Acute Muscle Rigidity Secondary to Tetanus: A Toxicology Simulation Case for Fourth-Year Medical Students

Introduction

Tetanus is uncommon in the United States secondary to vaccination. However, vaccination hesitancy is increasing. This case challenges medical students to consider tetanus in the differential and understand its complications.

Methods

Fourth-year medical students took a pretest on the neurotransmitter glycine and associated disease states. They received two 10-minute lectures on glycine and acid-base abnormalities. Students then participated in a simulation featuring a 27-year-old man bitten by a dog, resulting in tetanus. Required equipment included a mannequin with monitor, a defibrillator, and personal protective equipment. Critical actions consisted of learners dividing up roles amongst each other, using closed-loop communication, placing the patient on a cardiac monitor, choosing to establish IV access and intubate the patient, starting IV fluids, and administering tetanus immunoglobulin. The case ended after 20 minutes. Outcome measurements encompassed performance on a posttest and critical actions.

Results

Twenty students participated. Mean pretest and posttest scores were 69.5 and 92.5, respectively (p < .001). All groups completed the items on the critical actions checklist within a 20-minute time frame.

Discussion

Rising vaccine hesitancy may increase the likelihood of physicians encountering new cases of tetanus and require them to perform lifesaving management of a patient presenting with muscle rigidity. This simulation provides learners with hands-on experience caring for a patient with tetanus and muscle rigidity. It can improve their knowledge of recognition, assessment, and decision-making toward lifesaving management of tetanus by allowing them to practice their skills in a safe environment.

Paratonia, Gegenhalten and psychomotor hypertonia Back to the roots

In the first half of the 20th century, well before the antipsychotic era, paratonia, Gegenhalten and psychomotor hypertonia were described as new forms of hypertonia intrinsic to particular psychoses and catatonic disorders. A series of astute clinical observations and experiments supported their independence from rigidity seen in Parkinson's disease. After World War II, motor disorders went out of fashion in psychiatry, with drug-induced parkinsonism becoming the prevailing explanation for all involuntary resistance to passive motion. With the 'forgetting' of paratonia and Gegenhalten, parkinsonism became the prevailing reading grid, such that the rediscovery of hypertonia in antipsychotic-naive patients at the turn of the 21st century is currently referred to as "spontaneous parkinsonism", implicitly suggesting intrinsic and drug-induced forms to be the same. Classical descriptive psychopathology gives a more nuanced view in suggesting two non-parkinsonian hypertonias: (i) locomotor hypertonia corresponds to Ernest Dupré's paratonia and Karl Kleist's reactive Gegenhalten; it is a dys-relaxation phenomenon that often needs to be activated. (ii) Psychomotor hypertonia is experienced as an admixture of assistance and resistance that partially overlaps with Kleist's spontaneous Gegenhalten, but was convincingly isolated by Henri Claude and Henri Baruk thanks to electromyogram recordings; psychomotor hypertonia is underpinned by "anticipatory contractions" of cortical origin, occurrence of which in phase or antiphase with the movement accounted for facilitation or opposition to passive motions. This century-old knowledge is not only of historical interest. Some results have recently been replicated in dementia and as now known to involve specific premotor systems.

An Unusual Cause of Fever, Neck Pain, and Neck Stiffness: Acute Calcific Tendinitis of the Longus Colli Muscle

BACKGROUND

Acute calcific tendinitis (ACT) of the longus colli muscle (LCM) is an inflammatory response due to deposition of calcium hydroxyapatite crystals. It is typically correlated with whiplash and overuse injuries. A common presentation of this inflammatory response is acute but progressive neck pain. It is a rare but important cause of neck pain that should be considered on a differential diagnosis when distinguishing between life-threatening conditions and non-life-threatening causes of neck pain.

CASE REPORT

A 51-year-old woman presented to the emergency department (ED) reporting a mild sore throat that progressed to acute neck pain and stiffness. She also reported fatigue, fever, myalgias, and nausea. In the ED, the patient was tachycardic, hypertensive, and mildly febrile with normal oxygen saturation. Examination revealed meningismus and was negative for lymphadenopathy, oropharyngeal findings, and neurologic deficits. Laboratory studies were significant for leukocytosis. Computed tomography (CT) neck was obtained and was notable for calcification of the superior left longus colli muscle with prevertebral and retropharyngeal space edema along the muscle body. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: ACT of the LCM is a benign, self-limited condition that can present with features overlapping emergent causes of acute neck pain. Correct diagnosis relies on characteristic radiographic findings on CT. Fortunately, patients may be discharged home with a short course of anti-inflammatories and corticosteroids with near-complete resolution of symptoms. Emergency physicians, therefore, can rule out life-threatening causes of neck pain, while also making a definitive diagnosis and initiating effective management for this pathology.

