Abstracts

Epilepsy is associated with multiple co-morbid disorders and complaints. Many of these relate to central nervous system dysfunction, like depression, excessive daytime sleepiness (EDS) and headache. Obstructive sleep apnea (OSA) is associated with EDS and is increased in patients with epilepsy. Antiepileptic medications (AED) are known to cause sedation and at times sleepiness and frequent seizures could cause sleepiness. The possibilities of interactions are many and the causes of patient complaints during office visits are often unclear. We set out to investigate some of these interactions and this report is the first step in the development of a model of interactions.
Information was collected through a questionnaire answered by adult patients attending to a specialized epilepsy center. The questionnaire contained validated scales that measure EDS (Epworth Sleepiness Scale), obstructive sleep apnea (Sleep Apnea part of Sleep Disorder Questionnaire), and depression (Beck Depression Index). Number of days with headache per month was also measured. Chart review recorded the number of seizures per month over the last year and the number of current antiepileptic medications (AED). In a uni-variant manner we analyzed the correlation between the different variables using Spearman Correlation. First EDS was dependent variable and depression, headache, OSA, seizure frequency, number of AED were independent variables. Thereafter depression was dependent variable and, headache, OSA, seizure frequency, number of AED were independent variables.
A total of 136 patients participated, of these 53 men and 83 women. Mean age was 38 years (range 17 to 70 years). Mean EDS score was 7.8 (range 0 to 23), mean OSA score was 4.2 (range 9 to 37), mean depression score was 8.3 (range 0 to 43). Average days with headache per month were 6.4 (range 0 to 30). Mean monthly seizure frequency was 4.3 (range 0 to 50) and average number of AED was 0.75 (range 0 to 5).
EDS correlated with depression (p [lt] 0.0001) and with OSA (p[lt]0.05). Headache showed a modest correlation with EDS (p[lt]0.10), but seizure frequency and number of AED did not predict EDS.
Depression correlated with headaches (p[lt]0.01) and with OSA (p[lt]0.001), but not with seizure frequency or number of AED.
We found that excessive daytime sleepiness, depression and headache are significant co-morbidities in patients with intractable epilepsy. Excessive daytime sleepiness and depression are frequently not related to seizure frequency or number of antiepileptic medications and in the patient who has these complaints other causes need to be investigated, like obstructive sleep apnea.
These complex interactions need further analysis.