Sleep Medicine

Editorial Board

2012-05-01

Disturbed sleep and COPD outcomes: Cart meets horse

Brian D. Kent, Walter T. McNicholas, Johan Verbraecken — 2012-05-01

Chronic obstructive pulmonary disease (COPD) is a leading global cause of morbidity and mortality – indeed, COPD is predicted to become the third leading cause of death worldwide by 2020 . A number of factors have been found to predict adverse outcomes in subjects with COPD, ranging from lung function to ongoing cigarette smoking and low body mass index . Meanwhile, studies in general populations have identified sleep deprivation and insomnia as significant predictors of mortality, even following adjustment for potential confounding factors . However, very little is known about the impact of poor quality sleep on outcomes in COPD populations.

Long-term outcomes and predictors of chronic insomnia: A prospective study in Hong Kong Chinese adults

2012-05-01

Abstract: Objectives: We aimed to determine the longitudinal course and outcome of chronic insomnia in a five-year prospective study in Hong Kong Chinese adults.Methods: Two thousand three hundred and sixteen middle-aged adults (53.3% females, 46.3±5.1years old at follow-up) were recruited at baseline and follow-up. Participants were divided into three groups: non-insomnia, insomnia symptoms, and insomnia syndrome (insomnia symptoms plus daytime symptoms). Upper airway inflammatory diseases, mental problems, and medical problems were additionally assessed at follow up.Results: The incidence of insomnia (symptoms and syndrome) was 5.9%. The persistence rate of insomnia syndrome was 42.7% for insomnia syndrome and 28.2% for insomnia symptoms. New incidence of insomnia was associated with younger age, unemployment, and daytime symptoms, while persistence of insomnia was associated with female sex, lower education level, and daytime symptoms at the baseline (p<0.05). Baseline insomnia syndrome was significantly associated with upper airway inflammatory diseases (including asthma and laryngopharyngitis; adjusted OR=1.97–17.9), mental problems, and medical conditions (including arthritis, psychiatric disorders, chronic pain, and gastroesophageal reflux disease; AOR=2.29–3.77), whereas baseline insomnia symptoms were associated with poor mental health (AOR=2.43), psychiatric disorders (AOR=2.39), and chronic pain (AOR=2.95).Conclusions: Chronic insomnia is a common problem with considerable persistence and incidence rates among middle-aged Chinese adults. Insomnia syndrome has a higher persistence rate with more mental and medical comorbidities when compared with insomnia symptoms without daytime consequences.

Effectiveness of a cognitive behavioral self-help program for patients with primary insomnia in general practice – A pilot study

2012-05-01

Abstract: Objective: This study was conducted to evaluate the effectiveness of a cognitive behavioral self-help program (SHP) in combination with pharmacotherapy in patients with primary insomnia in general practice.Participants: Patients were recruited from 31 general practitioners (GPs) in the Hamburg area, who were randomly assigned to the two different study conditions. Eighty patients completed the study. They had suffered from insomnia for several years and showed a high impairment according to the Pittsburgh Sleep Quality Index.Intervention: According to assignment of their GP the patients either received a progressively reduced 4-week pharmacotherapy or a combination of pharmacotherapy and a SHP consisting of six chapters on progressive muscle relaxation, cognitive relaxation, modified stimulus control, thought stopping, and cognitive restructuring.Measures and results: After study enrollment patients had short weekly consultations with their GPs during treatment to receive sleep medication and questionnaires. They completed questionnaires measuring general sleep quality and sleep-disruptive beliefs and also sleep diaries before treatment, during treatment, immediately following treatment, and at a 6-week and 6-month follow-up time point. For collection of changes in mood the Beck Depression Inventory was used. The whole sample showed reductions of sleep onset latency and time awake after sleep onset. Total sleep time increased and mood improved. Patients additionally working with the SHP showed significantly more improvements in sleep quality and negative sleep-related cognitions like ruminating and focusing on sleep. Treatment effects were significant at the end of therapy and remained stable at the six-week and six-month follow-up.Conclusion: This study supports the use of a cognitive-behavioral SHP on primary insomnia in the setting of a general practice and should be investigated in more detail. Also, regular appointments and the utilization of sleep logs seem to have a positive influence on sleep disorders.

