Journal of sleep research
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Journal of sleep research · Aug 2016
Multicenter Study Comparative Study Observational StudyImproved vigilance after sodium oxybate treatment in narcolepsy: a comparison between in-field and in-laboratory measurements.
This two-centre observational study of vigilance measurements assessed the feasibility of vigilance measurements on multiple days using the Sustained Attention to Response Task and the Psychomotor Vigilance Test with portable task equipment, and subsequently assessed the effect of sodium oxybate treatment on vigilance in patients with narcolepsy. Twenty-six patients with narcolepsy and 15 healthy controls were included. The study comprised two in-laboratory days for the Maintenance of Wakefulness Test and the Oxford Sleep Resistance test, followed by 7-day portable vigilance battery measurements. ⋯ Patients with narcolepsy had a higher Sustained Attention to Response Task error count, lower Psychomotor Vigilance Test reciprocal reaction time, higher Oxford Sleep Resistance test omission error count adjusted for test duration (Oxford Sleep Resistance testOMIS / MIN ), and lower Oxford Sleep Resistance test and Maintenance of Wakefulness Test sleep latency compared with controls (all P < 0.01). Treatment with sodium oxybate was associated with a longer Maintenance of Wakefulness Test sleep latency (P < 0.01), lower Oxford Sleep Resistance testOMIS / MIN (P = 0.01) and a lower Sustained Attention to Response Task error count (P = 0.01) in patients with narcolepsy, but not with absolute changes in Oxford Sleep Resistance test sleep latency or Psychomotor Vigilance Test reciprocal reaction time. It was concluded that portable measurements of sustained attention as well as in-laboratory Oxford Sleep Resistance test and Maintenance of Wakefulness Test measurements revealed worse performance for narcoleptic patients compared with controls, and that sodium oxybate was associated with an improvement of sustained attention and a better resistance to sleep.
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Journal of sleep research · Apr 2016
White matter alterations in narcolepsy patients with cataplexy: tract-based spatial statistics.
Functional imaging studies and voxel-based morphometry analysis of brain magnetic resonance imaging showed abnormalities in the hypothalamus-thalamus-orbitofrontal pathway, demonstrating altered hypocretin pathway in narcolepsy. Those distinct morphometric changes account for problems in wake-sleep control, attention and memory. It also raised the necessity to evaluate white matter changes. ⋯ Among patients, mean diffusivity values of white matter in the bilateral superior frontal gyri, bilateral fronto-orbital gyri and right superior parietal gyrus were positively correlated with depressive mood. This tract-based spatial statistics study demonstrated that drug-naïve patients with narcolepsy had reduced fractional anisotropy of white matter in multiple brain areas and significant relationship between increased mean diffusivity of white matter in frontal/cingulate and depression. It suggests the widespread disruption of white matter integrity and prevalent brain degeneration of frontal lobes according to a depressive symptom in narcolepsy.
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Journal of sleep research · Feb 2016
Association of incident restless legs syndrome with outcomes in a large cohort of US veterans.
Restless legs syndrome is a common sleep disorder, but there is a paucity of large cohort studies examining the association of restless legs syndrome with clinical outcomes, including all-cause mortality, incident coronary heart disease, stroke and chronic kidney disease. From a nationally representative prospective cohort of over 3 million US veterans [93% male, median follow-up time of 8.1 years (interquartile range: 7.0-8.5 years)] with baseline estimated glomerular filtration rate ≥ 60 mL min(-1) 1.73 m(-2), a propensity-matched cohort of 7392 patients was created, and the association between incident restless legs syndrome and the following was examined: (1) all-cause mortality; (2) incident coronary heart disease; (3) incident strokes; and (4) incident chronic kidney disease defined as estimated glomerular filtration rate <60 mL min(-1) 1.73 m(-2). Associations were examined using Cox models. ⋯ Compared with restless legs syndrome-negative patients, incident restless legs syndrome was associated with 88% higher mortality risk [hazard ratio and 95% confidence interval: 1.88 (1.70-2.08)], and almost four times higher risk of coronary heart disease and stroke [hazard ratio: 3.97 (3.26-4.84) and 3.89 (3.07-4.94), respectively]. The risk of incident chronic kidney disease was also significantly higher in incident restless legs syndrome patients [hazard ratio: 3.17 (2.74-3.66)] compared with restless legs syndrome-negative counterparts. In this large and contemporary cohort of US veterans, incident restless legs syndrome was associated with higher risk of mortality, incident coronary heart disease, stroke and chronic kidney disease.
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Journal of sleep research · Aug 2015
Multicenter StudyAssociation between obstructive sleep apnea severity and glucose control in patients with untreated versus treated diabetes.
The purpose of this study was to determine whether the association between obstructive sleep apnea severity and glucose control differs between patients with newly diagnosed and untreated type 2 diabetes, and patients with known and treated type 2 diabetes. This multicentre cross-sectional study included 762 patients investigated by sleep recording for suspected obstructive sleep apnea, 497 of whom were previously diagnosed and treated for type 2 diabetes (treated diabetic patients), while 265 had no medical history of diabetes but had fasting blood glucose ≥126 mg dL(-1) and/or glycated haemoglobin (HbA1c ) ≥6.5% consistent with newly diagnosed type 2 diabetes (untreated diabetic patients). Multivariate regression analyses were performed to evaluate the independent association between HbA1c and obstructive sleep apnea severity in treated and untreated patients with diabetes. ⋯ The adjusted mean value of HbA1c increased from 6.68% in the lowest quartile of the apnea-hypopnea index (<17) to 7.20% in the highest quartile of the apnea-hypopnea index (>61; P = 0.033 for linear trend). In treated patients with diabetes, HbA1c was associated with non-sleep variables, including age, metabolic dyslipidaemia and insulin use, but not with obstructive sleep apnea severity. Obstructive sleep apnea may adversely affect glucose control in patients with newly diagnosed and untreated type 2 diabetes, but may have a limited impact in patients with overt type 2 diabetes receiving anti-diabetic medications.
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Journal of sleep research · Aug 2015
The spectrum of the non-rapid eye movement sleep electroencephalogram following total sleep deprivation is trait-like.
The sleep electroencephalogram (EEG) spectrum is unique to an individual and stable across multiple baseline recordings. The aim of this study was to examine whether the sleep EEG spectrum exhibits the same stable characteristics after acute total sleep deprivation. Polysomnography (PSG) was recorded in 20 healthy adults across consecutive sleep periods. ⋯ ICCs were high across all frequencies for baseline and recovery and for baseline and recovery combined. These results show that the spectrum of the NREM sleep EEG is substantially different among individuals, highly stable within individuals and robust to an experimental challenge (i.e. sleep deprivation) known to have considerable impact on the NREM sleep EEG. These findings indicate that the NREM sleep EEG represents a trait.