Neurophysiological basis of cognitive deficits in long-term survivors of childhood cancer
B. D. Moore 3rd, D. R. Copeland, H. Ried and B. Levy
Division of Pediatrics, University of Texas M. D. Anderson Cancer Center, Houston 77030.
Thirty-three survivors of childhood cancer were tested with event-related
potentials (P300), motor reaction time tests, and neuropsychological tests
to assess the underlying physiological basis of treatment-related cognitive
sequelae. Thirteen patients had received intrathecal chemotherapy, 11 had
received intrathecal chemotherapy plus cranial radiotherapy, and nine had
been treated without any form of central nervous system therapy.
Neuropsychological performance of the groups treated without cranial
radiotherapy was normal, but the group given cranial radiotherapy was
significantly impaired. Mean reaction time and P300 latency were somewhat
slower in the group given intrathecal chemotherapy relative to the group
given no central nervous system treatment, but were significantly delayed
in the group given cranial radiotherapy. Correlations of reaction time and
P300 latency with neuropsychological test scores were also obtained.
Results suggest that slowing of cortical activity secondary to white-matter
damage may underlie cognitive decline in children treated with intensive
central nervous system therapies, especially cranial radiotherapy.
