Attention, processing speed, and executive functioning in pediatric brain tumor survivors treated with proton beam radiation therapy

Abstract

Background and purpose: This study examines attention, processing speed, and executive functioning in pediatric brain tumor survivors treated with proton beam radiation therapy (PBRT).

Material and methods: We examined 39 survivors (age 6-19years) who were 3.61years post-PBRT on average. Craniospinal (CSI; n=21) and focal (n=18) subgroups were analyzed. Attention, processing speed, and executive functioning scores were compared to population norms, and clinical/demographic risk factors were examined.

Results: As a group, survivors treated with focal PBRT exhibited attention, processing speed, and executive functioning that did not differ from population norms (all p>0.05). Performance in the CSI group across attention scales was normative (all p>0.05), but areas of relative weakness were identified on one executive functioning subtest and several processing speed subtests (all p<0.01).

Conclusions: Survivors treated with PBRT may exhibit relative resilience in cognitive domains traditionally associated with radiation late effects. Attention, processing speed, and executive functioning remained intact and within normal limits for survivors treated with focal PBRT. Among survivors treated with CSI, a score pattern emerged that was suggestive of difficulties in underlying component skills (i.e., processing speed) rather than true executive dysfunction. No evidence of profound cognitive impairment was found in either group.

Keywords: Cognitive late effects; Executive functioning; Pediatric brain tumor; Processing speed; Proton radiation therapy.

Fig. 1

Mean scores by PBRT group (CSI vs. Focal) on the Conners’ CPT-II scales. The solid line indicates the mean of 50.0 for the CPT-II normative sample. Scores above the dashed line (1.5 standard deviations above the normative mean) are generally considered indicative of clinical impairment. ^‡indicates trend association (p < 0.05 and FDR > 0.1). *indicates a statistically significant association (p < 0.001 and FDR < 0.1).

Fig. 2

Mean scores by PBRT group (CSI vs. Focal) on the D-KEFS Color Word Interference subtests. The solid line indicates the mean of 10.0 for the D-KEFS normative sample. Scores below the dashed line (1.5 standard deviations below the normative mean) are generally considered indicative of clinical impairment. ^‡indicates trend association (p < 0.05 and FDR > 0.1). *indicates a statistically significant association (p < 0.001 and FDR < 0.1).

Fig. 3

Mean scores by PBRT group (CSI vs. Focal) on the D-KEFS Trail Making Test subtests. The solid line indicates the mean of 10.0 for the D-KEFS normative sample. Scores below the dashed line (1.5 standard deviations below the normative mean) are generally considered indicative of clinical impairment. ^‡indicates trend association (p < 0.05 and FDR > 0.1). *indicates a statistically significant association (p < 0.001 and FDR < 0.1).

Fig. 4

Mean scores by PBRT group (CSI vs. Focal) on the D-KEFS Verbal Fluency subtests. The solid line indicates the mean of 10.0 for the D-KEFS normative sample. Scores below the dashed line (1.5 standard deviations below the normative mean) are generally considered indicative of clinical impairment. ^‡indicates trend association (p < 0.05 and FDR > 0.1). *indicates a statistically significant association (p < 0.001 and FDR < 0.1).

Fig. 5

Mean scores by PBRT group (CSI vs. Focal) on the VMI subtests. The solid line indicates the mean of 100.0 for the VMI normative sample. Scores below the dashed line (1.5 standard deviations below the normative mean) are generally considered indicative of clinical impairment. ^‡indicates trend association (p < 0.05 and FDR > 0.1). *indicates a statistically significant association (p < 0.001 and FDR < 0.1).