Rehabilitation of visuospatial neglect by prism adaptation: effects of a mild treatment regime. A randomised controlled trial

ABSTRACT

Closely examining the effects, optimal regime and time window of prism adaptation (PA) promotes guidelines for effective rehabilitation practice. The effects of short-term repetitive PA on spatial neglect manifestations were evaluated in patients with heterogeneous post-stroke delays, using a digital Visuospatial Neglect Test Battery. Subsequently, potential differences in PA effects between acute, subacute or chronic neglect were explored. A multicentre randomised controlled trial was conducted in 43 right-hemisphere neglect patients. They were treated with a mild PA regime: seven sessions of experimental or placebo prism training over 7–12 days. The outcome measures were diverse neglect variables related to peripersonal navigation, visual extinction, visuospatial memory, bisection, cancellation, drawing and visual search. The treatment effects were assessed after a short and a long time interval. Two to 24 hours after PA, conventional effects were found for drawing and centred bisection, and novel effects for peripersonal visuospatial navigation, visual extinction, and non-motor memory (with caution). No effects were found for visual search times and cancellation. The assessments after three months were still indicative of PA benefits for navigational, drawing and memory functions. PA did not prove to be more effective in acute, subacute or chronic patients. The extension of effects is theoretically framed within the debate about the levels of cognitive processing that are impacted by PA. Clinical suggestions are formulated regarding PA implementation in neglect treatment.

KEYWORDS:

• Hemineglect
• short-term repetitive prism training
• computer-based navigation
• visual extinction
• memory

Acknowledgements

We express our gratitude to the patients who contributed to our study. We thank James Danckert and the anonymous reviewers for their constructive and valuable comments on earlier versions of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 The tests run on the DiagnoseIS software platform, Metrisquare BV, www.metrisquare.com, www.diagnoseis.com.

Additional information

Funding

This project was supported by grant [G.0906.10N] from the Fund for Scientific Research Flanders (FWO-Vlaanderen), Belgium.