Biochemical changes after repetitive transcranial magnetic stimulation (rTMS)
There have been no reports of biochemical changes associated with the use of rTMS except preliminary studies in our clinical program (1).
We have measured changes in several physiological parameters after use of rTMS. We have done this in an attempt to evaluate if biochemical changes after rTMS were associated with the inhibition of phantageusia (taste distortions in the absence of any oral stimulus) which we have been monitoring. Indeed, we have found that rTMS has been useful in inhibiting phantageusia in 80% of patients with these distortions (2,3).
Although rTMS has been used by many physicians to treat depression, tinnitus and several neurological disorders and we found it useful in treating sensory distortions, only in our studies have any biochemical changes after rTMS been demonstrated (2).
In order to verify and expand our prior studies in a larger group of patients, we measured carbonic anhydrase in red blood cells (CA I,II) and in saliva (CA VI) in 70 patients with phantageusia before and after rTMS. After rTMS, CA I,II in red blood cells and CA VI in saliva increased significantly from the untreated state consistent with inhibition of their phantageusia.
These results verify our prior studies demonstrating biochemical changes after rTMS. These results demonstrate that CA VI, a specific salivary growth factor necessary for normal taste and smell function, increases after rTMS consistent with its efficacy in improving taste function (4).