The neurophysiology of deforming spastic paresis: A revised taxonomy

This paper revisits the taxonomy of the neurophysiological consequences of a persistent impairment of motor command execution in the classic environment of sensorimotor restriction and muscle hypo-mobilization in short position. Around each joint, the syndrome involves 2 disorders, muscular and neurologic. The muscular disorder is promoted by muscle hypo-mobilization in short position in the context of paresis, in the hours and days after paresis onset: this genetically mediated, evolving myopathy, is called spastic myopathy. The clinician may suspect it by feeling extensibility loss in a resting muscle, although long after the actual onset of the disease. The neurologic disorder, promoted by sensorimotor restriction in the context of paresis and by the muscle disorder itself, comprises 4 main components, mostly affecting antagonists to desired movements: the first is spastic dystonia, an unwanted, involuntary muscle activation at rest, in the absence of stretch or voluntary effort; spastic dystonia superimposes on spastic myopathy to cause visible, gradually increasing body deformities; the second is spastic cocontraction, an unwanted, involuntary antagonist muscle activation during voluntary effort directed to the agonist, aggravated by antagonist stretch; it is primarily due to misdirection of the supraspinal descending drive and contributes to reducing movement amplitude; and the third is spasticity, one form of hyperreflexia, defined by an enhancement of the velocity-dependent responses to phasic stretch, detected and measured at rest (another form of hyperreflexia is “nociceptive spasms”, following flexor reflex afferent stimulation, particularly after spinal cord lesions). The 3 main forms of overactivity, spastic dystonia, spastic cocontraction and spasticity, share the same motor neuron hyperexcitability as a contributing factor, all being predominant in the muscles that are more affected by spastic myopathy. The fourth component of the neurologic disorder affects the agonist: it is stretch-sensitive paresis, which is a decreased access of the central command to the agonist, aggravated by antagonist stretch. Improved understanding of the pathophysiology of deforming spastic paresis should help clinicians select meaningful assessments and refined treatments, including the utmost need to preserve muscle tissue integrity as soon as paresis sets in.     

Subacute copper-deficiency myelopathy in a patient with occult celiac disease

Context: Acquired copper deficiency represents a rare cause of progressive myelopathy presenting with sensory ataxia and spastic gait. The time interval from neurological symptoms onset to diagnosis of myelopathy ranges from 2 months to several years in almost all cases, mimicking the clinical course of subacute combined degeneration due to vitamin B12 deficiency.

Findings: A 60-year-old man, without any gastrointestinal symptoms, developed over the course of one week rapidly progressive gait imbalance, tingling and numbness in his feet and ascending lower limb weakness. Spine magnetic resonance imaging revealed hyperintensity involving cervical and dorsal posterior columns of spinal cord. Blood analysis revealed undetectable serum copper levels, low serum ceruloplasmin and positive serum Immunoglobulin A anti-tissue transglutaminase. Upper gastrointestinal endoscopy was performed revealing duodenal villous atrophy consistent with a malabsorption pattern. A gluten-free diet in association with intravenous then oral copper supplementation prompted sustained normalization of serum copper levels and progressive clinical improvement.

Conclusion/Clinical Relevance: We report a rare case of myelopathy induced by copper deficiency secondary to undiagnosed celiac disease, peculiarly presenting with a subacute onset. This case expands the neurological presentation and clinical course of myelopathy due to acquired copper deficiency. We suggest investigation of copper deficiency in patients presenting with subacute or even acute sensory ataxia and spastic gait. Detection of hypocupremia in patients without a previous history of gastric surgery should lead to diagnostic testing for celiac disease even in the absence of any obvious gastrointestinal symptoms.     

Evoked potentials predict psychomotor development in neonates with normal MRI after hypothermia for hypoxic-ischemic encephalopathy

Objectives

To assess the prognostic role of evoked potentials (EP) in neonates with normal magnetic resonance imaging (MRI) after therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy (HIE).

