Background

Major depressive disorder (MDD) and chronic pain are highly comorbid, and pain symptoms are associated with a poorer response to antidepressant medication treatment. It is unclear whether comorbid pain also is associated with a poorer response to treatment with repetitive transcranial magnetic stimulation (rTMS).

Methods

162 MDD subjects received 30 sessions of 10 Hz rTMS treatment administered to the left dorsolateral prefrontal cortex (DLPFC) with depression and pain symptoms measured before and after treatment. For a subset of 96 patients, a resting-state electroencephalogram (EEG) was recorded at baseline. Clinical outcome was compared between subjects with and without comorbid pain, and the relationships among outcome, pain severity, individual peak alpha frequency (PAF), and PAF phase-coherence in the EEG were examined.

Results

64.8% of all subjects reported pain, and both depressive and pain symptoms were significantly reduced after rTMS treatment, irrespective of age or gender. Patients with severe pain were 27% less likely to respond to MDD treatment than pain-free individuals. PAF was positively associated with pain severity. PAF phase-coherence in the somatosensory and default mode networks was significantly lower for MDD subjects with pain who failed to respond to MDD treatment.

Conclusions

Pain symptoms improved after rTMS to left DLPFC in MDD irrespective of age or gender, although the presence of chronic pain symptoms reduced the likelihood of treatment response. Individual PAF and baseline phase-coherence in the sensorimotor and midline regions may represent predictors of rTMS treatment outcome in comorbid pain and MDD.

We examined the safety and efficacy of repetitive Transcranial Magnetic Stimulation (rTMS) of the right orbitofrontal cortex (OFC) in patients with refractory obsessive-compulsive disorder (OCD) and comorbid Major Depressive Disorder. All participants (n = 26) received excitatory stimulation of the left dorsolateral prefrontal cortex followed by inhibitory stimulation of bilateral supplementary motor area for 10 sessions. In 18 patients with poor early OCD response, treatment was augmented with OFC inhibitory stimulation after the tenth treatment session. Augmentation with OFC stimulation was well-tolerated, and associated with further alleviation of both OCD and depression symptoms, particularly in individuals with more severe illnesses.

Background

Tinnitus distress is related to both the loudness and intrusiveness of the tinnitus percept. Treatment approaches targeting both attentional/limbic and auditory systems may better alleviate tinnitus distress than approaches targeting the auditory system alone.

Materials and methods

Ten subjects with chronic tinnitus received sequential rTMS treatment involving: 1) excitatory stimulation administered to the left dorsolateral prefrontal cortex (DLPFC) or inhibitory stimulation administered to the right DLPFC, followed by 2) inhibitory stimulation administered to primary auditory cortex (Heschel's gyrus or HG). A systematic literature review was performed to evaluate the existing literature on sequential repetitive Transcranial Magnetic Stimulation (rTMS) treatment approaches for tinnitus. Results of the case series are interpreted in the context of tinnitus neurobiology and the extant literature.

Results

Subjects experienced a significant decrease (average 21.7%) in symptoms on the Tinnitus Functional Index (TFI). Those with tinnitus alone experienced a greater mean symptom reduction than those with comorbid MDD (27.7 vs. 17.0%, respectively). Adverse effects were transient and minor. Literature review confirmed that sequential approaches had some advantages compared to single site rTMS; in general, the addition of 1 Hz treatment at DLPFC was superior to single site rTMS in the short term (1-12 weeks), while the addition of 20 Hz treatment at DLPFC appeared superior in the long term (90-180 days).

Conclusions

Sequential rTMS approaches for the treatment of tinnitus-particularly those administering low-frequency treatment at left DLPFC-merit further investigation.

Background

Specific phobias represent the largest category of anxiety disorders. Previous work demonstrated that stimulating the ventromedial prefrontal cortex (vmPFC) with repetitive Transcranial Magnetic Stimulation (rTMS) may improve response to exposure therapy for acrophobia.

Objective

To examine feasibility of accelerating extinction learning in subjects with spider phobia using intermittent Theta Burst Stimulation (iTBS) rTMS of vmPFC.

Methods

In total, 17 subjects with spider phobia determined by spider phobia questionnaires [Spider Phobia Questionnaire (SPQ) and Fear of Spiders questionnaire (FSQ)] underwent ratings of fear of spiders as well as behavioral and skin conductance data during a behavioral avoidance test (BAT). Subjects then received a sequential protocol of in vivo spider exposure followed by iTBS for three sessions administered to either active or control treatment sites (vmPFC [n = 8] or vertex [n = 9], respectively), followed 1 week later by repetition of questionnaires and BAT.

Results

All subjects improved significantly regardless of group across both questionnaires (FSQ η² = 0.43, p = 0.004; SPQ η² = 0.39, p = 0.008) and skin conductance levels during BAT (Wald χ² = 30.9, p < 0.001). Subjects in the vmPFC group tolerated lower treatment intensity than in the control group, and there was a significant correlation between treatment intensity, BAT subjective distress improvement, and physiologic measures (all ρ > 0.5).

