Published: Oct 17, 2013
By John Gever

Full Story:  http://www.medpagetoday.com/MeetingCoverage/ANA/42345

NEW ORLEANS — About half of patients with restless legs syndrome (RLS) seen in a single neurology practice also qualified for diagnoses of bruxism and migraine, suggesting a possible common cause for these disorders, a researcher said here.

Among 470 patients RLS patients who fully completed a 35-item questionnaire about these and other aspects of their health, 60% said they ground or clenched their teeth at night and 83% reported having been diagnosed with migraine, according to David Dickoff, MD, of Metropolitan Neurological Consultants in Yonkers, N.Y., and Mount Sinai Hospital in New York City.

Both bruxism and migraine were reported by 52% of the RLS patients, he told attendees at the American Neurological Association’s annual meeting.

Dickoff said the high proportion of patients reporting both RLS and migraine suggests a common etiology, which, he speculated, could be a gene.

He said the latter possibility was supported by another finding in the study — that 47% of RLS patients also reported family histories of headache. He noted that 8% reported at least one first-degree relative with all three conditions, and 24% had close family members with two of the conditions.

Dickoff argued that RLS and bruxism may actually be the same disorder, such that bruxism could be considered restless jaw syndrome. In a study he reported earlier this year from the same patient group at the American Academy of Neurology annual meeting, about three-quarters of those with both conditions had a reduction in bruxism symptoms when they received dopamine agonist drugs for RLS.

The study involved a total of 870 RLS patients who completed the questionnaire at least partially. The RLS diagnosis was made according to criteria established by the International Restless Legs Syndrome Study Group (IRLSSG) and with additional electromyographic confirmation.

Dickoff said he had confirmed reports of migraine in the group with his own examination.

Although the IRLSSG criteria refer only to the legs, he emphasized that many patients reported nearly identical symptoms in their arms as well. Asked to recall their symptoms at first onset, 41% indicated that they had affected their arms either solely or in conjunction with leg symptoms.

When seen in Dickoff’s clinic, only 35% of patients had symptoms in their legs alone, he said.

As an aside, he noted that the arm manifestations could easily be confused with carpal tunnel syndrome, and that 43 of the patients had received surgical treatment on that basis.

Overall, 236 of the patients in the study reported having had surgery to relieve some type of pain, with only half of those who reported outcomes saying the treatment had been beneficial, Dickoff said.

He added that many of the patients reporting bruxism had been treated for temporomandibular joint misalignment, with appliances and even surgery in some cases, also with mixed results.

Dickoff emphasized that all of his findings needed confirmation in prospective studies. In particular, he recommended a double-blind trial of dopamine agonists for treatment of bruxism.