Motor cortex stimulation for amyotrophic lateral sclerosis. Time for a therapeutic trial?

Objective: Repetitive transcranial magnetic stimulation (rTMS) of the brain can modulate neurotransmission. The aim of this preliminary study was to investigate whether rTMS of the motor cortex at low (1 Hz) or high (20 Hz) frequencies can have any beneficial effect in a transgenic rat model of amyotrophic lateral sclerosis (ALS) and in a few patients with ALS.
Methods: The effects of chronic rTMS were evaluated in 20 transgenic rats overexpressing the human G93A mutant superoxide dismutase 1 gene. Several cycles of rTMS were also performed in 4 ALS patients and the rate of progression of the disease before and during rTMS treatment was compared.
Results: No effects of rTMS was observed in transgenic rats. The rTMS treatment was well tolerated by the patients. All ALS patients continued to deteriorate. However, in the patients exposed to low-frequency rTMS the rate of progression during treatment was slightly slower than that evaluated before treatment; an opposite tendency was observed in patients exposed to high frequencies.
Conclusions: Though we cannot be sure whether the effects observed in the patients can be attributed to rTMS, further investigation using low-frequency motor cortex stimulation on a larger group of ALS patients is warranted.
Significance: The results of the pilot study in humans might open up a new therapeutic perspective in ALS based on neuromodulation.