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Hemianopic anosognosia
G G Celesia1, M G Brigell, M S Vaphiades
1Department of Neurology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA.
Neurology
|July 1, 1997
Summary
Most patients with visual field loss from stroke are unaware of their deficit (hemianopic anosognosia). This unawareness is linked to lesion location and may indicate a distributed network for visual perception.
Area of Science:
- Neuroscience
- Ophthalmology
- Neurology
Background:
- Homonymous visual field defects often result from ischemic infarcts.
- Unawareness of neurological deficits, known as anosognosia, can occur in various neurological conditions.
Purpose of the Study:
- To investigate the prevalence and characteristics of hemianopic anosognosia (HAN) in patients with homonymous visual field defects.
- To explore the relationship between HAN, somatic anosognosia, and hemineglect.
- To understand the neural correlates of conscious visual perception.
Main Methods:
- Prospective study of 32 patients with homonymous visual field defects due to ischemic infarcts.
- Assessment of hemianopic anosognosia, somatic anosognosia, and hemineglect.
- Analysis of lesion locations and their association with awareness of visual deficits.
Main Results:
- 62% of patients (20/32) exhibited hemianopic anosognosia (HAN).
- HAN occurred in both right-sided (62%) and left-sided (67%) lesions.
- HAN was associated with somatic anosognosia and hemineglect, but dissociation between these phenomena was observed.
Conclusions:
- HAN is common in ischemic stroke causing visual field defects and is not strictly lateralized.
- Conscious visual perception is not localized to a single cortical area but involves a distributed network.
- Both hemispheres contribute to visual processing and awareness.