Objectives. To assess the relationship between nocturnal polysomnographic (PSG) findings and a group of key self-reported symptoms—fatigue, tiredness, lack of energy, and sleepiness—among sleep-laboratory referred patients with and without multiple sclerosis (MS). Methods. PSG and questionnaire data from MS patients and matched controls were analyzed retrospectively. Associations between symptoms of fatigue, tiredness, lack of energy, sleepiness, and PSG variables of interest were examined among MS patients and controls. Results. More MS patients than controls reported fatigue, tiredness, and lack of energy to occur often or almost always (Chi-square for each), but sleepiness was reported similarly by both groups ( ). Among MS patients, tiredness correlated with sleepiness (Spearman correlation ), and a trend emerged toward correlation between fatigue and sleepiness (Spearman correlation ). Decreased sleep efficiency on PSGs correlated with fatigue, tiredness, and lack of energy in MS patients (Spearman correlation , 0.029, and 0.048, resp.), but not sleepiness or any symptom among controls. Conclusion. In comparison to controls, MS patients report more fatigue, tiredness, and lack energy, but not sleepiness. Fatigue and related symptoms may arise from MS itself or in relation to reduced sleep efficiency. 1. Introduction Multiple sclerosis (MS) is an autoimmune disease of the central nervous system that causes myelin destruction and axonal damage in the brain and spinal cord. It is the leading cause of nontraumatic neurological disability among young adults and is associated with a variety of debilitating symptoms, including fatigue. Fatigue is the most common symptom experienced by persons with MS, affecting up to 90% of patients at some point in their disease course [1–3]. Fatigue imposes significant socioeconomic consequences, including loss of work hours and employment [4], and is a prominent cause of diminished quality of life among individuals with MS [3]. Despite its prevalence in MS as well as other medical conditions, there is no unified definition for fatigue. Consequently, there is potential for considerable overlap between fatigue and other subjective terms commonly used by MS patients to describe lack of energy or alertness, including sleepiness. Sleep disorders are traditionally recognized for their contributions to excessive daytime sleepiness. However, many subjects in the general population who have sleep disorders such as obstructive sleep apnea report that problems with fatigue, tiredness, or lack of energy supersede problems with
References
[1]
L. Krupp, “Fatigue is intrinsic to multiple sclerosis (MS) and is the most commonly reported symptom of the disease,” Multiple Sclerosis, vol. 12, no. 4, pp. 367–368, 2006.
[2]
A. Lerdal, E. G. Celius, L. Krupp, and A. A. Dahl, “A prospective study of patterns of fatigue in multiple sclerosis,” European Journal of Neurology, vol. 14, no. 12, pp. 1338–1343, 2007.
[3]
V. Janardhan and R. Bakshi, “Quality of life in patients with multiple sclerosis: the impact of fatigue and depression,” Journal of the Neurological Sciences, vol. 205, no. 1, pp. 51–58, 2002.
[4]
M. M. Smith and P. A. Arnett, “Factors related to employment status changes in individuals with multiple sclerosis,” Multiple Sclerosis, vol. 11, no. 5, pp. 602–609, 2005.
[5]
R. D. Chervin, “Sleepiness, fatigue, tiredness, and lack of energy in obstructive sleep apnea,” Chest, vol. 118, no. 2, pp. 372–379, 2000.
[6]
W. Chotinaiwattarakul, L. M. O'Brien, L. Fan, and R. D. Chervin, “Fatigue, tiredness, and lack of energy improve with treatment for OSA,” Journal of Clinical Sleep Medicine, vol. 5, no. 3, pp. 222–227, 2009.
[7]
T. J. Braley, B. M. Segal, and R. D. Chervin, “Sleep-disordered breathing in multiple sclerosis,” Neurology, vol. 79, no. 9, pp. 929–936, 2012.
[8]
C. Iber and American Academy of Sleep Medicine, The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications, American Academy of Sleep Medicine, Westchester, Ill, USA, 2007.
[9]
M. W. Johns, “A new method for measuring daytime sleepiness: the Epworth sleepiness scale,” Sleep, vol. 14, no. 6, pp. 540–545, 1991.
[10]
J. F. Kurtzke, “Rating neurologic impairment in multiple sclerosis: an expanded disability status scale (EDSS),” Neurology, vol. 33, no. 11, pp. 1444–1452, 1983.
[11]
A. Rechtshaffen and A. Kales, A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects, Brain Information Service/Brain Research Institute, UCLA, Los Angeles, Calif, USA, 1968.
