A descriptive analysis of neck myoclonus during routine polysomnography

Subjective Symptoms Linked to Sleep Duration: An Analysis from Japanese National Statistics

BACKGROUND

There is a high prevalence of sleep disorders in Japan, and they are a factor in a decreased quality of life. The main objective of this study was to clarify the background factors of sleep disorders that affect sleep duration, such as subjective symptoms and working hours.

METHODS

We performed a cross-sectional study on the Japanese national statistics data. Answers from a household questionnaire were used to analyze risk factors for decreases in sleep duration. The subjects were a total of 3972 men and women aged 40-59 years, the age group that forms the core of the working population. For the analysis, a univariate analysis (contingency table) between sleep duration (two groups: sleep duration ≥ 6 h and <6 h) and 42 subjective symptoms was carried out. A multivariate analysis (binomial logistic regression) was conducted using sleep duration and subjective health assessment as objective variables, and odds ratios (ORs) adjusted for sex, working hours, and other factors were obtained.

RESULTS

The univariate analysis by subjective symptom showed significant ORs for eight symptoms, including poor sleep quality (OR: 2.24), constipation (OR: 2.24), and dizziness (OR: 1.77). In the multivariate analysis, the model with sleep duration as the objective variable showed significantly adjusted ORs for four variables, including constipation (1.72) and poor sleep quality (1.66). The model with subjective health assessment as the objective variable showed significantly adjusted ORs for eight variables, including dizziness (4.18), while poor sleep quality (1.45) was not significant.

CONCLUSIONS

The present results suggest the presence of subjective symptoms that may be inferred to be related to decreases in sleep duration.

Improved automatic identification of isolated rapid eye movement sleep behavior disorder with a 3D time-of-flight camera

BACKGROUND AND PURPOSE

Automatic 3D video analysis of the lower body during rapid eye movement (REM) sleep has been recently proposed as a novel tool for identifying people with isolated REM sleep behavior disorder (iRBD), but, so far, it has not been validated on unseen subjects. This study aims at validating this technology in a large cohort and at improving its performances by also including an analysis of movements in the head, hands and upper body.

METHODS

Fifty-three people with iRBD and 128 people without RBD (of whom 89 had sleep disorders considered RBD differential diagnoses) were included in the study. An automatic algorithm identified movements from 3D videos during REM sleep in four regions of interest (ROIs): head, hands, upper body and lower body. The movements were divided into categories according to duration: short (0.1-2 s), medium (2-15 s) and long (15-300 s). For each ROI and duration range, features were obtained from the identified movements. Logistic regression models using as predictors the features from one single ROI or a combination of ROIs were trained and tested in a 10-runs 10-fold cross-validation scheme on the task of differentiating people with iRBD from people without RBD.

RESULTS

The best differentiation was achieved using short movements in all four ROIs (test accuracy 0.866 ± 0.007, test F1 score = 0.783 ± 0.010). Single group analyses showed that people with iRBD were distinguished successfully from subjects with RBD differential diagnoses.

CONCLUSIONS

Automatic 3D video analysis might be implemented in clinical routine as a supportive screening tool for identifying people with RBD.

Heart rate change and clinical characteristics in patients with neck myoclonus: An observational study

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Heart rates increased with neck myoclonus events.

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The rate of increase was higher for neck myoclonus with cortical arousal than for those without.

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Neck myoclonus may be associated with excessive daytime sleepiness or abnormal behaviors during REM sleep.

Objective

This study was conducted to evaluate heart rate (HR) change and clinical characteristics in patients with neck myoclonus (NM), a physiological motor phenomenon occurring during sleep.

Methods

For 18 consecutive patients in whom NM was confirmed from video-polysomnography, we analyzed 576 NMs. Change rate of HR at each 1 sec point towards the averaged HR in prior 5 sec period was calculated before and after all NM events.

