Visit Name Variable Definition Table:

Field Name


Field Values

Visit Name Visit name: M - in months, SC - screening visit, LOG - records without visit; #2 or #3 define repeated records at the same visit or repeated visit











Tables that Reference this Variable:

  • Caffeine History
  • Demographics
  • Enrollment
  • Epworth Sleepiness Scale
  • Family History
  • MMSE
  • MoCA
  • Modified Schwab England ADL
  • Participants
  • PD Medical History
  • PDQ-39
  • REM Sleep Behavior Disorder Questionnaire_Mayo
  • REM Sleep Behavior Disorder Questionnaire_Stiansy-Kolster
  • Smoking and Alcohol History
  • Biospecimen Analyses CSF_abeta_tau_ptau
  • Biospecimen Analyses CSF_beta_glucocerebrosidase
  • Biospecimen Analyses_other
  • Biospecimen Analyses_SomaLogic_plasma
  • DaTSCAN_visual_interpretation
  • DTI
  • MRI


Data Type Information:

Field Name



Visit_Name String Required

Curation Notations:

There are discrepancies across the cohorts in coding of baseline and screening visits. In some studies, screening takes place during the baseline visit, whereas in other studies screening takes place during a separate precursor visit. 

  • Baseline visits were labeled as M0 (month 0), with follow up visits as M1, M2, etc.
  • Screening visits were labeled as SC.
  • Visit 2 in BioFIND (week 2 visit) was labeled as M0_5.
    • If repeated record at the same visit #2 or #3 were added to visit label (e.g. M12, M12#2, etc.)

PPMI visits RS1, U01, U02, PW, ST were re-labeled using following approach:

  1. RS1 – Re-screen visit was labeled SC#2
  2. PW – Premature Withdrawal visits were aligned with closest to scheduled visit month difference calculated between dates of Baseline (M0) and PW visit using INFODT (e.g. if participant has M6 and M9 scheduled visits, PW visit would be M6 if month difference is 7 months).
  3. U01, U02 – Unscheduled Visit 1 and 2 were aligned with closest to scheduled visit month difference calculated between dates of Baseline (M0) and unscheduled visit using INFODT. In “Biospecimen_analyses_CSF_abeta_tau_ptau.csv” and “DaTSCAN_SBR.csv” unscheduled visits are manually replaced (after transform1 automatic run) by “visit_name” from “PPMI Unexpected Visit Listings - DATSCAN and CSF data_May2019.xlsx” provided by Clinical Trials Statistical & Data Management Center, University of Iowa.
  4. ST visits – Symptomatic Therapy visits were re-labeled with the regular visit label (e.g. V01=M3, V02=M6, V03=M9, V04=M12, etc.) using “ST Replaces Visit (STRPLCVS)” from ST_CATALOG.csv. If an ST visit replaced V01 or V03, then per protocol the subject was supposed to skip V02 or V04, respectively.  V01 and V03 in “STRPLCVS” were replaced by V02 and V04 only if V02 or V04 are missing, otherwise V01 and V03 were used (few cases where protocol was not followed).
  5. 8 participants do not have STRPLCVS in ST_CATALOG.csv. For these the date difference was calculated, and the closest visit was used to replace ST (e.g. if PP-3067 has date difference 22 months then ST is M24; if PP-3078 has date difference 19 months then ST is M18; if PP-3653 has date difference 19 months then ST is M18).
  6. The “LOG” visits were used to indicate that the time points are irrelevant for this particular data set (e.g. Smoking_and_alcohol_history.csv, Caffeine_history.csv, etc.), or for unscheduled/unknown visits where no date of visit is available. 

Baseline Visit: All AMP PD clinical data includes a baseline visit, which is defined as the participant’s first clinical evaluation as part of the cohort.*  All visit months are calculated relative to the participant's baseline visit (e.g., “Month 12” indicates data obtained 1 year after the baseline visit).   Other clinical data, such as diagnosis date, medication start date, etc. are calculated in months, relative to the baseline visit date, in order to allow researchers to establish a timeline for disease progression and treatment milestones.

For studies in which post-mortem samples were collected, such as the Postmortem Sequencing Data cohort, the date of death is used as a substitute for the baseline visit.  When premortem clinical data are available for a participant in a postmortem study, visit dates will be negative, indicating the number of months prior to death the event occurred.

*BioFIND participants had an initial screening visit, followed by a more comprehensive evaluation and biospecimen collection visit 2 weeks later.  Most BioFIND clinical and biospecimen data is therefore recorded as “Month 0.5”

Query Definition
Demographics.visit_name is not null

Clinical Data Forms Queried (available as a BigQuery Table and csv File)

visit_name is not null

SELECT left(participant_id, 2) Cohort, count(distinct participant_id) Count from `amp-pd-research.2021_v2_5release_0510.Demographics` WHERE visit_name is not null GROUP BY Cohort ORDER BY Cohort