ALGUNOS HALLAZGOS IMPORTANTES CON EMT

ˇ  Depression treatment with rTMS

ˇ  Effects of drugs to TMS-related measures

ˇ  Speech lateralization with single-pulse TMS

ˇ  Cortical plasticity studied with TMS

ˇ  Mapping and localization of cortical motor areas

ˇ  Conduction velocity determination in patients with pathologies

Depression treatment with rTMS

Some studies have suggested that repetitive TMS may be very useful in addition to and instead of electroconvulsive therapy in treatment of drug-resistant depression. More information about TMS/rTMS is available from the TMS resources pages maintained by Matthew Kirkcaldie.

A randomized placebo-controlled double-blind study by Prof. Alvaro Pascual-Leone et al. was recently published in Lancet (348:233-237, 1996). They administered rTMS to 17 patients with medication-resistant depression: 11 of the 17 patients showed improved mood. Similar results have been reported also by Mark George et al. from the NIH/NIMH (NeuroReport, 6:1853-1856, 1995) and some others.

One paper suggested that even single-pulse TMS may have mood-improving effects (Geller et al., Progr Neuro-Psychopharm & Biol Psych, 21:105-110, 1997).

For easily accessible writings on the subject, see, New Scientist, 5 August 1996, pages 24-29, and "A bright spot on the horizon: Transcranial magnetic stimulation in psychiatry," by Matthew Kirkcaldie and Saxby Pridmore.


Effects of drugs studied with magnetic stimulation

A recent paper by U. Ziemann et al. from the University of Göttingen addressed the effects of various epileptic drugs on motor cortex excitability with TMS (Annals of Neurology, 40:367-378, 1996; see also the editorial by Mark Hallett on pages 334-345).

The main results where that vigabatrin, baclofen and gababentin reduced facilitation when using double-pulse stimulation, which the concluded to reflect an increase in GABAergic influence; carmazepine, lamotrigine and losigane decreased the excitability, which is likely caused by inhibition of action potentials due to blocking of sodium or calcium channels.

Together with some previous papers that study the effects of medication with transcranial magnetic stimulation, the paper opens up a new exciting area of utility. TMS may appear useful in assessing the efficacy of various drugs in individual patients.


Speech lateralization with single-pulse TMS

Several studies have explored the use of TMS to assess the hemispheric dominance for speech. This would be important, e.g., before neurosurgical operations. While lateralized effects on speech have been previously found using long trains of repetitive stimuli, H. Tokimura et al. (Annals of Neurology, 40:628-634, 1996) reported that single-pulse stimulation had a lateralized effect on motor excitability when the subjects were reading aloud.


Brain plasticity studied with TMS

In a recent investigation, Leonardo G. Cohen et al. used rTMS to study the plasticity in the visual cortex of the blind (Nature, 389:180-183, 1997). Stimulation of the visual cortex impeded the interpretation of Braille in the blind but not in normal volunteers.

See also, TMS maps in explicit learning: Alvaro Pascual-Leone et al. (Science, 263:1287-1289, 1994)


Mapping and localization of motor cortex

Comparison of magnetic stimulation, functional MRI, and MEG has been done by Takato Morioka et al. in a patient (Neuroradiology, 37:526-530, 1995) and in 5 normal volunteers (Neurological Research, 17:361-367, 1995).


Conduction velocity changes in multiple sclerosis, ALS, etc


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Jarmo Ruohonen, 1997

 

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