Clinical, genetic, and functional characterization of the glycine receptor β-subunit A455P variant in a family affected by hyperekplexia syndrome

Hyperekplexia is a rare neurological disorder characterized by exaggerated startle responses affecting newborns with the hallmark characteristics of hypertonia, apnea, and noise or touch-induced nonepileptic seizures. The genetic causes of the disease can vary, and several associated genes and mutations have been reported to affect glycine receptors (GlyRs); however, the mechanistic links between GlyRs and hyperekplexia are not yet understood. Here, we describe a patient with hyperekplexia from a consanguineous family. Extensive genetic screening using exome sequencing coupled with autozygome analysis and iterative filtering supplemented by in silico prediction identified that the patient carries the homozygous missense mutation A455P in GLRB, which encodes the GlyR β-subunit. To unravel the physiological and molecular effects of A455P on GlyRs, we used electrophysiology in a heterologous system as well as immunocytochemistry, confocal microscopy, and cellular biochemistry. We found a reduction in glycine-evoked currents in N2A cells expressing the mutation compared to WT cells. Western blot analysis also revealed a reduced amount of GlyR β protein both in cell lysates and isolated membrane fractions. In line with the above observations, coimmunoprecipitation assays suggested that the GlyR α1-subunit retained coassembly with βA455P to form membrane-bound heteromeric receptors. Finally, structural modeling showed that the A455P mutation affected the interaction between the GlyR β-subunit transmembrane domain 4 and the other helices of the subunit. Taken together, our study identifies and validates a novel loss-of-function mutation in GlyRs whose pathogenicity is likely to cause hyperekplexia in the affected individual.

Different Behaviors of a Glycine Receptor Channel Pore Residue between Wild-Type-Mimicking and Disease-Type-Mimicking Formats

The glycine receptor (GlyR) is a neurotransmitter-gated chloride channel that mediates fast inhibitory neurotransmission, predominantly in the spinal cord and brain stem. Mutations of the GlyR are the major cause of hereditary hyperekplexia. Site-specific cysteine substitution followed by labeling with a fluorophore has previously been used to explore the behaviors of the hyperekplexia-related 271 (19') residue of the GlyR. However, this manipulation dramatically compromises sensitivity toward the agonist glycine and alters the pharmacological effects of various agents in manners similar to those of the hyperekplexia-causing R19'Q/L mutations, raising the question whether what is reported by the substituted and modified residue faithfully reflects what actually happens to the wild-type (WT) residue. In this study, a mechanism-rescuing second-site mutation was introduced to create a WT-mimicking GlyR (with the 19' residue cysteine substitution and modification still in place), in which the sensitivity toward glycine and pharmacological effects of various agents were restored. Further experiments revealed stark differences in the behaviors upon the various pharmacological treatments and consequently the underlying mechanisms of the 19' residue between this WT-mimicking GlyR and the GlyR without the mechanism rescue, which is correspondingly defined as the disease-type (DT)-mimicking GlyR. The data presented in this study warn generally that caution is required when attempting to deduce the behaviors of a WT residue from data based on substituted or modified residues that alter protein structure and function. Extra measures, such as rescuing mechanisms via alternative means as presented in this study, are needed to mitigate this challenge.

Iliopsoas Hematomas in a Patient with Progressive Encephalomyelitis with Rigidity and Myoclonus

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare and severe syndrome characterized by rigidity of the limb and truncal muscles, brainstem signs, myoclonus, and hyperekplexia. Iliopsoas hematoma is a serious complication of bleeding disorders that occurs most commonly in patients with hemophilia and also in association with anti-coagulant drug treatment. We herein present a case of PERM complicated with bilateral iliopsoas hematomas. His neurological symptoms improved after immunotherapy, and thereafter the iliopsoas hematomas disappeared. Neurologists should consider iliopsoas hematomas as a serious potential complication of PERM.

Progressive Encephalomyelitis with Rigidity and Myoclonus (PERM)-like Symptoms Associated with Anti-ganglionic Acetylcholine Receptor Antibodies

This report describes a 59-year-old woman who presented with progressive encephalomyelitis with rigidity and myoclonus (PERM)-like symptoms and severe dysautonomia, including orthostatic hypotension, sinus bradycardia, dysuria, and prolonged constipation. Her neurological symptoms improved after immunotherapy, but the dysautonomia persisted. Anti-ganglionic acetylcholine receptor (gAChR) α3 subunit antibodies, which are frequently identified in patients with autoimmune autonomic ganglionopathy, were detected in the pre-treatment serum. The central distribution of the nicotinic acetylcholine receptors, a target of anti-gAChR antibodies, and immunotherapeutic efficacy observed in this case indicate that anti-gAChR α3 subunit antibodies are associated with the PERM-like features accompanied by autonomic manifestations.

