TITLE 1: “In the News”
TITLE 2: “Correlation between rating scales and sleep laboratory measurements in restless legs
DATE: Winter 2005
AUTHOR/S: Garcia-Borreguero D, Larrosa O, de la Llave Y, Jose Granizo J, Allen R.
ABSTRACT OVERVIEW: Researchers in this study set out to compare the validity of the
International Restless Legs Scale (IRLS) with certain objective measures of RLS severity.
COPY OF ARTICLE:
The following articles have been adapted from recently published reports in medical journals. To
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Garcia-Borreguero D, Larrosa O, de la Llave Y, Jose Granizo J, Allen R.
Correlation between rating scales and sleep laboratory measurements in restless legs
Researchers in this study set out to compare the validity of the International Restless Legs Scale
(IRLS) with certain objective measures of RLS severity. They compared the IRLS scores with
results of polysomnography (PSG) – an overnight test that generally includes monitoring of a
patient’s airflow through the nose and mouth, blood pressure, electrocardiographic activity,
blood oxygen level, brain wave pattern, eye movement, and the movement of respiratory muscle
and limbs – and the suggested immobilization test (SIT), which is carried out by having the
patient lie perfectly still and recording any leg movements during polysomnography with EMG.
Test subjects were 30 untreated patients diagnosed with RLS according to the criteria of the
International RLS Study Group. The researchers found that IRLS scores correlated well with
PLMS index and PLMS-arousal index values derived during polysomnography. Periodic leg
movements of wakefulness measured during the suggested immobilization test also correlated
well with IRLS scores. No correlation was seen between IRLS scores and any other variables
measured on PSG. There was also no correlation found between IRLS scores and ferritin levels,
age, duration of illness, or any other clinical variable.
In conclusion, this is the first published study to show a correlation between IRLS scores and
objective evidence of motor dysfunction (such as is demonstrated by PLMS or the SIT). The
researchers suggest PLMS and SIT-PLMW may have a common mechanism.