Polysomnographic record and successful management of augmentation in restless legs syndrome/Willis-Ekbom disease

BACKGROUND: Dopamine agonists (DAs) represent the first-line treatment in restless legs syndrome (RLS); however, in the long term, a substantial proportion of patients will develop augmentation, which is a severe drug-related exacerbation of symptoms and the main reason for late DA withdrawal. Polysomnographic features and mechanisms underlining augmentation are unknown. No practice guidelines for management of augmentation are available. METHODS: A clinical case series of 24 consecutive outpatients affected by RLS with clinically significant augmentation during treatment with immediate-release DA was performed. All patients underwent a full-night polysomnographic recording during augmentation. A switchover from immediate-release DAs (l-dopa, pramipexole, ropinirole, rotigotine) to the long-acting, extended-release formula of pramipexole was performed. RESULTS: Fifty percent of patients presented more than 15 periodic limb movements per hour of sleep during augmentation, showing longer sleep latency and shorter total sleep time than subjects without periodic limb movements. In all patients, resolution of augmentation was observed within two to four weeks during which immediate-release dopamine agonists could be completely withdrawn. Treatment efficacy of extended-release pramipexole has persisted, thus far, over a mean follow-up interval of 13 months. CONCLUSIONS: Pramipexole extended release could be an easy, safe, and fast pharmacological option to treat augmentation in patients with restless legs syndrome. As such it warrants further prospective and controlled investigations. This observation supports the hypothesis that the duration of action of the drug plays a key role in the mechanism of augmentation.

Horizontal head titubation in infants with Joubert syndrome: a new finding

AIM Head thrusts are well documented in Joubert syndrome and ocular motor apraxia. We provide a detailed clinical characterization of head titubation in 13 young children with Joubert syndrome. METHOD Detailed characterization of head titubation was assessed by targeted clinical evaluation and/or analysis of videos. RESULTS In 12 of 13 children (eight males, five females; median age 6y, range 2mo-15y) head titubation was first recognized in the first 2 months of age and decreased in severity until spontaneous resolution. In all children, the head titubation was horizontal, high frequency (~3Hz), had small amplitude (5-10°), was never present during sleep, and did not interfere with the neurodevelopment during infancy. In the majority of children, emotion, anxiety, and tiredness were worsening factors for head titubation. INTERPRETATION Head titubation is a benign, early presentation of Joubert syndrome. Head titubation in hypotonic infants should prompt a careful search for Joubert syndrome. Awareness of its occurrence in Joubert syndrome may avoid unnecessary investigations.

Physiological time structure of the tibialis anterior motor activity during sleep in mice, rats and humans

The validation of rodent models for restless legs syndrome (Willis-Ekbom disease) and periodic limb movements during sleep requires knowledge of physiological limb motor activity during sleep in rodents. This study aimed to determine the physiological time structure of tibialis anterior activity during sleep in mice and rats, and compare it with that of healthy humans. Wild-type mice (n = 9) and rats (n = 8) were instrumented with electrodes for recording the electroencephalogram and electromyogram of neck muscles and both tibialis anterior muscles. Healthy human subjects (31 ± 1 years, n = 21) underwent overnight polysomnography. An algorithm for automatic scoring of tibialis anterior electromyogram events of mice and rats during non-rapid eye movement sleep was developed and validated. Visual scoring assisted by this algorithm had inter-rater sensitivity of 92-95% and false-positive rates of 13-19% in mice and rats. The distribution of the time intervals between consecutive tibialis anterior electromyogram events during non-rapid eye movement sleep had a single peak extending up to 10 s in mice, rats and human subjects. The tibialis anterior electromyogram events separated by intervals <10 s mainly occurred in series of two-three events, their occurrence rate in humans being lower than in mice and similar to that in rats. In conclusion, this study proposes reliable rules for scoring tibialis anterior electromyogram events during non-rapid eye movement sleep in mice and rats, demonstrating that their physiological time structure is similar to that of healthy young human subjects. These results strengthen the basis for translational rodent models of periodic limb movements during sleep and restless legs syndrome/Willis-Ekbom disease.

translin Is Required for Metabolic Regulation of Sleep

Dysregulation of sleep or feeding has enormous health consequences. In humans, acute sleep loss is associated with increased appetite and insulin insensitivity, while chronically sleep-deprived individuals are more likely to develop obesity, metabolic syndrome, type II diabetes, and cardiovascular disease. Conversely, metabolic state potently modulates sleep and circadian behavior; yet, the molecular basis for sleep-metabolism interactions remains poorly understood. Here, we describe the identification of translin (trsn), a highly conserved RNA/DNA binding protein, as essential for starvation-induced sleep suppression. Strikingly, trsn does not appear to regulate energy stores, free glucose levels, or feeding behavior suggesting the sleep phenotype of trsn mutant flies is not a consequence of general metabolic dysfunction or blunted response to starvation. While broadly expressed in all neurons, trsn is transcriptionally upregulated in the heads of flies in response to starvation. Spatially restricted rescue or targeted knockdown localizes trsn function to neurons that produce the tachykinin family neuropeptide Leucokinin. Manipulation of neural activity in Leucokinin neurons revealed these neurons to be required for starvation-induced sleep suppression. Taken together, these findings establish trsn as an essential integrator of sleep and metabolic state, with implications for understanding the neural mechanism underlying sleep disruption in response to environmental perturbation.

Definition and diagnostic criteria of sleep-related hypermotor epilepsy

The syndrome known as nocturnal frontal lobe epilepsy is recognized worldwide and has been studied in a wide range of clinical and scientific settings (epilepsy, sleep medicine, neurosurgery, pediatric neurology, epidemiology, genetics). Though uncommon, it is of considerable interest to practicing neurologists because of complexity in differential diagnosis from more common, benign sleep disorders such as parasomnias, or other disorders like psychogenic nonepileptic seizures. Moreover, misdiagnosis can have substantial adverse consequences on patients' lives. At present, there is no consensus definition of this disorder and disagreement persists about its core electroclinical features and the spectrum of etiologies involved. To improve the definition of the disorder and establish diagnostic criteria with levels of certainty, a consensus conference using formal recommended methodology was held in Bologna in September 2014. It was recommended that the name be changed to sleep-related hypermotor epilepsy (SHE), reflecting evidence that the attacks are associated with sleep rather than time of day, the seizures may arise from extrafrontal sites, and the motor aspects of the seizures are characteristic. The etiology may be genetic or due to structural pathology, but in most cases remains unknown. Diagnostic criteria were developed with 3 levels of certainty: witnessed (possible) SHE, video-documented (clinical) SHE, and video-EEG-documented (confirmed) SHE. The main research gaps involve epidemiology, pathophysiology, treatment, and prognosis.

Psychiatric Comorbidities in Restless Legs Syndrome.

Restless legs syndrome (RLS) is a neurological sleep disorder with frequent (39%) coexisting psychiatric comorbidities. Patients with any psychiatric comorbidity had fewer periodic leg movements in sleep. Psychiatric disorders should be taken into account in patients with RLS.