Palinopsia from a posteriorly placed glioma--an insight into its possible causes.

Palinopsia is a distortion of processing in the visual system in which images persist or recur after the visual stimulus has been removed. It is a dysfunction of the association areas at the junction of temporal, occipital and parietal lobes and can be triggered by any lesion or dysfunction in this region. Here, the authors report the case of a patient with a glioma involving this region of the brain, who presented with palinopsia that subsequently disappeared once the tumour was surgically debulked. In the few cases of palinopsia that have been published so far, no such case has ever been reported. Furthermore, we took an insight into this rare and elusive phenomenon's causes and suggested Bayesian inference as a possible cause. The authors also mentioned visual evoked potentials as a useful test to be considered in future palinoptic patients.