Early ictal speech and motor inhibition in fronto-mesial epileptic seizures: a polygraphic study in one patient.

OBJECTIVE: To investigate ictal motor inhibition occurring during seizures in a patient with a tumor located in the left fronto-mesial pre-central cortex. METHODS: Awake and sleep video-polygraphic monitoring, recording scalp EEG and EMG activities from several cranial, trunk and limbs muscles, was performed in a patient with drug-resistant recurrent focal motor seizures before surgical treatment. Speech/motor tasks were repeatedly administered to the patient during the recording sessions in order to evaluate the occurrence of early ictal motor inhibition. RESULTS: Thirty-four seizures were recorded during wakefulness showing a stereotyped pattern of inhibition of speech and voluntary movements followed by sequential activation of upper limb-trunk-lower limb muscles contralateral to the tumor. Polygraphic recordings showed that: (1) initial speech and motor arrest were associated with the EMG evidence of progressive muscle tone suppression in cranial and right distal upper limb muscles; (2) tonic contraction of right deltoid, biceps brachii, intercostalis and paraspinalis muscles appeared after motor inhibition; (3) tonic-clonic activity in the right tibialis anterior muscle occurred at the end of seizures. Eleven subclinical seizures were recorded during sleep showing mild focal tonic EMG activity in right side trunk muscles. CONCLUSIONS: Our findings evidenced early and somatotopically organized inhibition of voluntary movement at the beginning of epileptic seizures with fronto-mesial onset. The demonstration that speech and motor arrest were associated with progressive EMG suppression in cranial and limb muscles supports the hypothesis of motor inhibitory seizures originating in the mesial aspect of pre-motor frontal cortex.     

Sleep disorders in multiple system atrophy: a correlative video-polysomnographic study

OBJECTIVE: The reciprocal relation between breathing, heart and motor system abnormalities during sleep was studied in multiple system atrophy (MSA) by means of video-polysomnographic recordings (VPSG). PATIENTS AND METHODS: Nineteen consecutive MSA patients underwent VPSG with scoring for sleep, respiratory abnormalities, heart (HR) and breathing (BR) rates, and abnormal motor activities. A comparative analysis was performed versus 10 patients with obstructive sleep apnoea syndrome (OSAS). RESULTS: All MSA patients displayed snoring, 42% stridor, and 37% OSAS. Mean sleep SaO(2) was 92.7%, and lowest SaO(2) 86%. Patients with stridor had a significant increase in BR from Wake to NREM and REM sleep, and higher HR during sleep. Respiratory muscles and tibialis anterior EMG tonic activity was frequently found, more often in patients with stridor. All patients had REM sleep behaviour disorders (RBD) and 88% periodic limb movements during sleep (PLMS). No OSAS patient had RBD or respiratory muscles and tibialis anterior tonic activity. CONCLUSIONS: MSA patients, especially those with associated stridor, commonly display impaired breathing and abnormal control of respiratory and limb muscles during sleep. Breathing and motor abnormalities are often concomitant in the same patient, indicating a diffuse impairment of sleep homeostatic integration that should be included within the diagnostic features of MSA.     

Propriospinal myoclonus: a motor phenomenon found in restless legs syndrome different from periodic limb movements during sleep.

Three patients presented with a 25-, 15-, and 5-year history of restless legs syndrome (RLS) and periodic limb movements during sleep (PLMS). For 1, 4, and 5 years, they reported additional involuntary trunk and limbs jerks preceding falling asleep and occasionally during intrasleep wakefulness. Videopolysomnography revealed jerks during relaxed wakefulness arising in axial muscles with a caudal and rostral propagation at a slow conduction velocity, characteristic of propriospinal myoclonus (PSM). Jerk-related EEG-EMG back-averaging did not disclose any preceding cortical potential. During relaxed wakefulness preceding falling asleep and during intrasleep wakefulness, PSM coexisted with motor restlessness and sensory discomfort in the limbs. PSM disappeared when spindles and K-complexes appeared on the EEG. At this time, typical PLMS appeared every 20 to 40 seconds, especially during light sleep stages. PLMS EMG activity was limited to leg, especially tibialis anterior muscles, and did not show propriospinal propagation. In one patient, alternating leg muscle activation was also present. Jerks with a PSM pattern represent another motor phenomenon associated with RLS and different from the more usual PLMS.     