[Stiff-Person Syndrome]

Stiff-person syndrome (SPS) is a neurological disorder characterized by fluctuating muscle rigidity and painful spasms that occur spontaneously or are triggered by diverse stimuli. Partial or segmental forms of the disorder, such as stiff-limb syndrome (SLS) and the more severe disease called progressive encephalomyelitis with rigidity and myoclonus (PERM), are usually considered within the spectrum of SPS. SPS responds to immunotherapies, and several autoantigens have been identified. Most patients with SPS have high titers of antibodies against glutamic acid decarboxylase (GAD), the enzyme that limits the rate of the synthesis of γ-aminobutyric acid (GABA), and up to 15% have antibodies against the glycine receptor α-subunit.

Efficacy of postoperative radiotherapy combined with taxol+carboplatin chemotherapy regimens in the treatment of high-risk early-stage endometrial cancer

PURPOSE

To compare the efficacy and safety of postoperative extrapelvic irradiation intensity-modulated radiotherapy (IMRT)+concurrent chemotherapy and vaginal brachytherapy (VBT)+concurrent chemotherapy in the treatment of patients with high-risk early-stage endometrial cancer, and analyze the influencing factors for the prognosis of patients.

METHODS

A total of 126 patients with high-risk stage Ic-IIa endometrial cancer were divided into extrapelvic irradiation IMRT + concurrent taxol+carboplatin (TC) chemotherapy group (IMRT group, n=63) and VBT + concurrent TC chemotherapy group (VBT group, n=63). Then, the efficacy and the incidence rate of adverse reactions were compared between the two groups of patients. Additionally, the possible influencing factors for the prognosis of patients were analyzed.

RESULTS

In the Functional Assessment of Cancer Therapy-General Version 4 (FACT-G-V4) scale for the quality of life of patients, the scores of physiological status, social/family status, emotional status and functional status were dramatically higher in the VBT group than in the IMRT group at 3 months after treatment. The 5-year overall survival (OS) and progression-free survival (PFS) rates were 87.3% and 73.0% in the IMRT group and 82.5% and 66.7% in the VBT group, respectively. Furthermore, advanced age, lower uterine segment involvement and anemia before treatment were independent risk factors for tumor progression in patients with endometrial cancer.

CONCLUSIONS

For patients with high-risk early-stage endometrial cancer, postoperative VBT + concurrent TC chemotherapy has similar efficacy to postoperative extrapelvic irradiation IMRT + concurrent TC chemotherapy, but patients receiving the former have fewer adverse reactions and high quality of life. Advanced age, lower uterine segment involvement and anemia before treatment are independent risk factors affecting tumor progression in such patients.

Pair of Residue Substitutions at the Outer Mouth of the Channel Pore Act as Inputs for a Boolean Logic "OR" Gate Based on the Glycine Receptor

The glycine receptor (GlyR) is a ligand-activated chloride channel, whose mutations are the major cause of hereditary hyperekplexia. The hyperekplexia-causing R271Q mutation, which is located at the extracellular outer mouth of the channel pore, dramatically impairs the GlyR function manifesting a reduced sensitivity toward glycine. This study reports that a second mutation, S273D, rescues the function of the R271Q GlyR to that of the wild-type (WT) GlyR. Surprisingly, the S273D mutation, when introduced to the WT GlyR, does not further increase the receptor function. In other words, the compromised function of the 271Q 273S GlyR (i.e., the R271Q GlyR) can be rescued to WT levels by the introduction of either, or both, of the Q271R and S273D substitutions. From the perspective of Boolean logic gates, the Q271R and S273D substitutions act as inputs for an OR gate based on the GlyR. Further experiments revealed that the negative-charge carried by the 273 residue is essential for the expression of the OR gate and that the expression of the OR gate is residue-position-specific. In addition, mechanistic investigation implied that the 273 residue influences the 271 residue, which might underpin the unique nonadditive OR gate relationship between these two residues. Such an ion-channel-based OR gate, expressing output in the form of electrical current, could potentially be developed to digitally manipulate neuronal activity.

