Neuropsychological Correlates of the Electroencephalogram in Epileptics: II. The Waking Posterior Rhythm and its Interaction with Epileptiform Activity

Abstract

Relationships between psychological functions and waking dominant posterior rhythm frequency (DPRF) of the EEG were evaluated with and without simultaneous evaluation of epileptiform discharges. Ninety adult epileptics with uncontrolled seizure disorders treated solely by diphenylhydantoin underwent EEGs during wakefulness and administrations of an extensive battery of neuropsychological tests. The DPRF was particularly related to abilities simultaneously requiring attention an complex mental manipulations. Rhythms slower than 7.5-8.0 Hz were accompanied by relatively poorer performance than rhythms which were faster. When epileptiform discharges were considered in combination with the DPRF, larger differences in abilities were demonstrated, and the psycholoigcal correlates tended to be more substantial for the epileptiform discharge variable than for the DPRF variable. The selection of tests employed and the range of rhythms assessed are critical to these findings, and the substantial construction of these variables by many previous investigators is believed to be related to the negative findings often reported.

Changes in Intelligence Following Temporal Lobectomy: Relationship to EEG Activity, Seizure Relief, and Pathology

“…The results presented here confirm for temporal lobe epileptics the findings of Wilkus and Dodrill (1976) and Dodrill and Wilkus (1976), which demonstrated in a broader range of uncontrolled epileptics that interictal generalized surface discharges are associated with lower intelligence levels. The present data indicate that this relationship is unaffected by whether or not the bilaterally synchronous surface discharges are associated with simultaneous deep spikes.…”

Correlation of EEG with neuropsychological status in children with epilepsy

“…On the other hand, there is a (+, −) pattern in the alpha range with higher PIQ and fewer errors of omission. Although unexpected, this finding is not discordant with current literature, as most studies of the alpha band use frequency bins that are too coarse to discern these subtle shifts in sub-band power (e.g., see Dodrill, Wilkus, 1976; Schmid et al, 2002; Thatcher et al, 2005; Tedrus et al, 2006). …”

“…In adults with epilepsy, subjects with higher posterior alpha frequencies (8.8 to 11 Hz) perform better on neuropsychological measures than subjects with lower posterior frequencies (5.1 to 8.5 Hz) (Dodrill, Wilkus, 1976). In children with epilepsy associated with centrotemporal spikes, higher absolute delta power correlated negatively with performance IQ at the central, temporal, parietal and occipital channels bilaterally, and higher absolute theta correlated negatively with performance IQ in all channels except right central (Tedrus et al, 2006).…”

“…It is generally found that interictal epileptiform activity can cause transient cognitive impairment (TCI) for the duration of the epileptiform discharge (Schwab, 1939; Schwab, 1941; Goode et al, 1970), especially if the discharge lasts for 3 seconds or more, if it is generalized, or if the cognitive task is complex (Wilkus, Dodrill 1976; Dodrill, Wilkus, 1976; Aarts et al, 1984; Binnie et al, 1991; Holmes, Lenck-Santini, 2006; Fastenau, 2011). Some studies, however, find no correlation between interictal spikes and neuropsychological status (e.g., Fonseca et al, 2007).…”

“…In contrast, EEG-cognition studies in subjects without epilepsy have focused on other quantitative EEG measures, particularly frequency spectral analysis (Gasser et al, 1983; Benninger et al, 1984; Marosi et al, 1999; Schmid et al, 2002; Thatcher et al, 2005; Polunina and Davydov, 2006). Less is known about the relationship of EEG spectra to cognition in people with epilepsy, in either adults (Wilkus, Dodrill, 1976; Dodrill, Wilkus, 1976) or children (Tedrus et al, 2006). …”