[12]
“Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. The report of an American Academy of Sleep Medicine Task Force,” Sleep, vol. 22, no. 5, pp. 667–689, 1999.
[13]
M. Kaminska, R. Kimoff, A. Benedetti, et al., “Obstructive sleep apnea is associated with fatigue in multiple sclerosis,” Multiple Sclerosis, vol. 18, no. 8, pp. 1159–1169, 2012.
[14]
L. B. Krupp, N. G. LaRocca, J. Muir-Nash, and A. D. Steinberg, “The fatigue severity scale. Application to patients with multiple sclerosis and systemic lupus erythematosus,” Archives of Neurology, vol. 46, no. 10, pp. 1121–1123, 1989.
[15]
J. P. Neau, J. Paquereau, V. Auche, et al., “Sleep disorders and multiple sclerosis: a clinical and polysomnography study,” European Neurology, vol. 68, no. 1, pp. 8–15, 2012.
[16]
J. D. Fisk, A. Pontefract, P. G. Ritvo, C. J. Archibald, and T. J. Murray, “The impact of fatigue on patients with multiple sclerosis,” Canadian Journal of Neurological Sciences, vol. 21, no. 1, pp. 9–14, 1994.
[17]
D. J. Buysse, C. F. Reynolds III, T. H. Monk, S. R. Berman, and D. J. Kupfer, “The Pittsburgh sleep quality index: a new instrument for psychiatric practice and research,” Psychiatry Research, vol. 28, no. 2, pp. 193–213, 1989.
[18]
H. Kaynak, A. Altinta？, D. Kaynak et al., “Fatigue and sleep disturbance in multiple sclerosis,” European Journal of Neurology, vol. 13, no. 12, pp. 1333–1339, 2006.
[19]
C. Veauthier, H. Radbruch, G. Gaede, et al., “Fatigue in multiple sclerosis is closely related to sleep disorders: a polysomnographic cross-sectional study,” Multiple Sclerosis, vol. 17, no. 5, pp. 613–622, 2011.
[20]
C. Heesen, L. Nawrath, C. Reich, N. Bauer, K. H. Schulz, and S. M. Gold, “Fatigue in multiple sclerosis: an example of cytokine mediated sickness behaviour?” Journal of Neurology, Neurosurgery and Psychiatry, vol. 77, no. 1, pp. 34–39, 2006.
[21]
P. Flachenecker, I. Bihler, F. Weber, M. Gottschalk, K. V. Toyka, and P. Rieckmann, “Cytokine mRNA expression in patients with multiple sclerosis and fatigue,” Multiple Sclerosis, vol. 10, no. 2, pp. 165–169, 2004.
[22]
A. N. Vgontzas, E. Zoumakis, H. M. Lin, E. O. Bixler, G. Trakada, and G. P. Chrousos, “Marked decrease in sleepiness in patients with sleep apnea by etanercept, a tumor necrosis factor-α antagonist,” Journal of Clinical Endocrinology and Metabolism, vol. 89, no. 9, pp. 4409–4413, 2004.
[23]
A. N. Vgontzas, E. O. Bixler, H. M. Lin, P. Prolo, G. Trakada, and G. P. Chrousos, “IL-6 and its circadian secretion in humans,” NeuroImmunoModulation, vol. 12, no. 3, pp. 131–140, 2005.
[24]
A. Hegglin, O. D. Schoch, W. Korte, K. Hahn, C. Hürny, and T. Münzer, “Eight months of continuous positive airway pressure (CPAP) decrease tumor necrosis factor alpha (TNFA) in men with obstructive sleep apnea syndrome,” Sleep and Breathing, vol. 16, no. 2, pp. 405–412, 2012.
[25]
P. Steiropoulos, N. Papanas, E. Nena et al., “Inflammatory markers in middle-aged obese subjects: does obstructive sleep apnea syndrome play a role?” Mediators of Inflammation, vol. 2010, Article ID 675320, 6 pages, 2010.
[26]
R. D. Chervin, M. S. Aldrich, R. Pickett, and C. Guilleminault, “Comparison of the results of the Epworth sleepiness scale and the multiple sleep latency test,” Journal of Psychosomatic Research, vol. 42, no. 2, pp. 145–155, 1997.
[27]
R. D. Chervin, H. C. Kraemer, and C. Guilleminault, “Correlates of sleep latency on the multiple sleep latency test in a clinical population,” Electroencephalography and Clinical Neurophysiology, vol. 95, no. 3, pp. 147–153, 1995.
