Matt's Full Sleep Study Results

I picked up a copy of Matt's sleep study results from our pediatrician. We see the ENT on February 18 for both boys, and I have a feeling it will be an "involved" appointment, since we have to discuss Nolan's hearing, Nolan's apnea and laryngomalacia (and probably revision supraglottoplasty surgery), and Matt's results.

As a side note, some have asked about Matt and Nolan both having apnea - and whether that might mean that Nolan's apnea issues are not related to the other issues he has. In short, our kids both have apnea, but probably from radically different causes. Nolan has a condition called laryngomalacia, and he has an atypical version of the disorder. It didn't show until he was 2 years old (not diagnosed until 3 years old) and he has the form that is associated with neurological problems. A supraglottoplasty and epiglottopexy (lasering out the prolapsed tissue and tacking up his epiglottis to the base of his tongue) have been unsuccessful and his condition appears to be progressive. In Matt's case, he probably just has big tonsils and adenoids. The effect is the same, but the cause is radically different.

In any case, Matt's study shows the following (with abnormal results in bold):

EEG/EOG: Latency to sleep onset was within normal limits at 21.9 minutes. Latency to REM sleep was slightly prolonged at 188.5 minutes. Overall sleep efficiency was normal at 92.8%. The patient was observed in both the supine and non-supine position during the recording. Frequent arousals were present and were commonly associated with respiratory events. Spontaneous arousals and arousals associated with limb movements were also observed. All stages of sleep were identified.

What this means (in English): Matt was asleep for a normal percentage of the time, but it took longer than normal for him to fall into REM sleep. He woke up a lot, and he often woke up because he couldn't breathe.

Respiratory Parameters: The baseline respiration rate was 16-20 breaths per minute in NREM sleep. No snoring was noted by the technician. The overall respiratory disturbance index was 5.03 with a minimum oxyhemoglobin saturation of 83%. Mean oxyhemoglobin saturation was 96%. The respiratory events were most prominent in REM sleep. Clear hypopneas were noted. Rare central apneas were also observed.

What this means (in English): Matt has mild obstructive sleep apnea - something is blocking the airflow. His oxygen level dropped frequently, and the lowest it ever got was 83% (normal is above 95%). He had occasional central apneas, where his brain forgets to tell him to breathe. While some central apneas are normal for kids, the central apneas Matt is having are outside that range and are associated with desaturations.

EKG: The baseline heart rate was 82 beats per minute in REM sleep and 78 beats per minute in NREM sleep. Rare premature wide QRS-complex beats vs. artefact were observed.

What this means (in English): This will have to be discussed with the ENT. I am not sure what this might mean (or not mean). There is a good chance we'll have a consult with a cardiologist about this. 

EMG: There were 5.5 periodic limb movements per hour of sleep noted. They were occasionally assoicated with arousals.

What this means (in English): Matt's legs moved frequently while he was asleep. This sometimes woke him up. They don't know why he is doing this. He had 33 periodic limb movements during the sleep study. 

Interpretation:

These findings indicate the presence of mild obstructive sleep apnea (for the pediatric age range normal RDI <1.5) consisting mainly of hypopneas, with associated disruption in sleep architecture and oxyhemoglobin desaturation, especially in REM sleep (RDI: 5.03 and minimum oxyhemoglobin desaturation: 83%). If clinically indicated, evaluation by ENT for possible tonsillectomy and adenoidectomy should be considered. Clincal correlation is suggested. Central apneas were also observed. Although central sleep apnea can occur in the setting of obstructive sleep apnea, a cardiogenic or neurogenic cause could be considered and warrant further investigation. Please also note the presence of periodic limb movements. They are of unclear clinical significance in the setting, but may warrant further attention if the patient remains symptomatic despite adequate control of sleep-related breathing disturbance. If follow-up with a Sleep Center physician is required, please contact the center at xxx-xxxx.

What this means (in English): Matt has mild obstructive sleep apnea, which is causing his oxygen levels to drop and has wreaked havoc on the normal progression of sleep stages. He should see an ENT to determine if he needs his tonsils and adenoids removed. The central apnea needs to be evaluated and Matt should see a neurologist and cardiologist to rule out heart problems or a problem with the respiratory center of his brain. His legs are moving a lot, and we don't know why, but we can ignore it for now and see if it goes away once his breathing troubles are treated. If his leg movements remain once his breathing is better, they may need to further evaluation.

Sleep Architecture: In a normal child of Matt's age, about 7% of sleep time should be spent in stage 1 sleep, 46% of time should be spent in stage 2 sleep, ~5.5% in stage 3 sleep, and ~18.5% of the time in stage 4 sleep. 22% of the total sleep time should be spent in REM sleep (data from this article: "Polysomnographic Characteristics in Normal Preschool and Early School-Aged Children").

Matt spent the following % of time in each sleep stage, with the normal % in parathesis:

Stage 1: 1.2% (normal 7%)

Stage 2: 57.0% (normal 46%)

Stage 3: 32.6% (normal 5.5%)

Stage 4: 0% (normal 18.5%)

REM: 9.2% (normal 22%)

Essentially, the kid is sleep deprived. He isn't getting any slow-wave, deep sleep and most of his time is spent in light sleep. He is only getting about half of the necessary REM sleep a child his age should get. 

He had 88 arousals in 6 hours of sleep, many due to a lack of oxygen and others due to periodic leg movements. 

I'm anxious to talk to our ENT to find out what the plan is. The sleep neurologist wants to either have his tonsils and adenoids removed (with follow-up sleep study to prove his respiration is better at night) or to start C-Pap therapy. I have a feeling we'll be removing Matt's tonsils and adenoids, and hopefully that will improve his nighttime breathing.