PLM, PLMS, PLMD....what's the diff?

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ViewsAskew
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PLM, PLMS, PLMD....what's the diff?

Post by ViewsAskew »

I came across something in The Clinical Management of Restless Legs Syndrome* today that reminded me how easy it is to get these terms confused - and that I don't always use them correctly! More importantly, I often see medical sites on the Internet use them incorrectly!!!

"PLM - Periodic Limb Movements - one or more movements that meet the criteria for relatively stereotyped repetitive periodic movements

PLMS - Periodic Limb Movement(s) in sleep - one of more PLM occurring in sleep. Usually used as the plural to refer to all such movements restricted to sleep that occur during a night's study or the condition of having such movements.

PLMW - Periodic Limb Movement(s) in Wake - one or more PLM occurring during wake.

PLMD - Periodic Limb Movement Disorder - a medical disorder with symptoms indicative of sleep disturbance This diagnosis requires documentation of some minimum number of frequency of PLM plus some related clinical complaint such as daytime sleepiness that cannot be accounted for by another disorder. Patients with RLS cannot have PLMD [emphasis mine]."

Following this, none of us with RLS/WED have PLMD. Rather, we have PLMS or PLMW.

And, later on, the book notes:
"To reach a diagnosis of PLMD, no other sleep-related diagnosis can account for the patient's complaint. It is a rule that leg movements, even if periodic, are not considered to be PLM if they are associated regularly with respiratory disturbances, such as sleep apnea."

*Clinical Management of Restless Legs Syndrome; Hening, Wayne A; Buchfuhrer, Mark J., Lee, Hochang B. First Edition, 2008.
Ann - Take what you need, leave the rest

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sleepdancer
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PLMD

Post by sleepdancer »

Wow, that sure got confusing. The part about a person with RLS can't have PLMD especially. All the literature I've read gives statistics on what percentage of people are diagnosed with both. I wonder if what they were saying is that you can't experience both at the same time, since one generally happens while awake, the other while asleep.

The other part was where it made it seem like one couldn't have PLMD if they had another sleep disorder that could cause daytime symptoms. HELLO - haven't they heard of co-existing conditions?! Again, I'm guessing they mean one can't assume PLMD when there's presence of other sleep disorders. With sleep studies, it isn't a ruling out process or guessing game, it's fact based diagnostics. Limb Movements in general may have other causes like in sleep apnea, but a sleep study should distinguish most of them. It's my understanding that adding "Disorder" to the diagnosis is based on frequency and severity criteria.

You're right, I've read and heard discrepancies used even by medical professionals. No wonder I'm confused.

ViewsAskew
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Post by ViewsAskew »

See if this makes more sense:

If you have any sleep disorder (RLS/WED, apnea, etc.), you have PLM - periodic limb movements.

If you do not have any sleep disorders, you have PLMD.

So, if we have WED, we have movements, but it's not a disorder.
Ann - Take what you need, leave the rest

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Chipmunk
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Post by Chipmunk »

It seems as though PLMD is a diagnosis of exclusion - so if they can find anything else sleep-related to diagnose, then they can use that, otherwise it's PLMD.
Tracy

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ViewsAskew
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Post by ViewsAskew »

Chipmunk wrote:It seems as though PLMD is a diagnosis of exclusion - so if they can find anything else sleep-related to diagnose, then they can use that, otherwise it's PLMD.


YES!
Ann - Take what you need, leave the rest

Managing Your RLS

Opinions presented by Discussion Board Moderators are personal in nature and do not, in any way, represent the opinion of the RLS Foundation, and are not medical advice.

sleepdancer
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PLMD

Post by sleepdancer »

Any number of things can cause limb movements, but no other disorder causes movements that have the characteristics of limb movements caused by PLMD. They are distinct in their presentation. I was looking for material I've read before about the diagnostic criteria, but ran out of time to keep looking. Was recently going thru some of old medical files, and I have several sleep studies documenting and distinguishing the presence of respiratory related limb movements AND limb movements from PLMD. It doesn't have to be either/or. Without a sleep study it's all just an educated (hopefully) guess, but I think anyone with daytime sleepiness and nightime sleep problems should have a sleep study. It took multiple studies for them to figure out I have PLMD and sleep apnea. The movements were diagnosed first. Once they were treated and I was still sleepy, they tested me again and the sleep apnea showed up. When my legs are active, I don't sleep enough to have apneas. When my legs are quiet and I'm sleeping soundly, I have moderate to severe sleep apnea. Since the apnea is relatively easy to prevent, it's been my approach to do that by using CPAP. I have a data capable machine and the software to read my nightly data, so I can be reasonably sure any residual daytime sleepiness means my limb movements are not controlled.

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