Weak, but complex pulsed magnetic fields may reduce depression following traumatic brain injury

A Transmissive Theory of Brain Function: Implications for Health, Disease, and Consciousness

Identifying a complete, accurate model of brain function would allow neuroscientists and clinicians to make powerful neuropsychological predictions and diagnoses as well as develop more effective treatments to mitigate or reverse neuropathology. The productive model of brain function, which has been dominant in the field for centuries, cannot easily accommodate some higher-order neural processes associated with consciousness and other neuropsychological phenomena. However, in recent years, it has become increasingly evident that the brain is highly receptive to and readily emits electromagnetic (EM) fields and light. Indeed, brain tissues can generate endogenous, complex EM fields and ultraweak photon emissions (UPEs) within the visible and near-visible EM spectra. EM-based neural mechanisms, such as ephaptic coupling and non-visual optical brain signaling, expand canonical neural signaling modalities and are beginning to disrupt conventional models of brain function. Here, we present an evidence-based argument for the existence of brain processes that are caused by the transmission of extracerebral, EM signals and recommend experimental strategies with which to test the hypothesis. We argue for a synthesis of productive and transmissive models of brain function and discuss implications for the study of consciousness, brain health, and disease.

The management of depression following traumatic brain injury: A systematic review with meta-analysis

BACKGROUND

Traumatic brain injury (TBI) is prevalent. Declining mortality has led to increasing survivors with chronic sequalae, including depression. With a lack of guidelines, this review aims to provide a comprehensive, evidence-based summary of the management of depression following TBI.

METHODS

Systematic searches were conducted for quasi-experimental and randomized controlled trials (RCTs) assessing pharmacotherapy, psychological interventions, and transcranial magnetic stimulation (TMS). Databases searched CENTRAL, Medline, Embase, CINAHL, PsycINFO, Web of Science, and ProQuest dissertations. Data extraction and risk-of-bias tools were used. Where possible, outcomes were combined into meta-analyses.

RESULTS

2719 studies were identified. After abstract screening and full-text reading, 34 remained. Prophylactic sertraline significantly reduced the odds of depression (OR (odds ratio) = 0.31 [95%CI (confidence interval) = 0.12 to 0.82]). Meta-analysis of RCT's showed TMS to have the greatest reduction in depression severity (SMD (Standardized-Mean-Difference) = 2.43 [95%CI = 1.24 to 3.61]). Stimulants were the only treatment superior to control (SMD = -1.03 [95%CI = - 1.6 to -0.47]).

CONCLUSION

Methylphenidate was the most effective pharmacotherapy. Sertraline appears effective for prevention. The efficacy of psychological interventions is unclear. TMS as a combination therapy appears promising. Heterogeneity of study populations and dearth of evidence means results should be interpreted cautiously.

Does Phase-Modulation of Applied 40-Hz Transcerebral Magnetic Fields Affect Subjective Experiences and Hypnotic Induction?

12 men and 12 women were exposed to a sham-field, a 5-Hz sine-wave magnetic field, a 40-Hz sine-wave magnetic field, or the latter field-phase modulated five times per sec. (5-Hz) for 30 min. between two administrations of the Spiegel's Hypnotic Induction Profile. To replicate the geometry that has produced significant increases in these scores in previous studies, the weak (1 microT) magnetic fields were applied over the right parietotemporal region through a modified helmet. The hypothesis that the enhanced suggestibility previously observed was due to an intrinsic phase-modulation of the fields was not supported. However, the ratings of overall pleasantness of the experiences were negatively correlated ( r = –.36) with global geomagnetic activity at the time of the experiment. The pleasantness was ranked significantly greater by subjects exposed to the 40-Hz field (explaining 41% of the variance) relative to subjects exposed to the 5-Hz field who also reported more visual experiences within their left peripheral visual fields. The percentages of time alpha rhythms were measured over the temporal lobes (but not frontal or occipital lobes) during the treatments were moderately and positively correlated with scores on questionnaires administered before the experiment, from which the capacity to imagine, temporal lobe signs, and religious (but not exotic) beliefs were inferred. The groups exposed to either the 5-Hz or 40-Hz/5-Hz phase-modulated field displayed greater durations of alpha rhythms over the temporal lobes than the other two groups.

