Right Dorsolateral Prefrontal Cortex Research Articles

A single 1,500 m freestyle at maximal speed decreases cognitive function in athletes.

Physical exercise can improve cognitive function, and the degree of impact on cognitive function is related to exercise modality, intensity, and duration. However, few studies have been conducted on the effects of competitive sports on cognitive function. The 1,500 m freestyle is the longest pool-based swimming event in the Olympic Games. This study explores the effects of 1,500 m freestyle at maximal speed on athletes' cognitive function and analyzes the potential mechanism of cognitive function reduction in freestyle at maximal speed from the perspective of hemoglobin oxygenation difference (Hbdiff). A total of 13 male university swimmers were required to take part in a 1,500 m freestyle competition, swimming at maximal speed. The relevant indicators, including cognitive function and freestyle at maximal speed, before and after the competition were tested and analyzed. Cognitive function was assessed using the Schulte grid test (SGT), the trail-making test (TMT), and the digit span test (DST). The neurobiological characteristics of cognitive function, such as the prefrontal cortex (PFC), response time (RT), and accuracy rate (ACC), were tested using functional near-infrared spectroscopy (fNIRS). A significant decrease in scores for SGT, TMT, and digit span test-backward (DST-B) (p < 0.01). Oxygenated hemoglobin (Oxy-Hb) concentrations in the right frontopolar area (R-FPA) of brain channels 8 (p < 0.01) and 9 (CH8, 9) (p < 0.05), the right dorsolateral prefrontal cortex (R-DLPFC) CH10 (p < 0.05), and the middle dorsolateral prefrontal cortex (M-DLPFC) CH18 (p < 0.01) were significantly altered, and the right area of the brain was activated. The total Oxy-Hb concentrations in the regions of interest (ROIs) of R-FPA, R-DLFPC, and M-DLFPC were changed significantly (p < 0.01). The exhaustive performance of a 1,500 m freestyle event resulted in both physical fatigue and a decline in cognitive function. This decline may be attributed to the activation of specific regions of interest, namely the FPA, DLPFC, and M-DLPFC, within the prefrontal cortex (PFC), as well as alterations in functional connectivity.

Abnormal resting-state effective connectivity in large-scale networks among obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is a chronic mental illness characterized by abnormal functional connectivity among distributed brain regions. Previous studies have primarily focused on undirected functional connectivity and rarely reported from network perspective. To better understand between or within-network connectivities of OCD, effective connectivity (EC) of a large-scale network is assessed by spectral dynamic causal modeling with eight key regions of interests from default mode (DMN), salience (SN), frontoparietal (FPN) and cerebellum networks, based on large sample size including 100 OCD patients and 120 healthy controls (HCs). Parametric empirical Bayes (PEB) framework was used to identify the difference between the two groups. We further analyzed the relationship between connections and Yale-Brown Obsessive Compulsive Scale (Y-BOCS). OCD and HCs shared some similarities of inter- and intra-network patterns in the resting state. Relative to HCs, patients showed increased ECs from left anterior insula (LAI) to medial prefrontal cortex, right anterior insula (RAI) to left dorsolateral prefrontal cortex (L-DLPFC), right dorsolateral prefrontal cortex (R-DLPFC) to cerebellum anterior lobe (CA), CA to posterior cingulate cortex (PCC) and to anterior cingulate cortex (ACC). Moreover, weaker from LAI to L-DLPFC, RAI to ACC, and the self-connection of R-DLPFC. Connections from ACC to CA and from L-DLPFC to PCC were positively correlated with compulsion and obsession scores (r = 0.209, p = 0.037; r = 0.199, p = 0.047, uncorrected). Our study revealed dysregulation among DMN, SN, FPN, and cerebellum in OCD, emphasizing the role of these four networks in achieving top-down control for goal-directed behavior. There existed a top-down disruption among these networks, constituting the pathophysiological and clinical basis.