Results

Findings show NM events as more prevalent during REM sleep than during NREM sleep (83.9% vs. 16.1%). For NM without cortical arousal in REM and NREM sleep, the respective HR increased 20 s before NM (p < 0.05); the change rate was up to 13%. For NM with cortical arousal in REM sleep, the HR increased 50 s before NM (p < 0.05); the change rate reached 18%. Three NM subjects showed abnormal vocalization or shouting during REM. Six NM subjects had excessive daytime sleepiness without sleep disorder.

Conclusion

HR increased before NM events, which may be associated with pathophysiology of NM. NM may possibly be associated with excessive daytime sleepiness or abnormal behaviors during REM sleep.

Significance

HR increase is associated with pathophysiology of NM and clinical symptoms.

REM sleep behavior disorder: Mimics and variants

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia with dream-enactment behaviors occurring during REM sleep and associated with the lack of the physiological REM sleep muscle atonia. It can be isolated and secondary to other neurological or medical conditions. Isolated RBD heralds in most cases a neurodegenerative condition due to an underlying synucleinopathy and consequently its recognition is crucial for prognostic implications. REM sleep without atonia on polysomnography is a mandatory diagnostic criterion. Different conditions may mimic RBD, the most frequent being obstructive sleep apnea during sleep, non-REM parasomnia, and sleep-related hypermotor epilepsy. These diseases might also be comorbid with RBD, challenging the evaluation of disease severity, the treatment choices and the response to treatment evaluation. Video-PSG is the gold standard for a correct diagnosis and will distinguish between different or comorbid sleep disorders. Careful history taking together with actigraphy may give important clues for the differential diagnosis. The extreme boundaries of RBD might also be seen in more severe and complex conditions like status dissociatus or in the sleep disorders' scenario of anti IgLON5 disease, but in the latter both clinical and neurophysiological features will differ. A step-by-step approach is suggested to guide the differential diagnosis.

Sleep-related head jerks: toward a new movement disorder

STUDY OBJECTIVES

Sleep-related head jerks (SRHJ) are often considered as a physiological motor phenomenon, occurring mainly during rapid eye movement (REM) sleep. Their clinical relevance and links with other sleep parameters are unclear. We characterized the clinical and polysomnographic features of patients with excessive SRHJ and compare them with healthy controls and patients with isolated REM sleep behavior disorder (iRBD).

METHODS

A total of 30 patients (19 males, 27.5 y.o., 16.0-51.0) with a REM-HJ index >30/h were identified over a period of 5 years. All had a video-polysomnographic (PSG) recording to characterize the SRHJ, to assess associations with other sleep parameters and to quantify phasic and tonic electromyographic activity during REM sleep, compared with 30 healthy controls and 30 patients with iRBD.

RESULTS

Five among the 30 patients had a primary complaint of involuntary nighttime head movements associated with sleepiness or non-restorative sleep. The mean REM-HJ index was 57.22/h ± 24.42, a nonperiodic pattern, stable across the sleep cycles, and with a low between-test variability (for the nine patients with two PSG assessments in untreated condition). REM-HJs were often associated with arousals (65.2%) and leg movements (38.1%) and less with respiratory events (9.6%), without association with increased phasic and tonic electromyographic activities. SRHJ were also found in 36.7% of controls and 56.7% of iRBD patients, but with a lower index in REM sleep (0.79/h ± 1.59 and 2.76/h ± 4.57).

CONCLUSIONS

Although SRHJ are frequent in the general population and with uncertain clinical significance, rare severe symptomatic forms should be individualized and eventually be categorized as a new sleep-related movement disorder, distinct from RBD and periodic leg movements.

