We would like to comment on the work by Derry et al1 on distinguishing sleep disorders from nocturnal frontal lobe epilepsy (NFLE). The authors constructed a scale based on specific clinical questions to distinguish a sleep disorder from NFLE. It is certainly possible to reach a diagnosis based in the clinical history alone. However, we want to comment on some aspects of the scale. For example, 1 of the questions uses a cut-off age at onset of younger than 55 years. The onset of symptoms in patients older than 55 years may suggest rapid eye movement (REM) sleep behavior disorder (RBD), according to the authors. However, individuals who are taking selective serotonin reuptake inhibitors may have increased tone during REM sleep and be susceptible to RBD.2 These patients may be younger than those with idiopathic RBD but will be misclassified using the scale.
Rodriguez AJ, Kuzniecky RI. Scale for Distinguishing Sleep Disorders From Seizures. Arch Neurol. 2007;64(8):1206. doi:10.1001/archneur.64.8.1206-a