Counter-stereotype intervention for construction and demolition waste recycling products: A functional near infrared spectroscopy study

The generation and stock of construction and demolition (C&D) waste is increasing, which makes the environmental and economic problems serious. In recent years, China has also launched many policies to encourage and guide C&D waste recycling. However, most of these policies are aimed at contractors and recycling utilization parties, while the lack of publicity and promotion has led to the acceptance in the market is generally low. People may have a negative stereotype of this recycled material recycled from C&D waste.In order to explore a measure that can alleviate this problem, this study used experimental research methods from psychology and neuroscience to investigate the mechanisms of different presentation forms of counter-stereotype intervention materials. This study included two experiments: the pretest experiment verified the implicit-explicit stereotype and neuronal image representation of C&D recycling products through single category implicit association test (SC-IAT), semantic difference scale and functional near-infrared (fNIRS). The posttest experiment was based on the counter-stereotype intervention method and intergroup contact theory. A within-participants design was used to investigate the effectiveness of counter-stereotype intervention and the differences in two intervene presentation forms based on the pretest experiment.The results showed that the counter-stereotype intervention was effective in suppressing the activation of stereotypes. The effects of the intervention were similar for both the video and graphic formats. In the neuron imaging representation of the posttest experiment, the significantly activated brain region shifted from the right dorsolateral prefrontal cortex (R-dlPFC) to the left dorsolateral prefrontal cortex (L-dlPFC). L-dlPFC is highly associated with the modulation of cognition, indicating that after the counter-stereotype intervention, the necessity of C&D waste recycling and the credibility of the recycling product influenced the participants. So when the stereotype was reactivated, the signal in the L-dlPFC was suppressed, weakening the expression of the stereotype. This also suggests that the mechanism of counter-stereotype intervention is to strengthen the brain regulatory system rather than to inhibit the activation of stereotypes at the source.

Transcranial magnetic stimulation in late-aged people with depressive disorders

IntroductionOne of the most common mental disorders in the elderly is depression.Because of the high frequency of side effects of pharmacotherapy and the comorbid medical illnesses, there are not many ways to treat it.Non-drug therapies, such as repetitive transcranial magnetic stimulation (rTMS), could help overcome the limitations of standard drug therapy for this type of mental disorders.ObjectivesDevelopment of approaches to improving improve the provision of psychiatric care to elderly patients using rTMS.Methods30 patients over the age of 60 with anxiety-depressive spectrum disorders meeting criteria F30-39, F06.3, F06.4 (ICD-10) and a control group with similar criteria that were not treated with rTMS, were recruited from the psychiatric department at a university hospital (Moscow Scientific Research Institute of Psychiatry). Clinical, psychopathological, anamnestic, psychometric (Montgomery-Asberg scale (MADRS), Hamilton scale (HARS), Mini-mental state examination scale (MMSE) instrumental (electroencephalography) research methods were used. Patients of the experimental group underwent 15 sessions of low-frequency rTMS on the right dorsolateral prefrontal cortex (RDLPC). Conditions for the application of 1200 pulses were as follows: frequency - 1 Hz; intensity - 120% of the threshold of motor response (RMT) of the subject; pulse number - 1200; pulse sequence - 300; sequence duration - 300 seconds; sequence interval - 60 seconds; and stimulation time - 23 minutes. Subsequently, the patients were re-examined using the above-mentioned scales to assess their mental state in dynamics.ResultsAnalysis of the collected data shows an increase in the number of respondents and the frequency of achieving remission in the experimental group compared to the control group. No severe side effects of rTMS were observed.ConclusionsrTMS may be a safe method of adjuvant therapy in groups of elderly patients with anxiety-depressive spectrum disorders. Further studies will be needed to clarify the results.Disclosure of InterestNone Declared

Does intermittent theta burst stimulation improve working memory capacity? A randomized controlled cross-over experiment

