Kiyan E, Okumus G, Cuhadaroglu C, Deymeer F. Sleep apnea in adult myotonic dystrophy patients who have no excessive daytime sleepiness
ABSTRACT Sleep apnea is common in myotonic dystrophy (MD) and may cause respiratory failure. Most of the sleep studies have been performed in patients with excessive daytime sleepiness (EDS), which is a characteristic and strong predictor of sleep apnea. Therefore, we investigated the prevalence of sleep apnea in adult MD patients who have no EDS.
Epworth Sleepiness Scale was used to exclude EDS and a score over 10 was accepted as an indicator of EDS. Sleep studies of 17 adult MD patients with the Epworth sleepiness scale score < or =10 were retrospectively reviewed. Spirometry (n = 16) and daytime arterial blood gasses were used to evaluate the relationship with nocturnal parameters.
On admission to the outpatient chest clinic, seven patients had normal spirometry, and ten had daytime hypercapnia and/or hypoxemia. All but one had sleep apnea (apnea-hypopnea index > or =5 events/h of sleep; mild in five, moderate in seven, and severe in four). Hypopneas were more common than apneas (16.9 +/- 13.2 events/h vs. 4.6 +/- 4.1 events/h). Nocturnal desaturation episodes were very frequent (oxygen desaturation index, 19.7 +/- 20.3/h of sleep). Three patients had central sleep apnea and 13 had obstructive sleep apnea. Body mass index, spirometry parameters (FVC and FEV1) and arterial oxygen tension were moderately correlated with nocturnal oxygenation parameters. Apnea-hypopnea index showed moderate correlation with spirometry parameters (FVC and FEV1).
Sleep apnea and oxygen desaturations are very common in MD patients who report no excessive daytime sleepiness. Daytime lung function parameters are not sufficiently reliable for screening sleep apnea. Therefore, we recommend routine polysomnography in MD patients.
Conference Paper: Large-scale computations for high dimensional control systems[Show abstract] [Hide abstract]
ABSTRACT: We investigate a multiplexing communications system, with many independent users competing for space in the transmitter buffer. The control consists in the deletion of selected low priority cells, or various formally equivalent forms. Under reasonable conditions, such systems can be approximated by diffusion type processes. This approximation is the basis of numerical methods for the associated control problems, which are generally much simpler than what one would have by working directly with the original system. Markov chain approximations are used. They have the structure of the original problem, but are generally much simpler. The numerical data shows that performance can be greatly improved over standard operating procedures by the use of optimal controls or reasonable approximations to them. Details algorithms for 4D control problems are discussed. For high dimensional models, the numerical approximation might have millions of states. One needs to compute quantities which are the equivalent of probabilities of the order of 10<sup>-6</sup> or smaller. Once the basic form of the mathematical algorithm is fixed, efficiency in coding is essential. General software codes are discussed. The effectiveness of multigrid-type solution methods is demonstrated as well its limitations. We also investigate the performance of dynamic memory allocationDecision and Control, 1994., Proceedings of the 33rd IEEE Conference on; 01/1995
Conference Paper: A low torque ripple PMSM drive for EPS applications[Show abstract] [Hide abstract]
ABSTRACT: This paper describes the practical design considerations of a low torque ripple permanent magnet synchronous motor (PMSM) drive for electric power steering (EPS) application. The impact of various controller elements on torque ripple performance is discussed in detail. The experimental results show that the low cost dc-link current sensing scheme used in the design can achieve excellent and consistent torque ripple performance (less than 2% peak-to-peak at 1 N.m.), and is well suited for EPS application.Applied Power Electronics Conference and Exposition, 2004. APEC '04. Nineteenth Annual IEEE; 02/2004
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ABSTRACT: The purposes of the study are: (1) to establish if cephalometry and upper airway examination may provide tools for detecting facioscapulohumeral (FSHD) patients at risk for obstructive sleep apnea syndrome (OSAS); and (2) to correlate cephalometry and otorhinolaryngologic evaluation with clinical and polysomnographic features of FHSD patients with OSAS. Patients were 13 adults affected by genetically confirmed FSHD and OSAS, 11 men, with mean age 47.1 ± 12.8 years (range, 33-72 years). All underwent clinical evaluation, Manual Muscle Test, Clinical Severity Scale for FSHD, Epworth Sleepiness Scale, polysomnography, otorhinolaryngologic evaluation, and cephalometry. Cephalometric evidence of pharyngeal narrowing [posterior airways space (PAS) < 10 mm] was present in only one patient. The mandibular planus and hyoid (MP-H) distance ranged from 6.5 to 33.1 mm (mean, 17.5 ± 7.8 mm). The mean length of soft palate (PNS-P) was 31.9 ± 4.8 mm (range, 22.2 to 39.7 mm). No patient presented an ANB angle > 7°. There was no significant correlation between cephalometric measures, clinical scores, and PSG indexes. PAS and MP-H were not related to the severity of the disease. Upper airway morphological evaluation is of poor utility in the clinical assessment of FSHD patients and do not allow to predict the occurrence of sleep-related upper airway obstruction. This suggests that the pathogenesis of OSAS in FSHD is dependent on the muscular impairment, rather than to the anatomy of upper airways.Sleep And Breathing 02/2010; 15(1):99-106. DOI:10.1007/s11325-010-0330-y · 2.87 Impact Factor