'Recoupling' the attentional and motor control of preparatory postural adjustments to overcome freezing of gait in Parkinson's.

ABSTRACT

OBJECTIVES: This study examined if people with Parkinson's and freezing of gait pathology (FoG) could be trained to increase preparatory weight-shift amplitude, and facilitate step initiation during FoG. METHODS: Thirty-five people with Parkinson's and FoG attempted to initiate forward walking from a stationary position caused by a freeze (n = 17, FoG-F) or voluntarily stop (n = 18, FoG-NF) in a Baseline condition and two conditions where an increased weight-shift amplitude was trained via (i) explicit verbal instruction, and (ii) implicit movement analogies. RESULTS: At Baseline, weight-shift amplitudes were smaller during (i) unsuccessful, compared to successful step initiations (FoG-F group), and (ii) successful step initiations in the FoG-F group compared to FoG-NF. Both Verbal and Analogy training resulted in significant increases in weight-shift amplitude in both groups, and a corresponding pronounced reduction in unsuccessful attempts to initiate stepping (FoG-F group). CONCLUSIONS: Hypometric preparatory weight-shifting is associated with failure to initiate forward stepping in people with Parkinson's and FoG. However, impaired weight-shift characteristics are modifiable through conscious strategies. This current study provides a novel and critical evaluation of preparatory weight-shift amplitudes during FoG events. The intervention described represents an attractive 'rescue' strategy and should be further scrutinised regarding limitations posed by physical and cognitive deficits.