Scoring of large muscle group movements during sleep: An International Restless Legs Syndrome Study Group (IRLSSG) position statement

There is a gap in the manuals for scoring sleep-related movements because of the absence of rules for scoring large movements. A taskforce of the International Restless Legs Syndrome Study Group elaborated rules that define the detection and quantification of movements involving large muscle groups. Consensus on each of the criteria in this paper was reached by testing the presence of consensus on a first proposal; if no consensus was achieved, the concerns were considered and used to modify the proposal. This process was iterated until consensus was reached. A preliminary analysis of the duration of movements involving large muscle groups was also carried out on data from two previous studies, which, however, used a visual analysis of video-polysomnographic recordings obtained from children or adults. Technical specifications and scoring rules were designed for the detection and quantification of large muscle group movements during sleep with a duration between 3 and 45 s in adults or 3 and 30 s in children, characterized by an increase in electromyographic activity and/or the occurrence of movement artifact in any combination of at least two recommended channels and not meeting the criteria for any other type of movement. Large muscle group movements are often accompanied by sleep stage changes, arousals, awakenings, and heart rate rises. The absence of clear and detailed rules defining them has likely impeded the development of studies that might disclose their clinical relevance; these new rules fill this gap.

Electroclinical Features of Sleep-Related Head Jerk

STUDY OBJECTIVES

To evaluate clinical and electrophysiological features of sleep-related head jerk (SRHJ) and electromyographic activity of superficial neck muscles during head jerk.

METHODS

Totally, 850 cases with video-polysomnography recording were collected, among which 50 presented with SRHJ. In these 50 patients, 15 underwent electromyography (EMG) check on bilateral sternocleidomastoid (SCM) and trapezius muscles as well as chin, while 35 had only chin EMG check. Further, the sensitivity and specificity of the both EMGs were calculated and compared.

RESULTS

Six among the 50 SRHJ patients had a primary complaint of involuntary head jerks associated with impaired sleep. Approximately 76.1% of head jerks occurred during REM sleep with the median head jerk index of 5.9/h, 64.5% of which were associated with electroencephalogram arousals and 66.4% with body movements. One patient showed SRHJ predominantly in NREM sleep but also in wakefulness. Surface EMG of SCM/trapezius muscles showed a sensitivity of 92% and a specificity of 97.8%, whereas chin EMG had a sensitivity of 14.5% and a specificity of 98.8%.

CONCLUSION

SRHJ was associated with electroencephalogram arousals and might interfere with sleep. Surface EMG of SCM/trapezius muscles exhibited a good accuracy in the revelation of SRHJ.

Parasomnias, sleep-related movement disorders and physiological sleep variants in focal epilepsy: A polysomnographic study

PURPOSE

The link existing between epilepsy and sleep is widely recognized. However, little is known about the prevalence and the clinical consequences of the comorbidity between focal epilepsy and sleep disorders, especially those sleep phenomena classified as isolated symptoms or normal variants. Objective of the study was to evaluate the frequency of sleep disorders and physiological sleep variants in a group of adult patients with focal epilepsy as compared to healthy controls by means of nocturnal polysomnography.

METHODS

We performed a retrospective observational study in the Neurological Clinic of the University of Catania in adult patients with a diagnosis of focal epilepsy and in a group of control subjects. All subjects underwent an overnight polysomnography. The following sleep disorders were considered: NREM-related parasomnias; REM-related parasomnias; sleep-related movement disorders; isolated symptoms or normal variants.

RESULTS

100 patients [mean age 30.3 ± 14.7 years, 40 men] and 62 controls [mean age 36.4 ± 15.9, 20 men] were studied. A significant higher percentage of sleep disorders was recorded in patients as compared to controls (73 % vs 48.4 %; p = 0.002). In particular, we found a higher frequency of periodic limb movements (PLM) (20 % vs 4.8 %; p = 0.007), bruxism (20 % vs 4.8 %; p = 0.007) and neck myoclonus (22 % vs 4.8 %; p = 0.003). Moreover, alternating limb muscle activation was associated with sleep-related hypermotor epilepsy (OR = 7.9; p = 0.01).

CONCLUSION

Sleep disorders and physiological sleep variants are common in adult patients with focal epilepsy.

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

Purpose of review

Sleep-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 findings

Before 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.

Summary

Minor 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.