Clinical significance of night-to-night sleep variability in insomnia

2012-05-01

Abstract: Objectives: To evaluate the clinical relevance of night-to-night variability of sleep schedules and insomnia symptoms.Methods: The sample consisted of 455 patients (193 men, mean age=48) seeking treatment for insomnia in a sleep medicine clinic. All participants received group cognitive behavioral therapy for insomnia (CBTI). Variability in sleep parameters was assessed using sleep diary data. Two composite scores were computed, a behavioral schedule composite score (BCS) and insomnia symptom composite score (ICS). The Insomnia Severity Index, the Beck Depression Inventory, and the Morningness–Eveningness Composite Scale were administered at baseline and post-treatment.Results: Results revealed that greater BCS scores were significantly associated with younger age, eveningness chronotype, and greater depression severity (p<0.001). Both depression severity and eveningness chronotype independently predicted variability in sleep schedules (p<0.001). Finally, CBTI resulted in reduced sleep variability for all sleep diary variables except bedtime. Post-treatment symptom reductions in depression severity were greater among those with high versus low baseline BCS scores (p<0.001).Conclusions: Results suggest that variability in sleep schedules predict reduction in insomnia and depressive severity following group CBTI. Schedule variability may be particularly important to assess and address among patients with high depression symptoms and those with the evening chronotype.

Disturbed sleep among COPD patients is longitudinally associated with mortality and adverse COPD outcomes

2012-05-01

Abstract: Objective: To investigate the cross-sectional association between COPD severity and disturbed sleep and the longitudinal association between disturbed sleep and poor health outcomes.Methods: Ninety eight adults with spirometrically-confirmed COPD were recruited through population-based, random-digit telephone dialing. Sleep disturbance was evaluated using a 4-item scale assessing insomnia symptoms as: difficulty falling asleep, nocturnal awakening, morning tiredness, and sleep duration adequacy. COPD severity was quantified by: FEV1 and COPD Severity Score, which incorporates COPD symptoms, requirement for COPD medications and oxygen, and hospital-based utilization. Subjects were assessed one year after baseline to determine longitudinal COPD exacerbations and emergency utilization and were followed for a median 2.4years to assess all-cause mortality.Results: Sleep disturbance was cross-sectionally associated with cough, dyspnea, and COPD Severity Score, but not FEV1. In multivariable logistic regression, controlling for sociodemographics and body-mass index, sleep disturbance longitudinally predicted both incident COPD exacerbations (OR=4.7; p=0.018) and respiratory-related emergency utilization (OR=11.5; p=0.004). In Cox proportional hazards analysis, controlling for the same covariates, sleep disturbance predicted poorer survival (HR=5.0; p=0.013). For all outcomes, these relationships persisted after also controlling for baseline FEV1 and COPD Severity Score.Conclusions: Disturbed sleep is cross-sectionally associated with worse COPD and is longitudinally predictive of COPD exacerbations, emergency health care utilization, and mortality.

Predictors of sleep-disordered breathing in obese adults who are chronic short sleepers

Kristen L. Knutson, Xiongce Zhao, Megan Mattingly, Giulia Galli, Giovanni Cizza — 2012-05-01

