Get access

Objective detection of subtle freezing of gait episodes in Parkinson's disease

Authors

  • Arnaud Delval MD, PhD,

    Corresponding author
    1. Department of Neurology and Movement Disorders, Regional University Hospital, Lille Cedex, France
    2. Department of Clinical Neurophysiology, Regional University Hospital, Lille Cedex, France
    3. Department of Neurology, Donders Center for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    • Neurology Department, Hôpital Salengro, F-59037 Lille Cedex, France
    Search for more papers by this author
  • Anke H. Snijders MD,

    1. Department of Neurology, Donders Center for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    Search for more papers by this author
  • Vivian Weerdesteyn PT, PhD,

    1. Department of Rehabilitation, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    Search for more papers by this author
  • Jacques E. Duysens MD, PhD,

    1. Department of Rehabilitation, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    Search for more papers by this author
  • Luc Defebvre MD, PhD,

    1. Department of Neurology and Movement Disorders, Regional University Hospital, Lille Cedex, France
    Search for more papers by this author
  • Nir Giladi MD, PhD,

    1. Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
    Search for more papers by this author
  • Bastiaan R. Bloem MD, PhD

    1. Department of Neurology, Donders Center for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    Search for more papers by this author

  • Potential conflict of interest: Nothing to report.

  • The protocol has been approved by the local committee of ethics.

Abstract

Freezing of gait (FOG) is a clinically defined phenomenon of Parkinson's disease (PD). Recent evidence suggests that subtle FOG episodes can be elicited in a gait laboratory using suddenly appearing obstacles during treadmill walking. We evaluated which quantitative gait parameters identify such subtle FOG episodes. We included 10 PD patients with FOG, 10 PD patients without FOG, and 10 controls. Subjects walked on a motorized treadmill while avoiding unexpectedly appearing obstacles. Treadmill walking was videotaped, and FOG episodes were identified by two independent experts. Gait was also analyzed using detailed kinematics. Knee joint signals were processed using time–frequency analysis with combinations of sliding fast Fourier transform and wavelets transform. Twenty FOG episodes occurred during treadmill walking in 5 patients (all with clinically certified FOG), predominantly in relation to obstacle avoidance. FOG was brief when it occurred just before or after obstacle crossing and was characterized by short, rapid steps. Frequency analysis showed a typical qualitative pattern: before the FOG episode an increase in dominant frequency in the 0 to 3 Hz band (festination), followed by decreased power in 0 to 3 Hz band and an increased power in the 3 to 8 Hz band during the FOG episode. This pattern led to an increased FOG index as a qualitative measure. These approaches detected even very brief FOG with acceptable sensitivity (75–83%) and specificity (>95%). We conclude that time–frequency analysis is an appropriate approach to detect brief and subtle FOG episodes. Future work will need to decide whether this approach can support or even replace expert clinical opinion. © 2010 Movement Disorder Society

Get access to the full text of this article

Ancillary