Abstract
The incidence and the degree of P300 abnormalities in relation to psychometric findings
was assessed in two groups of long-term survivors of acute lymphoblastic leukemia
(ALL) in childhood. The study was performed as part of a follow-up trial, evaluating
CNS late-effects after antileukemic therapy, 7.1 ± 1.6 years after cessation of antileukemic therapy. Subject groups differed primarily
in terms of antileukemic CNS prophylaxis: combined radio-and chemotherapy (n = 8)
vs. chemotherapy alone (n = 5). Results were compared with those of a third group
of healthy controls (n = 13) matched for age and gender. P300 recordings were obtained
during a visual oddball-paradigm using checkerboard reversal stimuli of different
pattern sizes as target and background events. Neurophysiological data were correlated
with the results of a psychological test battery, which measured general intelligence,
non-verbal visual memory functioning and concentration. ERP analysis showed a significant
prolongation of the P300 latency in irradiated subjects when compared to healthy controls
and non-irradiated long-term survivors. Topographical data comparisons revealed substantial
P300 differences in both ALL long-term survivor groups when compared with healthy
controls. This demonstrated significantly lower amplitudes over the left frontal derivations,
associated with lowered concentration abilities, in the irradiated subject group.
Higher amplitudes over the parieto-temporal derivations of the right hemisphere, associated
with significantly impaired visual memory capabilities, were seen in both long-term
survivor groups.
Key words
Children - Acute lymphoblastic leukemia - Antileukemic therapy - CNS late-effects
- P300