Abstract: Background: Sleep disordered breathing (SDB) is common in obese adults, but not all obese adults have SDB. The aim of these analyses was to determine what predicted SDB in a sample of obese adults.Methods: We conducted cross-sectional analysis of 139 obese men and women aged 18–50years who are chronic short sleepers. Habitual sleep duration and sleep efficiency were estimated using two weeks of wrist actigraphy. Respiratory disturbance index (RDI) was assessed by a portable screening device. SDB was defined as RDI⩾15 eventsh−1. Subjective sleep quality, sleepiness, and sociodemographic characteristics were evaluated by questionnaires.Results: Increased sleep duration from actigraphy was associated with reduced odds of SDB (OR 0.44 per hour, p=0.043). Neither subjective sleep quality nor sleepiness was associated with SDB. Male sex, older age, and increased waist circumference were associated with increased odds of SDB.Conclusions: In this sample of obese adults, subjective measures of sleep quality and sleepiness were not indicators of SDB. These results suggest that, in obese patients, physicians should not rely on subjective measures to determine who should be referred for a clinical sleep study. A wider use of portable apnea screening devices should be considered in nonsymptomatic, non-Hispanic white males.

Auditory arousal responses and thresholds during REM and NREM sleep of sleepwalkers and controls

Mathieu Pilon, Alex Desautels, Jacques Montplaisir, Antonio Zadra — 2012-05-01

Abstract: Background: It has been suggested that sleepwalkers are more difficult to awaken from sleep than are controls. However, no quantified comparisons have been made between these two populations. The main goal of this study was to assess arousal responsiveness via the presentation of auditory stimuli (AS) in sleepwalkers and controls during normal sleep and recovery sleep following sleep deprivation.Methods: Ten adult sleepwalkers and 10 age-matched control subjects were investigated. After a screening night, participants were presented with AS during slow-wave sleep (SWS), REM, and stage 2 sleep either during normal sleep or daytime recovery sleep following 25h of sleep deprivation. The AS conditions were then reversed oneweek later.Results: When compared to controls sleepwalkers necessitated a significantly higher mean AS intensity (in dB) to induce awakenings and arousal responses during REM sleep whereas the two groups’ mean values did not differ significantly during SWS and stage 2 sleep. Moreover, when compared to controls sleepwalkers had a significantly lower mean percentage of AS that induced arousal responses during REM sleep while the opposite pattern of results was found during SWS.Conclusions: The data indicate that sleepwalkers have a higher auditory awakening threshold than controls, but only for REM sleep. These findings may reflect a compensatory mechanism of the homeostatic process underlying sleep regulation during sleepwalkers’ REM sleep in reaction to their difficulties maintaining consolidated periods of NREM sleep.

Effects of replacement therapy on sleep architecture in children with growth hormone deficiency

2012-05-01

Abstract: Objective: Children with GH deficiency (GHD) show a general decrease in electroencephalographic (EEG) arousability represented by a significant global decrease in Cyclic Alternating Pattern (CAP). The aim of the present study was to evaluate if sleep structure is influenced by GH substitutive therapy by analyzing the classical sleep architecture parameters and sleep microstructure by means of CAP.Subjects and methods: Laboratory polysomnographic sleep recordings were obtained from five children affected by GHD (two girls and three boys; mean age: 4.6±3.1years), at baseline and after GH therapy, and from 10 normal healthy children (four girls and six boys, mean age: 5.6±2.2years).Results: Compared to controls, GHD subjects showed a reduced total sleep time with increased wakefulness and a consequent decrease in sleep efficiency; GH therapy was associated with an increase of the awakenings/hour and a large effect size was evident for sleep latency, sleep efficiency, and stage N3, which were decreased, and for stage W, which was increased. CAP appeared to be globally reduced and all phase A subtypes and CAP cycle showed a longer duration in GHD children vs. controls. GH substitutive treatment was followed by an increase in CAP rate (total, in N2, and in N3); additionally, A1 index was also significantly increased, especially during stage N3, with a very large effect size. On the other hand, A2 and A3 index and CAP cycle mean duration were reduced.Conclusion: Sleep stage architecture seems to be influenced by the GH status, but the analysis of sleep microstructure by means of CAP reveals an enhancement of EEG slow oscillations in GHD patients (demonstrated by an increase in CAP rate and A1 index during N3) after the start of GH replacement therapy. These findings deserve to be verified in a larger trial.

