Evaluation of sleepiness in epilepsy

Excessive daytime sleepiness often complicates the clinical picture of epilepsy, facilitating the occurrence of seizures and aggravating cognitive disabilities and/or behavioral problems. Thus it further adversely affects social and working activities of epileptic subjects. Both unstructured and structured clinical reports documented a not negligible proportion of epilepsy patients suffering from excessive daytime sleepiness. Studies based on neurophysiological testing such as Multiple Sleep Latency Test or Maintenance Wakefulness Test revealed a degree of daytime sleepiness tendency in epilepsy patients greater than that they subjectively estimate. Antiepileptic drugs play a remarkable role in determining drowsiness in epilepsy patients and they are generally viewed as the only cause of sleepiness in these patients. However excessive daytime sleepiness has been documented in epilepsy patients before starting any drug treatment or after its discontinuation. Both clinical and neurophysiological studies have clearly documented the possible role of seizure occurrence and of co-morbidity as determinants of excessive daytime sleepiness in epilepsy patients. Nocturnal sleep fragmentation and daytime sleepiness have been reported in temporal lobe and frontal lobe epilepsy, namely nocturnal frontal lobe epilepsy. Some recent reports have stressed that obstructive sleep apnea and periodic limb movements during sleep can significantly account for sleepiness complaints in epilepsy patients; most of the antiepileptic drugs can worsen obstructive sleep apnea. To date the evaluation of daytime sleepiness of epilepsy patients in clinical practice has been based mainly or exclusively on clinical reports. To improve our understanding of this symptom in epilepsy patients, the use of standardized sleepiness scales should be encouraged. Patients with persistent daytime sleepiness without a clear cause-and-effect relationship with antiepiletic drugs treatment or in whom a coincident sleep pathology is suspected, should be investigated by means of neurophysiological testing such as Multiple Sleep Latency Test or Maintenance Wakefulness Test.