Repetitive TMS does not improve cognition in patients with TBI: A randomized double-blind trial

OBJECTIVE

To determine whether high-frequency repetitive transcranial magnetic stimulation (rTMS) improves cognition in patients with severe traumatic brain injury.

METHODS

A single-center, randomized, double-blind, placebo-controlled study of rTMS was conducted in patients aged 18-60 years with chronic (>12 months postinjury) diffuse axonal injury (DAI). Patients were randomized to either a sham or real group in a 1:1 ratio. A 10-session rTMS protocol was used with 10-Hz stimulation over the left dorsolateral prefrontal cortex (DLPFC). Neuropsychological assessments were performed at 3 time points: at baseline, after the 10th rTMS session, and 90 days after intervention. The primary outcome was change in executive function evaluated using the Trail Making Test Part B.

RESULTS

Thirty patients with chronic DAI met the study criteria. Between-group comparisons of performance on TMT Part B at baseline and after the 10th rTMS session did not differ between groups (p = 0.680 and p = 0.341, respectively). No significant differences were observed on other neuropsychological tests. No differences in adverse events between treatment groups were observed.

CONCLUSIONS

Cognitive function in individuals with chronic DAI is not improved by high-frequency rTMS over the left DLPFC, though it appears safe and well-tolerated in this population.

CLINICALTRIALSGOV IDENTIFIER

NCT02167971.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for individuals with chronic DAI, high-frequency rTMS over the left DLPFC does not significantly improve cognition.

Current understanding of the mixed pain concept: a brief narrative review

Despite having been referenced in the literature for over a decade, the term "mixed pain" has never been formally defined. The strict binary classification of pain as being either purely neuropathic or nociceptive once left a good proportion of patients unclassified; even the recent adoption of "nociplastic pain" in the IASP Terminology leaves out patients who present clinically with a substantial overlap of nociceptive and neuropathic symptoms. For these patients, the term "mixed pain" is increasingly recognized and accepted by clinicians. Thus, an independent group of international multidisciplinary clinicians convened a series of informal discussions to consolidate knowledge and articulate all that is known (or, more accurately, thought to be known) and all that is not known about mixed pain. To inform the group's discussions, a Medline search for the Medical Subject Heading "mixed pain" was performed via PubMed. The search strategy encompassed clinical trial articles and reviews from January 1990 to the present. Clinically relevant articles were selected and reviewed. This paper summarizes the group's consensus on several key aspects of the mixed pain concept, to serve as a foundation for future attempts at generating a mechanistic and/or clinical definition of mixed pain. A definition would have important implications for the development of recommendations or guidelines for diagnosis and treatment of mixed pain.

Preserved repetition in thalamic afasia. A pathophysiological hypothesis

The ability to repeat words is almost always preserved in thalamic aphasia. The pathophysiology of both thalamic aphasia and preservation of repetition are not fully understood. In a case of severe aphasia with preserved repetition after a left thalamic hemorrhage, MRI disclosed left thalamic lesion and loss of fractional anisotropy in the left centrum semiovale. FDG-PET showed severe hypometabolism in the left cerebral hemisphere, except for superior and transverse temporal gyri, calcarine fissure and frontopolar regions. Primary sensory function may be less functionally dependent on thalamic connections than heteromodal and paralimbic areas, which have connections with several thalamic nuclei. The extensive cortical hypometabolism due to diaschisis may have been responsible for the severity of the aphasia, whereas the less severe reduction of metabolism in the superior and transverse temporal gyri, and also, albeit less evident, in Broca’s area, might explain the preservation of repetition.

Insular and anterior cingulate cortex deep stimulation for central neuropathic pain: Disassembling the percept of pain

OBJECTIVE

To compare the analgesic effects of stimulation of the anterior cingulate cortex (ACC) or the posterior superior insula (PSI) against sham deep (d) repetitive (r) transcranial magnetic stimulation (TMS) in patients with central neuropathic pain (CNP) after stroke or spinal cord injury in a randomized, double-blinded, sham-controlled, 3-arm parallel study.

