Schizophrenia Daily News Blog

TMS for hallucinations: update

TMS for Auditory Hallucinations: An update

I have previously posted (http://www.schizophrenia.com/szresearch/archives/001085.html) about trancranial magnetic stimulation (TMS) for schizophrenia. For a brief explanation on TMS, please see that post. Some recent research has been published that I want to present as an update.

Article 1:
The first article, Lee et al., is a double-blind, sham-controlled study in which the authors took 39 patients with treatment refractory auditory hallucinations (AH) and performed TMS for 20 minutes daily for ten straight days. These patients were considered “refractory” because they had failed adequate trials with 2 different medications and in 2 different classes (i.e. they had failed both typical and atypical agents and had taken them for a time period in which they should have worked.) Using measures to evaluate the severity of the AH and overall symptoms scales, the authors found that when the magnet was applied to either the right or left hemisphere of the brain, there was an improvement compared to the sham treatment with respect to auditory hallucinations. The greatest effect was seen with frequency of voices and with “attentional salience” or the need for the patient to pay attention to the voices. In essence, the voices came less often and were perceived as less important by the subjects who received the treatment compared to those who received a sham treatment. Side effects were minimal and generally dissipated over 10 minutes (some dizziness, nausea and one case of brief amnesia that all resolved.) However, when looking at a more descriptive measure of hallucinations, there was a less robust difference between the groups. However, these authors do demonstrate at least a small difference in the level of auditory hallucinations particularly with their frequency.

Article 2:
Poulet et al., also performed a double-blind, crossover controlled study on rTMS to treat AH. A crossover study is one in which the subjects are given both the experimental treatment and the placebo/sham treatment. (They receive one or another first and then after a short period of time passes, they are then subjected to the other condition. In that way, they are able to act as a control because if they respond to the sham condition the same as the experimental treatment then it indicates that the sham is the same effectiveness.) The authors report that when the subjects were treated with the TMS, they reported on the same scale as the report above, that they had a decreased AH in all 7 categories of the rating scale (as opposed to the study above which noted only a difference in frequency of voices.) That means that the subjects also had other subjective relief from the voices; namely loudness, frequency, salience and other indices were diminished in this study. There are some caveats to this study though. The crossover design, while a good method, is a little troublesome in this case because it is thought that the TMS lasts longer than the 1 week between treatments that was used. Therefore, it is possible that some of the benefit was still being realized by patients if they had the TMS first and sham second. However, the authors noted no difference between the groups that had the sham first or the TMS first. Also, the precise placement of the coil that was used in this study may or may not have been done in the best possible manner. However, that would be more likely to have shown a worse effect, so that it was positive even with the questionable placement speaks well for the procedure. However, in this study the authors also report the first use of a more inert sham treatment. In the past, researchers have done the sham treatment by angling the TMS probe away from the head, but that provides some measure of treatment anyways. These researchers used a true sham in which the methodology looks precisely the same. This helps to more precisely separate a placebo effect (effect where the mind helps create the positive outcome based on an expected outcome, calling into question the efficacy of the treatment itself) from the TMS which is helpful also for future research in this area.

Overall, these studies are promising for the future of treatment with rTMS. While it is still unknown the precise dose that will be needed to make these treatments effective, or for how long they are going to be effective once the treatment is stopped, it is nevertheless promising. Larger studies are needed though because all studies on TMS so far have been small and therefore subject to the possibility that it might be something that works only for a small population rather than the entire community.

Article 1:
Lee SH, Kim W, Chung YC, Jung KH, Bahk WM, Jun TY, Kim KS, George MS, Chae JH. A double blind study showing that two weeks of daily repetitive TMS over the left or right temporoparietal cortex reduces symptoms in patients with schizophrenia who are having treatment-refractory auditory hallucinations. Neurosci Lett. 2005 Mar 16;376(3):177-81. Epub 2004 Dec 9.
Click here to access on PubMed

Article 2:
Poulet E, Brunelin J, Bediou B, Bation R, Forgeard L, Dalery J, d'Amato T, Saoud M. Slow transcranial magnetic stimulation can rapidly reduce resistant auditory hallucinations in schizophrenia. Biol Psychiatry. 2005 Jan 15;57(2):188-91.
Click here to access on PubMed