Center for Sleep Diagnostics  

Sleep disordered breathing disorder is a prevalent medical condition. Obstructive Sleep Apnea (OSA) is the most common condition in sleep disordered breathing. It affects 4% of males and 2% of females among the middle-aged population in Hong Kong. Obstructive sleep apnea (OSA) is caused by repetitive collapse of the pharyngeal airway during sleep, which results in ongoing respiratory effort during pharyngeal collapse. It leads to arterial oxygen desaturation and frequent awakenings of patients. Hence individuals suffering from OSA would have fragmented sleep and poor sleep quality.

Common Symptoms of OSA
1. habitual snoring,
2. excessive daytime sleepiness,
3. witnessed apnea and choking during sleep,
4. insomnia
5. headache
6. concentration deficit
7. nocturia
8. depression

Systemic Effect of OSA on Health  

OSA is a recognized contributing factor for hypertension, insulin resistance, cardiovascular and cerebrovascular diseases. Risk of motor vehicle accidents is also higher in patients with untreated OSA.

Risk Factors
1. Genetic: often have positive family history
2. Gender: male gender, menopause increase the predisposition for developing OSA in women
3. Age : progressively increases in middle age
4. Obesity
5. Smoking/alcohol
6. Small jaw
7. Hypothyroidism


If you think you may suffer from obstructive sleep apnea , there are several simple tests you can take that may suggest you should discuss the possibility with your doctor


Diagnostic Confirmation  

The golden standard of diagnostic modality for OSA is overnight Polysomnography (multi-channels overnight Sleep Study). It records EEG, EOG, chin & leg EMG, ECG, nasal airflow, abdominal & chest wall movements and digital oximetry of patients. Sleep Study will be conducted in a designated room. The sound and light proof fittings will provide a comfortable environment which allows people falling asleep easily.

Treatment Options  

1. Modification of lifestyles such as weight control is always the most fundamental measure.

2. The first line treatment in most patients with significant OSA is nasal Continuous Positive Airway Pressure (CPAP). CPAP splints up patient’s upper airway with air pressure in order to prevent its collapse during sleep.

3. Oral appliances (OA) will be considered in those who are intolerant or unwilling to adhere to CPAP. OA works by moving the lower jaw forward with a custom made dental device, thereby enlarging the upper respiratory tract of OSA patient.

4. Surgery are occasionally indicated when a surgically correctable abnormality is believed to be the source of the problem. These surgical procedures may resect or reposition throat structures obstructing the upper airway and all these operations target at restoring normal flow of air in and out of the lungs.

Our center offers a comprehensive consultative and diagnostic service for patients with OSAS through a multi-disciplinary approach. Continuous Positive Airway Pressure (CPAP) titration will be performed if CPAP is indicated. Structured scheme of follow up will be provided to evaluate the treatment response of the patients.

Comorbid insomnia and sleep apnea (COMISA)


Sleep is a significant but often neglected determinant of physical and mental health. A good quality sleep is vital for resting, recharging, and nourishing the body and the mind. Conversely, inadequate and disturbed sleep can affect daytime functioning and lead to a range of chronic health problems. A local population-based telephone survey in 2007 interviewed about 5000 Chinese adults aged 18 and above. Results showed that the average sleep duration was about 6.5 hours per night. 9.4% of respondents could not get to sleep within 30 minutes. Another local survey showed that telephone-interviewed over 2000 community-dwelling people aged 18 - 64 was conducted in 2011. During the 30 days prior to the survey, a substantial proportion (20.6%) of respondents reported that they frequently (three times or more a week) experienced insomnia symptoms, including trouble in falling asleep (11.8%), intermittent awakenings or difficulty in maintaining sleep during the night (12.2%), and early morning awakenings and unable to sleep again (9.4%).

Starting from year 2020, there was a new worldwide sleep problem. The ongoing coronavirus crisis has made getting a good night’s rest significantly harder. Some experts even have a term for it: ‘coronasomnia’ or ‘Covid-somnia’. This is the phenomenon that hit people all over the world as they experience insomnia linked to the stress of life during Covid-19. In the UK, an August 2020 study from the University of Southampton showed that the number of people experiencing insomnia rose from one in six to one in four, with more sleep problems in communities including mothers, and essential workers. In China, insomnia rates rose from 14.6% to 20% during peak lockdown. An “alarming prevalence” of clinical insomnia was observed in Italy, and in Greece, nearly 40% of respondents in a May study were shown to have insomnia.

Insomnia means having difficulty in fallen asleep, waking up too early, or waking intermittently, resulting in insufficient sleep. It is not defined by how long you sleep every night because different people need different duration of sleep. Of course, besides COVID-19 pandemic, a number of factors are known to cause insomnia: Psychological-[ including stress, anxiety or depression]; Lifestyle – [jet lag, consuming drinks with caffeine or other stimulants]; Environment – [noise, light or strange odour]; Physical –[ frequent urination, coughing, pa
in and other forms of discomfort].

Statistics have shown that insufficient sleep can double the chance of having an accident while operating machinery or driving a car. If insomnia lasts for an extended period of time, it can cause: Reduction of creativity, Slowing of response, Loss of memory, Inability to perform complicated tasks. Epidemiological studies have also shown that short sleep duration (with < 7 hours per night in general for adults) and/or suboptimal quality of sleep (such as difficulty in initiating or maintaining sleep) are associated with an increased risk of obesity, metabolic syndrome, type 2 diabetes, cardio-vascular diseases, certain cancers, mood disorders, suicide, injuries, as well as all-cause mortality.

Obstructive sleep apnea (OSA) is a sleep related breathing disorder that affects at least 5.3% of local middle aged adults and is associated with excessive daytime sleepiness, cardiovascular sequelae, neurocognitive deficits, and depression. Comorbid insomnia and sleep apnea (COMISA) are the most common cooccurring sleep disorders, with a global prevalence between 18% and 42%. COMISA is associated with increased medical (eg, cardiometabolic conditions) and psychiatric morbidity (eg, mood disorders, posttraumatic stress disorder), and worse daytime functioning relative to each condition alone. As a result, clinical management of COMISA is often very challenging.

Progress to date has provided evidence to shift the clinical management of COMISA toward a multidisciplinary and patient-centered approach. This allows clinicians with various backgrounds to use their expertise with the respective diagnostic tools to develop a more comprehensive symptom profile. For example, pulmonary specialists can focus on symptoms related to sleep-disordered breathing and daytime sleepiness through a history and physical examination and sleep study data. Behavioral specialists can focus on symptoms related to insomnia and hyperarousal by using sleep diaries and actigraphy and assessing sleep-related behaviors. For many patients, an ideal combination would be cognitive-behavioral therapy for insomnia, CBT-I (early in the course of treatment) along with CPAP therapy (initiated concurrently or shortly after CBT-I). After treatments are delivered, follow-up assessment on key outcomes of each treatment should be conducted to monitor treatment adherence and progress as part of quality care.


(Written by:Dr. Kwong Kwok Chu, Specialist in Respiratory Medicine)

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