METHODS

Participants were randomly allocated into the active PSI-rTMS, ACC-rTMS, sham-PSI-rTMS, or sham-ACC-rTMS arms. Stimulations were performed for 12 weeks, and a comprehensive clinical and pain assessment, psychophysics, and cortical excitability measurements were performed at baseline and during treatment. The main outcome of the study was pain intensity (numeric rating scale [NRS]) after the last stimulation session.

RESULTS

Ninety-eight patients (age 55.02 ± 12.13 years) completed the study. NRS score was not significantly different between groups at the end of the study. Active rTMS treatments had no significant effects on pain interference with daily activities, pain dimensions, neuropathic pain symptoms, mood, medication use, cortical excitability measurements, or quality of life. Heat pain threshold was significantly increased after treatment in the PSI-dTMS group from baseline (1.58, 95% confidence interval [CI] 0.09-3.06]) compared to sham-dTMS (-1.02, 95% CI -2.10 to 0.04, p = 0.014), and ACC-dTMS caused a significant decrease in anxiety scores (-2.96, 95% CI -4.1 to -1.7]) compared to sham-dTMS (-0.78, 95% CI -1.9 to 0.3; p = 0.018).

CONCLUSIONS

ACC- and PSI-dTMS were not different from sham-dTMS for pain relief in CNP despite a significant antinociceptive effect after insular stimulation and anxiolytic effects of ACC-dTMS. These results showed that the different dimensions of pain can be modulated in humans noninvasively by directly stimulating deeper SNC cortical structures without necessarily affecting clinical pain per se.

CLINICALTRIALSGOV IDENTIFIER

NCT01932905.

Changes in motor cortical excitability in schizophrenia following transcranial direct current stimulation

Schizophrenia is a disorder associated with cortical inhibition deficits. Transcranial direct current stimulation (tDCS) induces changes in cortical excitability in healthy subjects and individuals with neuropsychiatric disorders depending on the stimulation parameters. Our aim was to investigate whether a previously published tDCS protocol associated with symptomatic improvement in schizophrenia would induce changes in motor cortical excitability, assessed by transcranial magnetic stimulation paradigms, i.e., short-interval intracortical inhibition (SICI) and intra-cortical facilitation (ICF). We assessed cortical excitability measurements in 48 subjects with schizophrenia before and after a single session of active tDCS (20 min, 2 mA, anode over left dorsolateral prefrontal cortex, cathode over left temporoparietal cortex) or sham. Those who received active tDCS had a significant increase of SICI in the left motor cortex compared to those who received sham stimulation (Cohen's d = 0.54, p = .019). No changes were observed for ICF. In addition, lower SICI was associated with higher age (β = -0.448, p < .01). Increase in intracortical inhibition may indicate a mechanism of action of tDCS in this population. Future studies should investigate whether this finding is a biomarker of treatment response for schizophrenia.

Effects of intranasal oxytocin on tactile perception

In addition to its role in childbirth labor and lactation, oxytocin is a well-known neurohormone, having several prosocial effects. Moreover, oxytocin seems to play a significant modulatory role in painful experiences, due to its participation in central and peripheral processing of nociceptive somatosensory information. Despite studies on oxytocin in pain modulation, there is a scarce literature investigating the role of oxytocin in tactile perception. Here we investigate the effects of 24 and 40 IU intranasal administration of oxytocin in the non-harmful mechanical tactile detection threshold in men. The data showed a significant increase in tactile perception in an experimental 40 IU oxytocin group. We suggest that this effect could be the basis for the oxytocin-bonding effect via touch.

Persistent pain is a risk factor for frailty: a systematic review and meta-analysis from prospective longitudinal studies

Background

pain is prevalent in frail older adults; however, the association of pain and frailty has not been evaluated yet by a systematic assessment of prospective longitudinal studies.

