Prism adaptation aftereffects in stroke patients with spatial neglect: Pathological effects on subjective straight ahead but not visual open-loop pointing
2008

Effects of Prism Adaptation on Stroke Patients with Spatial Neglect

Sample size: 26 publication 10 minutes Evidence: moderate

Author Information

Author(s): Margarita Sarri, Richard Greenwood, Lalit Kalra, Ben Papps, Masud Husain, Jon Driver

Primary Institution: UCL Institute of Cognitive Neuroscience, University College London

Hypothesis

Prism adaptation may produce larger aftereffects on subjective straight ahead (SSA) pointing than on visual open-loop (VOL) pointing in stroke patients with spatial neglect.

Conclusion

Prism aftereffects in neglect patients were significantly larger for SSA than for VOL, indicating that SSA may reflect a pathological aspect of neglect.

Supporting Evidence

  • Prism aftereffects were much larger for SSA than VOL in neglect patients.
  • Patients showed a substantial pre-exposure rightward deviation in the SSA task.
  • The leftward aftereffect for SSA after prisms was significantly larger than for healthy controls.
  • Improvements in cancellation tasks correlated with the size of SSA aftereffects.
  • Lesion analysis suggested that damage to specific brain regions may affect neglect improvement.

Takeaway

When stroke patients with neglect wear special glasses that shift their vision, they point more accurately straight ahead than when they point at a visible target.

Methodology

The study involved 13 stroke patients with left neglect and 13 age-matched controls, comparing SSA and VOL pointing tasks before and after prism adaptation.

Potential Biases

Potential selection bias in patient recruitment and the influence of individual lesion characteristics on outcomes.

Limitations

The study had a small sample size and focused only on right-hemisphere stroke patients.

Participant Demographics

13 right-hemisphere stroke patients (6 females, 7 males; mean age 57.07) and 13 age-matched healthy controls (8 females, 5 males; mean age 53).

Statistical Information

P-Value

0.002

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1016/j.neuropsychologia.2007.11.005

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