ADNI3 screening visits

[Xin Zhao]

Hi Everyone

I have a question about ADNI3 visits and inclusion of scans, hope someone could help:

ADNI website states this "New participants are initially assessed at a ‘screening’ visit and if not excluded (due to inclusion/exclusion criteria or lost to follow-up), they will move to a ‘baseline’ visit to complete additional assessments/study tasks." So what about participants with screening scans only and no baseline, year 1 visit etc (ADNI3 doesn't seem to have any "baseline" visits though)? Should they still be included in any analyses or excluded?

Thank you!

Xin

[Danielle J Harvey]

Hi Xin,

 

MRI is done at screening, so if you are looking at MRI, you will not see one at baseline (really for any phase of ADNI).  Some of the information is collected at the screening visit (to aid in assessing eligibility for the study). If a participant is deemed eligible and wants to continue, the rest of the “initial” information is collected at the baseline visit. If you are not seeing any data at baseline, that participant likely did not proceed to the baseline visit (assuming the screening visit wasn’t recent, given that there can be some time between screening visit and baseline visit).

 

You will have limited data on those with just a screening visit. Personally, I would be considering folks who did complete a baseline visit, since those you are sure met eligibility criteria for the study.

 

Danielle

--
You received this message because you are subscribed to the Google Groups "Alzheimer's Disease Neuroimaging Initiative (ADNI) Data" group.
To unsubscribe from this group and stop receiving emails from it, send an email to adni-data+...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/adni-data/e31a3467-6c45-4b7b-aca7-6939c9d13fccn%40googlegroups.com.

**CONFIDENTIALITY NOTICE** This e-mail communication and any attachments are for the sole use of the intended recipient and may contain information that is confidential and privileged under state and federal privacy laws. If you received this e-mail in error, be aware that any unauthorized use, disclosure, copying, or distribution is strictly prohibited. If you received this e-mail in error, please contact the sender immediately and destroy/delete all copies of this message.

[Xin Zhao]

Thanks for your very quick response! Yes I was looking at MRI information I pulled from "Advanced Image Search". From there I could see "ADNI Screening" for some ADNI3 visits, where in ADNIMERGE I could only see VSCODE "bl" on those visits (same date). Please correct me if I'm wrong here: 

* Does it mean those participants went on to be included in ADNI3, such that their MRI scans from screening visits essentially becamee baseline visit and should be linked to other baseline data from further assessment?

* In that case, I can assume if those with one screening visit only are not included in ADNIMERGE, they should be excluded. 

* Further, those with only one screening visit but no DX_bl diagnosis in ADNIMERGE could be excluded too. 

[Danielle J Harvey]

Hi Xin,

 

For ease, in ADNIMERGE the screening and baseline visits were combined into VISCODE=”bl”, so that row in the table combines information from the screening and baseline visits, as those were both considered the “initial visit”.

 

If someone has a screening MRI, but does not have information in ADNIMERGE, chances are good that there was no baseline information (you can also check in the REGISTRY file to see if a baseline visit was conducted).

 

I believe DX_bl represents the screening diagnosis (used to determine the visitation schedule). For most people, that aligns with the baseline diagnosis, which was based on a more complete evaluation (you can compare DX to DX_bl for rows where VISCODE=”bl” in ADNIMERGE to see the few differences). The Clinical Core generally recommends the actual baseline diagnosis as the initial diagnosis, since it is based on a more complete evaluation.

To view this discussion visit https://groups.google.com/d/msgid/adni-data/7d3426f4-1f13-4cc2-b6ff-82ee2892f029n%40googlegroups.com.

[Xin Zhao]

Hi Danielle

Thank you for the clarifications -- they are super helpful!

Best

Xin