Objective

we aimed to assess the association of persistent pain as a risk factor for frailty incidence, using data from longitudinal studies in a systematic review and meta-analysis.

Methods

publications were identified using a systematic search on PubMed, Embase, Cochrane Library and clinicaltrials.gov databases from inception to October 2017. Since heterogeneity across studies was high, we used random-effects meta-analysis to calculate the pooled relative risk for the association between persistent pain and the incidence of frailty. We investigated sources of heterogeneity among studies using meta-regression and stratified analyses.

Results

we included five prospective longitudinal studies with 13,120 participants (46% women, mean age from 59 to 85 years old). Participants with persistent pain at baseline had twice the risk of developing frailty during the follow-up (pooled RR = 2.22, 95% CI = 1.14-4.29). No variables were related to study heterogeneity in sensitivity analyses.

Conclusion

persistent pain was a risk factor for the development of frailty in a meta-analysis of longitudinal studies. Better understanding of the association between pain and frailty with proper evaluation of potential confounders could allow the development of targeted interventions.

Altered cortical excitability in persistent idiopathic facial pain

Introduction

Persistent idiopathic facial pain is a refractory and disabling condition of unknown mechanism and etiology. It has been suggested that persistent idiopathic facial pain patients have not only peripheral generators of pain, but also central nervous system changes that would contribute to the persistence of symptoms. We hypothesized that persistent idiopathic facial pain would have changes in brain cortical excitability as measured by transcranial magnetic stimulation compared to healthy controls.

Methods

Twenty-nine persistent idiopathic facial pain patients were compared to age- and sex-matched healthy controls and underwent cortical excitability measurements by transcranial magnetic stimulation applied to the cortical representation of the masseter muscle of both hemispheres. Single-pulse stimulation was used to measure the resting motor threshold and suprathreshold motor-evoked potentials. Paired-pulse stimulation was used to assess short intracortical inhibition and intracortical facilitation. Clinical pain and associated symptoms were assessed with validated tools.

Results

Spontaneous pain was found in 27 (93.1%) and provoked pain was found in two (6.9%) persistent idiopathic facial pain patients. The motor-evoked potentials at 120% and 140% were significantly lower for both hemispheres compared to controls. Persistent idiopathic facial pain patients had lower short-interval intracortical inhibition compared with controls. These changes were correlated with some aspects of quality of life, and higher mood symptoms. These neurophysiological alterations were not influenced by analgesic medication, as similar changes were observed in patients with or without central-acting drugs.

Conclusions

Persistent idiopathic facial pain is associated with changes in intracortical modulation involving GABAergic mechanisms, which may be related to certain aspects of the pathophysiology of this chronic pain condition. Trial registration: NTC01746355.

Altered Intracortical Inhibition in Chronic Traumatic Diffuse Axonal Injury

Background

Overactivation of NMDA-mediated excitatory processes and excess of GABA-mediated inhibition are attributed to the acute and subacute phases, respectively, after a traumatic brain injury (TBI). However, there are few studies regarding the circuitry during the chronic phase of brain injury.

Objective

To evaluate the cortical excitability (CE) during the chronic phase of TBI in victims diagnosed with diffuse axonal injury (DAI).

Methods

The 22 adult subjects were evaluated after a minimum of 1 year from the onset of moderate or severe TBI. Each of the subjects first had a comprehensive neuropsychological assessment to evaluate executive functions-attention, memory, verbal fluency, and information processing speed. Then, CE assessment was performed with a circular coil applying single-pulse and paired-pulse transcranial magnetic stimulation over the cortical representation of the abductor pollicis brevis muscle on M1 of both hemispheres. The CE parameters measured were resting motor threshold (RMT), motor-evoked potentials (MEPs), short-interval intracortical inhibition (SIICI), and intracortical facilitation (ICF). All data were compared with that of a control group that consisted of the healthy age-matched individuals.

