Pathogenesis of Irradiation-Induced Cognitive Dysfunction

Abstract

Neurocognitive dysfunction is a common sequela of cranial irradiation that is especially severe in young children. The underlying mechanisms of this disorder have not been described. The present review describes the role of the hippocampus and the anatomically related cortex in memory function and its marked susceptibility to ischemic and hypoxic injury. Based on studies of animal models of human amnesia and histopathological findings in the irradiated brain, the neurocognitive sequela of cranial irradiation can be seen to be mediated through vascular injury, resulting in ischemia and hypoxia in the hippocampal region. Recognition of the site and mechanisms of this injury may lead to the development of techniques to minimize the risks.

Whole Brain Radiotherapy With Hippocampal Avoidance and Simultaneously Integrated Brain Metastases Boost: A Planning Study

“…(8) Recent studies indicate that the functions of learning, memory (short and long term), and spatial information processing are affected by irradiation of the hippocampus; the current postulate is that although several functional areas of the brain are responsible for these functions, the stem cell compartment housing the necessary progenitor cells resides within the hippocampus and is exquisitely radiosensitive. Hence, irradiation of this compartment causes depletion of cells necessary for neurogenesis, especially for the memory domains.…”

Pathogenesis of Cognitive Decline Following Therapeutic Irradiation for Head and Neck Tumors

“…Consequently, these patients are at an increased risk for temporal lobe injury (8,13). A major manifestation of temporal lobe injury is the development of memory problems and learning dif culties (14,15). There are no reports on the pathogenetic mechanisms of these sequelae following irradiation for cancer of the nasopharynx and paranasal sinuses.…”

Molecular stress response in the CNS of mice after systemic exposure to interferon-α, ionizing radiation and ketamine

“…Schatz et al, (2000) showed that deficits in processing speed and working memory following cranial radiation therapy may underlie declines in IQ. Low doses of irradiation can lead to cognitive dysfunction without inducing significant morphological changes (Abayomi, 1996). Such cognitive changes are often manifested as deficits in hippocampal-dependent functions of learning, memory, and spatial information processing (Mizumatsu et al, 2003).…”