La place de la compréhension des proverbes et des métaphores dans la compréhension des troubles du cours de la pensée dans la schizophrénie : apport de l’évaluation clinique,de l’imagerie cérébrale fonctionnelle et de la neurophysiologie

According to Bleuler (1911), language impairments were indicative of thought disorders, a fundamental feature of schizophrenia. The objectives of the present review are twofold: (1) to present the clinical interest of the use of the tests of proverbs and metaphors comprehension for the evaluation of the characteristics of thought disorders in schizophrenia, and to highlight the heterogeneity of the forms of their interpretations; (2) to present the results from neuroimaging and neurophysiological studies of metaphor comprehension in order to identify the neurocognitive mechanisms underlying metaphorical language comprehension of patients with schizophrenic disorders. Results from the reviewed clinical applications of proverbs tests showed that thought disorders in individuals with schizophrenia are illustrated by different forms of proverb interpretations: literal, concrete, idiosyncratic, over-inclusiveness and unconventional. Results from the reviewed brain imaging and neurophysiological studies showed that these different forms of figurative misinterpretations may be related to different neurocognitive mechanisms: concreteness appears to be related to the dysfunction of the left inferior frontal gyrus and inverted brain lateralization during metaphor processing in individuals with schizophrenia compared to healthy individuals. During novel metaphor comprehension, which is highly effortful, individuals with schizophrenia, relative to controls, demonstrate increased activation of the right precuneus, a region that mediates complex and highly integrated functions including retrieval of episodic memory and mental imagery. These results may suggest that individuals with schizophrenia use mental imagery to support comprehension of both literal and metaphoric language. Furthermore, it was demonstrated that over-inclusive thinking, which is exhibited by individuals with schizophrenia during figurative language comprehension, could be related to very early right hemispheric hyper-activation (when a left early activation is expected) and to reduced bilateral brain activity during semantic processing. Such as reversed brain activation may explain why the individuals with schizophrenia are relatively over reliant on early-stage coarse or large semantic processing and may be prone to form meanings that are idiosyncratic and highly unconventional.     

A clinical and neurophysiological motor signature of Unverricht–Lundborg disease

Objectives

Unverricht–Lundborg disease (ULD) is the most common form of progressive myoclonus epilepsy. Cerebellar dysfunction may appear over time, contributing along with myoclonus to motor disability. The purpose of the present work was to clarify the motor and neurophysiological characteristics of ULD patients.

多模态影像融合辅助手术治疗听神经瘤

目的在多模态影像融合技术辅助下手术治疗听神经瘤,以提高肿瘤的全切除率和神经功能的保留率,初步实现听神经瘤的“精准”手术治疗。方法回顾性纳入2016年1月至8月解放军总医院神经外科在多模态影像融合技术辅助下手术治疗的听神经瘤患者,共30例。患者术前均采用循环相位稳态采集快速成像（FIESTA—C）和弥散张量成像（DTI）技术重建面神经,术中显微镜下验证所重建面神经位置的准确性。将重建的面神经、内听道水成像、颞骨薄层CT扫描重建并进行多模态融合,判断肿瘤与周围结构的关系。CT导航下确定内听道后壁的准确位置及需要磨除的范围,术中持续应用神经电生理监测。结果30例患者中,面神经重建成功率为100．0％,与实际位置符合率为93．3％（28／30）。17例进行导航,导航注册误差为0．30～0．92mm,平均（0．47±0．15）mm。39例中,肿瘤全切除28例（93．3％）,次全切除2例（6．7％）;面神经解剖保留28例（93．3％）,功能保留26例（86．7％）。术前均为不可用听力,术后无听力保留及改善。围手术期无死亡患者,无脑脊液漏、术区血肿及后组脑神经损伤症状。结论采用多模态影像融合技术辅助手术治疗听神经瘤可以提高肿瘤的全切除率和面神经功能的保留率,减少手术相关并发症。     

Neuronal tuning: Selective targeting of neuronal populations via manipulation of pulse width and directionality

IntroductionMotor evoked potentials (MEP) in response to anteroposterior transcranial (AP) magnetic stimulation (TMS) are sensitive to the TMS pulse shape. We are now able to isolate distinct pulse properties, such as pulse width and directionality and evaluate them individually. Different pulse shapes induce different effects, likely by stimulating different populations of neurons. This implies that not all neurons respond in the same manner to stimulation, possibly, because individual segments of neurons differ in their membrane properties.ObjectivesTo investigate the effect of different pulse widths and directionalities of TMS on MEP latencies, motor thresholds and plastic aftereffects of rTMS.MethodsUsing a controllable pulse stimulator TMS (cTMS), we stimulated fifteen subjects with quasi-unidirectional TMS pulses of different pulse durations (40 μs, 80 μs and 120 μs) and determined thresholds and MEP AP latencies. We then compared the effects of 80 μs quasi-unidirectional pulses to those of 80 μs pulses with different pulse directionality characteristics (0.6 and 1.0 M ratios). We applied 900 pulses of the selected pulse shapes at 1 Hz.ResultsThe aftereffects of 1 Hz rTMS depended on pulse shape and duration. 40 and 80 μs wide unidirectional pulses induced inhibition, 120 μs wide pulses caused excitation. Bidirectional pulses induced inhibition during the stimulation but had facilitatory aftereffects. Narrower pulse shapes caused longer latencies and higher resting motor thresholds (RMT) as compared to wider pulse shapes.ConclusionsWe can tune the aftereffects of rTMS by manipulating pulse width and directionality; this may be due to the different membrane properties of the various neuronal segments such as dendrites.SignificanceTo date, rTMS frequency has been the main determinant of the plastic aftereffects. However, we showed that pulse width also plays a major role, probably by recruiting novel neuronal targets.     

