Frequently asked questions (FAQ)

For questions not addressed here, contact NACC (

What can I do if my project requires data that NACC doesn't have but that individual
ADCs do have?

Under those circumstances, the investigator should work with NACC to create a list of data/specimens available at each Center. Next, NACC consultants will help the investigator draft a memo to the Clinical Core Leaders or other appropriate contact persons at the Centers of interest.  All communication to Centers should clearly state that the request is not a NACC initiative and that Center participation is entirely voluntary. It is also important to note that NACC has a system of creating STUDYIDs to prevent the linking of NACC IDs to patient IDs, an IRB violation.

What kind of analytic support does NACC provide?

NACC routinely provides advice and guidance about the availability and interpretation of data in NACC data sets. A scientific liaison at NACC is assigned to each project. Through this liaison, investigators can seek advice about analysis and interpretation as the project proceeds. Data analysis for most projects, however, occurs at the investigator's home institution. On request, NACC can also provide statistical and methodological consultation.

By mutual consent and subject to staff time constraints, NACC scientists can sometimes take on a larger role, including hands-on data analysis, direct collaboration, and co-authorship. Those arrangements are made on a project-by-project basis and are normally initiated by the investigator.

For more information, please see Processing your request.

Is item-level neuropsychological test data available?

For most tests in the UDS Neuropsychological Battery, only the total score is captured in the UDS. Subscale scores are also recorded for the Mini-Mental State Examination. For further details, see UDS Form C1 and the corresponding UDS Data Element Dictionary entries.

Many ADCs do retain item-level neuropsychological test results, and access to the item-level data can be sought as described under Question 1 above.

Where can I find the UDS Neuropsychological Test Battery results (means, standard deviations, etc.) for normal, MCI and demented subjects?

Weintraub and colleagues [Weintraub 2009] provided descriptive information from initial neuropsychological data of more than 3,000 clinically cognitively normal, older adults and developed linear regression models to estimate the impact of age, sex, and education on test performance. The report by Weintraub et al. provided in-depth descriptive information about cognitively normal older adults in the UDS, but it was not intended as a normative study.

However, by combining the initial results of Weintraub and colleagues with additional statistical information obtained from the study's authors (for example, root mean square errors for model variables), we have sought to create a useful regression-based norms calculator that provides estimated z-scores while taking into consideration the individual's sex, education level, and/or age and to make this straightforward tool available on the web for clinical research use at the National Institute on Aging Alzheimer's Disease Program UDS sites. In addition, we aimed to provide an easy and accessible method for calculating norms that other researchers and clinicians can apply to their own unique, site-specific data sets.

Is APOE genotype available?

Yes. APOE data are available for approximately 60 percent of UDS subjects. These values may be requested by investigators through either a data request or a table request.