Few studies have looked at quantitative differences in the responses to each ESS question across different disease states. The ESS is a validated tool measuring excessive daytime sleepiness (EDS). The aim of this study is to assess differences to individual ESS questions in subjects presenting to a sleep clinic for evaluation of a sleep complaint by analyzing ESS scores 0–9 and 10–24 in different disease states.
Retrospective analysis of patients 15 years or older undergoing a baseline PSG was performed and two groups evaluated: those with ESS scores 0–9 and 10–24. The ESS was administered prior to the baseline PSG. The distribution of ESS scores are analyzed by ICD-9 diagnosis codes determined at the time of PSG interpretation. Disease states that were evaluated included: obstructive sleep apnea, hypersomnia, insomnia and normal PSG. Subjects were referred to a sleep center at a SleepMed site in the US between January 1, 2008 and December 31, 2008.
In 10136 subjects studied there were 48% female and 52% males. Each group studied included: OSA = 9154; hypersomnia 153; insomnia = 167; and normal PSG = 662. Means and standard deviations are: age = 52(15); BMI = 34(9); arousal index = 13(10); PLMS = 8(20); ESS score = 10(6). For groups with ESS scores 0–10, median scores for each ESS question were: #1 = 1; #2 = 1; #3 = 0; #4 = 0 except for insomnia group = 0.5; #5=1 except for OSA group = 2; #6–8 = 0.For groups with ESS scores 10–24 median scores for each ESS question were: question #1 = 2 except hypersomnia=3; #2 = 2; #3 = 2; #4 = 2 except hypersomnia and insomnia=3; #5 = 3; #6 = 1; #7 = 2: #8 = 0 except normals and hypersomnia=1.
Factor analysis of EDS has similar characteristics across disease states based on ESS scores. Those patients with marked elevation of ESS scores are more likely to have higher scores overall to each question and symptoms of driving impairment related to question #8.
Further research with the tool could be undertaken to determine if additional questions may be needed for more careful assessment of driving impairment which may be under-reported by some patients.
Richard Bogan, No Financial Disclosure Information; No Product/Research Disclosure Information