HHT based cardiopulmonary coupling analysis for sleep apnea detection

2012-05-01

Abstract: Study objectives: To validate the feasibility of the Hilbert–Huang transform (HHT) based cardiopulmonary coupling (CPC) technique in respiratory events detection and estimation of the severity of apnea/hypopnea.Methods: The HHT-CPC sleep spectrogram technique was applied to a total of 69 single-lead ECG signals downloaded from the Physionet Sleep Apnea Database. Sleep spectrograms generated by both the original and the improved CPC method were compared on the structure distribution and time–frequency resolution. The performance of respiratory events detection by using the power of low frequency coupling (pLFC) in the new method was estimated by receiver operating characteristic analysis. Furthermore, correlation between HHT-CPC index (temporal Variability of Dominant Frequency, TVDF) and conventional OSAHS scoring was computed.Results: The HHT-CPC spectrum provides much finer temporal resolution and frequency resolution (8s and 0.001Hz) compared with the original CPC (8.5min and 0.004Hz). The area under the ROC curve of pLFC was 0.79 in distinguishing respiratory events from normal breathing. Significant differences were found in TVDF among groups with different severities of OSAHS (normal, mild, moderate, and severe, p<0.001). TVDF has a strong negative correlation with the apnea/hypopnea index (AHI, correlation coefficient −0.71).Conclusions: The HHT-CPC spectrum could exhibit more detailed temporal-frequency information about cardiopulmonary coupling during sleep. As two spectrographic markers, pLFC and TVDF can be used to identify respiratory events and represent the disruption extent of sleep architecture in patients with sleep apnea/hypopnea, respectively. The proposed technique might serve as a complementary approach to enhance diagnostic efforts.

Impact of continuous positive airway pressure treatment on right ventricle performance in patients with obstructive sleep apnoea, assessed by three-dimensional echocardiography

2012-05-01

Abstract: Background: Obstructive sleep apnoea (OSA) is a predictor of right ventricle (RV) impairment. However, there is scant information on the effect of OSA treatment on RV performance. We sought to evaluate the impact of OSA treatment with a continuous positive airway pressure (CPAP) device on RV volume and function, as well as on variables related to pulmonary vascular haemodynamics.Methods: Fifty-six OSA patients and 50 controls were studied. All individuals underwent three-dimensional echocardiogram (3DE) to estimate RV volumes, function, pulmonary vascular resistance, and tricuspid regurgitation velocity. A total of 30 patients with apnoea-hypopnoea index greater than 20 were randomly selected to receive placebo (n=15) or effective CPAP (n=15) for 24weeks. They underwent 3DE examination on three different occasions: at baseline, after 12weeks, and after 24weeks of CPAP or placebo.Results: Higher pulmonary vascular resistance (2.1 Wood’s±0.5 vs. 1.8 Wood’s±0.4), larger end-diastolic RV volume index (52.2mL/m2±7.3 vs. 49.9mL/m2±6.0), larger end-systolic RV volume index (18.7mL/m2±4.3 vs. 15.4mL/m2±3.6), and lower RV ejection fraction (64.3%±6.8 vs. 68.4%±5.9) were observed in the OSA group compared to non-OSA controls (P<0.05, all). In the effective CPAP group we observed the following changes from the baseline to the 24-week echo evaluation: (A) reduction in pulmonary vascular resistance (2.2 Wood’s±0.3 to 1.8 Wood’s±0.3); (B) reduction in the RV end-systolic volume index (20.3mL/m2±4.5 to 16mL/m2±2.1); and (C) increase in RV ejection fraction (63.0%±7.2 to 70.8%±0.9) (P<0.05 for all).Conclusion: Twenty-four-week treatment with CPAP improved RV performance but did not change RV structural variables.