Adaptation and vision change the relationship between muscle activity of the lower limbs and body movement during human balance perturbations

ObjectiveInvestigate the relationship between changes in lower limb EMG root mean square (RMS) activity and changes in body movement during perturbed standing. Specifically, linear movement variance, torque variance and body posture were correlated against tibialis anterior and gastrocnemius RMS EMG activity during perturbed standing by vibration of the calf muscles.MethodsEighteen healthy participants (mean age 29.1 years) stood quietly for 30 s before vibration pulses were randomly applied to the calf muscles over a period of 200 s with eyes open or closed. Movement variance, torque variance and RMS EMG activity were separated into five periods, thereby allowing us to explore any time-varying changes of the relationships.ResultsChanges of tibialis anterior muscles EMG activity were positively correlated with changes in linear movement variance and torque variance throughout most of the trials, and negatively correlated with some mean angular position changes during the last 2 min of the trials. Moreover, the initial changes in Gastrocnemius EMG activity were associated with initial changes of mean angular position. Additionally, both tibialis anterior and gastrocnemius muscle activities were more involved in the initial control of stability with eyes closed than with eyes open.ConclusionsVisual information and adaptation change the association between muscle activity and movement when standing is perturbed by calf muscle vibration.SignificanceAccess to visual information changes the standing strategy to calf muscle vibrations. Training evoking adaptation could benefit those susceptible to falls by optimising the association between muscle activities and stabilising body movement.     

Submentalis Rapid Eye Movement Sleep Muscle Activity: A Potential Biomarker for Synucleinopathy

Accurate antemortem diagnosis of parkinsonism is primarily based on clinical evaluation with limited biomarkers. We evaluated the diagnostic utility of quantitative rapid eye movement (REM) sleep without atonia analysis in the submentalis and anterior tibialis muscles in parkinsonian patients (53 synucleinopathy, 24 tauopathy). Receiver operating characteristic curves determined REM sleep without atonia cutoffs distinguishing synucleinopathies from tauopathies. Elevated submentalis muscle activity was highly sensitive (70–77%) and specific (95–100%) in distinguishing synucleinopathy from tauopathy. In contrast, anterior tibialis synucleinopathy discrimination was poor. Our results suggest that elevated submentalis REM sleep without atonia appears to be a potentially useful biomarker for presumed synucleinopathy etiologies in parkinsonism. ANN NEUROL 2019;86:969–974     

选择性5-羟色胺再摄取抑制剂对抑郁症患者快动眼睡眠肌电活动的影响

目的 观察选择性5-羟色胺再摄取抑制剂(SSRIs)对抑郁症患者的快动眼(REM)睡眠肌张力的影响.方法 选择年龄和性别匹配的接受SSRIs治疗的抑郁患者(治疗组,21例)、未接受SSRIs治疗的抑郁患者(未治疗组,21例)和正常对照组(21例),根据Lapierre和Montplaisir的标准重新评估每组患者每个REM睡眠包含的张力性和位相性肌电活动.结果 (1)REM睡眠张力性:治疗组[(10.1±9.4)%]与未治疗组[(3.3±3.7)%]和正常对照组[(2.8±3.4)%]比较,REM睡眠张力性增加,差异有统计学意义(P＜0.001).(2)位相性肌电活动:治疗组[(11.5±6.8)%]与未治疗组[(6.3±4.1)%]和正常对照组[(5.0±3.7)%]比较,颌肌位相性肌电活动增加,差异有统计学意义(P＜0.05);治疗组[(18.8±13.2)%]与未治疗组[(10.3±7.2)%]和正常对照组[(9.8±5.5)%]比较,胫骨前肌位相性肌电活动增加,差异有统计学意义(P＜0.05).(3)治疗组REM睡眠的张力性和位相性肌电活动均与REM潜伏期呈正相关(γ=4.475,γ=0.397,γ=0.402),与REM比例呈负相关(γ=-0.353,γ=-0.511,γ=-0.463).结论 SSRIs阻碍了抑郁症患者REM睡眠肌张力消失.     