Charged residues at the pore extracellular half of the glycine receptor facilitate channel gating: a potential role played by electrostatic repulsion

KEY POINTS

The Arg271Gln mutation of the glycine receptor (GlyR) causes hereditary hyperekplexia. This mutation dramatically compromises GlyR function; however, the underlying mechanism is not yet known. This study, by employing function and computation methods, proposes that charged residues (including the Arg residue) at the pore extracellular half from each of the five subunits of the homomeric α1 GlyR, create an electrostatic repulsive potential to widen the pore, thereby facilitating channel opening. This mechanism explains how the Arg271Gln mutation, in which the positively charged Arg residue is substituted by the neutral Gln residue, compromises GlyR function. This study furthers our understanding of the biophysical mechanism underlying the Arg271Gln mutation compromising GlyR function.

ABSTRACT

The R271(19')Q mutation in the α1 subunit of the glycine receptor (GlyR) chloride channel causes hereditary hyperekplexia. This mutation dramatically compromises channel function; however, the underlying mechanism is not yet known. The R271 residue is located at the extracellular half of the channel pore. In this study, an Arg-scanning mutagenesis was performed at the pore extracellular half from the 262(10') to the 272(20') position on the background of the α1 GlyR carrying the hyperekplexia-causing mutation R271(19')Q. It was found that the placement of the Arg residue rescued channel function to an extent inversely correlated with the distance between the residue and the pore central axis (perpendicular to the plane of the lipid bilayer). Accordingly, it was hypothesized that the placed Arg residues from each of the five subunits of the homomeric α1 GlyR create an electrostatic repulsive potential to widen the pore, thereby facilitating channel opening. This hypothesis was quantitatively verified by theoretical computation via exploiting basic laws of electrostatics and thermodynamics, and further supported by more experimental findings that the placement of another positively charged Lys residue or even a negatively charged Asp residue also rescued channel function in the same manner. This study provides a novel mechanism via which charged residues in the pore region facilitate channel gating, not only for the disease-causing 19'R residue in the GlyR, but also potentially for charged residues in the same region of other ion channels.

Hyperekplexia and other startle syndromes

Abnormal startle syndromes are classified into hyperekplexia, stimulus-induced, and neuropsychiatric startle syndromes. Hyperekplexia is attributed to a genetic, idiopathic, or symptomatic cause. Hereditary hyperekplexia is a treatable neurogenetic disorder. In patients with a hyperactive startle response, the first step is to characterize the extent and associations of 'response.' Secondary or symptomatic causes are particularly important in children, as they provide useful clinical clues to an underlying neurodevelopmental or neurodegenerative disorders. Particular attention should be given to any neonate or infant with generalized or episodic stiffness, drug-refractory seizures, recurrent apnea, stimulus-sensitive behavioral states, or sudden infant death syndrome. Eliciting a non-habituating head-retraction reflex to repeated nose tapping should be a part of routine examination of all new-borns. Vigevano maneuver should be taught to all families and health-care workers as an emergency rescue measure. The onset of excessive startle after infancy should direct investigations for an acquired cause such as brainstem injury, antibodies against glycine receptors, and neurodegeneration. Finally, one should not forget to evaluate unexplained cases of abnormal gait and frequent falls in adults for underlying undiagnosed startle syndromes. Oral clonazepam is an effective therapy besides behavioral and safety interventions for hereditary cases. The outcomes in genetic cases are good overall.

PDMeter: A Wrist Wearable Device for an at-Home Assessment of the Parkinson's Disease Rigidity

This work focuses on the design and the validation of a wearable mechatronic device for an at-home assessment of wrist stiffness in patients affected by Parkinson's Disease (PD). The device includes one actuated joint and four passive revolute joints with a high overall intrinsic backdriveability. In order to allow the user to freely move the wrist during activities of daily living, we implemented a transparent controller on the basis of the interaction force sensed by the embedded load cell. Conversely, in order to provide perturbations for estimating the wrist flexion-extension rigidity, we implemented a torque controller. Firstly, we report a pilot study that aimed at characterizing the device in terms of range of motion (ROM) allowed, transparency perceived and torque-tracking capability. Then, we present a case study in which we tested our device with seven PD patients in both drug-OFF and drug-ON conditions and we compared the measured stiffness with the one measured in fourteen healthy controls and with the outcome of the most used clinical scale (MDS-UPDRS). The device allowed to successfully estimate the stiffness as different depending on the movement direction. Indeed, extension stiffness was higher than the flexion one, accordingly to the literature. Moreover, the device allowed to discriminate both Healthy subjects from PD subjects, and PD subjects in OFF condition from PD subjects in ON condition. In conclusion, we demonstrate the feasibility of the device in measuring wrist rigidity, thus enabling the possibility to implement an at-home assessment of the PD rigidity.