Results

No significant differences between the left and right hemispheres were detected in the DAI subjects. Therefore, parameters were analyzed as pooled data. Values of RMT, MEPs, and ICF from DAI patients were within normal limits. However, SIICI values were higher in the DAI group-DAI SIICI = 1.28 (1.01; 1.87) versus the control value = 0.56 (0.33; 0.69)-suggesting that they had a disarranged inhibitory system (p < 0.001). By contrast, the neuropsychological findings had weak correlation with the CE data.

Conclusion

As inhibition processes involve GABA-mediated circuitry, it is likely that the DAI pathophysiology itself (disruption of axons) may deplete GABA and contribute to ongoing disinhibition of these neural circuits of the cerebrum during the chronic phase of DAI.

Effects of cerebellar neuromodulation in movement disorders: A systematic review

BACKGROUND

The cerebellum is involved in the pathophysiology of many movement disorders and its importance in the field of neuromodulation is growing.

OBJECTIVES

To review the current evidence for cerebellar modulation in movement disorders and its safety profile.

METHODS

Eligible studies were identified after a systematic literature review of the effects of cerebellar modulation in cerebellar ataxia, Parkinson's disease (PD), essential tremor (ET), dystonia and progressive supranuclear palsy (PSP). Neuromodulation techniques included transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS). The changes in motor scores and the incidence of adverse events after the stimulation were reviewed.

RESULTS

Thirty-four studies were included in the systematic review, comprising 431 patients. The evaluation after stimulation ranged from immediately after to 12 months after. Neuromodulation techniques improved cerebellar ataxia due to vascular or degenerative etiologies (TMS, tDCS and DBS), dyskinesias in PD patients (TMS), gross upper limb movement in PD patients (tDCS), tremor in ET (TMS and tDCS), cervical dystonia (TMS and tDCS) and dysarthria in PSP patients (TMS). All the neuromodulation techniques were safe, since only three studies reported the existence of side effects (slight headache after TMS, local skin erythema after tDCS and infectious complication after DBS). Eleven studies did not mention if adverse events occurred.

CONCLUSIONS

Cerebellar modulation can improve specific symptoms in some movement disorders and is a safe and well-tolerated procedure. Further studies are needed to lay the groundwork for new researches in this promising target.

Prevalence of chronic pain in a metropolitan area of a developing country: a population-based study

Objective

To estimate the prevalence of chronic pain (CP) in the adult population living in the city of São Paulo, Brazil, and to identify factors associated with CP in developing countries.

Methods

A cross-sectional study using a computer-assisted telephone interview in a two-stage stratified sample of adults living in households.

Results

2,446 subjects were interviewed. The mean age was 39.8 years old. The majority was female and 42.7% had less than 10 years of education. The prevalence of CP was 28.1%. The independent factors associated with CP were female gender (OR = 2.0; p < 0.001), age older than 65 years (OR = 1.4; p = 0.019) and less than 15 years of education (OR = 1.3-1.6; p < 0.04).

Conclusions

The prevalence of CP was high and similar to that which has been reported in developed countries. These results raise awareness about CP and may potentially help clinicians and policy makers to design better health care programs for CP treatment in these populations.

Pregabalin for the Prevention of Oxaliplatin-Induced Painful Neuropathy: A Randomized, Double-Blind Trial

Lessons Learned.

Pregabalin is a medication that can decrease neuronal hyperexcitability, relieve neuropathic pain, and reach stable plasma levels after a titration period of only a few days.

Its use during oxaliplatin infusions was not able to decrease the incidence of chronic, oxalipaltin‐related neuropathic pain, compared with placebo.

Background.