Quantitative assessment of isolated rapid eye movement (REM) sleep without atonia without clinical REM sleep behavior disorder: clinical and research implications

BackgroundRapid eye movement (REM) sleep without atonia (RWA) is observed in some patients without a clinical history of REM sleep behavior disorder (RBD). It remains unknown whether these patients meet the refined quantitative electromyographic (EMG) criteria supporting a clinical RBD diagnosis. We quantitatively evaluated EMG activity and investigated its overnight distribution in patients with isolated qualitative RWA.MethodsFifty participants with an incidental polysomnographic finding of RWA (isolated qualitative RWA) were included. Tonic, phasic, and ‘any’ EMG activity during REM sleep on PSG were quantified retrospectively.ResultsReferring to the quantitative cut-off values for a polysomnographic diagnosis of RBD, 7/50 (14%) and 6/50 (12%) of the patients showed phasic and ‘any’ EMG activity in the mentalis muscle above the respective cut-off values. No patient was above the cut-off value for tonic EMG activity or phasic EMG activity in the anterior tibialis muscles. Patients with RWA above the cut-off value showed higher amounts of RWA during later REM sleep periods.ConclusionsThis is the first study showing that some subjects with incidental RWA meet the refined quantitative EMG criteria for a diagnosis of RBD. Future longitudinal studies must investigate whether this subgroup with isolated qualitative RWA is at an increased risk of developing fully expressed RBD and/or neurodegenerative disease.     

Differential effects of persistent nociceptive stimulation on sleep stages

The purpose of this work was to investigate the sequence of modifications of sleep and pain parameters in a condition of persistent nociceptive stimulation. In freely moving cats carrying implanted electrodes, continuous polygraphic and behavioral recordings were collected 24 h a day for several consecutive days before and after treatment. Injection of formalin (2 ml, 37%) elicited continuous wakefulness (1-6 h) associated with behavioral manifestations of pain. This insomnia was followed by the delayed appearance of LS (light, slow wave sleep) DS (deep slow wave sleep) and REM (rapid eye movement sleep). On days 1 and 2 after injection, pain manifestations displayed a gradual decrease, while total sleep time (LS + DS + REM) slowly returned to normal levels. On day 1, the amount of LS was not modified, but DS and REM were greatly decreased. For 12 h after the first REM episode, REM was decreased while DS was already at the basal levels. Formalin elicited a long-lasting increase in EMG activity of the tibialis anterior muscle which was suppressed during REM and returned to higher levels afterwards. Prolonged wakefulness and delay in sleep stage appearance were also recorded when a 24-h sleep deprivation preceded formalin injection. In this condition, LS, DS and REM amount were at basal levels from their first reappearance, and a rebound in total sleep time and DS occurred on day 2 after the injection. After injection of smaller doses of formalin (0.5 ml, 8%), the amount of LS, DS and REM was at control levels since day 1. The results suggest that (1) the amount of sleep depends on sleep debt and on the level of pain intensity and (2) sleep stages are differentially sensitive to persistent pain.     

Electromyography of rat soleus, medial gastrocnemius, and tibialis anterior during hind limb suspension

Hind limb suspension is a model frequently utilized to study muscle plasticity. One reason for its frequent use is that it is thought to mimic in many respects the conditions imposed on some muscles during spaceflight. Changes in muscle properties that follow hind limb suspension generally have been attributed to reductions in the recruitment of these muscles. To determine the validity of this assumption, the electromyographic (EMG) activity of three hind limb muscles, the soleus, a slow extensor, the medial gastrocnemius, a fast extensor, and the tibialis anterior, a fast flexor, was studied. The EMG was recorded in each rat for 25 min of each hour for 24 consecutive hours, 7 and 3 days prior, on the day of, and 3, 7, 14, 21, and 28 days after hind limb suspension. Control rats were treated similarly and their EMG recorded on corresponding days. Compared with presuspension, soleus activity was reduced significantly to 91% on the first day of suspension, but had recovered to 81% of its normal activity by the seventh day. Similarly, there was a significant reduction to 54% in activity of the medial gastrocnemius on the day of hind limb suspension which recovered to 98% of its presuspension values by day 7. In contrast, the tibialis anterior showed a significant increase in activity relative to presuspension values within 3 days of the initiation of suspension. These data indicate that hind limb suspension produced only a relatively short-term reduction in the activity of both the soleus and medial gastrocnemius and results in an increased activity in the tibialis anterior. Collaborative studies showed that significant alterations in muscle mass and metabolic and mechanical properties occurred and persisted in spite of the recovery of activation in the soleus and medial gastrocnemius. In addition, no alterations in mass and mechanical properties were evident in the tibialis anterior during a 4-week suspension even though the EMG increased after hind limb suspension. Together, these data indicate that the adaptations in muscle properties following hind limb suspension are not closely related to changes in the total amount of muscle EMG activity per day.     

