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Extinction during time controlled direct retinal stimulation after recovery from right hemispheric stroke
R F Kaplan1, R A Cohen, A Rosengart
1Department of Neurology, Tufts University School of Medicine, Boston, MA, USA.
Journal of Neurology, Neurosurgery, and Psychiatry
|November 1, 1995
Summary
Patients with right hemispheric stroke showed time-dependent extinction of double simultaneous stimulation (DSS). Recovery from neglect may involve the left hemisphere, as suggested by these temporal extinction patterns.
Area of Science:
- Neuroscience
- Ophthalmology
- Cognitive Psychology
Background:
- Right hemispheric stroke can lead to visual neglect.
- Assessing recovery from neurological damage requires precise measurement of temporal processing deficits.
Observation:
- A scanning laser ophthalmoscope (SLO) was used to study temporal extinction in two patients with right hemispheric stroke and two controls.
- Stimuli were presented using double simultaneous stimulation (DSS) at varying time intervals (50 ms, 100 ms, 200 ms).
Findings:
- Patients exhibited time-dependent extinction, with deficits more pronounced at shorter intervals (50 ms).
- Normal controls did not show extinction to DSS at any presentation time.
- Patient performance improved significantly with longer stimulus presentation times, indicating temporal processing recovery.
Implications:
- The findings suggest that the left hemisphere may play a role in mediating recovery from neglect after right hemispheric damage.
- This study highlights the importance of temporal dynamics in assessing neurological recovery and visual attention deficits.