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Academic Journal
OBSESSIVE COMPULSIVE DISORDER (OCD)
| Title: | Repetitive transcranial magnetic stimulation (rTMS) in the treatment of obsessive-compulsive disorder (OCD) and Tourette's syndrome (TS). | | Author(s): | Mantovani A, Lisanby SH, Pieraccini F, Ulivelli M, Castrogiovanni P, Rossi S. | | Source: | Int J Neuropsychopharmacol. 2006 Feb;9(1):95-100. Epub 2005 Jun 28. | | Abstract: | There is evidence that motor and premotor cortex are hyperexcitable in obsessive-compulsive disorder (OCD) and Tourette's syndrome (TS). We tested whether low-frequency repetitive transcranial magnetic stimulation (rTMS) could normalize overactive motor cortical regions and thereby improve symptoms. Subjects with OCD or TS were treated with active rTMS to the supplementary motor area (SMA) for 10 daily sessions at 1 Hz, 100% of motor threshold, 1200 stimuli/day. Suggestions of clinical improvement were apparent as early as the first week of rTMS. At the second week of treatment, statistically significant reductions were seen in the YBOCS, YGTSS, CGI, HARS, HDRS, SAD, BDI, SCL-90, and SASS. Symptoms improvement was correlated with a significant increase of the right resting motor threshold and was stable at 3 months follow-up. Slow rTMS to SMA resulted in a significant clinical improvement and a normalization of the right hemisphere hyperexcitability, thereby restoring hemispheric symmetry in motor threshold. |
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| | Title: | Right versus left prefrontal transcranial magnetic stimulation for obsessive-compulsive disorder: a preliminary investigation. | | Author(s): | Sachdev PS, McBride R, Loo CK, Mitchell PB, Malhi GS, Croker VM. | | Source: | J Clin Psychiatry. 2001 Dec;62(12):981-4. | | Abstract: | There is preliminary evidence that repetitive transcranial magnetic stimulation (rTMS) may be useful for the treatment of obsessive-compulsive disorder (OCD), but no definitive study has been published, and the effect of laterality of stimulation is uncertain. METHOD: Subjects (N = 12) with resistant OCD were allocated randomly to either right or left prefrontal rTMS daily for 2 weeks and were assessed by an independent rater at 1 and 2 weeks and 1 month later. RESULTS: Subjects had an overall significant improvement in the obsessions (p is less than .01), compulsions (p is less than .01), and total (p is less than .01) scores on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) after 2 weeks and at 1-month follow-up. This improvement was significant for obsessions (p is less than .05) and tended to significance for total Y-BOCS scores (p = .06) after correction for changes in depression scores on the Montgomery-Asberg Depression Rating Scale. There was no significant difference between right- and left-sided rTMS on any of the parameters examined. Two subjects (33%) in each group showed a clinically significant improvement that persisted at I month but with relapse later in I subject. CONCLUSION: A proportion (about one quarter) of patients with resistant OCD appear to respond to rTMS to either prefrontal lobe, although in the absence of a sham treatment group in this study, we cannot rule out the possibility of this being a placebo response. This treatment warrants further investigation to better establish its efficacy and examine the best parameters for response. |
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| | Title: | Altered Cortical Excitability in OCD | | Date: | 2000 | | Author(s): | Greenberg et al. | | Source: | NEUROLOGY 2000;54:142–147 | | Keywords: | OCD | | Abstract: |
Objective: To assess cortical inhibitory and excitatory mechanisms in obsessive–compulsive disorder (OCD).
Background: Transcranial magnetic stimulation (TMS) studies have found decreased neuronal inhibition and a reduced cortical silent period in the primary motor area in Tourette’s syndrome, focal dystonia, and other disorders believed to involve dysfunction of subcortical structures, including the basal ganglia. Dysfunction of the basal ganglia and linked regions also has been implicated in OCD, which has significant clinical and familial overlap with tic disorders.
Methods: We applied the TMS techniques previously used in Tourette’s syndrome to a group of 16 OCD patients (seven unmedicated) and 11 age-matched healthy volunteers extensively screened for psychopathology. Measures of motor cortex excitability included resting and active motor threshold, cortical silent period duration, and intracortical inhibition and
facilitation using a paired-pulse TMS technique with a subthreshold conditioning stimulus.
Results: Similar to recent findings in Tourette’s syndrome and focal dystonia, this study reports significantly decreased intracortical inhibition (ICI) relative to the volunteers at interstimulus intervals from 2 to 5 msec. We also found decreased active and resting motor evoked potential threshold in the OCD patients, another indication of increased cortical excitability. Neither abnormality appeared medication related. The decreases in ICI and motor threshold were greatest in OCD patients with comorbid tics,
but remained significant in patients without tics.
Conclusions: The data suggest abnormal cortical excitability in obsessive–
compulsive disorder. These findings are congruent with the hypothesis that Tourette’s syndrome and obsessive–compulsive disorder (OCD) are analogous disorders with overlapping dysfunction in corticobasal circuits. Patients with tic-related OCD may have more abnormal motor cortex excitability than OCD patients without tics.
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