Author(s)

Hans Callø Fledelius^1*, Kirsten Korsholm², Ian Law²

¹Copenhagen University Eye Clinics, Rigshospitalet and Glostrup Hospital, Capital Region, Denmark.
²Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Capital Region, Denmark.

Cognitive disturbances with neglect-like features have been reported occasionally in patients with chiasmal disorders, so far however with no obvious substrate by conventional brain imaging. Thus, there were no right hemisphere lesions that could explain the lateralised visual inattention as observed in particular during monocular visual acuity testing. On this background, we further examined four adult patients who consented to functional ¹⁸F-fluoro-deoxyglucose (FDG) positron emission tomography (PET) scan. In three there were no significant findings. The fourth patient, a 26-year-old male with cognitive defects after surgery for craniopharyngioma, will be discussed in more detail. His PET scan demonstrated a widespread reduction of regional metabolic activity in left hemisphere primary visual cortex and higher order visual areas, despite absence of explanatory pathological signal changes on MRI. As present in only one out of four patients, however, the findings do not allow specific pathogenetic mechanisms to be suggested, nor generally to substantiate involvement of higher cerebral circuits. Obviously, even developed imaging has its limits, and in the very theory the visual dysfunctions observed might still depend on higher brain centres’ faulty adaptation to loss of pre-geniculate visual information.

Chiasmal Lesions, Visual Field Defects, Neglect-Like Behaviour, Cognitive Disturbances, Functional PET Scan (FDG) of Brain

Fledelius, H. , Korsholm, K. and Law, I. (2015) Functional PET Scan in Four Patients with Higher Order Neglect-Like Cognitive Dysfunction Associated to Chiasm Related Pathology. Open Journal of Ophthalmology, 5, 54-60. doi: 10.4236/ojoph.2015.52009.