Electromyography of rat soleus, medical gastrocnemius, and tibialis anterior during hind limb suspension

Hind limb suspension is a model frequently utilized to study muscle plasticity. One reason for its frequent use is that it is thought to mimic in many respects the conditions imposed on some muscles during spaceflight. Changes in muscle properties that follow hind limb suspension generally have been attributed to reductions in the recruitment of these muscles. To determine the validity of this assumption, the electromyographic (EMG) activity of three hind limb muscles, the soleus, a slow extensor, the medial gastrocnemius, a fast extensor, and the tibialis anterior, a fast flexor, was studied. The EMG was recorded in each rat for 25 min of each hour for 24 consecutive hours, 7 and 3 days prior, on the day of, and 3, 7, 14, 21, and 28 days after hind limb suspension. Control rats were treated similarly and their EMG recorded on corresponding days. Compared with presuspension, soleus activity was reduced significantly to 91% on the first day of suspension, but had recovered to 81% of its normal activity by the seventh day. Similarly, there was a significant reduction to 54% in activity of the medial gastrocnemius on the day of hind limb suspension which recovered to 98% of its presuspension values by day 7. In contrast, the tibialis anterior showed a significant increase in activity relative to presuspension values within 3 days of the initiation of suspension. These data indicate that hind limb suspension produced only a relatively short-term reduction in the activity of both the soleus and medial gastrocnemius and results in an increased activity in the tibialis anterior. Collaborative studies showed that significant alterations in muscle mass and metabolic and mechanical properties occurred and persisted in spite of the recovery of activation in the soleus and medial gastrocnemius. In addition, no alterations in mass and mechanical properties were evident in the tibialis anterior during a 4-week suspension even though the EMG increased after hind limb suspension. Together, these data indicate that the adaptations in muscle properties following hind limb suspension are not closely related to changes in the total amount of muscle EMG activity per day.     

Paraspinal and limb motor neuron involvement within homologous spinal segments in ALS.

OBJECTIVE: We studied the involvement of motor neuron groups innervating paraspinal muscles in amyotrophic lateral sclerosis (ALS) and evaluated the value of paraspinal muscle EMG in the diagnosis of the disease. METHODS: We used quantitative concentric needle EMG to study denervation and reinnervation in a paraspinal muscle and a limb muscle innervated by the C6 and L5 segments in 32 patients with ALS. As control subjects we studied 11 patients with peripheral neuropathy, and 46 non-neurogenic control subjects. RESULTS: We found similar abnormalities in motor-unit potentials (MUPs) in paraspinal and limb muscles in these two segments in ALS. Fasciculation potentials (FPs) were more frequent in limb muscles than in paraspinal muscles and fibrillations and sharp waves (fibs-sw) were most frequent in tibialis anterior. In peripheral neuropathy paraspinal muscles were normal but tibialis anterior showed very abnormal motor unit potentials. CONCLUSIONS: These results are consistent with generalised involvement of motor neurons in motor neuron pools in spinal segments in early stages of ALS progression. However, distally predominant fibrillations indicate susceptibility to ongoing denervation in reinnervated distal axons. Complex FPs of similar morphology to MUP analysis in the same early affected muscle suggests a proximal origin for these FPs at this phase. SIGNIFICANCE: Our observations emphasize the value of paraspinal muscle EMG in the electrophysiological diagnosis of ALS.     

Unity of costal and crural diaphragmatic activity in respiration

In chronically implanted rats, we examined the respiratory EMG activity of the two parts of the diaphragm, costal and crural, during sleep and wakefulness. Their activity was compared and contrasted with that of the EMG activity of the cricothyroid muscle. Whether in wakefulness, while grooming and drinking, or in nonrapid eye movement (non-REM) sleep, and independent of the gas mixture breathed (4 to 5% CO2 or 10% O2 in nitrogen), the two parts of the diaphragm paused during REM apnea episodes whereas the cricothyroid muscle ceased its activity or exhibited sustained activity. We conclude that the diaphragm, mainly an inspiratory muscle, acts as a single functional unit when under the respiratory control system. The cricothyroid muscle functions as an inspiratory and/or expiratory muscle, also under the respiratory control systems. Both muscles in the rat come under other neural control mechanisms governing nonrespiratory functions, e.g., swallowing, defecation, and coughing, but not vomiting.     

