Journal: Brain Stimulation
Authors: M Graller, L Viner, J Viner
Background:
Evidence is accumulating in support of the use of TMS for the treatment of OCD. The anterior cingulate cortex (ACC) is the brain target of choice for OCD because it is central in the processing of negative emotions including fear and threat, which is at the core of OCD symptoms. Thus far, it has not been established whether a deregulated ACC may be associated with more positive outcomes for TMS treatment targeting the ACC.
Objective:
The purpose was twofold: 1) to examine whether dTMS targeting the anterior cingulate cortex is beneficial in reducing severe obsessional thinking in complex patients and 2) to determine whether treatment response may be associated with a deregulated anterior cingulate cortex and/or certain genotypes.
Methods:
A sample of 8 patients, 4 male and 4 female, aged 19-31, participated in the study. All 8 patients had severe obsessional thinking as determined independently by three senior psychiatrists. Baseline YBOCS, qEEG, and genomic analysis from Genomind were obtained at admission to treatment in an intensive outpatient facility. Patients underwent 29 DTMS treatments delivered over a 6-week period utilizing the H7 dTMS. YBOCS were measured weekly.
Results:
All 8 patients achieved at least partial response to treatment. Five patients achieved full (>30% reduction on the YBOCS) and 3 achieved partial (>20% reduction) response to treatment. Two of the 8 achieved full remission (<10 final YBOCS score). Severe deregulation (> 2 SD) was found in delta, theta, and gamma bands at Fz (over the ACC) in 5 of 8 qEEGs. Also, for the 6 patients who had full genomic analyses, all shared INS/INS genotype on ADRA2 and 5 of the 6 shared MET/MET genotype on COMT.
Conclusions:
The preliminary results support the use of dTMS, targeting the ACC, in the treatment of obsessional thinking. These findings also suggest that certain qEEG and genomic markers may be associated with treatment response in OCD. The increased delta and theta frequencies found are associated with the perseverative nature of OCD while the increased gamma is associated with increased anxiety and worry. The MET/MET genotype of COMT is linked with higher levels of dopamine in the prefrontal cortex associated in OCD. The ADRA2 genotype is associated with norepinephrine release and modulation and may be implicated in stress reactions in the severe cases.
Link to Article:
https://www.brainstimjrnl.com/article/S1935-861X(18)30243-2/abstract
