Imaging the Skull
For this study, researchers at the University of Indiana looked at patients who had a polysomnogram to determine whether they have sleep apnea. They cross-referenced this with patients who also had CT imaging of their skull, a total of 1012. They then only considered the patients who had moderate to severe sleep apnea (AHI of at least 25 per hour), compared to people who didn’t have sleep apnea (AHI no greater than 5 per hour). They matched 56 people with sleep apnea to 58 people without sleep apnea who were otherwise similar in terms of age and BMI.
They found that people with sleep apnea had thinner skulls in two places, the calvaria (“skull cap”) and the skull base. The difference was about 1/100th of an inch for the skull cap and about 3/100ths of an inch for the skull base. Measurements at the zygoma (cheekbone) showed no significant difference.
Researchers note that a thinner skull can increase the risk that cerebrospinal fluid (which bathes and cushions the brain and spine) could leak out of the skull. They propose that this might explain why previous research has shown people with sleep apnea are nearly five times more likely to experience a cerebrospinal fluid leak.
Causes and Effects
Researchers can’t yet explain why sleep apnea would lead to skull thinning. One potential explanation is that it disrupts the body’s natural rhythms for bone resorption and formation. The body does most of its bone remodeling in the late night and early morning , when we are supposed to be deep in REM sleep. Disrupting the normal REM cycle could disrupt the formation of bone. This could lead to thinner skull in the areas measured.
But it’s important to remember that this study doesn’t actually say that sleep apnea causes a thinner skull, just that they’re associated. It could be that anatomical variations that lead to sleep apnea are associated with this anatomical variation in the skull thickness.
Does this mean that sleep apnea treatment won’t help with cerebrospinal fluid leak? No, because the leaks aren’t just related to a thin skull. Instead, cerebrospinal fluid leaks often stem from high blood pressure in the brain. And sleep apnea can cause high blood pressure. This means that even if sleep apnea isn’t actually causing the skull to thin, it can still cause the fluid to leak.
Protect Yourself from Sleep Apnea Complications
Successful treatment of sleep apnea can help you avoid the complications associated with this potentially deadly condition. Whether spinal fluid leakage is caused by a thinning skull or high blood pressure, sleep apnea treatment can help. It can help you keep blood pressure under control and return you to a normal, healthy sleep cycle.