Reliability of the new freezing of gait questionnaire: agreement between patients with Parkinson's disease and their carers

Gait Posture. 2009 Nov;30(4):459-63. doi: 10.1016/j.gaitpost.2009.07.108. Epub 2009 Aug 5.


Freezing of gait (FOG) is difficult to measure due to its unpredictable occurrence. This study investigated: (1) whether the new freezing of gait questionnaire (NFOG-Q) is a reliable measure of freezing by comparing patients' ratings with those of carers' and (2) whether adding a video improved its reliability. Non-demented people with Parkinson's disease (PD) (N=102) and their carers of similar age and cognitive status were recruited from movement disorders clinics in three countries. The NFOG-Q was administered to carers and patients independently before and after watching a video showing several examples of FOG. Patients had very high agreement between their pre- and post-video detection of FOG (Kappa=0.91). However, this was less than in carers (Kappa=0.79). The video had a significant influence (p=0.01) on the rating of FOG severity (duration) but not on the estimation of its functional impact. Post-video freezing severity scores in the 69 freezers showed high agreement with carers' scores (ICC=0.78 [0.65;0.87]). We conclude that the NFOG-Q is a reliable tool to detect and evaluate the impact and severity of FOG. Adding a video does not add to the sensitivity and specificity of FOG detection but influences the estimation of FOG severity.

MeSH terms

  • Aged
  • Analysis of Variance
  • Caregivers
  • Chi-Square Distribution
  • Disability Evaluation
  • Female
  • Freezing Reaction, Cataleptic / physiology*
  • Gait Disorders, Neurologic / physiopathology*
  • Humans
  • Male
  • Middle Aged
  • Parkinson Disease / physiopathology*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Statistics, Nonparametric
  • Surveys and Questionnaires*
  • Video Recording