Fatigue, Tiredness, Lack of Energy, and Sleepiness in Multiple Sclerosis Patients Referred for Clinical Polysomnography

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 n = 30 MS patients and n = 30 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 P < 0.0001 for each), but sleepiness was reported similarly by both groups (P = 0.3409). Among MS patients, tiredness correlated with sleepiness (Spearman correlation P = 0.005), and a trend emerged toward correlation between fatigue and sleepiness (Spearman correlation P = 0.076). Decreased sleep efficiency on PSGs correlated with fatigue, tiredness, and lack of energy in MS patients (Spearman correlation P = 0.002, 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.