SleepyHead AHI Graph?

[KenTheriot]

Does anyone know why SleepyHead reports an AHI of 10 during a section of the night where no events were recorded?

I'm breaking in a new ASV machine - A ResMed VPAP Adapt - and using SleepyHead to analyze the data. Though my total AHI for the 6 hours I used the machine last night was 3.2, there was a period in the first hour - after the ramp - where the AHI graph stayed at 10 for about 45 minutes. But during that period, there were no apneas or hypopneas reported. Can anyone shed light on that?

Thanks.

Ken

[robysue]

Though my total AHI for the 6 hours I used the machine last night was 3.2, there was a period in the first hour - after the ramp - where the AHI graph stayed at 10 for about 45 minutes. But during that period, there were no apneas or hypopneas reported. Can anyone shed light on that?

How many apneas and hypopneas were record during the first 15 minutes of that hour?

Let's suppose the ramp goes off at 11:25pm.

• If 10 events are recorded between 11:25 and 11:40 pm, the SH AHI graph increases from 0 to 10 during this 15 minute period.
• If no additional events are recorded between 11:40 and 12:25, the SH AHI graph remains at 10 since there have been 10 events recorded in the last hour of run time.
• If no additional events are recorded between 12:25 and 12:40, the SH AHI graph will decrease from 10 to 0, with each reduction occurring when the oldest "event time stamp" becomes one hour old.

In other words, the value of the SH AHI graph at time t is the number of events recorded during the last hour of run time in the current session. NOTE: When you turn the machine off and back on, it resets the AHI to 0 at the beginning of the new session.

[HerbM]

Robisue gave a good explanation so allow me to add this:

I find the AHI "GRAPH" (or chart) to be generally unnecessary -- you don't need a graph to see CLUSTERS of events, and the graph is just trying to provide some integrated value for the 'recent' events.

Most of the time it is just easier to look at the Flow Rate and note the events directly on that graph.

If it helps you or someone, then by all means USE IT.

But for my part, I used the little "Grabber Hand" too and dragged that chart down near the bottom with the other charts I seldom use.

Did you folks ALL know you could do that? Just pull the particular chart UP or DOWN? There is no explanation on the screen that this is possible (you would need to read the manual or wonder why the cursor turns into a "Hand" when you move over the charts.

While on the topic of What can I do with SleepHead: You can also click on any one, two, etc. of your Sleep SESSIONS over in the AHI summary window way down at the left and see summary data etc for JUST that/those sessions of the night.