Transcranial magnetic stimulation reveals high test-retest reliability for phosphenes but not for suppression of visual perception

Objective: To investigate test-retest reliability of visual cortical excitatory and inhibitory phenomena. Methods: Transcranial magnetic stimulation (TMS) was applied over occipital cortex twice in 22 healthy young adults with at least a one-month interval between both measurements. The test-retest reliability of the phosphenes and TMS-induced suppression of visual perception was assessed using correlation and calculation of the repeatability coefficient. Results: Both analyses revealed a high reliability for phosphenes but not for the suppression of visual perception. Conclusions: It seems likely that the phosphenes may be better used than the TMS-induced suppression of visual perception in experiments which need repeated measurements (e. g., longitudinal studies or studies with pharmacological and non-pharmacological interventions). Significance: The study demonstrates a rather limited value of the TMS-induced suppression of visual perception for studies with repeated measurements. (C) 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.