Motor pattern of periodic limb movements during sleep

BACKGROUND: The pathophysiology of periodic limb movements in sleep (PLMS) in restless legs syndrome (RLS) is unclear. OBJECTIVE: The authors neurophysiologically investigated PLMS in patients with idiopathic RLS in order to obtain information on the origin and pathophysiology of the movements. METHODS: Ten patients with idiopathic RLS underwent electromyography with nerve conduction velocity (EMG-CV), somatosensory evoked potentials (SEPs), transcranial magnetic stimulation (TMS), nocturnal videopolysomnography, and multiple sleep latency test. The authors analyzed 100 consecutive PLMS for each patient to determine how frequently each muscle was involved in the PLMS; how frequently EMG activity started in a given muscle; and the time delay and pattern of activation between the first and the other activated muscles. RESULTS: EMG-CV, SEPs, and TMS findings were all normal; in PLMS, leg muscles were those more frequently involved, often with alternation of side. Axial muscles were rarely and upper limb muscles sometimes involved. The tibialis anterior was the most frequent starting muscle. There was no constant recruitment pattern from one PLMS episode to another, even in the same patient. There was no ordinate caudal or rostral spread of the EMG activity. CONCLUSION: The recruitment pattern indicates the engagement of different, independent, and sometimes unsynchronized generators for each PLMS. The authors hypothesize an abnormal hyperexcitability along the entire spinal cord, especially its lumbosacral and cervical segments, as the primary cause of PLMS, triggered by sleep-related factors located at a supraspinal but still unresolved level.     

Quantification of electromyographic activity during sleep: a phasic electromyographic metric.

Recording of electromyographic (EMG) activity is considered essential for defining rapid eye movement (REM) sleep and for quantifying certain types of movements in sleep, such as periodic leg movements in sleep (PLMS). However, routine analyses of EMG activity beyond such purposes is performed rarely and quantified seldom, and normative data are lacking. In this study, the authors examined systematic application of a visual scoring system for short-duration (approximately 100-millisecond) phasic EMG activity recorded from five different muscle groups (submentalis, left/right anterior tibialis, left/right brachioradialis) recorded from two different age groups of normal subjects and a group of patients with Parkinson's disease. Quantification of this activity was labeled as a phasic electromyographic metric (PEM). PEM data were compiled separately by REM and non-REM sleep. Results indicated that PEM is a normal part of REM sleep in all muscle groups, more specifically constituting about 5% (SD = 3.1%) of 2.5-second intervals of REM sleep in the mentalis in healthy young adults. It occurs at higher rates in patients with Parkinson's disease, and its quantification in the legs may be influenced to some degree by the presence of PLMS. PEM may be a useful metric amenable to quantification with digital techniques. It may have particular relevance for the identification of neurodegenerative conditions in which disinhibition of midbrain dopaminergic pathways results in excessive motor discharge during sleep.     

Defining muscle activities for assessment of rapid eye movement sleep behavior disorder: From a qualitative to a quantitative diagnostic level

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by dream enacting behavior. Its polysomnographic hallmark is loss of physiological REM muscle atonia. Current diagnostic criteria require both a typical history of RBD or videographic documentation of abnormal REM-sleep related behaviors and the polysomnographic demonstration of REM sleep without atonia with “the electromyographic (EMG) finding of excessive amounts of sustained or intermittent elevation of submental EMG tone or excessive phasic submental or limb EMG twitching”.Until now, there has not been a generally accepted consensus on how muscle activity during REM sleep should be scored. Moreover, current diagnostic criteria do not specify which muscle or muscle combinations are the most suitable for differentiating between RBD and non-RBD. The term “excessive” refers to the scorer’s subjective impression and not to objective quantitative cutoff values.This article reviews published manual and computer-assisted scoring methods of EMG activity that are applied in RBD research. It includes the existing studies on EMG activity assessment in different muscles, available data on night-to-night variability, as well as recently established quantitative EMG cutoff values. The research that has been undertaken in the last years has greatly improved RBD diagnosis, taking it from a qualitative to a quantitative level. This development is of upmost importance, since RBD is often the first non-motor symptom of a neurodegenerative disease.     