Review of Awakening Agents

Brain injuries are a serious burden of illness to Canada and the US. Advances in managing head trauma have allowed more patients to emerge from decreased levels of consciousness and helped them cope with neurocognitive, neurobehavioural, and neuropsychiatric deficits. In this article, we review the current (1986-2002) evidence surrounding the pharmacological management of arousal states and the aforementioned neurological sequelae of head injury in either acute or chronic conditions. This article will review the evidence for the use of psychostimulants (methylphenidate), antidepressants (amitriptyline, selective serotonin reuptake inhibitors, and buproprion), Parkinson’s medications (amantadine, bromocriptine, carbidopa/levodopa), anticonvulsants (valproic acid), modafinil (Provigil), lactate, hyperbaric oxygen chamber, electroconvulsive therapy, and transmagnetic stimulation, in patients following a head injury. The review did not include all anticonvulsants, neuroleptics, beta-blockers, benzodiazepines, azospirones or cognitive enhancers. Unfortunately, the quality of the evidence is generally poor, and sometimes conflicting, which in turn results in indecisive guidelines for treating patients. Accepting the inherent flaws in the evidence we feel that this paper may serve as a stepping-stone for future researchers to improve data gathering that targets neurocognitive, neurobehavioural and neuropsychiatric symptoms following a head injury.

Treatment for depression following mild traumatic brain injury in adults: a meta-analysis

PRIMARY OBJECTIVE

Development of depression after TBI is linked to poorer outcomes. The aim of this manuscript is to review evidence for the effectiveness of current treatments.

RESEARCH DESIGN

Two meta-analyses were undertaken to examine the effectiveness of both pharmacological and non-pharmacological interventions for depression after mild TBI.

METHOD AND PROCEDURES

PubMed, Medline, PsychInfo, Web of Science and Digital Dissertations were searched and 13 studies located. Meta Analyst Beta 3.13 was used to conduct analyses of pre- vs post-effects then to examine treatment group vs control group effects.

MAIN OUTCOMES AND RESULTS

Studies using a pre-post design produced an overall effect size of 1.89 (95% CI = 1.20-2.58, p < 0.001), suggesting that treatments were effective; however, the overall effect for controlled trials was 0.46 (95% CI = -0.44-1.36, p < 0.001), which favoured the control rather than treatment groups.

CONCLUSIONS

This study highlights the need for additional large well-controlled trials of effective treatments for depression post-TBI.

Diagnosis and Treatment of Depression Following Traumatic Brain Injury

Depression is one of the most common psychiatric diagnoses among individuals with traumatic brain injury (TBI). Prevalence of post-TBI depression (PTBID) ranges from 12 to 60% and is generally higher than rates reported in the general population. The wide range in reported rates is attributed to methodological variability across studies, including measurement and sampling differences. Several systematic reviews have been published in the past 5 years, reporting on outcomes for depression across different classes of interventions, including pharmacological, biomedical and behavioural. The consensus across reviews is that more research is necessary to develop evidence-based practice guidelines. The present narrative review synthesises the findings of previous studies, focusing on the nature of the interventions, the eligibility criteria for inclusion and the assessment of outcome. Pharmacological studies are generally more rigorous methodologically, but provide mixed findings. Other biomedical interventions are only at the initial stages of research development, including case and pilot studies. The results of behavioural studies are positive regarding improvements in mood. However, the number of efficacy studies of behavioural interventions for depression is extremely limited. Recommendations for designing interventions are provided.

Can the 8-Coil Shakti Alter Subjective Emotional Experience? A Randomized, Placebo-Controlled Study

At present, a commercially available device (the 8-coil Shakti) claims to produce weak and complex magnetic fields that alter neurobiological processes. The effects of the Shakti on emotional responses to photographs that varied on emotional valence were investigated. Participants ( N = 37) were exposed to either 30 min. of magnetic fields or a sham condition and rated their emotional reactions to a set of 54 color photographs. Although participants indicated significantly different emotional responses to images with distinct emotional valences, exposure to magnetic fields did not affect these responses, nor significantly interact with image emotional valence. Although the device's “amygdala signal” had no effect on the emotive response to images in this study, additional investigations examining the effects of weak and complex magnetic fields on various aspects of perception and cognition are warranted.

