Epworth Sleepiness Scale (ESS)

The Epworth Sleepiness Scale (ESS) is a simple, self-administered questionnaire commonly used to measure a person’s general level of daytime sleepiness. It’s often employed in the diagnosis and evaluation of sleep disorders, such as obstructive sleep apnea (OSA) and narcolepsy. Here’s a breakdown of its key aspects:

  1. Purpose: The primary purpose of the ESS is to provide a measure of a person’s daytime sleepiness. It helps to assess the impact of sleep disorders on a person’s daily life and can be used to monitor the effectiveness of treatment for sleep disorders.
  2. Format: The ESS consists of 8 questions. Each question asks the individual to rate, on a scale of 0 to 3, their likelihood of dozing off or falling asleep in different routine situations, commonly encountered in daily life. The situations include sitting and reading, watching TV, sitting inactive in a public place, as a passenger in a car for an hour, lying down in the afternoon, sitting and talking to someone, sitting quietly after a lunch without alcohol, and in a car, while stopped for a few minutes in traffic.
  3. Scoring: The scores for each item are added together to obtain a single number. The total score can range from 0 to 24. The higher the score, the higher the person’s level of daytime sleepiness.
    • 0-5: No significant daytime sleepiness.
    • 6-10: Average daytime sleepiness.
    • 11-15: Moderate excessive daytime sleepiness.
    • 16-24: Severe excessive daytime sleepiness.
  4. Interpretation: The ESS score helps to gauge the severity of the person’s daytime sleepiness. However, it’s important to note that it is subjective and should be interpreted in the context of an individual’s overall health and sleep habits.
  5. Usage in Clinical Practice: The ESS is widely used in clinical settings to help diagnose sleep disorders. It’s often one of the first tools used when a patient presents with symptoms of excessive sleepiness.
  6. Limitations: While the ESS is a valuable tool, it has its limitations. It is subjective, relying on the individual’s perception of their sleepiness. Additionally, it does not measure the actual sleep or the quality of sleep, nor does it diagnose specific sleep disorders.
  7. Complementary Assessments: The ESS is often used alongside other assessments, such as sleep diaries, actigraphy, and polysomnography (sleep studies), to provide a more comprehensive view of a person’s sleep health.

In summary, the Epworth Sleepiness Scale is a widely used and valuable tool for assessing daytime sleepiness. It provides a quick, subjective measure of a person’s tendency to fall asleep in common daily situations, which can be crucial for identifying potential sleep disorders and guiding further diagnostic processes.

Questions

The Epworth Sleepiness Scale consists of eight questions. Each question asks the individual to rate, on a scale of 0 to 3, their likelihood of dozing off or falling asleep in various common situations. The situations are as follows:

  1. Sitting and Reading: How likely are you to doze off or fall asleep while sitting and reading?
  2. Watching TV: How likely are you to doze off or fall asleep while watching television?
  3. Sitting Inactive in a Public Place: How likely are you to doze off or fall asleep while sitting inactive in a public place (e.g., a theater or a meeting)?
  4. As a Passenger in a Car for an Hour: How likely are you to doze off or fall asleep while you are a passenger in a car for an hour without a break?
  5. Lying Down to Rest in the Afternoon: How likely are you to doze off or fall asleep when you lie down to rest in the afternoon when circumstances permit?
  6. Sitting and Talking to Someone: How likely are you to doze off or fall asleep while sitting and talking to someone?
  7. Sitting Quietly After Lunch (Without Alcohol): How likely are you to doze off or fall asleep while sitting quietly after a lunch without alcohol?
  8. In a Car, While Stopped for a Few Minutes in Traffic: How likely are you to doze off or fall asleep while you are in a car, stopped for a few minutes in traffic?

For each situation, the person rates their likelihood of dozing off or falling asleep as follows:

  • 0 = would never doze
  • 1 = slight chance of dozing
  • 2 = moderate chance of dozing
  • 3 = high chance of dozing

The total score is calculated by adding up the scores from all eight questions, providing an overall measure of the person’s average daytime sleepiness.

ESS and Driving

Commercial vehicle drivers who are diagnosed with sleep apnoea and require treatment must have an annual review by a sleep specialist to ensure adequate treatment is maintained. For drivers who are treated with CPAP, it is recommended that they use CPAP machines with a usage meter to allow objective assessment and recording of treatment compliance. Minimally acceptable adherence with treatment is defined as four hours or more per day of use 5 or more days a week (70% of days). An assessment of sleepiness should be made, and an objective measurement of sleepiness should be considered (MWT), particularly if there is a concern about persisting sleepiness or treatment compliance.

MWT (Maintenance of Wakefulness Test)

The Maintenance of Wakefulness Test (MWT) is a diagnostic tool used in sleep medicine to assess a person’s ability to stay awake in a quiet, relaxing environment. This test is often used to evaluate the effectiveness of treatment for sleep disorders that can affect wakefulness, such as narcolepsy or obstructive sleep apnea, especially in cases where the patient’s ability to stay awake is critical for safety (e.g., for professional drivers or machine operators). Here’s an overview of how the MWT works:

  1. Purpose: The primary purpose of the MWT is to measure how well a person can stay awake in a situation that is conducive to sleep. This is important for assessing the risk of unintentional sleep or sleepiness in daily activities, especially in occupations requiring high levels of alertness.
  2. Procedure: The MWT is typically conducted in a sleep lab. The test usually involves four trial periods spread throughout the day, each lasting about 40 minutes. The patient is asked to sit comfortably in a chair, in a quiet, dimly lit room, and try to stay awake for as long as possible.
  3. Preparation: Prior to the test, the patient is usually advised to have a normal night’s sleep. They may be asked to refrain from consuming caffeine or other stimulants, and their medication schedule might be adjusted to ensure accurate test results.
  4. During the Test: In each trial, the patient is instructed to sit quietly and remain awake. They are not allowed to engage in activities that might help them stay awake, such as reading or watching TV. The patient’s ability to stay awake is monitored.
  5. Scoring and Interpretation: The main outcome measure of the MWT is the average time taken to fall asleep across the test trials. If the patient falls asleep quickly in most trials, it suggests difficulty maintaining wakefulness. The specific criteria for “normal” versus “abnormal” results can vary based on the testing protocols and the reason for the test.
  6. Clinical Use: The MWT is particularly useful in occupational health settings, where there’s a need to assess a person’s ability to stay awake in situations where falling asleep could be dangerous. It’s also used to evaluate the effectiveness of treatment for sleep disorders.
  7. Limitations: Like many sleep tests, the MWT has its limitations. It is conducted in an artificial environment, which may not perfectly replicate the patient’s usual circumstances. The test is also influenced by many factors, including the patient’s sleep schedule, medication use, and individual variability in sleep tendency.

In summary, the Maintenance of Wakefulness Test is a controlled, clinical procedure used to assess a person’s ability to stay awake in a sedentary, non-stimulating environment. It’s an important tool in diagnosing and managing sleep disorders, especially in contexts where wakefulness is critical for safety and job performance.