Applicability of NeuroTrend as a bedside monitor in the neuro ICU

Objective

To assess whether ICU caregivers can correctly read and interpret continuous EEG (cEEG) data displayed with the computer algorithm NeuroTrend (NT) with the main attention on seizure detection and determination of sedation depth.

Improved method for the isolation, characterization and examination of neuromuscular and toxic properties of selected polypeptide fractions from the crude venom of the Taiwan cobra Naja naja atra

An improved chromatographic method was developed to isolate and purify polypeptides and proteins from the crude venom of the Taiwan cobra Naja naja atra. The procedure devised is simple, easy to reproduce, and enables large scale isolation of almost all polypeptides and proteins in this cobra venom. Six pure polypeptide fractions of the venom were isolated and characterized using gel filtration on Sephadex G50 (medium), ion exchange chromatography on SP-Sephadex C25, desalting on Sephadex G25 (fine) and preparative HPLC on a RPC 18 column. The neuromuscular activity of these fractions was tested on the chick biventer cervicis nerve-muscle preparation and their toxicity (LD₅₀) was determined after i.v. administration in mice. Their antinociceptive activity was tested in the mouse abdominal test by i.v. application. Two of these polypeptide samples had major physiological effects: one acted as a cardiotoxin causing reversible myocardial contractures with no effect on muscle twitches elicited by nerve stimulation (NS); another was a neurotoxin that blocked muscle contractions in response to NS and exogenously added acetylcholine. The cardiotoxic fraction was identified as CTX I, a well-known cardiotoxin present in this venom, and the neurotoxin was identified as neurotoxin-α with an LD50 in mice of 0.075 mg/kg.     

The effect of neuroscience education on pain, disability, anxiety, and stress in chronic musculoskeletal pain

Louw A, Diener I, Butler DS, Puentedura EJ. The effect of neuroscience education on pain, disability, anxiety, and stress in chronic musculoskeletal pain.

Objective

To evaluate the evidence for the effectiveness of neuroscience education (NE) for pain, disability, anxiety, and stress in chronic musculoskeletal (MSK) pain.

Data Sources

Systematic searches were conducted on Biomed Central,BMJ.com, CINAHL, the Cochrane Library, NLM Central Gateway, OVID, ProQuest (Digital Dissertations), PsycInfo, PubMed/Medline, ScienceDirect, and Web of Science. Secondary searching (PEARLing) was undertaken, whereby reference lists of the selected articles were reviewed for additional references not identified in the primary search.

Study Selection

All experimental studies including randomized controlled trials (RCTs), nonrandomized clinical trials, and case series evaluating the effect of NE on pain, disability, anxiety, and stress for chronic MSK pain were considered for inclusion. Additional limitations: studies published in English, published within the last 10 years, and patients older than 18 years. No limitations were set on specific outcome measures of pain, disability, anxiety, and stress.

Data Extraction

Data were extracted using the participants, interventions, comparison, and outcomes (PICO) approach.

Data Synthesis

Methodological quality was assessed by 2 reviewers using the Critical Review Form–Quantitative Studies. This review includes 8 studies comprising 6 high-quality RCTs, 1 pseudo-RCT, and 1 comparative study involving 401 subjects. Most articles were of good quality, with no studies rated as poor or fair. Heterogeneity across the studies with respect to participants, interventions evaluated, and outcome measures used prevented meta-analyses. Narrative synthesis of results, based on effect size, established compelling evidence that NE may be effective in reducing pain ratings, increasing function, addressing catastrophization, and improving movement in chronic MSK pain.

Conclusions

For chronic MSK pain disorders, there is compelling evidence that an educational strategy addressing neurophysiology and neurobiology of pain can have a positive effect on pain, disability, catastrophization, and physical performance.