Response to the letter regarding the impact of psychogenic nonepileptic seizures and our seizure assessment tool

I have reviewed the letter by Dr Villano and colleagues and appreciate the importance of distinguishing psychogenic nonepileptic seizures (PNES) from epileptic seizures (ES). As they adequately state, the incidence of PNES in patients with brain tumors is unknown. However, the incidence of seizures in brain tumor patients is well known and has been described.¹ Due to the high incidence of seizures in this population, ES are the primary concern. It is possible that some patients may harbor PNES and ES from tumor-associated epilepsy. Distinguishing these conditions would require video EEG and intensive monitoring of their habitual events, neither of which is feasible for routine use in our population. However, in the appropriate clinical situation, intensive video monitoring should be pursued to distinguish these 2 entities.

Primary endpoints of most brain tumor treatment trials evaluate progression-free survival and overall survival.² Historically, response to tumor treatment had been limited to radiographic response.³ New, secondary endpoints are being assessed, and seizures are an important endpoint to treatment. Our tool was not designed to identify patients with epilepsy or for the treatment of this condition. Rather, our tool was designed to assess seizure control as a metric for brain tumor treatment. For our purposes, patients enrolled in a clinical trial for the treatment of a brain tumor would have an a priori diagnosis of ES. With an established diagnosis of ES, the primary use of this tool will be to assess a response to treatment of a brain tumor.

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