Unilateral Spatial Neglect without Hemiplegia: The Output-Mode Effect Revisited

Shay Ofir-Geva, Corinne Serfaty, Yaron Sacher, Nachum Soroker

Research output: Contribution to journalArticlepeer-review

Abstract

Background: The occurrence of unilateral spatial neglect (USN) in non-hemiplegic right-hemisphere damaged patients is rare. Earlier studies of such patients revealed a significant advantage when typical neglect tests were performed by the patient's left hand as compared to the dominant right hand. The mechanism underlying this "output-mode effect" remains elusive. Methods: We analyzed the temporal dynamics of this effect using line-bisection task in 9 non-hemiplegic stroke patients with left-USN. Results: In 4 patients tested shortly after stroke onset (≤ 6 weeks), the impact of hand laterality was variable (left-hand advantage in one patient; right-hand advantage in 2 patients; similar performance in both hands in one patient). Only later (> 6 weeks) a clear advantage of the left hand emerged in the majority of patients, similar to the earlier reports which were all based on late testing. Conclusions: We found variable dynamics in the expression of the output-mode effect in the first weeks following stroke onset, which may reflect changes of inter-hemispheric balance, related to recovery processes. We propose that therapeutic interventions aiming to manipulate the inter-hemispheric balance (e.g., by non-invasive brain stimulation) take into account the existence of such dynamics and their highly variate nature.

Original languageEnglish
Article number105777
JournalJournal of Stroke and Cerebrovascular Diseases
Volume30
Issue number7
DOIs
StatePublished - Jul 2021

Keywords

  • Hand laterality
  • Line bisection
  • Output mode effect
  • Unilateral spatial neglect
  • stroke

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