ObjectiveIt has been hypothesized that intermittent theta burst stimulation (iTBS) can produce a memory-enhancing effect by inducing long-term potentiation (LTP)-like plasticity in the dorsolateral prefrontal cortex (DLPFC). However, the hemispheric difference by which iTBS modulates working memory in healthy adults has not been well investigated. The objective of the present study is to investigate the effects of iTBS on the left dorsolateral prefrontal cortex (LDLPFC) and right dorsolateral prefrontal cortex (RDLPFC) on working memory performance in healthy adults. MethodsIn this randomized cross-over experiment, 31 right-hand dominant healthy adults received a single-session of iTBS to their LDLPFC, RDLPFC and sham stimulation, in three different visits separated by a seven-day waiting period. Working memory capacity was assessed before and immediately after stimulation, by using 2-and 3-back tasks. ResultsAfter stimulation, significant time effects were found in overall accuracy when performing both 2- (p = 0.013) and 3-back tasks (p = 0.027), as well as the total reaction time during 3-back tasks (p = 0.021). Analysis of secondary outcomes showed an increase in the number of correction rejections in 2-back tasks (p = 0.009). However, all of the time-by-group interaction effects were not significant. ConclusionThis experiment did not find any additional memory-enhancing effects with a single-session of iTBS to either the RDLPFC or the LDLPFC in healthy adults beyond the practice effects.

Activation in Right Dorsolateral Prefrontal Cortex Underlies Stuttering Anticipation.

People who stutter learn to anticipate many of their overt stuttering events. Despite the critical role of anticipation, particularly how responses to anticipation shape stuttering behaviors, the neural bases associated with anticipation are unknown. We used a novel approach to identify anticipated and unanticipated words, which were produced by 22 adult stutterers in a delayed-response task while hemodynamic activity was measured using functional near infrared spectroscopy (fNIRS). Twenty-two control participants were included such that each individualized set of anticipated and unanticipated words was produced by one stutterer and one control participant. We conducted an analysis on the right dorsolateral prefrontal cortex (R-DLPFC) based on converging lines of evidence from the stuttering and cognitive control literatures. We also assessed connectivity between the R-DLPFC and right supramarginal gyrus (R-SMG), two key nodes of the frontoparietal network (FPN), to assess the role of cognitive control, and particularly error-likelihood monitoring, in stuttering anticipation. All analyses focused on the five-second anticipation phase preceding the go signal to produce speech. The results indicate that anticipated words are associated with elevated activation in the R-DLPFC, and that compared to non-stutterers, stutterers exhibit greater activity in the R-DLPFC, irrespective of anticipation. Further, anticipated words are associated with reduced connectivity between the R-DLPFC and R-SMG. These findings highlight the potential roles of the R-DLPFC and the greater FPN as a neural substrate of stuttering anticipation. The results also support previous accounts of error-likelihood monitoring and action-stopping in stuttering anticipation. Overall, this work offers numerous directions for future research with clinical implications for targeted neuromodulation.

Scarcity Mindset Neuro Network Decoding With Reward: A Tree-Based Model and Functional Near-Infrared Spectroscopy Study.

Resource scarcity imposes challenging demands on the human cognitive system. Insufficient resources cause the scarcity mindset to affect cognitive performance, while reward enhances cognitive function. Here, we examined how reward and scarcity simultaneously contribute to cognitive performance. Experimental manipulation to induce a polar scarcity mindset and reward conditions within participants under functional near-infrared spectroscopy (fNIRS) recording was implemented to explore the mechanism underlying the scarcity mindset and reward in terms of behavior and neurocognition. Participants showed decreased functional connectivity from the dorsolateral prefrontal cortex (DLPFC) to the ventrolateral prefrontal cortex (VLPFC) with a scarcity mindset, a region often implicated in cognitive control. Moreover, under reward conditions, the brain activation of the maximum total Hb bold signal was mainly located in the left hemisphere [channels 1, 3, and 4, left ventrolateral prefrontal cortex (L-VLPFC) and channel 6, left dorsolateral prefrontal cortex (L-DLPFC)], and there was also significant brain activation of the right dorsolateral prefrontal cortex (R-DLPFC) in the right hemisphere (channel 17). Furthermore, these data indicate the underlying neural changes of the scarcity mentality and demonstrate that brain activities may underlie reward processing. Additionally, the base-tree machine learning model was trained to detect the mechanism of reward function in the prefrontal cortex (PFC). According to SHapley Additive exPlanations (SHAP), channel 8 contributed the most important effect, as well as demonstrating a high-level interrelationship with other channels.

