Hemianopia or visuospatial neglect: differences in information processing
Reviewed by Claire Howard

It is widely reported that visuospatial neglect and hemianopia may be superimposed, and disentangling the two conditions can be pose difficulties for clinicians. The authors of this paper explored the differences in implicit information processing which is effective in patients with neglect, but not with hemianopia. They hypothesise that a prime-world in the neglected field should determine a sematic activation effect, but not in a blind hemifield. They explored the eye movements between the two conditions to provide further details. In this article, the authors consider a single patient with a bilateral visual defect, with the presence of a left sided visual neglect and a right sided homonymous hemianopia. The patient suffered a recent onset right sided stroke with evidence of a chronic lesion in the left occipital lobe in keeping with a longstanding right sided hemianopia. To test their hypothesis the authors realised a categorisation task using a repetition priming paradigm, testing the response time and accuracy in responding or not to the prime. The results support implicit information processing in the space affected by neglect but not by hemianopia. The authors suggest this work as an early indication of using a differential diagnosis for the two conditions and has possible future applications in a clinical setting. Further research is required in a range of patients to obtain stronger results about if and how half of the world is perceived. 

Which differences in priming effect between neglect and hemianopia? A case description of a bilateral brain-lesioned patient.
Sozzi M, Marzoli SB, Melzi L, et al.
NEURO-OPHTHALMOLOGY
2017;41(5):259-67.