Patients with colorectal cancer (CRC) receiving oxaliplatin (OXA) develop acute and chronic painful oxaliplatin‐induced peripheral neuropathy (OXAIPN). Acute and chronic OXA‐related neuropathies have different pathophysiological bases, but both lead to a common phenomenon: central sensitization (CS) of nociceptive neuronal networks, leading to increased sensitivity (hyperlgesia, allodynia) in the somatosensory system, the common ground of chronic neuropathic pain. Because CS is related to increased risk of painful OXAIPN, we hypothesized that preemptive use of the anti‐hyperalgesic drug pregabaline (known to decrease CS) during OXA infusions would decrease the incidence of chronic OXAIPN.

Methods.

Pain‐free, chemotherapy‐naïve CRC patients receiving at least one cycle of modified‐FLOX [5‐FU(500 mg/m²)+leucovorin(20 mg/m²)/week for] 6 weeks+oxaliplatin(85 mg/m²) at weeks 1‐3‐5 every 8 weeks] were randomized (1:1) into the study. Patients received either pregabalin or placebo for 3 days before and 3 days after each OXA infusion and were followed for up to 6 months. Clinical assessments were performed at baseline, at the end of chemotherapy, and after the follow‐up period. The main outcome was average pain at the last visit assessed by the visual analogic scale (0–10) item of the Brief Pain Inventory (BPI). Secondary endpoints were presence of neuropathic pain according to the Douleur Neuropathique‐4 (DN‐4), pain dimensions (short‐ form McGill Pain Questionnaire [MPQ]), Neuropathic Pain Symptom Inventory (NPSI), and changes in nerve conduction studies (NCS) and side effect profile.

Results.

One hundred ninety‐nine patients (57.0 ± 10.7 years old, 98 female, 101 male) were randomized. Data from 56 patients were not included in the analyses (as they did not receive at least one full cycle of modified FLOX). Data from 78 patients in the pregabalin group and 65 patients in the placebo group were retained for analyses. At the last visit, pain intensity in the pregabalin group was 1.03 (95% confidence interval [CI] = 0.79–1.26), and 0.85 (95% CI = 0.64–1.06) in the placebo group, which did not reach significance. Scores from the BPI, MPQ, DN‐4, NPSI, and NCS and side‐effect profiles and incidence of death did not differ between groups. Quality of life (QoL) score did not differ between groups (placebo = 76.9 ± 23.1, pregabalin group 79.4 ± 20.6). Mood scores were not significantly different between groups (placebo 9.7 [8.1–11.2]; pregabalin 6.8 [5.6–8.0]).

Conclusion.

The preemptive use of pregabalin during OXA infusions was safe, but did not decrease the incidence of chronic pain related to OXAIPN.

Rating Scales for Pain in Parkinson's Disease: Critique and Recommendations

BACKGROUND

We aimed at critically appraising the clinimetric properties of existing pain scales or questionnaires and to give recommendations for their use in Parkinson's disease (PD).

METHODS

Clinimetric properties of pain scales used in PD were systematically evaluated. A scale was classified as 'recommended' if was used in PD, showed adequate clinimetric properties, and had been used by investigators other than the original developers; as 'suggested' if it was used in PD and fulfilled only one other criterion; and as 'listed' if it was used in PD but did not meet the other criteria. Only scales rating pain intensity or for syndromic classification were assessed.

RESULTS

Eleven of the 34 scales initially considered fulfilled inclusion criteria. Among the scales rating pain intensity, the "Brief Pain Inventory short form," "McGill Pain Questionnaire short and long forms," "Neuropathic Pain Symptoms Inventory," "11-point Numeric Rating Scale," "10-cm Visual Analog Scale," and "Pain-O-Meter" were "recommended with caution" because of lack of clinimetric data in PD, whereas the "King's PD Pain Scale" was "recommended." Among scales for pain syndromic classification, the "DN4" was "recommended with caution" because of lack of clinimetric data in PD; the "Leeds Assessment of Neuropathic Symptoms and Signs," "Pain-DETECT," and the "King's PD Pain Scale" were "suggested."