Evaluation of a 5 day accelerated 1 Hz repetitive transcranial magnetic stimulation protocol in major depression: A feasibility study

• rTMS is an effective intervention in major depressive disorder, but has limited accessibility. • Shortening rTMS courses while retaining similar effectiveness would increase scalability. • We delivered 8 daily sessions of 1 Hz rTMS over 5 days. • Treatment was safe, well-tolerated and effective. • Validation in a randomized trial will be required. Repetitive transcranial magnetic stimulation (rTMS) is an effective intervention in major depressive disorder (MDD) but requires daily travel to a treatment clinic over several weeks. Shorter rTMS courses retaining similar effectiveness would thus increase the practicality and scalability of the technique, and therefore its accessibility. We assessed the feasibility of a novel 5 day accelerated 1 Hz rTMS protocol. We hypothesized that this novel rTMS protocol would be safe and well-tolerated while shortening the overall treatment course. We conducted a prospective, single-arm, open-label feasibility study. Thirty (30) participants received a one-week (5 days) accelerated (8 sessions per day, 40 sessions total) course of 1 Hz rTMS (600 pulses per session, 50-minute intersession interval) over the right dorsolateral prefrontal cortex (R-DLPFC) using a figure-of-eight coil at 120% of the resting motor threshold (rMT). Primary outcomes were response and remission rates on the Beck Depression Inventory-II (BDI-II). Response and remission rates 1 week after treatment were 33.3% and 13.3% respectively and increased to 43.3% and 30.0% at follow-up 4 weeks after treatment. No serious adverse events occurred. All participants reported manageable pain levels. 1 Hz rTMS administered 8 times daily for 5 days is safe and well-tolerated. Validation in a randomized trial will be required. ClinicalTrials.gov Identifier: NCT04376697.

Repetitive transcranial magnetic stimulation in chronic tension-type headache: A pilot study.

Background & objectives:Tension-type headache (TTH) is the most common type of primary headache disorder. Its chronic form is often the most ignored and challenging to treat. Transcranial magnetic stimulation (TMS) is a novel technique in the treatment of chronic pain. The aim of this pilot study was to explore the effect of low-frequency repetitive TMS (rTMS) on pain status in chronic TTH (CTTH) by subjective and objective pain assessment.Methods:Patients (n=30) diagnosed with CTTH were randomized into rTMS (n=15) and placebo (n=15) groups in this study. Pre-intervention detailed history of patients was taken. Numerical Rating Scale (NRS) for Pain and questionnaires [Headache Impact Test-6 (HIT-6), McGill Pain Questionnaire, Pain Beliefs Questionnaire, Coping Strategies Questionnaire, State-Trait Anxiety Inventory Test, Hamilton Rating Scale for Depression and WHO-Quality of Life Questionnaire-Brief version] were filled, and objective assessments such as nociceptive flexion reflex (NFR) and conditioned pain modulation were done. The tests were repeated after 20 sessions (5 days/week). In the rTMS group, 1200 pulses in eight trains of 150 pulses each were given at 1Hz over the right dorsolateral prefrontal cortex (RDLPFC). In the placebo group, the rTMS coil was placed such that magnetic stimulation did not reach the cortex.Results:The NRS score decreased significantly (P<0.001) and NFR thresholds increased significantly (P=0.011) in the rTMS group when compared to placebo group.Interpretation & conclusions:Subjective improvements in the NRS, HIT-6, McGill Present Pain Intensity, trait of anxiety and psychological pain beliefs were observed. The increase in the thresholds of NFR served as an objective marker for improvement in pain status. Further studies need to be done to confirm our preliminary findings.