Sleep-related motor and behavioral disorders: Recent advances and new entities

Patients with sleep-related motor and behavioral disorders present to a variety of subspecialty clinics (neurology, sleep medicine, respiratory medicine, psychiatry). Diagnosing these disorders can be difficult, and sometimes they have a significant impact on quality of life. Alongside a number of common and well-recognized conditions, several new disease entities have been described in recent years that present with abnormal nocturnal motor phenomena (such as ADCY5-associated disease and anti-IgLON5 disease). Our understanding of the neural basis and prognostic significance of other sleep-related disorders has also grown, particularly rapid eye movement sleep behavior disorder. This review (along with a collection of previously unpublished videos) is intended to aid in the recognition and treatment of these patients. The recent change in terminology from nocturnal frontal lobe epilepsy to sleep-related hypermotor epilepsy is also discussed. © 2018 International Parkinson and Movement Disorder Society.

Oculomotor apraxia and disrupted sleep with nocturnal ballistic bouts in ADCY5-related disease

OBJECTIVE

To characterise the distinctive eye movement disorder and the sleep-related dyskinesia in Adenylate cyclase 5 (ADCY5) related disease.

METHODS

Formal eye movement examination and video-polysomnography in a cohort of patients with ADCY5 mutations.

RESULTS

All three patients had an eye movement disorder characterised by oculomotor apraxia with gaze limitation most prominently in the vertical plane. All patients had disrupted sleep architecture with reduced sleep efficiency due to frequent and prolonged arousals and awakenings in the context of dyskinesia, which could arise from any sleep stage. The nocturnal movements could last up to 30 min and be more severe than those seen during day-time.

CONCLUSION

Nocturnal exacerbations of dyskinesia ("ballistic bouts") seem to be a characteristic feature of the disease, affect the quality of life of patients and therefore require awareness and symptomatic treatment approaches. Apraxia of eye movements, with predominant difficulties in the vertical plane, was a common finding in our patients with ADCY5 mutations. These features may prompt the diagnosis and help to distinguish ADCY5-related disease from other childhood-onset hyperkinetic movement disorders.

Motor events during healthy sleep: a quantitative polysomnographic study

STUDY OBJECTIVES

Many sleep disorders are characterized by increased motor activity during sleep. In contrast, studies on motor activity during physiological sleep are largely lacking. We quantitatively investigated a large range of motor phenomena during polysomnography in physiological sleep.

DESIGN

Prospective polysomnographic investigation.

SETTING

Academic referral sleep laboratory.

PARTICIPANTS

One hundred healthy sleepers age 19-77 y were strictly selected from a representative population sample by a two-step screening procedure.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Polysomnography according to American Academy of Sleep Medicine (AASM) standards was performed, and quantitative normative values were established for periodic limb movements in sleep (PLMS), high frequency leg movements (HFLM), fragmentary myoclonus (FM), neck myoclonus (NM), and rapid eye movement (REM)-related electromyographic (EMG) activity. Thirty-six subjects had a PLMS index > 5/h, 18 had a PLMS index > 15/h (90th percentile: 24.8/h). Thirty-three subjects had HFLM (90th percentile: four sequences/night). All subjects had FM (90th percentile 143.7/h sleep). Nine subjects fulfilled AASM criteria for excessive FM. Thirty-five subjects had NM (90th percentile: 8.8/h REM sleep). For REM sleep, different EMG activity measures for the mentalis and flexor digitorum superficialis muscles were calculated: the 90th percentile for phasic mentalis EMG activity for 30-sec epochs according to AASM recommendation was 15.6%, and for tonic mentalis EMG activity 2.6%. Twenty-five subjects exceeded the recently proposed phasic mentalis cutoff of 11%. None of the subjects exceeded the tonic mentalis cutoff of 9.6%.

CONCLUSION

Quantification of motor phenomena is a basic prerequisite to develop normative values, and is a first step toward a more precise description of the various motor phenomena present during sleep. Because rates of motor events were unexpectedly high even in physiological sleep, the future use of normative values for both research and clinical routine is essential.