Article

Despite the strong relationship between freezing of gait (FOG) and
turning in Parkinson's disease (PD), few studies have addressed specific postural
characteristics during turning that might contribute to freezing. METHODS: Thirty
participants with PD (16 freezers, 14 non-freezers) (all tested OFF medication)
and 14 healthy controls walked 5 meters and turned 180 degrees in a 3D gait
laboratory. COM behavior was analyzed during four turning quadrants of 40 degrees
between 10 degrees and 170 degrees pelvic rotation and during 40 degrees before
actual FOG episodes. These pre-FOG segments were compared with similar turning
sections in turns of freezers without FOG. Outcome parameters were turn time, COM
distance, COM velocity, step width and the medial- and anterior COM position.
RESULTS: Turn time was increased in freezers compared to non-freezers (p=.000).
No differences were found regarding COM distance and velocity during turning
quadrants between groups and between freezers' pre-FOG segments and similar
turning segments without FOG. Medial COM deviation was reduced in PD patients
compared to controls (p=.004), but no differences were found between freezers and
non-freezers. In turns with freezing, turn time increased (p=.005) and step width
decreased (p=.025) pre-FOG. Freezers also showed a less medial (p=.020) and more
anterior (p=.016) COM position pre-FOG compared to turning sections without FOG.
CONCLUSIONS: Our results revealed no subgroup differences in COM behavior during
uninterrupted turning. However, we found a reduced medial deviation, a forward
COM shift and a decreased step width in freezers just before FOG episodes. These
abnormalities may play a causal role, as they could hamper stability and fluent
weight shifting necessary for continued stepping during turning.
CI - Copyright (c) 2015 Elsevier B.V. All rights reserved.

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