Brain regions associated with periodic leg movements during sleep in restless legs syndrome

Abstract

The neural substrates related to periodic leg movements during sleep (PLMS) remain uncertain, and the specific brain regions involved in PLMS have not been evaluated. We investigated the brain regions associated with PLMS and their severity using the electroencephalographic (EEG) source localization method. Polysomnographic data, including electromyographic, electrocardiographic, and 19-channel EEG signals, of 15 patients with restless legs syndrome were analyzed. We first identified the source locations of delta-band (2–4 Hz) spectral power prior to the onset of PLMS using a standardized low-resolution brain electromagnetic tomography method. Next, correlation analysis was conducted between current densities and PLMS index. Delta power initially and most prominently increased before leg movement (LM) onset in the PLMS series. Sources of delta power at −4~−3 seconds were located in the right pericentral, bilateral dorsolateral prefrontal, and cingulate regions. PLMS index was correlated with current densities at the right inferior parietal, temporoparietal junction, and middle frontal regions. In conclusion, our results suggest that the brain regions activated before periodic LM onset or associated with their severity are the large-scale motor network and provide insight into the cortical contribution of PLMS pathomechanism.

Periodic limb movements during sleep: a narrative review

“…Synchronization of large-scale cortical motor neurocircuitry comprising pericentral, dorsolateral, prefrontal and cingulate regions of the brain has been recorded in delta band prior to motor demonstration of PLMS (155). In addition, activity in those areas and the default mode network, appeared significantly associated with PLMI severity scores (155).…”

“…Some imaging studies, on the other hand, have been potentially taken to implicate the role of the sympathetic nervous system and the red nucleus of the brain stem in triggering PLMS (154). Synchronization of large-scale cortical motor neurocircuitry comprising pericentral, dorsolateral, prefrontal and cingulate regions of the brain has been recorded in delta band prior to motor demonstration of PLMS (155). In addition, activity in those areas and the default mode network, appeared significantly associated with PLMI severity scores (155).…”

Temporal relations between peripheral and central arousals in good and poor sleepers

“…( 11 ) reported that following a cortical arousal, heart rate remained elevated for 12 beats. From the literature, we note that EEG arousals can occur before, simultaneous with, or after a periodic leg movement, and previous authors have considered the leg movement and central arousal to be related using time frames from 0.5 to 10 s ( 67 , 72 – 74 ).…”

Myoclonus and other jerky movement disorders

“…However, only a small subgroup of these patients shows leg movements (LMs) with a clear periodicity, so that it can be hypothesized that a genetic predisposition is required for the LMs to assume the periodic character ( Ferri et al, 2015 ). For what concerns supraspinal neural substrates of PLMS, an EEG study showed an involvement of a large-scale motor network (which includes pericentral, dorsolateral prefrontal, and cingulate regions) ( Kim et al, 2020 ). Moreover, part of the default mode network and motor control area (including the right inferior parietal, temporoparietal junction, and middle frontal regions) correlated with the PLMS index ( Kim et al, 2020 ).…”

“…For what concerns supraspinal neural substrates of PLMS, an EEG study showed an involvement of a large-scale motor network (which includes pericentral, dorsolateral prefrontal, and cingulate regions) ( Kim et al, 2020 ). Moreover, part of the default mode network and motor control area (including the right inferior parietal, temporoparietal junction, and middle frontal regions) correlated with the PLMS index ( Kim et al, 2020 ). Further research focused on better clarifying the pathogenetic mechanisms underlying PLMS is much needed, particularly in light of the potential clinical implications of PLMS (discussed in the next section).…”