Treatment for depression after traumatic brain injury: a systematic review

The aim of this systematic review was to critically evaluate the evidence on interventions for depression following traumatic brain injury (TBI) and provide recommendations for clinical practice and future research. We reviewed pharmacological, other biological, psychotherapeutic, and rehabilitation interventions for depression following TBI from the following data sources: PubMed, CINAHL, PsycINFO, ProQuest, Web of Science, and Google Scholar. We included studies written in English published since 1980 investigating depression and depressive symptomatology in adults with TBI; 658 articles were identified. After reviewing the abstracts, 57 articles met the inclusion criteria. In addition to studies describing interventions designed to treat depression, we included intervention studies in which depressive symptoms were reported as a secondary outcome. At the end of a full review in which two independent reviewers extracted data, 26 articles met the final criteria that included reporting data on participants with TBI, and using validated depression diagnostic or severity measures pre- and post-treatment. Three external reviewers also examined the study methods and evidence tables, adding 1 article, for a total of 27 studies. Evidence was classified based on American Academy of Neurology criteria. The largest pharmacological study enrolled 54 patients, and none of the psychotherapeutic/rehabilitation interventions prospectively targeted depression. This systematic review documents that there is a paucity of randomized controlled trials for depression following TBI. Serotonergic antidepressants and cognitive behavioral interventions appear to have the best preliminary evidence for treating depression following TBI. More research is needed to provide evidence-based treatment recommendations for depression following TBI.

INFLUENCE OF A COMPLEX MAGNETIC FIELD APPLICATION IN RATS UPON THERMAL NOCICEPTIVE THRESHOLDS: THE IMPORTANCE OF POLARITY AND TIMING

The application of a weak (1 microTesla) complex magnetic field pattern with a relevant electrophysiological signature produced an analgesic response in rats to thermal stimuli when the pattern was presented once every 4 sec for 30 min through iron-core solenoids. In one experiment, the burst-firing pattern was presented once every 4 s for 30 min and restricted to the positive polarity, negative polarity or a bipolar equivalent. The strongest analgesia occurred when the burst-firing pattern was presented with positive polarity or as the typical bipolar signal. Administrations of the burst-firing pattern once per week for four consecutive weeks produced analgesia that was clearly evident during the first, third, and fourth weeks but not during the second week of treatment. A telephone sensor coil (that can be readily obtained from local electronic shops) was then used instead of the solenoids along with an audio (.wav) file to generate the magnetic field; the analgesia was still apparent. However, when the magnetic pattern was generated from a compact disc source the analgesia was not evoked. The current results suggest that these fields can be generated through simple commercial devices controlled by available computer software.

Guidelines for the pharmacologic treatment of neurobehavioral sequelae of traumatic brain injury

There is currently a lack of evidence-based guidelines to guide the pharmacological treatment of neurobehavioral problems that commonly occur after traumatic brain injury (TBI). It was our objective to review the current literature on the pharmacological treatment of neurobehavioral problems after traumatic brain injury in three key areas: aggression, cognitive disorders, and affective disorders/anxiety/ psychosis. Three panels of leading researchers in the field of brain injury were formed to review the current literature on pharmacological treatment for TBI sequelae in the topic areas of affective/anxiety/ psychotic disorders, cognitive disorders, and aggression. A comprehensive Medline literature search was performed by each group to establish the groups of pertinent articles. Additional articles were obtained from bibliography searches of the primary articles. Group members then independently reviewed the articles and established a consensus rating. Despite reviewing a significant number of studies on drug treatment of neurobehavioral sequelae after TBI, the quality of evidence did not support any treatment standards and few guidelines due to a number of recurrent methodological problems. Guidelines were established for the use of methylphenidate in the treatment of deficits in attention and speed of information processing, as well as for the use of beta-blockers for the treatment of aggression following TBI. Options were recommended in the treatment of depression, bipolar disorder/mania, psychosis, aggression, general cognitive functions, and deficits in attention, speed of processing, and memory after TBI. The evidence-based guidelines and options established by this working group may help to guide the pharmacological treatment of the person experiencing neurobehavioral sequelae following TBI. There is a clear need for well-designed randomized controlled trials in the treatment of these common problems after TBI in order to establish definitive treatment standards for this patient population.