CONCLUSIONS

King's PD pain scale can be recommended for the assessment of pain intensity in PD. Syndromic classification of pain in PD may be achieved by the DN4, but clinimetric data in PD are needed for this scale.

Wilson's disease with and without rapid eye movement sleep behavior disorder compared to healthy matched controls

OBJECTIVE

Quantitative data are reported on rapid eye movement (REM) sleep behavior disorder (RBD) in a cohort of predominantly neurological Wilson's disease (WD).

METHODS

A total of 41 patients with WD and 41 healthy, age- and gender-matched controls were studied by conducting face-to-face interviews, neurological and clinical examinations, laboratory tests, and WD- and RBD-specific scales. Video-polysomnography and quantification of REM sleep without atonia (RWA) were conducted in 35 patients and 41 controls.

RESULTS

Patients with WD showed significantly worse sleep quality, less sleep efficiency, increased wakefulness after sleep onset, and more arousals compared to healthy controls. Five patients with WD (four women) fulfilled the diagnostic criteria for RBD with significantly higher values in RWA, RBD Questionnaire-Hong Kong, and RBD Screening Questionnaire compared to patients with WD without RBD. In three patients with WD, RBD had manifested before any other symptom that could be attributed to WD. Percentage of RWA was significantly lower in WD without RBD than in WD with RBD, but still significantly increased compared to controls.

CONCLUSIONS

RBD can be comorbid with WD. RWA is commonly present in WD, both in the presence or absence of clinical RBD. A causal connection is possible, though retrospective determination of RBD onset and the low number of patients do not allow a definitive conclusion at this point. However, screening for WD in idiopathic RBD is available at low cost and is recommended. Early-stage copper chelation therapy provides a highly effective treatment to prevent further WD manifestations and might also control the comorbid RBD.

Pain in Parkinson's Disease: Current Concepts and a New Diagnostic Algorithm

Background

Pain is a significant burden for patients with Parkinson's disease (PD) with a high impact on quality of life. The present article aims at summarizing epidemiological, pathophysiological, clinical, and neurophysiological data regarding pain in PD.

Methods

In this domain, a procedure of systematic assessment is still lacking for the syndromic diagnosis and should take into account pain characteristics, effects of dopaminergic treatment, motor fluctuations, and non-PD-associated pain.

Findings

We propose an original questionnaire addressing an algorithm suitable for daily clinical practice. The questionnaire is based on a three-step approach addressing first the relationship between pain and PD (including temporal relationship with the course of the disease, association with motor fluctuations, and impact of antiparkinsonian treatment), before classifying pain into one of three main syndromes (i.e., musculoskeletal pain, psychomotor restlessness pain, and neuropathic pain).

Conclusions

The proposed questionnaire allows the characteristics of each pain type to be determined according to its relationship with the disease and its treatment. The validation of the clinical use of this questionnaire will be the goal of a forthcoming work.

Liposomal topical capsaicin in post-herpetic neuralgia: a safety pilot study

Topical treatments have gained popularity for general use as an adjunct to systemic drugs in neuropathic pain, but their use produces variable clinical results and local adverse events.

OBJECTIVE

To evaluate the safety and analgesic effect of a formulation of liposomal capsaicin (LC) (0.025%) in patients with post herpetic neuralgia (PHN).

METHOD

Patients who remained symptomatic after first-and second-line treatment were randomized to receive LC for six weeks in a placebo-controlled, crossover design study. Clinical assessment was performed at baseline, in the second, fourth and sixth week of treatment.

RESULTS

Thirteen patients completed both treatment periods. Visual Analog Scale (VAS) was significantly decreased after the end of the study (p = 0.008), however the effect of treatment was not significant (p = 0.076). There was no difference on global impression of change and other pain characteristics. LC was safe and well tolerated. However, at the concentration used, its analgesic effects were marginal and not significant.