Abstracts

Increased Right Anterior Temporal and Lateral Frontal Slow-Wave Resting Brain Activation in Patients with Right TLE.

Abstract number : 2.030
Submission category :
Year : 2001
Submission ID : 2302
Source : www.aesnet.org
Presentation date : 12/1/2001 12:00:00 AM
Published date : Dec 1, 2001, 06:00 AM

Authors :
D.C. Jackson, MS, Psychology, University of Wisconsin - Madison, Madison, WI; C.A. Burghy, BA, Psychology, University of Wisconsin, Madison, WI; B.P. Hermann, PhD, Neurology, University of Wisconsin, Madison, WI; M. Seidenberg, PhD, Psychology, Finch Univ

RATIONALE: Some patients with temporal lobe epilepsy (TLE) exhibit disruption of frontal lobe, as well as temporal lobe, metabolic and neuropsychological functioning. In the current study, resting baseline EEG was assessed for 26 TLE patients. In patients with either a primarily left or right-sided temporal lobe seizure focus, the laterality and focality of slow-wave activity was examined.
METHODS: Twenty-six patients with a history of complex partial seizures of definite or probable temporal lobe origin participated in a research protocol, which included 128-channel EEG and a comprehensive neuropsychological assessment. Patients previously had been classified as having a left or right-sided seizure focus on the basis of interictal or ictal clinical EEG. Each patient participated in a session in which eight one-minute baseline periods (four eyes-open, four eyes-closed) of 128-channel EEG data were recorded using the Geodesic Sensor Net. Patients were instructed to simply relax and attempt to minimize head and eye movement during each recording period. Power density values (delta, theta, alpha, beta) were computed using whole-head average reference. Data from multiple scalp sites were aggregated across channels to yield reliable estimates of activity corresponding to standard 10-20 sites.
RESULTS: T tests assessed differences in slow-wave activity in the delta (1-4 Hz), theta (4-8 Hz), and alpha (8-13 Hz) bands. Differences were found in the delta band for right-sided lateral frontal (F8) and anterior temporal (T4) sites. Patients with right TLE had significantly more right-sided delta activity at both sites than did patients with left TLE. Such differences were not found in other bands, nor were they were found at other sites for any band.
CONCLUSIONS: Anatomical/functional abnormalities may be reflected in increased extreme slow-wave activity. In this study, right TLE indeed was associated with increased right-sided delta activity in specific frontal and anterior temporal brain regions. This activity may have both neuropsychological and affective correlates among TLE patients. Future research will examine the relationship between this focal pattern of brain activation and neuropsychological functioning in TLE.
Support: NIH and NIMH grants NS37738, MH00875, MH40747, P50-MH52354, and T32-MH18931