Wednesday, May 7, 2008

Forbes article on Vascular Depression and TMS

Forbes Magazine has a write-up about treatments for vascular depression that are up-and-coming. rTMS seems to be the front-runner. I will be excited to read the actual results of the study when they are published.

Saturday, May 3, 2008

Neuromodulation Explained

Here is an eloquent explanation of neuromodulation by Alan Wu, a neurologist at UCLA. I had the pleasure of meeting Dr. Wu while I was learning TMS and tDCS techniques at Dr. Alvaro Pascual-Leone's lab at Harvard.

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are promising noninvasive cortical stimulation methods for adjunctive treatment of movement disorders. They avoid surgical risks and provide theoretical advantages of specific neural circuit neuromodulation. Neuromodulatory effects depend on extrinsic stimulation factors (cortical target, frequency, intensity, duration, number of sessions), intrinsic patient factors (disease process, individual variability and symptoms, state of medication treatment), and outcome measures. Most studies to date have shown beneficial effects of rTMS or tDCS on clinical symptoms in Parkinson’s disease (PD) and support the notion of spatial specificity to the effects on motor and nonmotor symptoms. Stimulation parameters have varied widely, however, and some studies are poorly controlled. Studies of rTMS or tDCS in dystonia have provided abundant data on physiology, but few on clinical effects. Multiple mechanisms likely contribute to the clinical effects of rTMS and tDCS in movement disorders, including normalization of cortical excitability, rebalancing of distributed neural network activity, and induction of dopamine release. It remains unclear how to individually adjust rTMS or tDCS factors for the most beneficial effects on symptoms of PD or dystonia. Nonetheless, the noninvasive nature, minimal side effects, positive effects in preliminary clinical studies, and increasing evidence for rational mechanisms make rTMS and tDCS attractive for ongoing investigation.

rTMS makes you stronger?

A study by a group out of the University of Cologne in Germany has demonstrated that rTMS over the unaffected motor cortex of patients that have had a stroke will make their use of the affected hand more efficient and quicker.
The paper explains how rTMS is thought to work in a very nice manner and backs it up with a diagram that puts it into very understandable terms. Essentially there is imbalance between the two sides of the brain after a stroke. There are excitatory and inhibitory inputs from both sides of the brain which help us fine tune our movements, making them efficient, accurate and adaptable. Add a prehensile thumb and you start to understand the magnitude of the human brain. Now that we are figuring out how to rebalance a damaged brain the possibilities are becoming apparent. And I am sure that when we look back in twenty years or more at the preliminary data and concepts we will laugh at our shallow understanding of the subject.
Once again, I am amazed by the clinical implications of this. As a physiatrist (Physical Medicine and Rehabilitation specialist that works with stroke patients) I am encouraged and excited by the possibilities that are starting to present themselves. This is a technology that is going to revolutionize stroke rehabilitation; I am unsure if there are other advances that have occurred in this field that are comparable. The advent of clot busting drugs was a milestone, the development and use of advanced imaging techniques as well. Neuromodulation as a therapeutic intervention and as a research tool has staggering possibilities.