Surface EMG activity during REM sleep in Parkinson's disease correlates with disease severity

ObjectivesOver 40% of individuals with Parkinson's disease (PD) have rapid eye movement sleep behavior disorder (RBD). This is associated with excessive sustained (tonic) or intermittent (phasic) muscle activity instead of the muscle atonia normally seen during REM sleep. We examined characteristics of manually-quantitated surface EMG activity in PD to ascertain whether the extent of muscle activity during REM sleep is associated with specific clinical features and measures of disease severity.MethodsIn a convenience sample of outpatients with idiopathic PD, REM sleep behavior disorder was diagnosed based on clinical history and polysomnogram, and severity was measured using the RBD sleep questionnaire. Surface EMG activity in the mentalis, extensor muscle group of the forearms, and anterior tibialis was manually quantitated. Percentage of REM time with excessive tonic or phasic muscle activity was calculated and compared across PD and RBD characteristics.ResultsAmong 65 patients, 31 had confirmed RBD. In univariate analyses, higher amounts of surface EMG activity were associated with longer PD disease duration (srho = 0.34; p = 0.006) and greater disease severity (p < 0.001). In a multivariate regression model, surface EMG activity was significantly associated with RBD severity (p < 0.001) after adjustment for age, PD disease duration, PD severity and co-morbid sleep abnormalities.ConclusionSurface EMG activity during REM sleep was associated with severity of both PD and RBD. This measure may be useful as a PD biomarker and, if confirmed, may aid in determining which PD patients warrant treatment for their dream enactment to reduce risk of injury.     

Different laws govern motor activity in sleep than in wakefulness

Summary A wide range of elementary and complex motor activities are known to occur during sleep, but very little is known about the basic physiologic condition of the skeletal muscle during sleep. The present study provides evidence that a minute electric random activity constitutes the basic physiologic condition of the skeletal muscles during sleep. During the NonREM stages of each sleep cycle a regression of the continuous random minute activity occurs, followed by a sudden increase of the isolated motor unit action potentials during REM sleep. Particular structural features of the anterior tibial (AT) muscle make it the most active skeletal muscle during sleep. During wakefulness, at rest, the random muscle activity disappears.     

Electroencephalographic correlates of cataplectic attacks in narcoleptic canines

Cataplectic attacks were monitored behaviorally and polygraphically in 4 narcoleptic dogs, of which three inherited the disorder. The recorded EEG signals were evaluated by power spectral analysis. We found 3 distinct stages of cataplexy: an initial stage which resembled wakefulness with tonic suppression of EMG activity, a later stage which was highly similar to REM sleep, and a final transitional stage to wakefulness or NREM sleep. The first stage of cataplexy was characterized by full postural collapse, a waking-like EEG spectrum, visual tracking, and a hypotonic EMG. The second stage of cataplexy differed electrographically from the previous stage by the onset of hypersynchronous hippocampal theta activity, a REM-like EEG spectrum, larger amplitude EEG signals, and a higher peak theta frequency. Glazed eyes, sporadic rapid eye movements and muscle twitches were also present. The final stage of cataplexy was characterized by mixed amplitude, mixed frequency EEG activity, and by the absence of rapid eye movements, visual tracking, directed movements, and muscle twitches. The EEG spectra of two other narcoleptic phenomena, sleep-onset REM periods and NREM sleep onsets from cataplexy, were nearly identical to the spectra of the normally occurring REM and NREM sleep periods.     

Respiratory functions of the inferior pharyngeal constrictor and sternohyoid muscles during sleep

We studied the respiratory activity of the inferior pharyngeal constrictor and sternohyoid muscles of the rat during non-rapid eye movement (non-REM) and REM sleep. Each animal carried chronically implanted electrodes for recording the integrated EMG activity of respiratory muscles as well as the electrocorticogram (ECoG) and postural tone (dorsal neck EMG). The latter permitted polygraphic identification of sleep states. Curled up postures enhanced inspiratory activity of both upper airway muscles during non-REM sleep, an effect which CO2 breathing failed to augment except in the well curled up position. Hypoxia reduced their activity. During REM sleep, the inferior pharyngeal constrictor and sternohyoid muscles retained their inspiratory activity. No tonic activity could be detected in either muscle. We conclude that the inferior pharyngeal constrictor and sternohyoid muscles safeguard upper airway patency in the two main sleep states.     

Respiratory muscle activity during REM sleep in patients with diaphragm paralysis

The diaphragm is the main inspiratory muscle during REM sleep. It was hypothesized that patients with isolated bilateral diaphragm paralysis (BDP) might not be able to sustain REM sleep. Polysomnography with EMG recordings was undertaken from accessory respiratory muscles in patients with BDP and normal subjects. Patients with BDP had a normal quantity of REM sleep (mean +/- SD, 18.6 +/- 7.5% of total sleep time) achieved by inspiratory recruitment of extradiaphragmatic muscles in both tonic and phasic REM, suggesting brainstem reorganization.