title: The role of actigraphy in the assessment of primary insomnia: a retrospective study.
abstract: OBJECTIVE
  The aim of our study was to evaluate quantitative actigraphic criteria obtained using the Actiwatch device (AW64; Cambridge Neurotechnology Ltd., Cambridge, UK) to differentiate participants with insomnia from normal sleepers.
  
  
  METHODS
  In our retrospective study, we recovered 493 actigraphic records from two sleep measure databases of patients with insomnia (n=151) and one of normal sleepers (n=342). We considered the following actigraphic sleep parameters: time in bed (TIB), sleep-onset latency (SOL), total sleep time (TST), wake after sleep onset (WASO), sleep efficiency (SE), number of awakenings (NWAK), terminal wakefulness (TWAK), fragmentation index (FI), and mean motor activity (MA). We also considered two actigraphic circadian indexes: interdaily stability and intradaily variability. Using the Youden index, we calculated the quantitative actigraphic criteria that performed best for each actigraphic sleep parameter. Finally, we created receiver operating characteristic curves to test the accuracy of each criterion identified.
  
  
  RESULTS
  All sleep parameters except TST and TWAK differentiated the two groups of participants, allowing calculation of quantitative actigraphic criteria. There were no differences in the circadian indices.
  
  
  CONCLUSIONS
  The quantitative actigraphic criteria obtained in our study were not the same as those obtained previously with a different device, suggesting the need to adopt shared technical solutions for actigraphy.
authors: Department of Psychology, University of Bologna, Bologna, Italy. Electronic address: vincenzo.natale@unibo.it.
authors: Vincenzo
authors: V
authors: Natale
authors: Université Paris Descartes, Sorbonne Paris Cité, APHP, Hôtel-Dieu de Paris, Centre du sommeil et de la vigilance, Paris, France.
authors: Damien
authors: D
authors: Léger
authors: Department of Specialised, Experimental and Diagnostic Medicine, University of Bologna, Bologna, Italy.
authors: Monica
authors: M
authors: Martoni
authors: Université Paris Descartes, Sorbonne Paris Cité, APHP, Hôtel-Dieu de Paris, Centre du sommeil et de la vigilance, Paris, France.
authors: Virginie
authors: V
authors: Bayon
authors: Department of Psychology, University of Bologna, Bologna, Italy.
authors: Alex
authors: A
authors: Erbacci
mesh_terms: D056044:Actigraphy / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis* / Q000503:physiopathology; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult
keywords: Actigraphy; Circadian indexes; Fragmentation index; Insomnia patients; Normal sleepers; ROC analyses