REBUTTAL FROM DR. MAHOWALD

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The following comments are offered for the seven instances in which Dr. Walters suggests monitoring PLMs during routine polysomnography: (1) Monitoring of anterior tibialis EMG to confirm the diagnosis of REM sleep behavior disorder is absolutely appropriate. Monitoring in this setting is performed to identify REM sleep without atonia, not to identify PLMs. (2) If PLMs are bothering the bedpartner(s), the diagnosis is best made by history, not polysomnography. The patient and bothered bedpartner may then decide on the ethics of treating a person with PLMs, which for him/her are asymptomatic, with nightly neuroactive agents to improve the sleep of another. (3) Identification of PLMs during wakefulness in patients with restless legs syndrome is irrelevant in establishing the diagnosis of or determining a treatment plan for restless legs syndrome. Daytime treatment is indicated if there are daytime symptoms, with or without PLMs during wakefulness. (4) Monitoring anterior tibialis EMG activity to identify leg movements as a surrogate for sleep-disordered breathing is appropriate. Such monitoring may identify sleep-disordered breathing, but must not result in a diagnosis of PLM disorder. (5) The identification of PLMs in children with attention-deficit hyperactivity disorder is potentially important. Categorical cause and effect must be documented before developing nervous systems are exposed to chronic neuroactive medication. Until evidence-based scientific data become available, such studies should be confined to rigorous research protocols. The same holds true for other psychiatric disorders possibly associated with (but probably not worsened by) PLMs. (6) PLM monitoring in the setting of chronic renal failure for the specific purpose of predicting mortality may be appropriate (particularly if it could be demonstrated that treatment improved prognosis). (7) An unequivocal cause-and-effect relationship between PLMs and hypertension and cardiovascular disease (with therapeutic implications) must be scientifically established before there can be any conceivable practical utility for PLM monitoring in this patient population. (Are all patients with hypertension and/or cardiovascular disease to undergo polysomnography?)

In summary, the basic science and clinical scientific communities can and must identify the true significance of PLMs before routine PLM monitoring can be sanctioned.