The application of transcranial magnetic stimulation in psychiatry and neurosciences research

2008

Can J Psychiatry

D eveloped for various investigative and potential therapeutic purposes, rTMS is a relatively new technique. Its use in experimental settings is growing rapidly 1 and its potential as a treatment is being tested in numerous neurological and psychiatric conditions. Most research and interest has focused on the potential application of rTMS in the treatment of depression. In addition, in recent years an increasing number of open and double-blind studies of rTMS were conducted in patients with schizophrenia. However, owing to the complexity of this disorder, the development of therapeutic rTMS paradigms is problematic. At least partially in response to this, most investigators have chosen to focus on the treatment of specific refractory symptoms or syndromes within the disorder. We aim to review the current status of the development of the therapeutic applications of rTMS in the treatment of schizophrenia or its symptoms. Highlights • Low-frequency rTMS applied to the temporoparietal cortical region appears to be able to modulate the severity of auditory hallucinations. • Prefrontal rTMS has promise but requires further evaluation in the treatment of negative symptoms of schizophrenia. • rTMS can be safely used in patients with schizophrenia and warrants further investigation.

Section: Tms Methods Have Become Widely Used Inmentioning

confidence: 99%

“…Its use in experimental settings is growing rapidly 1 and its potential as a treatment is being tested in numerous neurological and psychiatric conditions. Most research and interest has focused on the potential application of rTMS in the treatment of depression.…”

mentioning

confidence: 99%

A Review of Repetitive Transcranial Magnetic Stimulation Use in the Treatment of Schizophrenia

Fitzgerald

2008

Can J Psychiatry

“…Depending on the parameters of stimulation, rTMS can modulate cortical excitability in relatively focal areas , with frequencies p1 Hz (low-frequency rTMS or LF-rTMS) being usually inhibitory, and higher frequencies (X5 Hz; high-frequency rTMS or HF-rTMS) being usually excitatory (Fitzgerald et al, 2002;Marangell et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Clinically Meaningful Efficacy and Acceptability of Low-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) for Treating Primary Major Depression: A Meta-Analysis of Randomized, Double-Blind and Sham-Controlled Trials

Berlim

Eynde

2012

Neuropsychopharmacol

248

141

Clinical trials on low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the right dorsolateral prefrontal cortex have yielded conflicting evidence concerning its overall efficacy for treating major depression (MD). As this may have been the result of limited statistical power of individual trials, we have carried the present systematic review and meta-analysis to examine this issue. We searched the literature for English language randomized, double-blind and sham-controlled trials (RCTs) on LF-rTMS for treating MD from 1995 through July 2012 using EMBASE, PsycINFO, Cochrane Central Register of Controlled Trials, SCOPUS, and ProQuest Dissertations & Theses, and from October 2008 until July 2012 using MEDLINE. The main outcome measures were response and remission rates as well as overall dropout rates at study end. We used a random-effects model, odds ratios (ORs) and number needed to treat (NNT). Data were obtained from eight RCTs, totaling 263 subjects with MD. After an average of 12.6±3.9 rTMS sessions, 38.2% (50/131) and 15.1% (20/132) of subjects receiving active LF-rTMS and sham rTMS were classified as responders (OR ¼ 3.35; 95% CI ¼ 1.4-8.02; p ¼ 0.007). Also, 34.6% (35/101) and 9.7% (10/103) of subjects receiving active LF-rTMS and sham rTMS were classified as remitters (OR ¼ 4.76; 95% CI ¼ 2.13-10.64; po0.0001). The associated NNT for both response and remission rates was 5. Sensitivity analyses have shown that protocols delivering 41200 magnetic pulses in total as well as those offering rTMS as a monotherapy for MD were associated with higher rates of response to treatment. No differences on mean baseline depression scores and dropout rates for active and sham rTMS groups were found. Finally, the risk of publication bias was low. In conclusion, LF-rTMS is a promising treatment for MD, as it provides clinically meaningful benefits that are comparable to those of standard antidepressants and high-frequency rTMS. Furthermore, LF-rTMS seems to be an acceptable intervention for depressed subjects.

“…A number of TMS paradigms have been used to assess the activity of the GABA A and GABA B receptors in the motor cortex in human subjects (Chen, 2000;Fitzgerald et al, 2002a), and changes in this functioning in disease states such as schizophrenia and depression (Daskalakis et al, 2002(Daskalakis et al, , 2008Fitzgerald et al, 2003;Wobrock et al, 2008). One of these paradigms involves suprathreshold stimulation of the motor cortex during the tonic contraction of a muscle in the contralateral hand.…”

Section: Introductionmentioning

confidence: 99%

A Transcranial Magnetic Stimulation Study of the Effects of Cannabis Use on Motor Cortical Inhibition and Excitability

Fitzgerald

Williams

2009

Neuropsychopharmacol

Active compounds in cannabis such as tetrahydrocannabinol (THC) interact with the inhibitory neurotransmitter d-aminobutyric acid (GABA) but little is known about the functional effects of cannabis on human cortical brain processes. Therefore, the aim of the study was to investigate whether patients with chronic cannabis use demonstrate abnormalities in cortical inhibition or excitability. In all, 42 chronic cannabis using subjects (divided into heavy and light using subjects) and 19 controls were included in the study. Single and paired pulse transcranial magnetic stimulation were used to assess a number of parameters of cortical inhibition and cortical excitability. In addition, psychomotor function and THC plasma levels were measured. Both cannabis using groups (heavy and light use) demonstrated a reduction in short interval cortical inhibition compared with healthy controls, but there was no difference in other measures of cortical inhibition or cortical excitability. There was also no difference between the two groups on measures of psychomotor performance. Chronic cannabis use is associated with a reduction in cortical inhibition potentially related to activity at the GABA A receptors. Further research is required to explore whether this results from chronic cannabis use or reflects an underlying predisposition to developing chronic substance use problems.