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@ARTICLE{SahandiFar:896732,
      author       = {Sahandi Far, Mehran and Eickhoff, Simon B and Goni, Maria
                      and Dukart, Juergen},
      title        = {{E}xploring {T}est-{R}etest {R}eliability and
                      {L}ongitudinal {S}tability of {D}igital {B}iomarkers for
                      {P}arkinson {D}isease in the m-{P}ower {D}ata {S}et:
                      {C}ohort {S}tudy},
      journal      = {Journal of medical internet research},
      volume       = {23},
      number       = {9},
      issn         = {1438-8871},
      address      = {Richmond, Va.},
      publisher    = {Healthcare World},
      reportid     = {FZJ-2021-03559},
      pages        = {e26608 -},
      year         = {2021},
      abstract     = {Background: Digital biomarkers (DB), as captured using
                      sensors embedded in modern smart devices, are a promising
                      technology for home-based sign and symptom monitoring in
                      Parkinson disease (PD).Objective: Despite extensive
                      application in recent studies, test-retest reliability and
                      longitudinal stability of DB have not been well addressed in
                      this context. We utilized the large-scale m-Power data set
                      to establish the test-retest reliability and longitudinal
                      stability of gait, balance, voice, and tapping tasks in an
                      unsupervised and self-administered daily life setting in
                      patients with PD and healthy controls (HC).Methods:
                      Intraclass correlation coefficients were computed to
                      estimate the test-retest reliability of features that also
                      differentiate between patients with PD and healthy
                      volunteers. In addition, we tested for longitudinal
                      stability of DB measures in PD and HC, as well as for their
                      sensitivity to PD medication effects.Results: Among the
                      features differing between PD and HC, only a few tapping and
                      voice features had good to excellent test-retest
                      reliabilities and medium to large effect sizes. All other
                      features performed poorly in this respect. Only a few
                      features were sensitive to medication effects. The
                      longitudinal analyses revealed significant alterations over
                      time across a variety of features and in particular for the
                      tapping task.Conclusions: These results indicate the need
                      for further development of more standardized, sensitive, and
                      reliable DB for application in self-administered remote
                      studies in patients with PD. Motivational, learning, and
                      other confounders may cause variations in performance that
                      need to be considered in DB longitudinal applications.},
      cin          = {INM-7},
      ddc          = {610},
      cid          = {I:(DE-Juel1)INM-7-20090406},
      pnm          = {5252 - Brain Dysfunction and Plasticity (POF4-525)},
      pid          = {G:(DE-HGF)POF4-5252},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:34515645},
      UT           = {WOS:000695742000004},
      doi          = {10.2196/26608},
      url          = {https://juser.fz-juelich.de/record/896732},
}