Periodic leg movements predict total sleep time in persons with cognitive impairment and sleep disturbance.
Richards KC, Roberson PK, Simpson K, Lambert CW, Bliwise DL, Cole CS, Enderlin C, Shue VM, Siddiqui N, Williams JS. Periodic leg movements predict total sleep time in persons with cognitive impairment and sleep disturbance. Sleep. 2008 Feb; 31(2):224-30.