Ancillary Studies


The PPMI study was designed with the flexibility to incorporate new biomarker assessments throughout the life of the project. Ancillary studies include additional study assessments that involve all or a subset of PPMI participants.  All data and samples collected from these studies will be included in the study biorepository available through this site.


Submit an Ancillary Study

Ancillary study submissions are reviewed on an ongoing basis by the PPMI Ancillary Study Committee, chaired by Caroline Tanner, M.D., Ph.D.

Ongoing Ancillary Studies

SWEDD (Scans Without Evidence of Dopaminergic Deficit) Study

PD subjects who fulfilled clinical criteria for inclusion in PPMI but did not show evidence of a dopamine transporter deficit on the baseline DaTSCAN are offered the opportunity to enroll in a parallel study. This study will evaluate the probability of change in clinical diagnosis of PD in subjects with Scans Without Evidence of Dopaminergic Deficit (SWEDD), and compare baseline characteristics of SWEDD to non-SWEDD PD subjects and healthy controls. The change in DAT uptake in the SWEDD subjects over a 24-month period will be evaluated and compared with the change in DAT uptake for PPMI PD subjects. Enrolled SWEDDs will undergo the same schedule of events outlined in the PPMI battery for 2 years (visits at 6 months, 12 months, 18 months, and 24 months). This study will take place at all 24 PPMI sites and the number of SWEDDs enrolled is expected to be around 80 by the time the cohort completes recruitment.

TAP-PD (Three Site Assessment of the Potential for Home Dexterity Monitoring in a PD Biomarker Study)

This sub-study will assess the feasibility of incorporating a home dexterity testing device in a longitudinal study. Through PPMI, home use of the device will be compared to examiner-based measures. The subject is guided through three different test elements which include a keyboard test (digitography), a paced keyboard test (like a metronome), and pegboard tests that consists of timed peg grip, lift, move, align, and drop actions. The TAP-PD device is designed solely for eliciting specific subject behavior, and will capture, store, and deliver in a secure and reliable manner the 3 month self-administration results of that behavior for further analysis.

Additionally, this study will assess the validity of home dexterity testing relative to examiner-based measures (e.g. UPDRS), the reliability of home dexterity testing over repeated short-term administrations, and the sensitivity to change of the device by comparing baseline and year 1 data. If home dexterity testing is found to be a useful and reliable measure, future clinical studies may incorporate this objective motor assessment. This sub-study will take place at 3 sites in a total of 45 PD subjects.

Click here to review the TAP-PD protocol.

18F AV 133

This sub-study will add 18F AV133 imaging, targeting the vesicular monoamine transporter, to the PPMI study. The study will assess progressive dopaminergic degeneration in PD subjects using repeat 18F AV133 imaging at 12, 24, and 48 months following baseline. The value of this ligand in comparison to DaTSCAN, will be determined. The future role of 18F AV 133 as a possible longitudinal marker of PD progression will be assessed. This sub-study will take place at 5 PPMI sites, including the Australia site and four US sites, and will include PD, control and SWEDD subjects.

Resting State fMRI

The goal of this study is to add the acquisition of resting state fMRI data to the standard MRI protocol for the PPMI study. The availability of this data will allow a variety of analyses to examine functional brain networks, correlate these results with structural networks that can be measured using diffusion tensor imaging data, and correlate network changes with disease status, medication status and other biological markers being obtained in this study, including DAT imaging. Biswal and colleagues have demonstrated that rsfMRI data can be combined across multiple subjects (> 1400) obtained at different imaging centers and demonstrate stable and robust results. The additional scan time is approximately13 min per subject and 8 min per phantom. This sub-study will be conducted at 7 sites in 30 PD and 30 control subjects. PD Subjects will be scanned at baseline and annually thereafter. Controls will be scanned at baseline only.

Tracking Mild Cognitive Impairment (MCI) and Dementia

This study will complement the existing PPMI neuropsychological battery and clinical/demographic data with an annual diagnostic interview to be completed by a physician or neuropsychologist with expertise in PD cognition. The interview will allow serial (i.e., baseline + annually) categorization of PPMI patients as having normal cognition (PD-NC), mild cognitive impairment (PD-MCI), or dementia (PDD). The interview will focus on reporting of cognitive decline (necessary for diagnosis of PD-MCI) and impairments in cognitive functioning (necessary for diagnosis of PDD). Developing methods for prospective assessment of cognitive status in this population will provide a foundation for future investigations of interventions to treat or prevent cognitive impairment and dementia in PD. This sub-study will take place at all PPMI sites and will be incorporated in to the battery of assessments for all subjects.

Characterization of Motor Function – Gait Assessment

The motor assessment sub-study measures the gait variability of participants during challenging walks.  The goal of this study is to provide a detailed analysis of motor function for individuals at risk for PD.  The subtle differences between individual assessments will increase the likelihood of identifying pre-diagnostic motor changes.  Participants will complete gait assessments at yearly intervals.  Assessments include wearing wireless sensors while 1) standing still with eyes closed to measure sway, 2) walking at a preferred speed, 3) walking at a fast speed, and 4) walking while serially subtracting seven from a predefined number.  This study is led by Dr. Anat Mirelman of Tel Aviv Medical Center and will be conducted at six PPMI sites.

Click here to view the Characterization of Motor Function – Gait Assessment protocol.