title: Improving motor activity assessment in depression: which sensor placement, analytic strategy and diurnal time frame are most powerful in distinguishing patients from controls and monitoring treatment effects.
abstract: BACKGROUND
  Abnormalities in motor activity represent a central feature in major depressive disorder. However, measurement issues are poorly understood, limiting the use of objective measurement of motor activity for diagnostics and treatment monitoring.
  
  
  METHODS
  To improve measurement issues, especially sensor placement, analytic strategies and diurnal effects, we assessed motor activity in depressed patients at the beginning (MD; n=27) and after anti-depressive treatment (MD-post; n=18) as well as in healthy controls (HC; n=16) using wrist- and chest-worn accelerometers. We performed multiple analyses regarding sensor placements, extracted features, diurnal variation, motion patterns and posture to clarify which parameters are most powerful in distinguishing patients from controls and monitoring treatment effects.
  
  
  RESULTS
  Whereas most feature-placement combinations revealed significant differences between groups, acceleration (wrist) distinguished MD from HC (d=1.39) best. Frequency (vertical axis chest) additionally differentiated groups in a logistic regression model (R2=0.54). Accordingly, both amplitude (d=1.16) and frequency (d=1.04) showed alterations, indicating reduced and decelerated motor activity. Differences between MD and HC in gestures (d=0.97) and walking (d=1.53) were found by data analysis from the wrist sensor. Comparison of motor activity at the beginning and after MD-treatment largely confirms our findings.
  
  
  CONCLUSIONS
  Sample size was small, but sufficient for the given effect sizes. Comparison of depressed in-patients with non-hospitalized controls might have limited motor activity differences between groups.
  
  
  CONCLUSIONS
  Measurement of wrist-acceleration can be recommended as a basic technique to capture motor activity in depressed patients as it records whole body movement and gestures. Detailed analyses showed differences in amplitude and frequency denoting that depressed patients walked less and slower.
authors.affiliation: Department of Sports and Sports Science, Karlsruhe Institute of Technology (KIT), Baden-Wuerttemberg, Germany; Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Mannheim, Baden-Wuerttemberg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Reichert
authors.affiliation: Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, Mannheim, Baden-Wuerttemberg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Lutz
authors.affiliation: Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, Mannheim, Baden-Wuerttemberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Deuschle
authors.affiliation: Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, Mannheim, Baden-Wuerttemberg, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Gilles
authors.affiliation: Department of Sports and Sports Science, Karlsruhe Institute of Technology (KIT), Baden-Wuerttemberg, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Hill
authors.affiliation: Department of Sports and Sports Science, Karlsruhe Institute of Technology (KIT), Baden-Wuerttemberg, Germany; Department of Psychosomatic Medicine and Psychotherapy, Central Institute of Mental Health, Mannheim, Baden-Wuerttemberg, Germany.
authors.forename: Matthias F
authors.initials: MF
authors.lastname: Limberger
authors.affiliation: Department of Sports and Sports Science, Karlsruhe Institute of Technology (KIT), Baden-Wuerttemberg, Germany; Department of Psychosomatic Medicine and Psychotherapy, Central Institute of Mental Health, Mannheim, Baden-Wuerttemberg, Germany.
authors.forename: Ulrich W
authors.initials: UW
authors.lastname: Ebner-Priemer
mesh_terms: D056044:Actigraphy / Q000295:instrumentation / Q000379:methods*; D000328:Adult; D000928:Antidepressive Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D002940:Circadian Rhythm; D003865:Major Depressive Disorder / Q000188:drug therapy / Q000503:physiopathology*; D016903:Drug Monitoring / Q000295:instrumentation / Q000379:methods; D005260:Female; D005868:Gestures; D006760:Hospitalization; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects; D009928:Organ Specificity; D011187:Posture; D013909:Thorax; D016138:Walking; D014953:Wrist; D055815:Young Adult
chemical_list: D000928:Antidepressive Agents