Figuring Out Fitful Feet

This chapter describes a case of alternating leg muscle activation (ALMA) followed by discussion of this condition and the related hypnagogic foot tremor (HFT). HFT and ALMA are benign sleep-related movements of unknown etiology, typically found incidentally on polysomnography. Both HFT and ALMA are characterized by bursts of tibialis anterior activity occurring in sequences with an inter-burst interval shorter than found in periodic limb movements in sleep. There is no specific treatment for HFT and ALMA. Rather, treatment should focus on the other comorbid sleep disorders such as obstructive sleep apnea, as HFT and ALMA motor activity associated with respiratory events may be responsive to positive airway pressure therapy. In this chapter the diagnostic criteria and clinical features are summarized, and polysomnographic tracings and video samples are provided.