Diagnostic Criteria, Differential Diagnosis, and Treatment of Minor Motor Activity and Less Well-Known Movement Disorders of Sleep

Abstract

Purpose of reviewSleep-related movement disorders (SRMD) include several different motor activities during sleep. Few of them are well known and well classified, whereas others are minor motor disorders of sleep which are neither thoroughly characterized and classified nor have been extensively investigated to clarify their pathogenesis and clinical relevance. This review will focus on those minor sleep-related movement disorders.Recent findingsBefore diagnosing periodic limb movement (PLM) disorder in patients with PLM during polysomnography, other disorders associated with PLM need to be excluded, namely restless legs syndrome (RLS), narcolepsy, REM sleep behavior disorder (RBD), and sleep-related breathing disorder. For the diagnosis of propriospinal myoclonus at sleep-onset, multi-channel surface electromyography recording during polysomnography is required and a possible psychogenic origin of the movement disorder has to be considered. Excessive fragmentary myoclonus (EFM) does not require symptomatic treatment, but further evaluation is suggested as electrophysiological abnormalities are present in 50% of cases. Nine percent of healthy sleepers meet the criteria for EFM, raising the question if current, arbitrarily defined, cutoffs are valid. Hypnagogic foot tremor, rhythmic feet movements, alternating leg muscle activation, and high-frequency leg movements are somewhat overlapping minor motor activities during sleep which may exist on their own or represent stereotyped movements to relieve RLS-like symptoms. Neck myoclonus is probably a physiological phenomenon related to REM twitching. RBD is formally a parasomnia but a relevant differential diagnosis when evaluating sleep-related movement disorders. In particular, prodromal RBD is characterized by electromyographic and behavioral findings on video-polysomnography which needs to be differentiated by minor sleep-related movement disorders.SummaryMinor SRMD beyond the well-known main motor disorders of sleep should be correctly diagnosed, distinguished from differential diagnosis, and understood in their potential clinical relevance, in order also to start an appropriate treatment if needed.

A Sleep Disorder Detection Model based on EEG Cross-Frequency Coupling and Random Forest

“…If EMG activity overcomes the threshold of 8 microvolts at rest with a duration between 0.5 and 10 seconds, then this epoch is characterized as limb movement [48]. According to ICSD-3 of the American Academy of Sleep Medicine, the diagnostic criteria for PLMS are: the detection of more than 15 periodic limb movements per hour in adults and more than 5 periodic limb movements per hour in children that cause in both cases strong sleep problems [49]. In the present study, we aimed to apply a common analytic framework across sleep disorders using EEG-based characteristics.…”

Sleep Disorders in Mitochondrial Diseases

“…Surprisingly, the presence of RLS was not associated to increased sleep latency neither to worst subjective sleep quality. Regarding polysomnographic findings, they found a high prevalence of periodic limb movements (PLM) in their population (mean PLM index 25.5 events/h), and in nine cases (45%), the PLM index was higher than 15 events/h which is considered the pathological cut-off [ 48 ]. PLM were more common in those patients who complained poor subjective nocturnal sleep quality, suggesting a high prevalence of periodic limb movement disorder (PLMD) in their cohort of patients affected by genetic mitochondrial dysfunction.…”

Alte Methoden: Der heutige Stellenwert der Elektroenzephalografie (EEG)

“…Die Unterscheidung verschiedener Parasomien erfolgt durch die typischen EEG-Befunde bei z. B. Non-REM-Parasomnien (Somnambulismus) und REM-Schlaf-Verhaltensstörung [35].…”