Should I combine OASIS-1, OASIS-2, OASIS-3, and OASIS-4 datasets?

No, we do not recommend combining OASIS-1, OASIS-2, or OASIS-3. However, OASIS-4 is a unique dataset that can be combined with any of the other datasets. For class projects we recommend using OASIS-1 or OASIS-2. For all other research questions please review the data summary to select the best dataset.

How do I match visits in OASIS-3?

This is a longitudinal study that had various visit intervals and these visits are represented in the datatype label (visit = days from entry = d#### (ex. MR_d1234)). You will have to determine your own criterion for matching clinical visit to imaging visit (ex: +- 6months or only -6months).
This R script can be used to match visits by “days from entry”:

Where is Diagnosis information in OASIS-3 and OASIS-4?

All diagnostics, assessments, and json information are provided in csv documents under ‘OASIS3_data_files’ and ‘OASIS4_data_files’


This document will help you navigate OASIS on XNAT.

OASIS-4 CSF Disclaimer

OASIS-4 CSF assays should not be combined with assays measured with Elecsys or Lumipulse assay methods. See data dictionary for more information.

Dataset DOI/Scan ID

Each subject and data session receives a unique XNAT accession/ID number. For downloaded imaging sessions this can be found in the dataset_description.json file.
Ex. of Subject ID/Accession#: CENTRAL_S05094

We also recommend using these IDs for supplementary information when referencing data used in publications and tools.

Can I request more data?

No. All available data is included in the released datasets.

How do I find OASIS data on NITRC?

Details can be found here: