’s why it’s called obstructive sleep apnea. People stop breathing during their sleep because of the obstruction, and this can happen as often as every minute as long as they are asleep. I have some patients who stop breathing up to 60 times per hour, so that’s 360 times a night [assuming they sleep six hours].”

The doctor estimates that at least one in three people in Singapore currently suffer from OSA. Hypertension, stroke and sudden death are just some of the extreme consequences of leaving it untreated. The effects are even more dire should this condition affect children, especially those aged under seven, as their brains are at a major stage of neuroplasticity.

“The first seven years of a child’s life is very important. Studies have shown that if children’s brains don’t have enough oxygen during this period, they become very lethargic, they don’t develop properly, their school results are poor and they get temperamental. Insufficient or poor sleep quality also hinders their growth hormones, which are produced only during Stage Four sleep. They end up remaining very small, a condition which we [doctors] call failure to thrive,” he explains.

Pang says about a third of his patients are children, with the youngest being just two years old. While prevailing causes of sleep apnea for adults are mainly weight gain or obesity, he found his younger patients suffer from OSA owing to sinus-, tonsil- or adenoid- (lymphatic tissue mostly found in the neck) related problems.

Obstructive sleep apnea, the condition that causes periodic cessations in breathing due to the blockage of a sleeping individual’s airways, is one of the main causes of loud, regular snoring

Making surgical strides

A typical approach to treating OSA would be to use a continuous positive airway pressure machine, which draws air from the user’s surroundings and pressurises and humidifies it before the air is pushed through the respiratory airways, keeping them open throughout the night to prevent the onset of sleep apnea. While it is an effective, non-surgical method that has existed since the 1960s, there is also the obvious discomfort of having to wear a CPAP mask strapped to your face as you sleep. Pang also highlights that -usage of the device is not a cure but a way of keeping OSA under control.

He says there have been a number of surgical methods to treat sleep apnea since the 1970s, but in many cases CPAP would be deemed a preferred option because the success rates for these traditional methods were only about 50%.

He invented his own technique, which he named Pang’s Expansion Sphincter Pharyngoplasty, in 2006. The method expands the patient’s upper airway using the lateral pharyngeal walls. It has shown a significantly higher 80% success rate in patients with snoring and OSA, says Pang. He has spent the past 12 years or so travelling and teaching this procedure — along with another technique which he -pioneered, anterior palatoplasty — to other surgeons.

And what does he get in return for his efforts?

“If you’re asking about financial gains, zero. Zero dollars. I don’t earn any money from teaching these surgeons. But the good news is, those I’ve taught have shared their own studies and results with me [after using the technique], and it is found to work for patients of all races, and not just Asians. In fact, the US just started using this technique in recent years as well,” he replies.

Surgeon, researcher and friend

Noticing the squareness of my jaw, Pang asks me whether I happen to have a habit of clenching or grinding my teeth at night — a spot-on diagnosis that I affirm and one that brings us to the subject of his latest research discovery.

“In the past, teeth grinding [or bruxism] was believed to be a behaviour formed in response to occlusal problems, meaning that the person’s bite was ‘off’. But that is not the case; we recently found that teeth grinding is in fact a reflex to the collapse of the airway. Just over a year ago, I was talking with a dentist from Camden, and we realised that most of our patients with sinus problems also had a tendency to grind their teeth.”

Together, Pang and his dentist friend conducted a study of 86 Asian patients and found that symptoms of teeth grinding and ear pain were likely caused by nasal congestion that causes upper airway collapse. Fifty-eight per cent of their subjects also turned out to have had some form of depression previously, if not currently, which was attributed to poor sleep quality.

Aside from OSA and sinus-related problems, Pang tends to insomniacs, hypersomniacs and sleepwalkers, among others. He also regularly keeps in close contact with his patients on a daily basis: “My personal mobile number is on my name card, so they are free to reach out to me anytime. Every morning, I’ll get messages and pictures from at least five or six patients updating me about how they’re recovering or improving, and it makes me very happy to see them make progress.”

Of all the patients he has received at Asia Sleep Centre, Pang says he has never once prescribed sleeping pills for any of them, save for mild sleep aids such as melatonin tablets to help with insomnia. In fact, he proudly declares that he does not have a single sleeping pill stored behind his counter.

“I don’t believe in sleeping pills because they’re addictive. The more you take them, the more you’ll need them to sleep, and the more tolerant your body will become to it. That is why I refuse to stock them — I don’t ever want to start anyone on sleeping pills. It’s for [my patients’] own good,” insists Pang.

Glossary of terms

Bruxism: Excessive teeth grinding or jaw clenching, which often happens unconsciously while awake or asleep

Continuous positive airway pressure (CPAP): A positive airway pressure ventilator system that continuously delivers compressed air throughout the airway to prevent episodes of airway collapse

Hypersomniacs: People who suffer from hypersomnia, a disorder of excessive time spent sleeping, or excessive sleepiness even after long periods of sleep

Lateral pharyngeal walls: Muscular walls of the oropharynx (the throat) that play a part in the process of swallowing. Many patients with OSA have bulky, thick lateral pharyngeal walls, which play a part in the collapse of the upper airway

Obstructive sleep apnea (OSA): Sleep apnea caused by blockage of the airways, as opposed to central sleep apnea that occurs when the brain fails to send proper signals to the muscles that control breathing

Occlusal: Referring to the contact between the upper and lower teeth while chewing or at rest. Underbites and overbites or common malocclusions.

Palatoplasty: Surgery to correct or reconstruct the palate in a person with a cleft palate. Anterior palatoplasty primarily involves the anterior surface of the soft palate, and is used to treat patients with snoring and OSA.

Pharyngoplasty: Surgery to change the shape and function of the soft palate, and the area around it (the pharynx)

Sleep apnea: A sleep disorder involving the repeated stopping and starting of breathing

Sleep hygiene: Practices, habits and rituals that are considered crucial to ensuring good sleep quality

This story appears in Issue 875 (April 1) of The Edge Singapore.

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