Asymmetric responses to repetitive transcranial magnetic stimulation (rTMS) over the left and right primary motor cortex in a patient with lateralized progressive limb-kinetic apraxia

Francesca Gilio, Elisa Iacovelli, Antonella Conte, Vittorio Frasca, Maria Gabriele, Elena Giacomelli, Chiara Marini Bettolo, Nicola Scaldaferri, Alessandro Trebbastoni, Massimiliano Prencipe, Maurizio Inghilleri

Research output: Contribution to journalArticle

Abstract

Repetitive transcranial magnetic stimulation (5 Hz-rTMS, 10 stimuli, 120% resting motor threshold intensity, RMT) produces in healthy subjects a progressive facilitation of motor-evoked potential (MEP) amplitude probably through a short-term enhancement of cortical excitatory interneurones. We had the opportunity to investigate the effect of 5 Hz-rTMS delivered over the right and left primary motor cortex (M1) in a patient with limb-kinetic apraxia of the left hand and fingers and reduced cerebral perfusion in the fronto-parietal cortex of the right hemisphere documented by single-photon emission computed tomography scans. Changes in the MEP size during the trains and the RMT were measured and compared between the hemispheres. 5 Hz-rTMS was also delivered in a group of healthy subjects over both hemispheres in order to compare changes in the MEP size from the right and left M1. In the patient, 5 Hz-rTMS delivered over the left hemisphere elicited normal MEPs that progressively increased in size during the trains whereas 5 Hz-rTMS delivered over the right affected hemisphere failed to facilitate the MEP size. RMT was similar in both hemispheres. In healthy subjects, 5 Hz-rTMS delivered over either hemisphere elicited a similar, significant MEP size facilitation. Despite the limitations of a single case, our findings suggest an altered response to 5 Hz-rTMS over the M1 of the affected hemisphere. This asymmetric response correlated with the altered perfusion in the right hemisphere and the patient's lateralized clinical manifestations of apraxia.

Original languageEnglish
Pages (from-to)125-129
Number of pages5
JournalNeuroscience Letters
Volume437
Issue number2
DOIs
Publication statusPublished - May 30 2008

Keywords

  • Cerebral perfusion
  • Cortical excitability
  • Limb-kinetic apraxia
  • Repetitive transcranial magnetic stimulation
  • Short-term synaptic plasticity

ASJC Scopus subject areas

  • Neuroscience(all)

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