Seizure frequency, patient-perceived seizure severity and the psychosocial consequences of intractable epilepsy.

It is generally recognised that the assessment of treatment effects in epilepsy using seizure frequency as the only outcome measure may lack sensitivity. A patient-based seizure severity scale has been developed and initial results confirm its reliability and validity. As part of the further development of this scale it is important to explore the relationship between seizure severity, seizure frequency and the psychosocial consequences of intractable epilepsy. One hundred patients with medically refractory partial seizures completed a quality of life questionnaire including measures of physical (seizure severity and frequency), social and psychological well-being (anxiety, depression, self-esteem, locus of control and happiness). Multivariate analysis demonstrated that individual psychological variables were best predicted by other psychological variables. However, when these were removed from analysis, seizure severity was the most significant predictor of self-esteem (P = 0.005), locus of control P = 0.039) and anxiety (P = 0.048). Seizure frequency did not contribute significantly to the variance of any of the psychological factors. These results highlight the importance of considering seizure severity when assessing treatment effects in epilepsy and provide further evidence for the construct validity of a novel patient-based seizure severity scale.