Brief Communication Accuracy of portable polygraphy for the diagnosis of sleep apnea in multiple system atrophy Wassilios G. Meissner a,b,c,d,⇑ , Olivier Flabeau b , Paul Perez e , Jacques Taillard f,g , Fabienne Marquant e , Sandrine Dupouy a,b , François Tison a,b,c,d , Pierre Philip f,g , Imad Ghorayeb c,d,h a Centre de référence atrophie multisystématisée, CHU de Bordeaux, Pessac, France b Service de Neurologie, CHU de Bordeaux, Pessac, France c Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France d CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France e CHU de Bordeaux, Unité de Soutien Méthodologique à la Recherche Clinique (USMR), Pôle de santé publique, Bordeaux, France f Université Bordeaux, Sommeil, Attention et Neuropsychiatrie, USR 3413, Bordeaux, France g CNRS, Sommeil, Attention et Neuropsychiatrie, USR 3413, Bordeaux, France h Department of Clinical Neurophysiology, University Hospital Bordeaux, France article info Article history: Received 7 September 2013 Received in revised form 20 November 2013 Accepted 8 December 2013 Available online 21 February 2014 Keywords: Atypical parkinsonism Striatonigral degeneration Olivopontocerebellar atrophy Autonomic Respiratory Polysomnography abstract Objective: To assess the diagnostic accuracy of portable polygraphy (PG) for the detection of sleep apnea (SA) in multiple system atrophy (MSA). Methods: Thirty consecutive patients with probable MSA underwent PG (overnight recording of nasal flow, thoracic/abdominal movements and pulse oximetry), followed 4 weeks later by full polysomnogra- phy (PSG) (reference standard). The accuracy of PG was first assessed using the same threshold as for PSG (apnea–hypopnea index [AHI] P 5), then for all possible AHI thresholds using the area under the receiver operating characteristics (AUROC) curve. Inter-rater reliability of PG was assessed using the kappa coef- ficient. Results: Among 30 patients enrolled, seven were excluded for technical problems on PG or PSG and 23 were included in the main analysis. Eight out of 23 had an AHI P 5 on PSG. With the same threshold, sensitivity, specificity, positive and negative predictive values of PG for the diagnosis of SA were 87.5% (95% confidence interval: 47–99), 80% (52–96), 70% (35–93) and 92.3% (64–99), respectively. The kappa between PG raters was 0.75 (0.49–1.00) indicating good agreement. The AUROC was 0.93 (0.82–1.00). No association was found between sleep and excessive daytime sleepiness questionnaires and SA. Conclusion: Portable PG seems to be valuable for ruling out SA in MSA. Ó 2014 Elsevier B.V. All rights reserved. 1. Introduction Multiple system atrophy (MSA) is a relentlessly progressive neurodegenerative disorder leading to severe motor disability and death after nine years from symptom onset [1]. Autonomic failure is a prominent feature of MSA and may present with breathing disorders including sleep apnea (SA); the latter occurs in 15–69% of patients (overall mean prevalence of previous studies is 45% and 39% when considering those with unbiased recruitment) [2–8]. Breathing disorders may develop at any stage and the presence of nocturnal stridor is associated with a poor prognosis in MSA [8]. Moreover, around 20% of MSA patients suc- cumb to nocturnal sudden death which may be related to stridor or other respiratory disturbances including sleep apnea [9]. SA is mostly obstructive, and is mixed or central in some MSA patients [2–8]. Continuous positive airway pressure has been suggested as an effective therapy for SA without distinguishing between central, obstructive or mixed origins [7,10,11]. Limited availability and related cost restrict the systematic use of reference standard full polysomnography (PSG) for SA screening in MSA. Whereas portable polygraphy (PG) can be easily performed at home, its diagnostic accuracy in MSA patients is unknown. The primary objective of this study was the estimation of the accuracy of PG compared with PSG in the diagnosis of SA. The secondary, exploratory objective was to assess the association between http://dx.doi.org/10.1016/j.sleep.2013.12.013 1389-9457/Ó 2014 Elsevier B.V. All rights reserved. ⇑ Corresponding author at: Department of Neurology, University Hospital Bordeaux, Avenue Magellan, 33604 Pessac cedex, France. Tel.: +33 5 57 65 64 61; fax: +33 5 57 65 66 97. E-mail address: wassilios.meissner@chu-bordeaux.fr (W.G. Meissner). Sleep Medicine 15 (2014) 476–479 Contents lists available at ScienceDirect Sleep Medicine journal homepage: www.elsevier.com/locate/sleep