Below is an updated list of the GSE datasets from a GEO dataset and series search using the word "Alzheimer". I've only included results under "homo sapiens". The first page include all the datasets listed, but I've removed Super Series results. The Super Series results just contain a list of the subseries which are listed in the first page of the file.
The GSE datasets in red do not match the search criteria. They may include samples from cell lines, induced pluripotent stem cells (iPSCs), non-human samples, or may lack AD samples. The entries highlighted in green are already included in the cleaned combined dataset (except for GSE84422, GPL97).
I haven't listed all the numbers for the diseased/ control samples since not all the studies were focused on AD. Some were studies that focused on another disease and the samples also had AD. Also, AD categorization differed among the datasets. Some were categorized with AD pathology but were non-demented, some were categorized as probable AD. I can post the numbers of AD samples once it's decided what samples really count as AD.
In the sheet labeled "Datasets potentially included", the entries in white would still need to be cleaned up but these include brain samples with age, sex, and gene names. The Notes column lists problems I'd run into cleaning these entries. For some, the gene name would be difficult to extract because of the GPL file layout. Other datasets would greatly reduce the number of common genes in the combined dataset.
I think that the studies labeled with "high throughput sequencing" are the deep sequencing studies previously mentioned in the meetings. 17 out of the 131 search results included "high throughput sequencing". These can be found in the last tab. It doesn't look like the gene expression values can be found in the SOFT file or series matrices. There are several supplemental files that are a few large files (a couple of GBs), available. I'd need to try opening them on path 5 because of their sizes