Clinical Data FAQ
Q1: How do I get the clinical data?
A1: The clinical data set may be downloaded from LONI
here (authorized users only).
The ADNI Biostatistics Core at UC Davis has provided a
tutorial on downloading and importing the data into SAS, Stata, and R.
Q2: How is missing data coded in the datasets?
A2: Missing data is coded with -1 and -4. Generally, -4 is used for "passively" missing or not applicable (e.g. item is not collected at a particular visit), and -1 is used for data which is confirmed missing at point of data entry.
Q3: Which column in all the CSV files is the ADNI subject ID number correspondent to the "Subject ID" number in the LONI-ADNI database, the "ID" column or the "RID" column?
A3: In the ADNI subject IDs of the form 123_S_5678, the last 4 digits correspond to the roster ID (RID) which you see in every CSV file. You can also refer to the adni_roster table which lists RIDs and their associated PTIDs (of the form 123_S_5678).
Q4: Where can I find a copy of the cognitive assessment worksheets (ADAS-Cog, etc.) used to score patients at each visit?
A4: There are three versions of the ADNI cognitive assessments (
baseline,
month 6,
month 12). Refer to Cognitive Assessment section of the
Procedures Manual for information regarding cognitive assessments at visits other than BL, M6 and M12.
Q5: Where can I find ADAS-Cog total scores?
A5: Item level scores and two versions of total scores are available in the adni_adasscores file. TOTAL11 corresponds to the total score on the 11-item ADAS (items 4 and 13 omitted) and TOTALMOD corresponds to the total score on the modified 13-item ADAS (item 13 omitted).
| | ADAS-Cog | Modified ADAS-Cog |
|---|
| | (TOTAL11) | (TOTALMOD) |
| | Rosen et al., 1984 (modified Mohs, 1994)* | Petersen et al., 2005 |
| 1 | Word Recall | 10 | 10 |
| 2 | Commands | 5 | 5 |
| 3 | Construction | 5 | 5 |
| 4 | Delayed Word Recall | -- | 10 |
| 5 | Naming | 5 | 5 |
| 6 | Ideational Praxis | 5 | 5 |
| 7 | Orientation | 8 | 8 |
| 8 | Word Recognition | 12 | 12 |
| 9 | Recall Instructions | 5 | 5 |
| 10 | Spoken Language | 5 | 5 |
| 11 | Word Finding | 5 | 5 |
| 12 | Comprehension | 5 | 5 |
| 14 | Number Cancellation | -- | 5 |
| | Total | 70 | 85 |
|---|
* unpublished manual
Raw item level responses are available in the adni_adas file.
Q6: What is the meaning of the visit identifier "Not Yet Determined" (NV)?
A6: The NV ("No Visit" or "Not Yet Determined") visit code is applied when
we receive scan QC data (e.g. mrinclusio) before we receive scan
information sheets (e.g. mrimeta). In these instances, we do not yet
know with which visit the scan QC data is associated.
Occasionally scan QC and scan information records which should be linked
are not linkable because of discrepant data (e.g. exam dates do not
match). The NV data code will be used in these cases as well, until the
discrepancies are corrected.
Topic permissions
adniproceduresmanual12.pdf