Can the sensory symptoms of restless legs syndrome be assessed using a qualitative pain questionnaire?

OBJECTIVES: The sensations of restless legs syndrome (RLS) are described as paresthesias and dysesthesias, sensations which also occur in neuropathic pain. Whether validated pain assessment tools can be used to measure the quality and severity of RLS sensations has not been explored.

METHODS: Patients with RLS (n=25) completed the RLS severity scale of the International Restless Legs Syndrome Study Group, the McGill Pain Questionnaire (MPQ), and a Visual Analog Scale. Words chosen frequently were also compared with those describing different pain types.

RESULTS: The International Restless Legs Syndrome Study Group RLS severity scale score correlated significantly with the Pain Rating Index, and number of words chosen derived from the MPQ, but not with the visual analog scale estimate of pain intensity. The words chosen by patients with RLS showed no significant correlation with words chosen by patients with either neuropathic or nociceptive pain.

DISCUSSION: The quality and severity of the sensation of RLS can be measured on the MPQ, and severity calculated from MPQ indices correlates significantly with a standard RLS severity measure. Thus the nonpainful sensations of RLS appear to be a subclinical form of pain.