Response and Remission Rates Following High-Frequency vs. Low-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) Over Right DLPFC for Treating Major Depressive Disorder (MDD): A Meta-Analysis of Randomized, Double-Blind Trials

Background: High-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (L-DLPFC) is the most widely applied treatment protocol for major depressive disorder (MDD), while low-frequency (LF) rTMS over the right DLPFC (R-DLPFC) also exhibits similar, if not better, efficacy for MDD. Therefore, a meta-analysis is warranted to compare the efficacy of the two protocols for MDD.Method: We searched the literature from 1990 through to August 1, 2017 using MEDLINE, and the literature from 1995 through to August 1, 2017 using EMBASE, PsycINFO, the Cochrane Central Register of Controlled Trials (CENTRAL), SCOPUS, and ProQuest Dissertations and Theses (PQDT). We included randomized controlled trials (RCT) comparing the efficacy of HF rTMS over the L-DLPFC and LF rTMS over the R-DLPFC for MDD, which used response and/or remission rates as the primary endpoints, with and without sham-controlled.Results: (1) The meta-analysis of the response rates was based on 12 studies, including 361 patients with MDD (175 for HF (> 5 Hz) over the L-DLPFC, and 186 for LF (<5 Hz) over the R-DLPFC; odds ratio = 1.08; 95%, confidence interval = 0.88–1.34). (2) The meta-analysis of the remission rate was based on 5 studies, including 131 MDD patients (64 for HF over the L-DLPFC and 67 for LF over the R-DLPFC; odds ratio = 1.29; 95% confidence interval = 0.54–3.10).Conclusion: Both HF rTMS over the L-DLPFC and LF over the R-DLPFC demonstrated similar therapeutic efficacy for the treatment of patients with MDD. The results suggested that further investigation on treatment efficacy indicators before/during treatment is necessary and helpful for optimizing a personalized protocol for patients.

Spatial working memory encoding type modulates prefrontal cortical activity.

Spatial working memory (SWM) involves both simultaneous and sequential encoding, but the differences in their neural correlates are unclear. We investigated the differences in prefrontal cortex activity related to these SWM encoding types. We also examined the patterns of brain activity influencing individual visuospatial abilities (VSA). We conducted SWM tasks with two different conditions, sequential and simultaneous encoding, and examined hemodynamic activity in 39 healthy adults using near-infrared spectroscopy. The bilateral dorsolateral prefrontal cortex was activated more strongly in the sequential condition compared with the simultaneous condition. This suggests that prefrontal cortex activity underlying SWM is modulated by the type of encoding. We also found that individuals with high VSA showed weaker activation in the right-dorsolateral prefrontal cortex compared with those with lower VSA during the simultaneous condition. This hypoactivation is thought to reflect neural efficiency in the individuals with high ability. These findings are expected to lead to a better understanding of neural substrates for SWM.

Preliminary results from a randomized sham-controlled trial of augmentative Neuro-navigated right-dorsolateral prefrontal cortex low-frequency repetitive transcranial magnetic stimulation for antidepressant non-responding Bipolar depression

Preliminary results from a randomized sham-controlled trial of augmentative Neuro-navigated right-dorsolateral prefrontal cortex low-frequency repetitive transcranial magnetic stimulation for antidepressant non-responding Bipolar depression

Anodal tDCS to Right Dorsolateral Prefrontal Cortex Facilitates Performance for Novice Jazz Improvisers but Hinders Experts.

