The early effects of radiotherapy on intellectual and cognitive functioning in patients with frontal brain tumours: the use of a new neuropsychological methodology.

Investigations of the effects of radiation on neuropsychological functions have revealed variable outcomes, ranging from no effect to severe cognitive impairment. However, many of the previous studies have relied on retrospective data or have been limited by methodological problems. In this study, prospective neuropsychological assessments were compared at baseline (after surgery and before radiotherapy) and within 4 months of completion of radiotherapy (except one case), to examine early-delayed effects of radiation on intellectual and cognitive functioning. Sixteen adult patients with either low- or high-grade brain tumours, 15 of whom were treated with radiotherapy, were compared with 8 control participants with nonmalignant brain tumours whom did not undergo radiotherapy. All participants had lesions situated mainly in the frontal lobes. All groups of patients had evidence of intellectual and cognitive impairment at baseline. The low- and high-grade brain tumour groups showed a differential pattern of performance following radiotherapy, with the low-grade tumour group's performance being more competent on all of the five main neuropsychological measures. Their pattern of improvement was very similar to that of the nonmalignant brain tumour group who had not undergone radiotherapy. The present study provides some preliminary information about the neuropsychological deficits associated with primary brain tumours, their severity, and the relationship between neuropsychological functioning and brain tumours and radiotherapy.