title: Responsiveness and minimal important changes for the Neck Disability Index and the Neck Pain Disability Scale in Italian subjects with chronic neck pain.
abstract: OBJECTIVE
  To evaluate the responsiveness and minimal important changes (MICs) for the Italian Neck Disability Index (NDI) and Neck Pain Disability Scale (NPDS) as well as which questionnaire was the most responsive in subjects with chronic neck pain (NP).
  
  
  METHODS
  At the beginning and end of an 8-week rehabilitation programme, 200 patients completed the NDI and NPDS. After the programme, the global perceived effect (GPE) was also evaluated and collapsed to produce a dichotomous outcome (improved vs. stable). Responsiveness was calculated by distribution [effect size (ES); standardised response mean (SRM)] and anchor-based methods (ROC curves; correlations between change scores of NPDS and NDI, and GPE). ROC curves were also used to compute the best cutoff levels between improved and stable subjects (MICs).
  
  
  RESULTS
  The ES was 0.66 and 0.73, and the SRM was 1.09-1.26 for the NDI and NPDS, respectively. The ROC analyses revealed AUCs of 0.96 and 0.91 for the NDI and NPDS, respectively; the MICs were 7-percentage points for the NDI (sensitivity: 98%; specificity: 81%) and 10 for NPDS (93; 83%), showing equivalent responsiveness properties. Baseline NPDS scores did not affect MIC estimate for the NPDS, while, for the NDI, higher MICs were found for patients with worst disability levels. Correlations between change scores of the NDI and NPDS and GPE were, respectively, high (0.71) and moderate (0.59).
  
  
  CONCLUSIONS
  The Italian NDI and NPDS were equally sensitive in detecting clinical changes in subjects with chronic NP undergoing rehabilitation. We recommend taking the MICs into account when assessing patient improvement or planning studies in this clinical context.
authors: Physical Medicine and Rehabilitation Unit, Scientific Institute of Lissone, Institute of Care and Research (IRCCS), Salvatore Maugeri Foundation, Via Monsignor Bernasconi, 16, 20035, Lissone, Milan, Italy. marco.monticone@fsm.it.
authors: Marco
authors: M
authors: Monticone
authors: Physical Medicine and Rehabilitation Unit, Scientific Institute of Lissone, Institute of Care and Research (IRCCS), Salvatore Maugeri Foundation, Via Monsignor Bernasconi, 16, 20035, Lissone, Milan, Italy.|Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
authors: Emilia
authors: E
authors: Ambrosini
authors: Canadian Memorial Chiropractic College, Toronto, ON, Canada.
authors: Howard
authors: H
authors: Vernon
authors: Physical Medicine and Rehabilitation Unit, Scientific Institute of Lissone, Institute of Care and Research (IRCCS), Salvatore Maugeri Foundation, Via Monsignor Bernasconi, 16, 20035, Lissone, Milan, Italy.
authors: Roberto
authors: R
authors: Brunati
authors: Physical Medicine and Rehabilitation Unit, Scientific Institute of Lissone, Institute of Care and Research (IRCCS), Salvatore Maugeri Foundation, Via Monsignor Bernasconi, 16, 20035, Lissone, Milan, Italy.
authors: Barbara
authors: B
authors: Rocca
authors: Chair of Physical and Rehabilitation Medicine, Tor Vergata University of Rome, Rome, Italy.
authors: Calogero
authors: C
authors: Foti
authors: Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
authors: Simona
authors: S
authors: Ferrante
mesh_terms: D059350:Chronic Pain / Q000534:rehabilitation*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000534:rehabilitation*; D011594:Psychometrics
keywords: Chronic neck pain; Minimal important changes; NDI; NPDS; Responsiveness