Assessment of drowsiness in epilepsy patients receiving chronic antiepileptic drug therapy.
Drowsiness is a common complaint among patients with epilepsy taking antiepileptic drugs (AEDs) and may be of particular importance because of the potential effects on cognitive abilities. We used a novel EEG-based measure (the Awake Maintenance Task, AMT) to determine objectively whether patients on chronic, stable AED therapy had impaired ability to maintain wakefulness. Thirty patients receiving AEDs [carbamazepine (CBZ), phenytoin (PHT), phenobarbital (PB), valproate (VPA)] were compared to 35 healthy controls, 12 seizure patients not taking AEDs, and 16 patients with multiple sclerosis. A structured EEG recording was conducted under controlled conditions, and subjects were tested to determine their ability to maintain wakefulness during a 6-min unstimulated trial. Testing also included Digit Symbol, auditory reaction time, and subjective measures of fatigue or sleepiness [Profile of Mood States (POMS), Stanford Sleepiness Scale (SSS)]. Patients receiving AEDs had a mean total drowsiness score of 101 s compared with < or = 12 s for each of the three control groups (P < 0.001). One third of the AED-treated patients had > 120 s of drowsiness, in contrast to only 1 of 63 controls (p < 0.001). Among patients receiving AEDs, objective EEG drowsiness did not correlate with AED levels or performance measures. Untreated seizure patients had significantly greater complaints of lack of vigor despite a near absence of objective drowsiness on the AMT. These results suggest that epilepsy patients receiving chronic AED therapy have impaired ability to maintain wakefulness. Patient self-reports of AED-related sleepiness may not accurately represent this problem.
Salinsky
M C
MC
Department of Neurology, Portland Veterans Affairs Medical Center, Oregon, USA.
Oken
B S
BS
Binder
L M
LM
D000328:Adult; D000367:Age Factors; D000927:Anticonvulsants / Q000009:adverse effects* / Q000494:pharmacology; D002220:Carbamazepine / Q000009:adverse effects / Q000494:pharmacology; D004569:Electroencephalography / Q000187:drug effects*; D004827:Epilepsy / Q000188:drug therapy* / Q000523:psychology; D006801:Humans; D008875:Middle Aged; D010634:Phenobarbital / Q000009:adverse effects / Q000494:pharmacology; D010672:Phenytoin / Q000009:adverse effects / Q000494:pharmacology; D011569:Psychiatric Status Rating Scales; D011581:Psychological Tests / Q000706:statistics & numerical data*; D012894:Sleep Stages / Q000502:physiology; D014635:Valproic Acid / Q000009:adverse effects / Q000494:pharmacology; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology
D000927:Anticonvulsants; D002220:Carbamazepine; D014635:Valproic Acid; D010672:Phenytoin; D010634:Phenobarbital