Objective: Visual hallucinations in children need a differential diagnostic effort.
Methods and patients: In a retrospective cohort study we identified all children, admitted to the Department of Neuropediatrics of a University Hospital between 1.1.2001 and 31.12.2003 suffering from visual hallucinations. All children underwent neurologic examination and electroencephalography (EEG).
Results: 14 children with visual hallucinations were identified. Disturbed perception of the size (9 of 14 cases), of the form (5 of 14 cases), and irregular perceptions of movements (5 of 14 cases) were most frequently reported. One child showed a transient hemihypesthesia, the only pathologic finding in the neurologic examination. Three children had features of hypersynchronic activity in EEG: one child undergoing immunosuppressive drug therapy and with a visual hallucination in context of a reversible posterior leucoencephalopathy showed a focal slow background activity, whereas three children had a sharp wave activity. Two of these children fulfilled the criteria for a focal epilepsy, one of them of the frontal lobe, one of the temporal lobe.
Conclusion: Recurrent visual hallucinations are frequently transient and show clinical and pathophysiologic features reminiscent of infantile migraine. Psychic etiology, focal epilepsy and, under special circumstances, a reversible posterior leucoencephalopathy have to be considered when making a differential diagnosis.