Understanding the Sleep Apnea Rating Scale and Its Importance
Some people experience only mild forms of obstructive sleep apnea (OSA). Others are seemingly cursed to endure relatively severe outbreaks. While there are numerous effective treatment options, their usefulness can sometimes depend on the symptoms themselves.
This is why scientists have developed a method to grade the severity of sleep apnea. Their technique is known as the Apnea-Hypopnea Index (often simply referred to as AHI within medical circles).
How does this system function, what is it used to measure, and why is it often beneficial when determining your treatment options? The answers to these questions will be found immediately below.
Understanding What is Meant by "Respiratory Events"
Some of the most important variables that are examined by the AHI are collectively known as respiratory events. The first is known as an apnea. Apneas are periods of interrupted breathing that can be as short as 10 seconds, and on occasion last for over 30 seconds.
Hypopneas are another metric within this scale. Hypopneas are defined as partial cessations in normal breathing, primarily resulting from a narrowing of the airways. Breathing may be impeded by up to 90 per cent, and the duration of a typical episode exceeds ten seconds.
Respiratory effort-related arousals (known as RERAs) are another somewhat nebulous term. While they do not technically qualify as apneas or hypopneas, they still result in broken sleeping patterns.
A Quick Look at the AHI Scale
The American Academy of Sleep Medicine has constructed a scale that can be used to determine the severity of an OSA case. This scale is broken down into hierarchical sections depending on the perceived impact, and it can be viewed as follows:
- Mild (between five and 15 respiratory events each hour.
- Moderate (the individual experiences more than 15 but less than 30 events per hour.
- Severe (over 30 events each hour; generally resulting in extremely poor sleep).
At first glance, it would appear as if the symptoms associated with obstructive sleep apnea will become more noticeable in relation to the frequency of events. This is not necessarily the case, and it also leads us into the next portion of our analysis.
Severity Versus Symptoms
One of the confounding issues with OSA is that symptoms and severity might not correlate with one another. In some cases, individuals who have been diagnosed with a mild form of OSA (according to AHI classifications) could report profound symptoms.
It is also possible for a person with a high AHI reading to hardly notice any sleep disruptions. However, there are still numerous symptoms which may appear if a case of sleep apnea remains untreated. These can also be broken down into nighttime observations and those felt throughout the day. Overnight symptoms may include:
- Constant and/or loud snoring (often loud enough to awaken a partner)
- Periods where breathing pauses
- Waking up in the middle of the night choking or gasping for air
- Disrupted overall sleep patterns
- The inability to fall asleep
- A frequent need to urinate
There are also daytime symptoms that may indicate a problem. Some of the most predominant can be:
- Feeling drowsy throughout the day (known as excessive daytime sleepiness)
- Headaches in the morning
- Sensations of fatigue immediately after waking up
- Issues with memory and/or concentration
- Sexual problems such as a lack of libido and/or erectile dysfunction (in males)
- Irritability and anxiety
- Poor performance at school or work
Note that having one of the symptoms alone does not always confirm the presence of sleep apnea. This is when medical professionals will also take additional factors into account.
What Increases the Risk of Developing Severe Obstructive Sleep Apnea?
Although doctors will often employ the previously mentioned sleep apnea rating scale when performing a diagnosis, they are also likely to examine several concurrent factors.
Some of these are physical in nature while others are considered to represent lifestyle habits. For instance, individuals with a larger neck circumference or who are obese (a body mass rating of 25 or higher) are at risk of experiencing more severe symptoms.
Other issues such as naturally narrower airways play additional roles. Here are some other potential variables:
- Age
- A family history of obstructive sleep apnea
- Post-menopausal females
- Gender (males seem to be at an increased risk)
- Existing health conditions including (but not limited to) high blood pressure, diabetes, heart disease, and hypothyroidism
As stated above, lifestyle habits such as smoking cigarettes or regularly consuming alcohol can play a key role, and may lead to more profound symptoms.
What Treatment Options Exist?
The first step is always to obtain a professional diagnosis. Treatments will then depend on the individual in question as well as his or her score within the sleep apnea rating scale. Many cases can be effectively managed with the help of a continuous positive airway pressure (CPAP) machine. However, keep in mind that other steps can be taken such as:
- Changing sleeping positions
- Abstaining from alcohol and nicotine
- Losing weight
- Regular exercise
- Oxygen supplementation (in more severe cases)
- The introduction of an implant that stimulates the hypoglossal nerve
- Surgery (i.e. maxillofacial and UPPP surgery)
Ultimately, determining one's score within the sleep apnea rating scale is only one portion of a larger puzzle. This is the same reason why physicians will adopt a well-rounded approach when determining what type of treatment is the most applicable. The good news is even those considered to have a severe form of OSA can find relief if they seek assistance (as opposed to simply ignoring the underlying symptoms).
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