Reduced contralateral center of pressure displacement during lateral weight-shifting in patients with lateropulsion after acute brainstem infarction.

BACKGROUND

The center of pressure (COP) position in lateropulsion cases has been reported to deviate toward the lateropulsion side and then shift toward the non-lateropulsion side during recovery. However, research on dynamic postural control in patients with lateropulsion is limited, and the kinematic characteristics remain unclear.

OBJECTIVE

To investigate the characteristics of dynamic postural control in patients with lateropulsion following acute brainstem infarction by comparing COP displacement during a lateral weight-shifting task.

METHODS

This retrospective cross-sectional study included twenty patients diagnosed with lateropulsion after brainstem infarction. Patients were classified into mild (Grades I - II, n = 8) and severe (Grades III - IV, n = 12) lateropulsion groups based on the Grading of Lateropulsion. The main outcomes were maximum lateral COP displacement on the lateropulsion and non-lateropulsion sides during a 30-s lateral weight-shifting task. The COP symmetry index was calculated as follows: [(lateropulsion - non-lateropulsion)/(lateropulsion + non-lateropulsion)] × 100. Balance was evaluated using the Berg Balance Scale (BBS).

RESULTS

In all participants, non-lateropulsion side COP displacement was significantly smaller than lateropulsion side displacement (lateropulsion: 8.4 ± 2.8 cm, non-lateropulsion: 6.0 ± 3.4 cm; p = 0.007, d = 0.770). The severe lateropulsion group showed greater COP symmetry index values (32.7 ± 29.7% vs. 0.6 ± 31.2%, p = 0.031, d = 1.050) and significantly lower BBS scores (24.1 ± 9.5 vs. 43.3 ± 10.2, p < 0.001, d = 2.020) than those of the mild lateropulsion group.

CONCLUSIONS

Among patients with lateropulsion after acute brainstem infarction, COP displacement toward the non-lateropulsion side was smaller than that toward the lateropulsion side during a dynamic standing task, with greater asymmetry in patients with more severe lateropulsion.