Not Just Language: Persisting Lateralized Visuospatial Impairment after Left Hemisphere Stroke

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurology

Background:

• Spatial attention deficits are typically linked to right hemisphere brain injuries.
• The role of the left hemisphere in spatial attention balance is less understood.
• Chronic stroke patients often present with attentional biases.

Purpose of the Study:

• To assess attentional bias in patients with chronic left hemisphere stroke.
• To investigate the contribution of the left hemisphere to spatial attention.
• To challenge the predominant focus on the right hemisphere in attention theories.

Main Methods:

• Evaluated 25 chronic left hemisphere stroke patients and 20 age-matched controls.
• Utilized a computerized visual search task to measure reaction times.
• Administered the Behavioral Inattention Test (BITC) for neuropsychological assessment.

Main Results:

• The Behavioral Inattention Test (BITC) showed minimal attentional impairment.
• The visual search task revealed significant contralesional attentional impairment in the left hemisphere stroke group.
• Left hemisphere stroke patients required significantly more time (208 ms) to detect targets on the right compared to the left, unlike controls (8 ms difference).

Conclusions:

• Left hemisphere stroke patients exhibit a significant leftward visuospatial bias.
• This finding supports the involvement of the left hemisphere in maintaining visual attention balance.
• Results have implications for clinical screening of left hemisphere patients and attention theories.