Impaired driving simulation in patients with Periodic Limb Movement Disorder and patients with Obstructive Sleep Apnea Syndrome

2012-05-01

Abstract: Background: Excessive daytime sleepiness (EDS) is considered to be responsible for increased collision rate and impaired driving simulator performance in Obstructive Sleep Apnea Syndrome (OSAS) patients. Periodic Limb Movement Disorder (PLMD) patients also frequently report EDS and may also have impaired driving capacities.Methods: PLMD patients (n=16), OSAS patients (n=18), and controls (n=16) performed a monotonous 25-min driving simulation task. Parameters for driving capacity were the slope of the standard deviation of the lane position, lapses of attention (LOA), and structural deviations. The severity of sleep disruption and the degree of subjective sleepiness were measured.Results: Slope and LOA were significantly higher in patients than controls, pointing to a decreased driving performance. At start patients and controls had similar driving capacity. The PLMD and OSAS groups did not differ on any scale or simulation performance, although OSAS patients generally performed worse. Subjective sleepiness was higher in patients than controls, and correlated positively with driving simulator parameters. Severity of the disorder and performance were uncorrelated.Conclusion: PLMD and OSAS patients showed impaired performance in a simulated monotonous driving task. At start, patients and controls performed similarly, but patient performance decreased clearly with time, suggesting that decreased vigilance as a result of disturbed sleep is an important component of deteriorated simulated and, possibly, real driving performance.

Obesity plays an independent worsening modifying effect on nocturnal hypoxia in obstructive sleep apnea

Itay E. Gabbay, Uri Gabbay, Peretz Lavie — 2012-05-01

Abstract: Objective: Obesity’s association with obstructive sleep apnea syndrome (OSAS) is well established. The aim of this study was to examine the impact of obesity on nocturnal hypoxia.Methods: Twenty two thousand seven hundred and ninety three patients aged 21–80years who underwent whole night polysomnography during 2000–2009 were included in the study. For each patient, percent sleep time spent with oxyhemoglobin desaturation lower than 90% was calculated (%NODP). Nocturnal hypoxia was analyzed by gender, age, OSAS severity, and body mass index (BMI) categories.Results: Nocturnal hypoxia was positively correlated with BMI, OSAS severity, and age, but not with gender. The differences in %NODP between the two obese groups and non-obese varied from 0.55% to more than a 20% increase and were correlated with age and OSAS severity. The %NODP ratio between the two obese groups and the non-obese was independent of age and OSAS severity. There was a nearly twofold increase in %NODP in obese patients and a threefold increase in the morbidly obese relative to the non-obese.Conclusions: Our results indicate that obesity plays an independent worsening modifying effect on nocturnal hypoxia in OSAS.

Leg movements during wakefulness in restless legs syndrome: Time structure and relationships with periodic leg movements during sleep

2012-05-01

Abstract: Background and objective: Approximately one third of patients with restless legs syndrome (RLS) also show periodic leg movements (PLM) during relaxed wake fulness (PLMW). In contrast with the large amount of data published on periodic leg movements during sleep (PLMS), PLMW have received less attention from the scientific community. The objective of this study was to evaluate the correlations/differences of time–structure and response to a dopamine-agonist between PLMW and PLMS in patients with RLS.Methods: Ninety idiopathic RLS patients and 28 controls were recruited. Subjects underwent clinical and neurophysiological evaluation, hematological screening, and one or two consecutive full-night polysomnographic studies. A subset of patients received 0.25mg of pramipexole or placebo before the second recording. Polysomnographic recordings were scored and LM activity was analyzed during sleep and during the epochs of wakefulness occurring during the first recording hour.Results: RLS patients had higher LM activity during wakefulness than controls, but with a similar periodicity. Even if correlated, the ability of the PLMW index to predict the PLMS index decreased with increasing LM activity. Intermovement intervals during wakefulness showed one peak only at approximately 4s, gradually decreasing with increasing interval in both patients and controls. The effect of pramipexole was very limited and involved the small periodic portion of LM activity during wakefulness.Conclusions: PLMW index and PLMS index were correlated; however, the magnitude of this correlation was not sufficient to suggest that PLMW can be good predictors of PLMS. Short-interval LM activity during wakefulness and sleep might be linked to the severity of sleep disruption in RLS patients and the differences between their features obtained during wakefulness or sleep might be relevant for the diagnosis of sleep disturbances in RLS.

