Test-retest assessment of cortical activation induced by repetitive transcranial magnetic stimulation with brain atlas-guided optical topography

J Biomed Opt. 2012 Nov;17(11):116020. doi: 10.1117/1.JBO.17.11.116020.

Abstract

Repetitive transcranial magnetic stimulation (rTMS) is a technology that stimulates neurons with rapidly changing magnetic pulses with demonstrated therapeutic applications for various neuropsychiatric disorders. Functional near-infrared spectroscopy (fNIRS) is a suitable tool to assess rTMS-evoked brain responses without interference from the magnetic or electric fields generated by the TMS coil. We have previously reported a channel-wise study of combined rTMS/fNIRS on the motor and prefrontal cortices, showing a robust decrease of oxygenated hemoglobin concentration (Δ[HbO2]) at the sites of 1-Hz rTMS and the contralateral brain regions. However, the reliability of this putative clinical tool is unknown. In this study, we develop a rapid optical topography approach to spatially characterize the rTMS-evoked hemodynamic responses on a standard brain atlas. A hemispherical approximation of the brain is employed to convert the three-dimensional topography on the complex brain surface to a two-dimensional topography in the spherical coordinate system. The test-retest reliability of the combined rTMS/fNIRS is assessed using repeated measurements performed two to three days apart. The results demonstrate that the Δ[HbO2] amplitudes have moderate-to-high reliability at the group level; and the spatial patterns of the topographic images have high reproducibility in size and a moderate degree of overlap at the individual level.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain Mapping
  • Cerebrovascular Circulation
  • Female
  • Humans
  • Male
  • Middle Aged
  • Motor Cortex / anatomy & histology
  • Motor Cortex / blood supply
  • Motor Cortex / physiology*
  • Optical Imaging / instrumentation
  • Optical Imaging / methods*
  • Optical Phenomena
  • Oxyhemoglobins / metabolism
  • Prefrontal Cortex / anatomy & histology
  • Prefrontal Cortex / blood supply
  • Prefrontal Cortex / physiology*
  • Reproducibility of Results
  • Spectroscopy, Near-Infrared / instrumentation
  • Transcranial Magnetic Stimulation*
  • Young Adult

Substances

  • Oxyhemoglobins