Suppressing visual hallucinations in an adolescent by occipital transcranial magnetic stimulation: A single-case experimental research design

Visual hallucinations after central or peripheral impairment, commonly called Charles Bonnet syndrome, are often highly distressing and with few available treatment options. Here we report a case where an adolescent developed severely distressing visual hallucinations after hypoxic damage to the occipital cortex following a suicide attempt. The patient received active and sham occipital continuous theta-burst stimulation (cTBS) in a single-case experimental research design and a subsequent open phase, to evaluate cTBS as a Charles Bonnet treatment. The visual hallucinations seemed to decrease more during active than sham cTBS in the blind phase, and in the following week of repeated five daily treatments they almost disappeared. A normalization of increased activity in the lateral visual network after cTBS was observed on a functional magnetic resonance imaging resting-state analysis compared with 42 healthy controls. Visual evoked potentials stayed largely unchanged both in the sham-controlled blind phase and the subsequent open phase. During the two weeks after the open phase with repeated cTBS sessions, the visual hallucinations gradually reappeared and almost returned to the baseline level. Our findings suggest that active cTBS over the primary visual cortex can reduce visual hallucinations through modulation of downstream visual regions, though the effect is temporally limited.