Sleep and time course of consolidation of visual discrimination skills in patients with narcolepsy–cataplexy

The level of procedural skills improves in normal individuals when the acquisition is followed by a period of sleep rather than wake. If sleep plays an important role in the consolidation process the advantage it provides should be reduced or delayed when its organization is altered, as in patients with chronic sleep disorders. To test this prediction in patients with narcolepsy–cataplexy (NC), who usually have a more fragmented organization of sleep than normals, we compared the initial, intermediate and delayed level of consolidation of visual skills . Twenty-two drug-naive NC patients and 22 individually-matched controls underwent training at a texture discrimination task (TDT) and were re-tested on the next morning (after a night spent in laboratory with polysomnography) and after another six nights (spent at home). TDT performance was worse in patients than controls at training and at both retrieval sessions and the time course of consolidation was different in NC patients (who improved mainly from next-day to 7th-day retrieval session) compared with controls. Moreover, the less-improving patients at next-day retrieval had a wider disorganization of sleep, probably because of an episode of rapid eye movement (REM) sleep at sleep onset REM, on post-training night more frequently than more-improving patients. These findings suggest that the time course of the consolidation process of procedural skills may be widely influenced by the characteristics of sleep organization (varying night-by-night much more in NC patients than controls) during post-training night.     

Overnight emotional adaptation to negative stimuli is altered by REM sleep deprivation and is correlated with intervening dream emotions

Rapid eye movement (REM) sleep and dreaming may be implicated in cross-night adaptation to emotionally negative events. To evaluate the impact of REM sleep deprivation (REMD) and the presence of dream emotions on a possible emotional adaptation (EA) function, 35 healthy subjects randomly assigned to REMD ( n  = 17; mean age 26.4 ± 4.3 years) and control ( n  = 18; mean age 23.7 ± 4.4 years) groups underwent a partial REMD and control nights in the laboratory, respectively. In the evening preceding and morning following REMD, subjects rated neutral and negative pictures on scales of valence and arousal and EA scores were calculated. Subjects also rated dream emotions using the same scales and a 10-item emotions list. REMD was relatively successful in decreasing REM% on the experimental night, although a mean split procedure was applied to better differentiate subjects high and low in REM%. High and low groups differed – but in a direction contrary to expectations. Subjects high in REMD% showed greater adaptation to negative pictures on arousal ratings than did those low in REMD% ( P  < 0.05), even after statistically controlling sleep efficiency and awakening times. Subjects above the median on EA_valence had less intense overall dream negativity ( P  < 0.005) and dream sadness ( P  < 0.004) than subjects below the median. A correlation between the emotional intensities of the morning dream and the morning picture ratings supports a possible emotional carry-over effect. REM sleep may enhance morning reactivity to negative emotional stimuli. Further, REM sleep and dreaming may be implicated in different dimensions of cross-night adaptation to negative emotions.     

Cost‐Effectiveness of Cardiac Resynchronization Therapy in the MADIT‐CRT Trial

Cost Effectiveness of MADIT‐CRT. Background: The Multicenter Automatic Defibrillator Implantation Trial‐Cardiac Resynchronization Therapy (MADIT‐CRT) trial demonstrated that cardiac resynchronization therapy (CRT) when added to the implantable cardiac defibrillator (ICD) reduces risk of heart failure or death in minimally symptomatic patients with reduced cardiac ejection fraction and wide QRS complex. Objectives: To evaluate 4‐year cost‐effectiveness of CRT‐ICD compared to ICD alone using MADIT‐CRT data. Research Design: Patients enrolled in the trial were randomized to implantation of either ICD or CRT‐ICD in a 2:3 ratio, with up to 4‐year follow‐up period. Cost‐effectiveness analyses were conducted, and sensitivity analyses by age, gender, and left bundle branch block (LBBB) conduction pattern were performed. Subjects: A total of 1,271 patients with ICD or CRT‐ICD (US centers only) who reported healthcare utilization and health‐related quality of life data. Measures: We used the EQ‐5D (US weights) to assess patient HRQOL and translated utilization data to costs using national Medicare reimbursement rates. Results: Average 4‐year healthcare expenditures in CRT‐ICD patients were higher than costs of ICD patients ($62,600 vs 57,050, P = 0.015), mainly due to the device and implant‐related costs. The incremental cost‐effectiveness ratio of CRT‐ICD compared to ICD was $58,330/quality‐adjusted life years (QALY) saved. The cost effectiveness improved with longer time horizon and for the LBBB subgroup ($7,320/QALY), with no cost‐effectiveness benefit being evident in the non‐LBBB group. Conclusions: In minimally symptomatic patients with low ejection fraction and LBBB, CRT‐ICD is cost effective within 4‐year horizon when compared to ICD‐only. (J Cardiovasc Electrophysiol, Vol. 24, pp. 66‐74, January 2013)