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ABSTRACT
There is an increased scientific interest in cognitive impairments caused by brain tumors during the last decade. It has lead to the introduction and routine clinical usage of neuropsychological test batteries in brain tumor patients, thus making them an important clinical measure for the assessment of the efficacy of the different treatment regimens such as surgery, radiotherapy and chemotherapy. The effect of cognitive deficit on patients' quality of life and survival has been unequivocally proven. These are among the most com· mon neurological symptoms associated with brain tumors. The improvement in cognitive function and delay in neurocognitive decline are acceptable endpoints in clinical trials. Cognition has been demonstrated to be an independent predictor of survival in patients with cerebral neoplasms.
Key words: cognitive deficit, brain tumor, glioma, neurotoxicity, surgery
INTRODUCTION
Cognitive function (from Latin "cognoscere" - to know, to leam) is the process by which sensory input is elaborated, transformed, reduced, stored, recovered, and used.1 Cognition is considered to be a complex multifaceted system, composed of several interwoven mental domains: attention/concentration, visuospacial and constructional skills, sensory and perceptive function, language, memory, executive functions, and intellectual functioning.2·3 Those are regarded to be determined by either localized or distributed substrate in the central nervous system.4·5
The clinical psychopathological correlates brain tumors have been thoroughly discussed over the past decades.6 However, cognition is relatively underestimated in current literature. Therefore, mis review aims to cast light on the latest achievements in the diagnosis and prognosis of cognitive dysfunction before and after neurosurgical interventions.
ETIOLOGY OF THE COGNITIVE DEFICIT IN BRAIN TUMOR PATIENTS
Patients wiüi brain tumors often experience cognitive dysfunction associated with the disease its treatment, including surgery, radiotherapy (RT), and chemotherapy. As more effective therapies have prolonged survival for many patients, cognitive dysfunction has been recognized as the most complication among long-term survivors.7 Visuoconstruction, processing speed, and verbal memory measures may be the most important domains to assess when evaluating cognitive change in brain tumor clinical trials.8 Executive functions, which are also commonly affected in the brain tumor population, influence the patient's safety and abilities of daily living.9 Cognitive difficulties often have an impact on quality of life and interfere with the patient's ability to function at premorbid levels.10·" Cognitive deterioration, which may eventually progress...