We agree with most points Dr Coetzer raised, especially that future studies should include more sensitive tests, as there could be subtle cognitive functions that are affected by ECT, which our tests didn't pick up. We fully support the need to obtain comprehensive baseline assessments with as many cognitive tests as possible. These should be repeated around each new course, or at regular intervals for maintenance ECT. This will serve as a safety measure if deterioration is noticed, and give reassurance if no problems are found. The latest Electroconvulsive Therapy Accreditation Service (ECTAS) guidelines reflect this change in practice and recognise the need for standardised assessment pre- and post-ECT. The current guidelines on cognitive testing are not prescriptive about the assessment tool used. At each revision of the ECTAS guidelines, there is much debate about cognitive assessments and we can only encourage the use of more comprehensive tests.

Regarding Dr Coetzer's suggestion that pre-morbid performance be used as a baseline, this is another excellent suggestion, but the comparison might not always be meaningful. Cognitive performance changes with age, with the development of vascular or degenerative changes in later life, due to the depression and other illness-related factors. We therefore feel that assessments closer to the start of the ECT session would be more meaningful for comparison purposes. Baseline assessments are likely to be performed at a time when the patient is depressed, causing further problems. We can't see an easy way out of this problem, therefore we suggest that repeated assessments after each course (i.e. at times when patients are relatively free from depression) will provide a better picture of any potential effect from repeated ECT courses.

Regarding the question on how many patients who had never had ECT were included for testing, the number is indeed 122, as stated in the paper (i.e. nearly two-thirds of the patients were tested before their first-ever ECT session). The results from this subgroup were not specifically reported, but we can now report on the most meaningful analysis on these patients (those who were tested before their first-ever ECT and tested again after they had >12 ECT sessions). This applies to 37 of the 55 patients who we reported in the paper as having had >12 ECT sessions (average of 21) between their first and their last tests (Table 2 in the paper). The results are basically indistinguishable from those reported in Table 2, with the only significant change (an improvement) found again for the reaction time.

We welcome further research in this field, but want to reiterate that our results refer to cognitive performance, although retrograde memory problems do exist and can upset some patients. Such patients feel more reassured when they are able to compare their performance on cognitive tests pre- and post-ECT.