Documenting abnormal anticipatory control prior to gait initiation in sub-acute stroke

Get your PT excited and ask them about this paper and anticipatory movements.
From the 2011 Canadian Stroke Congress.
page 125 here:
http://www.strokecongress.org/2011/wp-content/uploads/2011/12/CSC_Abstracts.pdf
Background: Anticipatory postural adjustments (APAs) are medio-lateral centre of pressure (ML COP) shifts towards the swing limb to preserve lateral stability prior to gait initiation. Previous research demonstrated that APAs are reduced in magnitude or delayed among individuals with stroke compared to healthy controls.
Clinically, we have observed multiple APAs prior to gait initiation in individuals post-stroke, which has not been reported in the literature. The purpose of this study was to document the prevalence of abnormal APA patterns and to examine the differences in APA timing and magnitude in a sub-acute stroke population prior to gait initiation. Methods: Sixty-six independently ambulatory stroke inpatients stood on two force plates and were instructed to initiate gait at a self-selected speed. Six trials were completed, three leading with each limb. MLCOP was obtained from the force plates. An APA was defined as a shift in ML COP >10mm from baseline. An
abnormal APA pattern could involve either no APA or multiple APAs (mAPA). Results: Fifty-six percent of patients (37/66) exhibited trials with both one and multiple APAs. Foot-off time was significantly faster for trials with
mAPAs than those with one APA (p=0.0029). Unloading time for trials with mAPAs was also faster than those with one APA (p=0.014). Forty-eight percent of patients (32/66) demonstrated trials with both normal APAs and no
APA activity. When comparing trials with one APA to those with no APA, there were no significant differences in timing. Conclusions: This study reports a high prevalence of abnormal anticipatory control prior to gait initiation
in individuals with stroke. Significant temporal differences associated with multiple APAs exist, which alter the normal gait initiation sequence. The clinical significance of these abnormal APA patterns in individuals with stroke prior to voluntary gait initiation warrants further investigation.