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Updated: Sep 30, 2026
Quantifying Cognitive Decrements Caused by Cranial Radiotherapy
Published on: October 18, 2011
Acute effects of irradiation on cognition: changes in attention on a computerized continuous performance test during
Thomas E Merchant1, Erin N Kiehna, Mark A Miles
1Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. thomas.merchant@stjude.org
Insights
Pediatric brain tumor patients showed trends in attention and impulsivity during radiotherapy (RT), with some age-related changes in reaction time. Overall, RT had limited acute effects on cognitive function tests.
Area of Science:
- Neuro-oncology
- Pediatric oncology
- Cognitive neuroscience
Background:
- Pediatric brain tumors and their treatments can impact cognitive functions.
- Assessing sustained attention, impulsivity, and reaction time is crucial for understanding treatment side effects.
Purpose of the Study:
- To evaluate sustained attention, impulsivity, and reaction time in pediatric patients undergoing radiotherapy for primary brain tumors.
- To analyze longitudinal changes in cognitive performance during the initial 50 days of conformal radiotherapy.
Main Methods:
- Prospective evaluation of 39 pediatric patients using the Conners' continuous performance test (CPT).
- Data modeling to assess changes in CPT scores and the influence of clinical variables during conformal radiotherapy (CRT).
Main Results:
- Trends observed in CPT scores included increased inattentiveness and slower reaction times, though not statistically significant.
- Older patients (>12 years) demonstrated better baseline attention and impulsivity, with divergent reaction time changes during treatment compared to younger patients.
- Factors like shunted hydrocephalus, seizure history, and residual tumor were associated with increased impulsivity; nonshunted patients and those with more extensive resections had slower reaction times.
Conclusions:
- Children with brain tumors exhibit pre-existing attention and reaction time deficits.
- Radiotherapy, as administered in this trial, demonstrated limited acute effects on the measured cognitive functions.
- Younger patients (<12 years) experienced a significant slowing of reaction time during treatment.
Purpose:
To assess sustained attention, impulsivity, and reaction time during radiotherapy (RT) for pediatric patients with localized primary brain tumors.
Methods And Materials:
Thirty-nine patients (median age 12.3 years, range 5.9-22.9) with primary brain tumors were evaluated prospectively using the computerized Conners' continuous performance test (CPT) before and during conformal RT (CRT). The data were modeled to assess the longitudinal changes in the CPT scores and the effects of clinical variables on these changes during the first 50 days after the initiation of CRT.
Results:
The CPT scores exhibited an increasing trend for errors of omission (inattentiveness), decreasing trend for errors of commission (impulsivity), and slower reaction times. However, none of the changes were statistically significant. The overall index, which is an algorithm-based weighted sum of the CPT scores, remained within the range of normal throughout treatment. Older patients (age >12 years) were more attentive (p < 0.0005), less impulsive (p < 0.07), and had faster reaction times (p < 0.001) at baseline than the younger patients. The reaction time was significantly reduced during treatment for the older patients and lengthened significantly for the younger patients (p < 0.04). Patients with a shunted hydrocephalus (p < 0.02), seizure history (p < 0.0006), and residual tumor (p < 0.02) were significantly more impulsive. Nonshunted patients (p < 0.0001), those with more extensive resection (p < 0.0001), and patients with ependymoma (p < 0.006) had slower initial reaction times.
Conclusion:
Children with brain tumors have problems with sustained attention and reaction time resulting from the tumor and therapeutic interventions before RT. The reaction time slowed during treatment for patients <12 years old. RT, as administered in the trial from which these data were derived, has limited acute effects on changes in the CPT scores measuring attention, impulsiveness, and reaction time.