Thermal analgesic effects from weak, complex magnetic fields and pharmacological interactions

In several experiments, robust analgesia (equivalent to about 4 mg/kg of morphine) in male rats to thermal stimuli following exposures to weak (1 microT) complex magnetic fields was explored. The analgesia occurred when patterns of magnetic fields with burst-firing-like configurations were presented for 30 min once every approximately 4 s. The analgesic effects were intensity dependent. A different frequency-modulated pattern produced analgesia more quickly. The analgesic effects following exposure to the burst-firing magnetic fields were augmented conspicuously by preinjections of morphine (4 mg/kg) or agmatine (10 mg/kg), but blocked by naloxone (1 mg/kg). The results of these experiments suggest that rational design of the temporal structure of weak magnetic fields may be a novel, inexpensive, and reliable technique for elevating thresholds to some classes of painful stimuli.

Mechanical impacts to the skulls of rats produce specific deficits in maze performance and weight loss: evidence for apoptosis of cortical neurons and implications for clinical neuropsychology

The purpose of this experiment was to induce closed head injuries that might be applicable to clinical neuropsychology. Six adult female albino rats were struck over the right dorsal skull by a 200-gm weight that fell through a 0.9-m tube while another six rats served as controls. The rats that received the impact to the skulls displayed significantly more weight loss and fewer completions of the maze during the subsequent two to four days (effect size about 40%) while their open field behaviors, response latencies to thermal stimulation of the feet, and immobility within a conditioned fear setting did not differ significantly from those of controls. Histological analyses of the brains about 35 days after the impact indicated striking alterations in the morphology of cerebral cortical neurons, strongly suggestive of an apoptotic-like process, within the dorsal cerebral cortices below the likely impact site. Distributions of clusters of these aberrant-looking cells were also evident opposite to the impact site within the ventral cerebrum. Because apoptosis is involved with minimal inflammation and edema, detection of diffuse apoptosis by MRI and CT would be unlikely even though the influence on adaptability would be significant.

Spatial heterogeneity not homogeneity of the magnetic field during exposures to complex frequency-modulated patterns facilitates analgesia

24 young (4 mo.) and 24 old (8 mo.) male Wistar rats were exposed for 30 min. on two consecutive days to either a sham-field or to a frequency-modulated magnetic field applied through a pair of solenoids (spatially heterogeneous strength) or a Helmholtz coil (spatially homogeneous strength). The maximum field strength was about 2 microTesla. The rats exposed to the spatially heterogeneous magnetic field but not the homogeneous magnetic field exhibited strong analgesia to thermal stimuli applied to the footpads immediately after the treatment and 30 min. later. The effect accommodated 38% of the variance in the latency to respond to the thermal stimuli. These results suggest that the practice by many researchers in bioelectromagnetism to design coils to generate maximum spatial homogeneity of intensities within the exposure volume when applying complex weak magnetic fields may actually diminish any biological effects.

Intermittent burst-firing weak (1 microTesla) magnetic fields reduce psychometric depression in patients who sustained closed head injuries: a replication and electroencephalographic validation

14 patients who reported chronic depression more than one year after closed head injuries were exposed to weak (1 microTesla), burst-firing magnetic fields either across the temporal lobes or over the left frontal lobe. The treatment was for 30 min. once per week for 6 wk. The reduction in depression scores after 5 wk. of treatments and after 6 wk. of no treatment (follow-up) accommodated 54% of the variance for both groups. The changes in depression scores did not differ significantly between the two groups (temporal vs frontal). Following treatment, the frequency of complex partial epileptic-like experiences decreased significantly only for the 7 who received the bilateral stimulation over the temporal lobes. Quantitative bipolar electroencephalographic measurements over the occipital, prefrontal, and temporal regions showed increased power within the 16-Hz to 18-Hz range 6 wk. after termination of treatment for those 7 patients who received the burst-firing magnetic fields bilaterally over the temporal lobes but not over the left prefrontal region.

