Reply: The challenges for research on deep brain stimulation and memory.

Sir, We thank Drs van den Noort et al. (2015) and Fried (2015) for their interest in our study (Miller et al. , 2015) reporting improvement in visual-spatial memory during theta burst deep brain stimulation of the fornix in four individuals with temporal lobe epilepsy, a translational study previously tested in rodents by our team (Sweet et al. , 2014). While echoing our cautionary statements regarding interpretation, Dr Fried (2015) applauded the use of a unique clinical opportunity to provide intriguing preliminary data. Dr van den Noort et al. (2015) describe the study as being ‘highly innovative’, ‘a promising direction for various disorders’ and ‘a pioneering study’, adding that ‘it is a strength that the authors of the present study use neuropsychological tests’. Their group also raised some concerns, so we appreciate this opportunity to respond. Dr van den Noort et al. (2015) stated that ‘stimulation settings were different from previous studies, making comparisons … impossible.’ It would have been ideal to directly …