EEG and clinical changes in patients with chronic seizures associated with slowly growing brain tumors
J. R. Hughes and S. M. Zak
The goal of this study was to define the electroencephalographic (EEG) and
clinical features in 25 patients with chronic seizures (szs) associated
with slowly growing (three to 36 years) brain tumors (BTs). A matched
control group was also studied. When all EEGs were considered together
without regard to their changes, no significant differences were found
between the two groups, especially with respect to the high incidence (60%)
of EEG abnormalities both ipsilateral and contralateral to the tumor. Exact
localization of the BT by EEG (within one electrode) was found in 88% of
patients. When changes in time were considered, the BT group more often
showed increasing slow waves, increasing sharp-wave discharges, depression
of normal rhythms, a change in type of sz, increase in frequency of szs,
and a change in neurological signs and symptoms, especially motor. For
single, double, or triple criteria, a change in clinical signs was the most
discriminative, with a deteriorating EEG as the next best indication of a
tumor. Patients with the latter signs should then be selected for a
computed tomographic or magnetic resonance imaging scan, even if the scan
was normal initially, rather than following the expensive policy that all
patients at all ages with chronic szs should undergo these later tests.
