Effects of exercise on gait and motor imagery in people with Parkinson disease and freezing of gait

Parkinsonism Relat Disord. 2018 Aug;53:89-95. doi: 10.1016/j.parkreldis.2018.05.006. Epub 2018 May 8.


Introduction: Exercise improves gait in Parkinson disease (PD), but whether exercise differentially affects people with PD with (freezers) and without freezing of gait (non-freezers) remains unclear. This study examines exercise's effects on gait performance, neural correlates related to these effects, and potential neural activation differences between freezers and non-freezers during motor imagery (MI) of gait.

Methods: Thirty-seven participants from a larger exercise intervention completed behavioral assessments and functional magnetic resonance imaging (fMRI) scans before and after a 12-week exercise intervention. Gait performance was characterized using gait velocity and stride length, and a region of interest (ROI) fMRI analysis examined task-based blood oxygen-level dependent (BOLD) signal changes of the somatomotor network (SMN) during MI of forward (IMG-FWD) and backward (IMG-BWD) gait.

Results: Velocity (F(1,34) = 55.04, p < 0.001) and stride length (F(1,34) = 77.58, p < 0.001) were significantly lower for backward versus forward walking in all participants. The ROI analysis showed freezers had lower BOLD signal compared to non-freezers in the cerebellum (F(1,32) = 7.01, p = 0.01), primary motor (left: F(1,32) = 7.09, p = 0.01; right: F(1,32) = 7.45, p = 0.01), and primary sensory (left: F(1,32) = 9.59, p = 0.004; right: F(1,32) = 8.18, p = 0.007) cortices during IMG-BWD only. The evidence suggests the exercise intervention did not affect gait or BOLD signal during MI.

Conclusion: While all participants had significantly slower and shorter backward velocity and stride length, respectively, the exercise intervention had no effect. Similarly, BOLD signal during MI did not change with exercise; however, freezers had significantly lower BOLD signal during IMG-BWD compared to non-freezers. This suggests potential decreased recruitment of the SMN during MI of gait in freezers.

Keywords: Cerebellum; Freezing of gait; Neuroimaging; Parkinson disease.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cerebellum / diagnostic imaging
  • Cerebellum / physiopathology*
  • Exercise Therapy / methods*
  • Female
  • Gait Disorders, Neurologic / diagnostic imaging
  • Gait Disorders, Neurologic / etiology
  • Gait Disorders, Neurologic / physiopathology*
  • Gait Disorders, Neurologic / rehabilitation*
  • Humans
  • Imagination / physiology*
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Motor Activity / physiology*
  • Nerve Net / diagnostic imaging
  • Nerve Net / physiopathology*
  • Outcome Assessment, Health Care*
  • Parkinson Disease / complications
  • Parkinson Disease / diagnostic imaging
  • Parkinson Disease / rehabilitation*
  • Sensorimotor Cortex / diagnostic imaging
  • Sensorimotor Cortex / physiopathology*