Research on creative cognition reveals a fundamental disagreement about the nature of creative thought, specifically, whether it is primarily based on automatic, associative (Type-1) or executive, controlled (Type-2) processes. We hypothesized that Type-1 and Type-2 processes make differential contributions to creative production that depend on domain expertise. We tested this hypothesis with jazz pianists whose expertise was indexed by the number of public performances given. Previous fMRI studies of musical improvisation have reported that domain expertise is characterized by deactivation of the right-dorsolateral prefrontal cortex (r-DLPFC), a brain area associated with Type-2 executive processing. We used anodal, cathodal, and sham transcranial direct current stimulation (tDCS) applied over r-DLPFC with the reference electrode on the contralateral mastoid (1.5 mA for 15 min, except for sham) to modulate the quality of the pianists' performances while they improvised over chords with drum and bass accompaniment. Jazz experts rated each improvisation for creativity, esthetic appeal, and technical proficiency. There was no main effect of anodal or cathodal stimulation on ratings compared to sham; however, a significant interaction between anodal tDCS and expertise emerged such that stimulation benefitted musicians with less experience but hindered those with more experience. We interpret these results as evidence for a dual-process model of creativity in which novices and experts differentially engage Type-1 and Type-2 processes during creative production.

Examining the feasibility and tolerability of a clinically informed multisite, repetitive transcranial magnetic stimulation protocol

BackgroundMulti-site repetitive transcranial magnetic stimulation (rTMS) has been applied experimentally in the treatment of obsessive compulsive disorder (OCD). New methodThis study was conducted to systematically evaluate the safety, tolerability and neurocognitive effects of rTMS applied to three cortical regions over a period of three months. New methodTwenty healthy participants aged 22–33 years were randomly allocated to receive one session of active or sham stimulation of low and high frequency rTMS applied sequentially to the pre-supplementary motor area, right-dorsolateral prefrontal cortex and left-orbitofrontal cortex totalling 9min. Tolerability and safety was evaluated using a standardised safety questionnaire. Neurocognitive functioning was examined using the Cambridge Neuropsychological Test Automated Battery and measures of verbal fluency from the Delis-Kaplan Executive Functioning Test™ at five time points over three months. ResultsThe protocol was safe and tolerable. Frequencies of minor adverse effects were higher in active (17 endorsements) than sham (1 endorsement) conditions. No between group differences in neurocognitive functioning were identified over three months.Comparison with existing method: This study is the first to evaluate the feasibility of low and high frequency parameters applied sequentially in a single session to the three selected cortical regions whilst providing neurocognitive data. ConclusionsrTMS applied sequentially over three cortical regions was found to be safe and tolerable in healthy individuals with no major neurocognitive effects over three months. Such findings can be used to inform the development of rTMS protocols involving multi-site stimulation for OCD.

Migration and time to first tobacco cigarette after waking

Migration and time to first tobacco cigarette after waking

A Retrospective Analysis of Right Dorsolateral Prefrontal Cortex (RDLPFC) Transcranial Magnetic Stimulation Treatments for Patients Showing Symptoms of Anxiety and/or Irritability

A Retrospective Analysis of Right Dorsolateral Prefrontal Cortex (RDLPFC) Transcranial Magnetic Stimulation Treatments for Patients Showing Symptoms of Anxiety and/or Irritability

Selective Medial Prefrontal Cortex Responses During Live Mutual Gaze Interactions in Human Infants: An fNIRS Study.

