Modifying postural adaptation following a CVA through prismatic shift of visuo-spatial egocenter

Abstract

Objective: To demonstrate that Visual Midline Shift Syndrome (VMSS) following a cerebrovascular accident (CVA) can be corrected with yoked prisms.

Research design: This randomized study describes how the use of yoked prisms affects visual midline and documents the influence of yoked prisms on improving postural orientation.

Methods and procedures: Evaluation of VMSS and its correlation with postural lean during ambulation were studied in 30 post-CVA subjects and 30 controls.

Experimental interventions: Yoked prisms were used to treat VMSS by correcting posture and balance.

Outcomes and results: Over 50% of post-CVA subjects showed positive visual midline shift (p < 0.001; 95% confidence interval [CI], 0.660.93 for right CVAs and p = 0.001; 95% CI, 0.61–0.93 for left CVAs). A statistically significant proportion of those with a positive shift showed a decrease in shift utilizing yoked prisms (p < 0.001; 95% CI, 0.73–0.97 for right CVAs and p = 0.001; 95% CI, 0.07–0.39 for left CVAs). Additionally, over 50% of CVA subjects developed lean or drift away from hemiparesis and many subjects showed increased weight-bearing on the hemiparetic side with yoked prisms.

Conclusions: Yoked prisms are an effective means of treating VMSS in this population and may be useful in other neurological syndromes with visuo-spatial involvement.

• Cerebrovascular accident (CVA)
• hemiparesis
• prisms
• vision
• visuo-spatial
• visual midline
• egocenter