Electroencephalographic and clinical changes in an epileptic child during repeated photic stimulation

Abstract

1. 1. A case of intractable petit mal epilepsy is described in a 9-year-old girl. 2. 2. An attempt was made to effect an alteration in the child's bioelectric activity by repeated application of a visual stimulus (intermittent bursts of photic stimulation) whenever spike and wave paroxysms were present in the EEG. This procedure was carried out for a 0.5 h period on 16 days. 3. 3. EEG alterations were observed, in the form of a redistribution of spike and wave activity during the recording period, but the absolute number of spike and wave complexes in successive EEGs was not significantly affected. The EEG changes were accompanied by a marked behavioural change, the paroxysmal spike and wave complexes being accompanied gradually less often by any clinical manifestation. This was parallelled by a general clinical improvement in all other hospital situations. 4. 4. Examination of background activity showed that alpha and beta rhythms remained relatively constant during the 16 day period: the amount of activity in the theta and delta bands progressively fell; variability in theta and delta voltage was also reduced. 5. 5. In follow-up, the child's clinical condition has shown a number of fluctuations but in general she has maintained excellent progress. 6. 6. Brief mention is made of possible mechanisms which may have played a part in the changes.