Sleep instability and cognitive status in drug-resistant epilepsies

Alessandra Marques Pereira, Oliviero Bruni, Raffaele Ferri, Magda Lahorgue Nunes — 2012-05-01

Abstract: Objective: The aims of this study were to evaluate the sleep habits of children with drug resistant epilepsy and to correlate sleep abnormalities with epilepsy and level of intelligence.Subjects and methods: Twenty five subjects with drug resistant epilepsy (14 males, age range 2–16.4years) were recruited for this study. A control group was formed by 23 normal children. Two instruments to assess sleep habits were administered to the patients with epilepsy: a questionnaire on sleep habits (to preschool children) and a questionnaire on sleep behavior (for children aged more than seven years old); a cognitive test (Wechsler Intelligence Scale for Children-WISC) was also performed. Patients underwent a complete polysomnographic study and sleep parameters, including CAP, were analyzed and correlated according to cognitive-behavioral measures in children with epilepsy.Results: Children with drug-resistant epilepsy and severe mental retardation showed sleep abnormalities such as low sleep efficiency, high percentage of wakefulness after sleep onset, reduced slow wave sleep, and reduced REM sleep. Sleep microstructure evaluated by means of CAP analysis showed a decrease in A1 index during N3 in patients with more severe cognitive impairment. Children with epilepsy and cognitive impairment (n=10) had higher Sleep Behavior Questionnaire for Children (SBQC) total scores (65.60±18.56) compared to children with epilepsy and normal IQ (50.00±10.40), p<0.05.Conclusions: Children with drug-resistant epilepsy have a greater incidence of sleep problems regarding qualitative aspects, macrostructure, and CAP. The decrease of CAP rate and of A1, mainly during slow wave sleep (associated to REM sleep reduction), might represent a sleep microstructural pattern of intellectual disability.

Efficacy of vitamins C, E, and their combination for treatment of restless legs syndrome in hemodialysis patients: A randomized, double-blind, placebo-controlled trial

2012-05-01

Abstract: Background: Restless legs syndrome (RLS) is a common disorder in hemodialysis patients that leads to insomnia and impaired quality of life. Because high oxidative stress has been implicated in the pathogenesis of RLS, we sought to evaluate the efficacy of vitamins C and E and their combination in reducing the severity of RLS symptoms in hemodialysis patients in this randomized, double-blind, placebo-controlled, four-arm parallel trial.Methods: Sixty stable hemodialysis patients who had all four diagnostic criteria for RLS developed by the International Restless Legs Syndrome Group with no acute illness or history of renal stone were randomly allocated to four fifteen-patient parallel groups to receive vitamin C (200mg) and vitamin E (400mg), vitamin C (200mg) and placebo, vitamin E (400mg) and placebo, and double placebo daily for eight weeks. International Restless Legs Scale (IRLS) scores were measured for all patients at baseline and at the end of treatment phase. The primary outcome was absolute change in IRLS sum score from baseline to the end of treatment phase.Results: Means of IRLS sum score decreased significantly in the vitamins C and E (10.3±5.3, 95%CI: 7.4–13.3), vitamin C and placebo (10±3.5, 95%CI: 8.1–11.9), and vitamin E and placebo groups (10.1±6, 95%CI: 6.8–13.5) compared with the double placebo group (3.1±3, 95%CI: 1.5–4.8), (P<0.001); however, no differences were observed between these treatment groups.Conclusions: Vitamins C and E and their combination are safe and effective treatments for reducing the severity of RLS in hemodialysis patients over the short-term.

