Rapid eye movement (REM) sleep: a reliable biomarker of intractability in epilepsy

Quantitative evaluation of the microstructure of rapid eye movement sleep in refractory epilepsy: a preliminary study using electroencephalography and heart rate variability analysis

INTRODUCTION

Patients with epilepsy have a disturbed sleep architecture. Polysomnographic studies have shown that patients with refractory epilepsy have decreased rapid eye movement (REM) sleep and longer REM latency than those with medically controlled epilepsy. However, little is known about the differences in the REM sleep microstructure between these patient groups.

METHODS

We conducted a retrospective case-control study of 20 patients with refractory epilepsy (refractory group) and 28 patients with medically controlled epilepsy (medically controlled group). All patients completed sleep questionnaires and underwent overnight in-lab polysomnography. Five-minute electroencephalogram recordings at the C3 and C4 electrodes from each REM sleep were selected for spectral analysis, and 5-min electrocardiogram segments recorded during REM sleep were used for heart rate variability analysis. The groups' scores on the sleep questionnaires, polysomnographic sleep parameters, indices of sleep-related breathing disorders, and REM sleep electroencephalogram spectra were compared.

RESULTS

The refractory group had decreased REM sleep (p < 0.001) and longer REM latency (p = 0.0357) than those of the medically controlled group. Moreover, electroencephalogram spectral analysis revealed that the refractory group had decreased absolute beta power (p = 0.0039) and relative beta power (p = 0.0035) as well as increased relative delta power (p = 0.0015) compared with the medically controlled group.

CONCLUSIONS

Differences in the polysomnographic macrostructure and REM sleep microstructure between the study groups suggest REM sleep dysregulation in patients with refractory epilepsy.

Drug-Resistant Epilepsy and Obstructive Sleep Apnea: Exploring a Link Between the Two

Drug-resistant epilepsy accounts for approximately one third of all epilepsy cases; yet its exact etiopathogenesis still remains under intense exploration. Several factors have been advocated for predicting drug resistance in patients with epilepsy. Obstructive sleep apnea (OSA) is a commonly prevalent sleep disorder that exhibits a bidirectional and strong comorbidity with epilepsy. The exact pathophysiology of this comorbidity is not yet clearly explained. This study analyzes the relationship between drug-resistant epilepsy and OSA, and the findings indicate a strong role of rapid eye movement sleep (REMS) in the pathogenesis of this relationship. It also emerges from the study that REMS reduction is a prominent feature of OSA, and drug resistance in patients with epilepsy and treatment of OSA has been shown to restore REMS in several studies with concomitant improvement in seizure control.

The connectivity between the olfactory and auditory cortex predicts an individual's sleep quality

Sleep disorders and multiple sensory impairments have been noticed as the potential first sign of neurodegenerative diseases such as the Parkinson disease. The relationship between sleep quality and the sensory neural basis would help us consider their combination in early diagnosis. In the present study, 32 out of 45 healthy subjects' resting-state functional magnetic resonance imaging data survived from motion correction and entered into the connectivity analysis. We found that the connectivity between two regions of interest (the left olfactory gyrus and the left superior temporal pole) and the regional homogeneity in the left middle temporal gyrus were negatively correlated with their Pittsburgh sleep quality index. These results suggest that these sensory-related brain regions are related to sleep quality and they may together predict the diseases.

Rapid eye movement (REM) sleep and seizure control in idiopathic generalized epilepsy

BACKGROUND

Sleep and epilepsy are bedfellows, and they affect each other reciprocally. Despite the well-known relationship between sleep and epilepsy, data about the impact of sleep on seizure control and responsiveness to therapy are scarce.

OBJECTIVE

The aim of this work was to study the impact of sleep architecture in drug-naïve patients with idiopathic generalized epilepsy (IGE) on seizure control and responsiveness to treatment.

METHODS

This is a prospective cohort study conducted on thirty newly diagnosed patients with IGE attending the epilepsy clinic in Alexandria University Hospital in Egypt and thirty healthy controls. All recruited subjects had a baseline overnight polysomnographic study, then patients were given sodium valproate in therapeutic doses and followed up for six months for assessment of seizure control. After follow-up, they were classified into fully controlled and inadequately controlled patients, and a comparison between them was made.

RESULTS

Of the recruited patients, 13 were fully controlled. Rapid eye movement (REM) sleep % was significantly lower among inadequately controlled patients (9.01 ± 6.23) than fully controlled group (19.6 ± 9.01) and controls (18.17 ± 4.85) (p = 0.002), and the REM sleep latency was significantly longer among the inadequately controlled patients (115.7 ± 72.8 min) than fully controlled patients (54.6 ± 77.3 min) and controls (68.75 ± 37.95 min) (p = 011). On univariate regression analysis, the Odd's ratio (OR) for REM sleep percentage was 3.04 (p = 0.001).

CONCLUSION

Rapid eye movement sleep percentage and latency can contribute to seizure control in IGE.

Overnight Video-Polysomnographic Studies in Children with Intractable Epileptic Encephalopathies

Background

The aim of this study was to assess sleep architecture and respiration during sleep in children with intractable epileptic encephalopathies using overnight video-polysomnography (V-PSG).

Material/Methods

Between 2015 to 2017 overnight V-PSG recordings were made for 31 children (22 boys and 9 girls) with intractable epileptic encephalopathy with a mean age of 6.78±3.61 years and a mean body mass index (BMI) of 15.83±3.16 kg/m³. Thirty-one healthy children were matched for sex, age, and BMI as the control group. The phases of sleep studied included rapid eye movement (REM) sleep, and non-REM (NREM) phases NREM 1, NREM 2, and NREM 3. Respiratory function during sleep was evaluated.

Results

Children with epileptic encephalopathies receiving antiepileptic treatment had significantly decreased total sleep time (TST) (p=0.038), significantly increased percentage of NREM1 (p=0.033), and a significantly lower percentage of total REM (p<0.0001), compared with the control group. All children 31/31 (100%) with epileptic encephalopathies had interictal epileptiform discharges, and 4/31 (12.9%) had ictal events. The number of respiratory events did not differ significantly between the two groups (p=0.118), but children in the epileptic encephalopathy group had a significantly shorter average duration (p=0.008) and longest duration (p=0.048) of respiratory events. Average (p=0.006) and least (p=0.0004) oxygen saturation (SatO₂) were significantly lower in children with epileptic encephalopathies compared with the control group.

Conclusions

Children with epileptic encephalopathies had altered sleep architecture and marked oxygen desaturation, which supports the need for referral of children with epileptic encephalopathy for overnight sleep evaluation.