Conclusion

This proof-of-concept study provides preliminary evidence that a sequential exposure and iTBS over vmPFC is feasible and may have rTMS intensity-dependent effects on treatment outcomes, providing evidence for future areas of study in the use of rTMS for phobias.

Background

Repetitive Transcranial Magnetic Stimulation (rTMS) is an effective intervention for treatment-resistant Major Depressive Disorder (MDD). Early improvement during high-frequency left-sided (HFL) stimulation of the dorsolateral prefrontal cortex (DLPFC) is an important predictor of longer-term outcome, but most patients benefit later in their treatment course. We examined patients without early improvement with HFL to determine whether augmentation with additional stimulation approaches improved treatment outcome.

Methods

139 participants received HFL in a measurement-based care paradigm. Participants who achieved < 20% improvement by treatment 10 could continue with HFL (N = 17) or receive one of two augmentation strategies: bilateral stimulation (BL; HFL followed by low-frequency stimulation of right DLPFC) (N = 69) or intermittent theta-burst priming of left DLPFC (iTBS-P) (N = 17) for their remaining treatment sessions. The primary outcome was the percent reduction in depressive symptoms at treatment 30.

Results

Participants who achieved < 20% improvement by treatment 10 and continued with HFL showed limited benefit. iTBS-P participants had significantly greater improvement, while those receiving BL trended toward improved outcomes. Ten sessions of either augmentation strategy appeared necessary to determine the likelihood of benefit.

Conclusions

Augmentation of early non-response to HFL appears to improve rTMS outcomes, with a novel iTBS-P strategy surpassing both continued HFL or BL treatment in participants with < 20% improvement after 10 treatments. These findings suggest that measurement-based care with addition of augmented stimulation for those not showing early improvement may yield superior rTMS treatment outcomes.

Background

Symptoms of major depressive disorder (MDD) are reported to change early in treatment with repetitive transcranial magnetic stimulation (rTMS). We evaluated early changes in sleep, anxiety, and mood as predictors of nonresponse to rTMS treatment.

Methods

Three hundred twenty-nine subjects with nonpsychotic MDD completed a 6-week course of rTMS treatment. Subjects were stratified by the severity of their baseline depression, and had their overall depressive symptoms recorded every week of treatment. We evaluated lack of improvement in sleep, anxiety, and mood symptoms after 1 and 2 weeks as potential predictors of eventual nonresponse, defined as <50% improvement in compositive depressive symptoms after 6 weeks. This was measured as negative predictive value (NPV; the likelihood that lack of early symptom improvement accurately predicted eventual treatment nonresponse).

Results

Subjects with severe or very severe baseline depression achieving <20% improvement in mood at 1 week were correctly predicted as nonresponders with NPVs largely >90%. At 2 weeks, subjects with very severe baseline depression who failed to demonstrate any improvement in mood were all nonresponders. Lack of improvement in sleep at 2 weeks was also a significant predictor.

Conclusions

Identifying a lack of early mood improvement is a practical and robust method to predict rTMS nonresponse. This suggests a treatment protocol change may be indicated in patients with more severe baseline depression showing minimal early mood improvement.

Background

Intermittent theta-burst stimulation priming (iTBS-P) can improve clinical outcome of patients with Major Depressive Disorder (MDD) who do not show early benefit from 10 Hz stimulation of left dorsolateral prefrontal cortex (DLPFC), also known as high-frequency left-sided (HFL) stimulation. The intensity and pulse number for iTBS-P needed to induce clinical benefit have not been systematically examined.

Objective

To study the effect of intensity and pulse number on the clinical efficacy of iTBS-P.

Methods

We conducted a retrospective review of 71 participants who received at least five sessions of HFL with limited clinical benefit and received iTBS-P augmentation for between 5 and 25 sessions. Intensity of iTBS-P priming stimuli ranged from 75 to 120% of motor threshold (MT) and pulse number ranged from 600 to 1800. Associations among intensity, pulse number, and clinical outcome were analyzed using a mixed methods linear model with change in IDS-SR as the primary outcome variable, priming stimulation intensity (subthreshold or suprathreshold), pulse number (<1200 or >1200 pulses), and gender as fixed factors, and number of iTBS-P treatments and age as continuous covariates.

Results

Subjects who received subthreshold intensity iTBS-P experienced greater reduction in depressive symptoms than those who received suprathreshold iTBS-P (p = 0.011) with no effect of pulse number after controlling for stimulus intensity.

Conclusions

Subthreshold intensity iTBS-P was associated with greater clinical improvement than suprathreshold stimulation. This finding is consistent with iTBS-P acting through homeostatic plasticity mechanisms.