To investigate the role of the prefrontal cortex (PFC) in processing multimodal communicative ostensive signals in infants, we measured cerebral hemodynamic responses by using near-infrared spectroscopy (NIRS) during the social interactive play "peek-a-boo", in which both visual (direct gaze) and auditory (infant-directed speech) stimuli were presented. The infants (mean age, around 7 months) sat on their mother's lap, equipped with an NIRS head cap, and looked at a partner's face during "peek-a-boo". An eye-tracking system simultaneously monitored the infants' visual fixation patterns. The results indicate that, when the partner presented a direct gaze, rather than an averted gaze, toward an infant during social play, the infant fixated on the partner's eye region for a longer duration. Furthermore, hemodynamic activity increased more prominently dorsomedial prefrontal cortex (mPFC) in response to social play with a partner's direct gaze compared to an averted gaze. In contrast, hemodynamic activity increased in the right dorsolateral prefrontal cortex (R-lPFC) regardless of a partner's eye gaze direction. These results indicate that a partner's direct gaze shifts an infant's attention to the partner's eyes for interactive communication, and specifically activates the mPFC. The differences in hemodynamic responses between the mPFC and R-lPFC suggest functional differentiation within the PFC, and a specific role of the mPFC in the perception of face-to-face communication, especially in mutual gaze, which is essential for social interaction.

Neural Correlates of Attention-Deficit/Hyperactivity Disorder in Adulthood

Neural Correlates of Attention-Deficit/Hyperactivity Disorder in Adulthood

P 245. rTMS in the management of depression subtypes-an analysis of 160 cases

This placebo-controlled study was designed to investigate the influence of repetitive transcranial magnetic stimulation (rTMS) on depressive symptoms in patients with subtypes depressive disorders. Furthermore, effects on cognitive functions and psychomotor functioning were tested. One hundred and sixty patients with depression were included. They were treated with a stable dosage of antidepressant medication. They received either high frequency rTMS (10 Hz) over the left dorsolateral prefrontal cortex (LDLPFC) and low frequency rTMS (1 Hz) over the right dorsolateral prefrontal cortex (RDLPFC) as add on treatment at 30 days ithin 8 weeks. Depressive symptoms were registered by means of observer ratings (Hamilton Depression Rating Scale-HDRS) and self reports (Beck Depression Inventory-BDI). Psychomotor retardation was investigated by the Motor Agitation and Retardation Scale and cognitive function by d2 test. Differences between the groups regarding depressive symptoms could not be found. Motor abnormalities, however, significantly improved exclusively after stimulation procedures. Patients with less severe deficits in psychomotor speed and concentration responded more intensively than patients with severe deficits. rTMS is effective across various subgroups of depression and needs further detailed symptom based study to ascertain further effects.

(203) Slow-frequency prefrontal rTMS for refractory neuropathic pain

Treatment approaches to chronic pain include a number of antidepressant therapies, and electroconvulsive therapy (ECT) has been shown to reduce chronic pain. Slow frequency repetitive transcranial magnetic stimulation (rTMS) applied to the right dorsolateral prefrontal cortex (R-DLPFC) has also been shown to have an antidepressant effect. Given the high degree of suffering experienced by subjects with chronic neuropathic pain and the treatment resistance noted in this population, the use of slow frequency rTMS as adjuvant therapy may be of significant clinical benefit. Fifteen sessions of 1 Hz rTMS (1600 stimulations/session) was applied to the R-DLPFC as adjuvant treatment in nine subjects with refractory neuropathic pain over three weeks. Pain and depression ratings were performed at baseline, weekly during rTMS treatment and monthly for up to three months after treatment. Five males and four females participated, and all had longstanding refractory neuropathic pain (range 1-19 years), with an average baseline pain rating of 7.3 and no depression (HRSD average 3.6; range 0-8). No medication change was allowed during the trial. Three subjects had a greater than 50% decline in pain ratings by the completion of rTMS treatments and one subject responded more slowly with a greater than 50% improvement in pain by the end of the three month follow-up. An improvement in pain ratings was noted in responders by the end of the first week. Responders who were followed for three months continued to have a significant improvement in pain. Although these are preliminary findings in an open treatment trial, the subjects in this trial are among the least likely to have a placebo response. Given that rTMS is a well tolerated and non-invasive intervention, any sustained improvement in neuropathic pain with rTMS is encouraging.