LETTERTOTHEEDITOR Sleep disorders require a comprehensive evaluation and confirmation with polysomnography in patients with multiple sclerosis T. Ekiz a and A. C. Pazarli b a Department of Physical Medicine and Rehabilitation, Dermancan Medical Center, Adana, and b Department of Pulmonary Diseases, Elbistan State Hospital, Kahramanmaras, Turkey Correspondence: T. Ekiz, Dermancan Medical Center, Cukurova, 01012 Adana, Turkey (tel.: +90 322 231 22 24; fax: +90 322 231 22 28; e-mail: timurekiz@gmail.com). Keywords: central apnea, positive airway pressure treatment, polygraphy, polysomnography, sleep apnea syndrome doi:10.1111/ene.13284 Received: 5 February 2017 Accepted: 21 February 2017 To the editor, We read the article by Levy et al. [1] with great interest. The authors studied respiratory impairment in patients with multiple sclerosis (MS) by presenting pul- monary function tests and sleep parame- ters. We congratulate the authors on their successful study. However, we have a few key practice points that need to be clarified. The authors presented the sleep disor- ders by using respiratory polygraphy (PG). It has been established that PG cannot reliably assess the severity of sleep apnea. Therefore, PG is used as a screening method. The exact diagnosis of sleep apnea and type of sleep disor- der requires a comprehensive evaluation and confirmation with polysomnography (PSG) in a sleep laboratory [2,3]. Sleep apnea should be accepted as a chronic disease that can result in various compli- cations, even respiratory impairment, and it requires long-term follow-up and a multidisciplinary approach. According to the results of the PSG, positive air- way pressure (PAP) treatment, which can be delivered in continuous, bilevel or autotitrating modes, is an option for management [2]. However, auto-continu- ous PAP is contraindicated if there is central sleep apnea. The coexistence of MS and sleep apnea makes the clinical scenario more challenging. Previous studies have suggested that patients with MS are at increased risk of sleep disor- ders, not only obstructive but also cen- tral apnea [4]. In other words, PAP treatment is not given to patients with MS according to PG and blood gas results without performing PSG as in the study of Levy and colleagues. Again, the pressure applied in PAP treatment cannot be determined without titration. In addition, the body mass indices of patients, which are important for both sleep apnea and respiratory impairment, were not mentioned in this study. Obe- sity alone is the cause of the restrictive type of lung impairment [5]. Diaphragm problems can be seen in obese patients and can result in coughing and deterio- ration in secretion excretion. Accord- ingly, further studies considering the sleep apnea syndrome and respiratory impairment in patients with MS are awaited. Disclosure of conflicts of interest The authors declare no financial or other conflicts of interest. References 1. Levy J, Bensmail D, Brotier-Chomienne A, et al. Respiratory impairment in multiple sclerosis: a study of respiratory function in wheelchair-bound patients. Eur J Neurol 2017; 24: 497–502. 2. Epstein LJ, Kristo D, Strollo PJ Jr, et al.; Adult Obstructive Sleep Apnea Task Force of the American Academy of Sleep Medi- cine. Clinical guideline for the evaluation, management and long-term care of obstruc- tive sleep apnea in adults. J Clin Sleep Med 2009; 5: 263–276. 3. Qaseem A, Dallas P, Owens DK, Starkey M, Holty JE, Shekelle P; Clinical Guideli- nes Committee of the American College of Physicians. Diagnosis of obstructive sleep apnea in adults: a clinical practice guideline from the American College of Physicians. Ann Intern Med 2014; 161: 210–220. 4. Lin M, Krishnan AV, Eckert DJ. Central sleep apnea in multiple sclerosis: a pilot study. Sleep Breath 2016; doi: 10.1007/ s11325-016-1442-9. [Epub ahead of print]. 5. Robinson HC. Respiratory conditions update: restrictive lung disease. FP Essent 2016; 448: 29–34. EUROPEANJOURNALOFNEUROLOGY LETTERTOTHEEDITOR © 2017 EAN e28