Brief morning light treatment for sleep/wake disturbances in older memory-impaired individuals and their caregivers

2012-05-01

Abstract: Background: Scheduled exposure to bright light (phototherapy) has been used, with varying degrees of success, to treat sleep disruption in older individuals. Most of these studies have been done in institutional settings and have used several hours of daily light exposure. Such a regimen in the home setting may be untenable, especially when the individual with the sleep disruption has memory impairment and is being cared for by a family member. As such, we examined the effectiveness of a “user-friendly” phototherapy protocol that would be readily usable in the home environment.Methods: We exposed a group of 54 older caregiver/care recipient dyads, in which the care recipient had memory impairment, to two weeks of morning bright light phototherapy. Dyads were exposed to either bright white (∼4200lux) or dim red (∼90lux) light for 30min every day, starting within 30min of rising. All subjects also received sleep hygiene therapy. Objective (actigraphy) and subjective measures of sleep and mood were obtained at baseline and at the end of the two weeks of phototherapy.Results: In care recipients, actigraphy- and log-determined time in bed and total sleep time declined in the active condition (p<0.05, ANOVA); there was no corresponding change in subjective insomnia symptoms (p’s>0.37, ANOVA). The decrease in the time in bed was associated with an earlier out of bed time in the morning (p<0.001, Pearson correlation). The decrease in the total sleep time was associated with a decrease in sleep efficiency (p<0.001, Pearson correlation) and an increase in wake after sleep onset (p<0.001, Pearson correlation). In caregivers, there were no differential changes in actigraphic measures of sleep (p’s>0.05, ANOVA). Actigraphy-measured wake after sleep onset and sleep efficiency did, however, improve in both conditions, as did sleepiness, insomnia symptoms, and depressive symptomatology (p’s<0.05, ANOVA).Conclusions: Exposure to this regimen of phototherapy diminished sleep in older individuals with memory impairments. Their caregivers, however, experienced an improvement in sleep and mood that appeared independent of the phototherapy and likely due to participation in this protocol or the sleep hygiene therapy.

Introduction to Video-Clinical Corners

2012-05-01

Video-polysomnographic study of a patient with Morvan’s Fibrillary Chorea

2012-05-01

Morvan’s Fibrillary Chorea (MC) is a rare disorder (approximately 100 cases described to date) characterized by severe insomnia (with practically complete lack of sleep for weeks or months in a row) associated with autonomic alterations consisting of profuse perspiration with characteristic skin miliaria, tachycardia, increased body temperature, and hypertension . In 90% of cases remission is spontaneous in a few weeks or months but in the remainder the disease progresses until death . Needle electromyography (EMG) typically reveals spontaneous muscle fiber activity with fasciculations, multiplets, and myokymic and neuromyotonic discharges (fibrillary chorea) . Several studies support the concept that this syndrome is an autoimmune disorder because some patients have been shown to respond to immunotherapy and mice injected with neuromyotonia immunoglobulins have prolonged neuronal action potentials and increased neurotransmitter release. Recent findings of antibodies to mature surface membrane-expressed Shaker-type (Kv1) K+ channels (anti-VGKC) in MC confirms the hypothesis that MC is an autoimmune disorder . MC can be clinically associated with myasthenia gravis and certain neoplasms (thymoma and small-cell lung carcinoma, in particular) .

Full recovery of agrypnia associated with anti-Lgi1 antibodies encephalitis under immunomodulatory treatment: A case report with sequential polysomnographic assessment

2012-05-01

Antibodies to Kv1 potassium channel-complex proteins have been observed in various syndromes, including limbic encephalitis, Morvan’s syndrome, and neuromyotonia . However, specific targets of potassium channel antibodies have been recently identified, such as leucine-rich glioma inactivated 1 (Lgi1) or contactin-associated protein-2 (caspr2), and specific relationships between the immunologic pattern and the clinical phenotype have been suggested. Thus, insomnia in the context of Morvan’s syndrome has mainly been associated with caspr2 antibodies, whereas patients with Lgi1 antibodies typically demonstrate limbic encephalitis without sleep disturbance .

News and announcement

2012-05-01