Neurobehavioral and neurometabolic (SPECT) correlates of paranormal information: involvement of the right hemisphere and its sensitivity to weak complex magnetic fields

Experiments were designed to help elucidate the neurophysiological correlates for the experiences reported by Sean Harribance. For most of his life he has routinely experienced "flashes of images" of objects that were hidden and of accurate personal information concerning people with whom he was not familiar. The specificity of details for target pictures of people was correlated positively with the proportion of occipital alpha activity. Results from a complete neuropsychological assessment, Single Photon Emission Computed Tomography (SPECT), and screening electroencephalography suggested that his experiences were associated with increased activity within the parietal lobe and occipital regions of the right hemisphere. Sensed presences (subjectively localized to his left side) were evoked when weak, magnetic fields, whose temporal structure simulated long-term potentiation in the hippocampus, were applied over his right temporoparietal lobes. These results suggest that the phenomena attributed to paranormal or "extrasensory" processes are correlated quantitatively with morphological and functional anomalies involving the right parietotemporal cortices (or its thalamic inputs) and the hippocampal formation.

Emotional Disturbances Following Traumatic Brain Injury

Mood disturbances are common sequelae of traumatic brain injury (TBI), but the scientific database for such disorders is very limited in descriptive, prognostic, and treatment data. Post-TBI symptoms often cross diagnostic boundaries and include cognitive loss, amotivation, psychosis, mood, changes, or other domains. The treating physician must be mindful that clear diagnostic boundaries may not exist. Premorbid level of functioning commonly affects post-TBI level of functioning. When setting treatment goals, this must be considered. Patients who had lower levels of psychosocial functioning before the injury may not fare as well afterwards. Treatment of post-TBI mood symptoms should proceed after a full diagnostic work-up including imaging and electroencephalographic (EEG) studies, neuropsychologic testing, and physical and laboratory examinations. Once the diagnostic picture is established, treatment should then proceed with a multidisciplinary team (physician, social worker, neuropsychologist, and others). For the medications, consider both target symptoms and side effects; start medications with low doses and raise slowly, give full therapeutic trials before switching or adding second agents, avoid benzodiazepines if possible, limit anticholinergic or antidopaminergic agents, and avoid providing large quantities of lethal medications. When starting medications for the treatment of mood disorders following TBI, several general principles of treatment in this population should be considered, including: balancing treatment of target symptoms with the potential for adverse effects; making use of side effects to treat comorbid problems when present (ie, relatively antidepressant for depression and marked insomnia); using a "start low, go slow" approach; continuing dose escalation to full therapeutic levels (ie, completing therapeutic trials) before switching or adding augmenting agents; avoiding agents with predictable and functionally important adverse effects (ie, benzodiazepines, strongly anticholinergic or antidopaminergic agents); and avoiding prescription of large and potentially lethal quantities of medications.

Magnetic field exposure and behavioral monitoring system

To maximize the availability and usefulness of a small magnetic field exposure laboratory, we designed a magnetic field exposure system that has been used to test human subjects, caged or confined animals, and cell cultures. The magnetic field exposure system consists of three orthogonal pairs of coils 2 m square x 1 m separation, 1.751 m x 0.875 m separation, and 1.5 m x 0.75 m separation. Each coil consisted of ten turns of insulated 8 gauge stranded copper conductor. Each of the pairs were driven by a constant-current amplifier via digital to analog (D/A) converter. A 9 pole zero-gain active Bessel low-pass filter (1 kHz corner frequency) before the amplifier input attenuated the expected high frequencies generated by the D/A conversion. The magnetic field was monitored with a 3D fluxgate magnetometer (0-3 kHz, +/- 1 mT) through an analog to digital converter. Behavioral monitoring utilized two monochrome video cameras (viewing the coil center vertically and horizontally), both of which could be video recorded and real-time digitally Moving Picture Experts Group (MPEG) encoded to CD-ROM. Human postural sway (standing balance) was monitored with a 3D forceplate mounted on the floor, connected to an analog to digital converter. Lighting was provided by 12 offset overhead dimmable fluorescent track lights and monitored using a digitally connected spectroradiometer. The dc resistance, inductance of each coil pair connected in series were 1.5 m coil (0.27 Omega, 1.2 mH), 1.75 m coil (0.32 Omega, 1.4 mH), and 2 m coil (0.38 Omega, 1.6 mH). The frequency response of the 1.5 m coil set was 500 Hz at +/- 463 microT, 1 kHz at +/- 232 microT, 150 micros rise time from -200 microT(pk) to + 200 microT(pk) (square wave) and is limited by the maximum voltage ( +/- 146 V) of the amplifier (Bessel filter bypassed).

