The EEGs and cognitive responses during a go-no go Continuous Performance Test (CPT) were studied in two groups of 58 epileptic and 20 healthy control chiuldren, ages 8 to 12 years, at the Hospital Civil de Guadalajara, Mexico. Paroxysmal discharges occurred in 88% of the epileptic compared to 5% of the control group. Transitory cognitive impairments (TCI) with higher numbers of behavioral errors and longer reaction times were detected in 36% of the epilepsy patients, in the absence of clinical seizures. TCI was correlated with the frequency and duration of paroxysmal discharges, occurring with discharges at more than 5 per second and lasting longer than 500 ms. [1]
COMMENT. The epileptic paroxysm, even without clinical seizure, can be associated with transitory cognitive impairment. Treatment of epilepsy may need to focus on control of EEG epileptiform discharges in addition to control of seizures.
Hirsch E and colleagues (Strasbourg, France) report a significant relationship between a slow EEG focus and neuropsychological impairment, in a prospective study of 18 children with benign epilepsy with centro-temporal spikes (BECTS). Low performance on Koh’s cube and WISC coding test correlate with the amount of spike and wave on sleep EEGs. [2]
Caplan R et al (UCLA, CA) studied thought disorder in 92 children with complex partial seizures (CPS), 51 with petit mal (PGE), and in 117 normal children, ages 5 to 16 years. The CPS group had more severe thought disorder and cognitive impairments than the PGE group. EEG evidence of fronto-temporal dysfunction in children with CPS was associated with thought disorder as well as global cognitive dysfunction. In the PGE group, thought disorder was related to poor seizure control and cognitive dysfunction. [3]