Restless Nocturnal Eating: A Common Feature of Willis-Ekbom Syndrome (RLS)

Abstract

upon SRED. However, we have noticed subtler non-dysfunctional forms of NE, commonly in the setting of RLS. Also, we have noted that many cases of zolpidem-induced SRED had been originally misdiagnosed as having psychophysiological insomnia (INS), a condition for which a benzodiazepine receptor agonist was prescribed, but later noted to have underlying motor restlessness as the cause of their sleep diffi culties.To establish whether NE is common in RLS and whether NE is a product of frequent nocturnal awakenings, we compared the frequency of NE as well as SRED among patients presenting with RLS and INS, a distinct condition of cognitive hypervigilance that manifests with frequent nocturnal awaken- Measurements and Results:Patients presenting with RLS (n = 88) or INS (n = 42) were queried for the presence of NE and SRED. RLS patients described nocturnal eating (61%) and SRED (36%) more frequently than INS patients (12% and 0%; both p < 0.0001). These fi ndings were not due to arousal frequency, as INS patients were more likely to have prolonged nightly awakenings (93%) than RLS patients (64%; p = 0.003). Among patients on sedative-hypnotics, amnestic SRED and sleepwalking were more common in the setting of RLS (80%) than INS (8%; p < 0.0001). Further, NE and SRED in RLS were not secondary to dopaminergic therapy, as RLS patients demonstrated a substantial drop (68% to 34%; p = 0.0026) in the frequency of NE after dopamine agents were initiated, and there were no cases of dopaminergic agents inducing novel NE or SRED. Conclusion: NE is common in RLS and not due to frequent nocturnal awakenings or dopaminergic agents. Amnestic SRED occurs predominantly in the setting of RLS mistreatment with sedating agents. In light of previous reports, these fi ndings suggest that nocturnal eating is a non-motor manifestation of RLS with several clinical implications discussed here. S C I E N T I F I C I N V E S T I g A T I O N SR estless legs syndrome, or Willis-Ekbom Syndrome (labeled RLS), is characterized by an underlying discomfort, primarily in the lower extremities that compels the affl icted to move. These symptoms are relieved, although only momentarily, with movement and may interfere with sleep initiation or maintenance. 1 RLS has been associated with non-motor phenomena. In particular, patients with RLS often describe other comorbidities such as mood and anxiety disorders, 2 as well as other nocturnal compulsions such as nocturnal smoking that interfere with sleep.3 Further, patients with these non-motor manifestations of RLS have more severe motor restlessness as measured by the International RLS Rating Scale. Recently, an investigation demonstrated a high frequency of dysfunctional nocturnal eating (SRED) in patients with RLS. This community-based case-control study found that 33 of 100 RLS patients met criteria for SRED compared to only 1% of normal population controls. 4 The authors pondered whether SRED was related to underlying RLS brain pathology or whether it was merely "killing time" during prolonged nocturn...

Parasomnias: An Updated Review

“…Another apparent variation is SRED (see as follows), manifesting with dysfunctional nocturnal eating often leading to weight gain. Interestingly, nocturnal eating is a common nonmotor manifestation of RLS [6,9], and the misdiagnosis and treatment of RLS as insomnia (with sedative hypnotics) frequently leads to amnestic SRED [6].…”

“…Intriguingly, many cases of BRA-induced SW are noted to have comorbid RLS which could be easily misdiagnosed and treated as insomnia [6,13]. Then, not surprisingly, BRA, which has a mechanism of action of suppression of memory, along with executive function, unleashes prolonged amnestic ambulating events by disinhibiting hippocampal and frontal lobe function [6,13,27].…”

“…Then, not surprisingly, BRA, which has a mechanism of action of suppression of memory, along with executive function, unleashes prolonged amnestic ambulating events by disinhibiting hippocampal and frontal lobe function [6,13,27].…”

“…However the vast majority of SRED cases emanate from NREM [4], and the complex amnestic behaviors with ambulation are striking similar to sleepwalking [5]. Furthermore, both SRED and sleepwalking are frequently triggered by sedating agents in the setting of underlying motor restlessness [6]. Thus, considering these similarities, SRED will be reviewed immediately after NREM parasomnias.…”

Darwin's Predisposition and the Restlessness that Drives Sleepwalking

“…Subsequently, as zolpidem inhibits executive and hippocampal function, it is to be expected that it would unleash inappropriate amnestic walking behaviors in patients predisposed to ambulation. 2,5,20,[22][23][24] Lopez et al 16 cited a transcranial magnetic stimulation study of sleepwalkers that demonstrated altered excitability of the motor cortex (with reductions in the short interval intracortical inhibition, the cortical silent period, and in the short latency afferent inhibition). 25 Intriguingly, these same TMS findings have been repeatedly demonstrated in TMS studies of RLS patients, which suggests an overlap between these two conditions.…”