Neuropsychiatric Aspects of Traumatic Brain Injury

Traumatic brain injury (TBI) may produce a variety of neuropsychiatric problems, including impaired cognition, depression, mania, affective lability, irritability, anxiety, and psychosis. Despite the common occurrence of these symptoms following TBI, there are relatively few studies that provide clear guidance regarding management. Many symptoms (eg, irritability, affective lability, fatigue, sleep disturbance, and impaired cognition) are primarily consequences of brain injury rather than symptoms of a comorbid psychiatric disorder such as major depression. Although it is difficult to study the complicated treatments needed for such symptom complexes, we are able to recommend an approach to the evaluation and treatment of neuropsychiatric problems following traumatic brain injury. A thorough assessment of the patient is a prerequisite to the prescription of any treatment. This assessment should include a thorough developmental, psychiatric, and medication history; a detailed mental status examination; a complete neurologic examination; and quantification of neuropsychiatric symptoms using standardized and accepted inventories (eg, Neurobehavioral Rating Scale, Neuropsychiatric Inventory ). All symptoms must be evaluated in the context of the patient's premorbid history and current treatment because neuropsychiatric symptoms may be influenced by either factor or by both factors. Psychotherapy is an important component of the treatment of neuropsychiatric problems following TBI. Additionally, patients should be encouraged to become involved with local TBI support groups. When medications are prescribed, it is essential to use cautious dosing (low and slow) and empiric trials with continuous reassessment of symptoms using standardized scales and monitoring for drug-drug interactions. In general, medications with significant sedative, antidopaminergic, and anticholinergic properties should be avoided, and benzodiazepines should be used sparingly, if at all. Although patients with TBI may be particularly susceptible to adverse effects of psychopharmacologic medications, at times dosages similar to those used for the non-brain-injured psychiatric patient may be needed. When a single medication does not provide adequate relief of symptoms or cannot be tolerated at therapeutic doses, an alternative strategy is to augment the effect of one medication by using a second low-dose agent with a different mechanism of action.

Subjective improvement following treatment with carbamazepine (Tegretol) for a subpopulation of patients with traumatic brain injuries

Over a 3-yr period, 19 patients who had sustained brain traumas during motor vehicle incidents and who exhibited abnormal scores for a dichotic word-listening task and Roberts' Epileptic Spectrum Disorder Inventory more than one year after the injury were recommended for treatment with carbamazepine (Tegretol). The psychiatric profile of these patients, as defined by the Minnesota Multiphasic Personality Inventory, was similar to the profile of patients from other studies who had displayed more objective improvement following this treatment. Of the 14 patients 12 who followed the recommendation retrospectively reported that within a few weeks after treatment they experienced marked reductions in the incidence of sudden confusion and depression, increased attention and focus, and either elimination or attenuation of an aversive sensed presence. Such results suggest that many of the debilitating symptoms that persist for months to years after a traumatic brain injury may be electrical in nature rather than due to "psychological responses" and might be treatable by appropriate dosages of carbamazepine or other, e.g., Gabapentin (Neurontin) antiepileptic compounds.

Depression following brain trauma is enhanced in patients with mild discrepancies between intelligence and impairment on neuropsychological scores

Analysis of the MMPI (Minnesota Multiphasic Personality Inventory) scores from 135 (20 years to 60 years old) patients who had sustained closed head injuries supported the hypothesis of a nonlinear relationship between the severity of depression and the magnitude of the discrepancy between intelligence and neuropsychological proficiency. Although the MMPI Depression T scores for all groups of patients were elevated (M = 78, SD = 13), patients with the least and greatest discrepancies between intelligence and neuropsychological proficiency scored lower on Depression than patients with discrepancies within the z-score ranges -2.0 and -1.1. The results of symmetrical covariance for either depression or complex partial epileptic-like experiences before comparisons between groups suggested depression and the epileptic-like experiences share the same source of variance.