Support Center

How Do I Interpret the Periodic Leg Movement Output?

Last Updated: Feb 21, 2018 04:20PM CST
After scoring files for Periodic Leg Movement (see How Do I Use the Periodic Leg Movement (PLM) tool?), click on the different sleep periods to view the graph and PLM stats for each sleep period.  
Clicking on a sleep period will load a PLM score graph.  The green background represents the total time in bed (sleep period) as logged by the user.  The graph will automatically show data 1 hour before the time in bed and 1 hour after the time out of bed.  The blue horizontal line represents the onset threshold and the red horizontal line represents the decay threshold.  The bar graph below the main activity graph gives users a quick reference to PLM bouts (bouts of activity that meet the qualifications of Periodic Leg Movement).  Both graphs can be zoomed in or out simultaneously by dragging the mouse over the area of interest.  To zoom back out, click the small circle in the lower left-hand corner of the graph until the desired zoom level is achieved.
  • PLMI (per hour) - PLMI stands for Periodic Leg Movement Indices.  This value represents the number of qualifying periodic leg movements per hour, averaged over the entire sleep period.
  • Minutes of PLM Kicks - The total number of minutes of "kicks" or activity spikes that exceed the onset threshold AND the total minutes of consecutive "kicks" thereafter that exceed the decay threshold.
  • Number of PLM Kicks - The number of "kicks" or activity spikes that exceed the onset threshold AND the number of consecutive "kicks" that exceed the decay threshold.
  • Number of PLM Bouts - A count of the number of bouts of PLM that occurred during the selected sleep period.
  • Average PLM Bout Length (min) - The average length, in minutes, of all of the PLM bouts for the selected sleep period.
  • Minutes of PLM Bouts - The total time, in minutes, of PLM bouts.  This time is different from the PLM kicks because kicks do not necessarily qualify as valid PLM.
  • Avg PLMS Intensity - The average intensity of the PLM during Sleep of all of the PLM bouts.  Essentially, this is the duty cycle of all PLM bouts.  Avg PLMS Intensity = total minutes of valid PLM / total PLM bout length.
For more information regarding the source of our PLM calculations, see "How were the Periodic Leg Movement algorithms derived?"


If you need any further assistance, please visit our support portal at From there, you can view many helpful FAQ's and Troubleshooting Articles; log in to check any existing Support Requests; or create a new Support Ticket if you are unable to find a solution. You can also email us at or give us a call at (877) 497-6996, Monday through Friday, 8 am to 5 pm CST.

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