Supporting the idea that repeated anaesthesia in children can lead to memory impairment, a rodent study has revealed that repeated anaesthesia wiped out a large portion of the stem cells in the hippocampus. This was associated with impaired memory in young animals, which worsened as they got older. The effect did not occur in adult animals. A similar effect has also been found with radiotherapy, and animal studies have found physical activity after radiotherapy results in a greater number of new stem cells that partly replace those that have been lost.
Repeated anesthesia can affect children's ability to learn
Reference
Zhu, C., Gao, J., Karlsson, N., Li, Q., Zhang, Y., Huang, Z., … Blomgren, K. (2010). Isoflurane anesthesia induced persistent, progressive memory impairment, caused a loss of neural stem cells, and reduced neurogenesis in young, but not adult, rodents. J Cereb Blood Flow Metab. Retrieved from http://dx.doi.org/10.1038/jcbfm.2009.274