Impaired finger dexterity and nigrostriatal dopamine loss in Parkinson's disease

Impaired finger dexterity occurs in Parkinson's disease (PD) and has been considered a limb-kinetic apraxia associated with primary sensory cortical dysfunction. To study the role of nigrostriatal dopamine loss and elementary parkinsonian motor deficits in impaired finger dexterity of PD. Thirty-two right-handed untreated PD patients and 30 right-handed healthy controls were included. All patients underwent [¹⁸F] FP-CIT positron emission tomography studies. We examined the associations among unilateral coin rotation (CR) score, Unified Parkinson's Disease Rating Scale (UPDRS) subscores for bradykinesia and rigidity of the corresponding arm, and contralateral regional striatal dopamine transporter (DAT) uptake. We also measured the effect of oral levodopa dose on CR scores and UPDRS subscores. PD patients performed worse than controls on the CR task. Unilateral arm UPDRS bradykinesia scores were associated with DAT uptake in the contralateral putamen. The left CR score was associated with left arm bradykinesia and rigidity scores and DAT uptake in the right posterior putamen, whereas no such associations were found for the right CR score. There was a significant effect of handedness on the association of putamen DAT uptake with CR scores, but not with UPDRS subscores. An oral levodopa challenge improved CR scores and UPDRS subscores on both sides. Impaired finger dexterity in PD is related to elementary parkinsonian motor deficits and nigrostriatal dopamine loss. Impaired dominant hand dexterity associated with nigrostriatal dopamine loss seems to be compensated to some extent by the dominant cerebral cortex specialized for controlling precise finger movements.

Development and Pilot Testing of a Novel Electromechanical Device to Measure Wrist Rigidity in Parkinson's Disease

Quantitative assessment of the muscle tone is important when studying patients with neurological disorders such as Parkinson's disease (PD). For the assessment of therapeutic progress, quantitative and objective outcome measures are needed. This article presents a novel electromechanical device to monitor the quantitative rigidity of the wrist joint against passive movement. The novel device is equipped with an electrical motor to move the wrist joint in a flexion-extension manner with different velocity profiles. The accuracy of the device was measured in terms of position, velocity and torque accuracy. The feasibility of the measurement procedure was tested in a pilot study with four PD patients and 12 healthy controls (HC), at velocities of 10 °/s,50 °/s, and 100 °/s. {The position and velocity of the developed device were (0.005 ± 0.105)° and (0.734 ±0.276) °/s, unloaded, and (0.003 ± 0.113) ° and (0.013 ± 0.038) °/s, loaded with a relaxed arm, respectively. The torque accuracy was (15.029 ± 2.235) mNm. The comparison of the median rigidity between the PD patients and HC showed significant differences at all tested velocities, during both flexion and extension movements. This device proved to have sufficient accuracy and sensitivity to precisely measure the interaction torque at the wrist joint and to differentiate PD rigidity from normal muscle tone. The device, thus provides a quantitative and objective measure of rigidity in PD.

Tetanus in a partially immunized child

A 13-year-old boy developed tetanus, although he had protective antitoxin antibody raised by three doses of tetanus toxoid vaccine. Four days after injury, he presented with muscle rigidity of his posterior neck, excessive diaphoresis, and risus sardonicus and was subsequently diagnosed with tetanus. Tetanus is rare in developed countries, particularly during childhood, but must be promptly diagnosed based on clinical symptoms.

[Stiff-Person Syndrome and Related Autoantibodies]

Stiff-person syndrome (SPS) is a disorder characterized by fluctuating muscle rigidity and painful spasms that occur spontaneously or are triggered by diverse stimuli. Partial or segmental forms of the disorder, such as stiff-limb syndrome (SLS) and a more severe disease called progressive encephalomyelitis with rigidity and myoclonus (PERM), are usually considered within the spectrum of SPS. SPS responds to immunotherapies, and several autoantigens have been identified. Most patients with SPS have a high-titer of antibodies against glutamic acid decarboxylase (GAD), the rate-limiting enzyme for the synthesis of γ-aminobutyric acid (GABA), and up to 15% have antibodies to the glycine receptor α-subunit. This review explains milestones in defining SPS including autoantibodies.

Whole body vibration exercise training for fibromyalgia

BACKGROUND

Exercise training is commonly recommended for adults with fibromyalgia. We defined whole body vibration (WBV) exercise as use of a vertical or rotary oscillating platform as an exercise stimulus while the individual engages in sustained static positioning or dynamic movements. The individual stands on the platform, and oscillations result in vibrations transmitted to the subject through the legs. This review is one of a series of reviews that replaces the first review published in 2002.

OBJECTIVES

To evaluate benefits and harms of WBV exercise training in adults with fibromyalgia.

SEARCH METHODS

We searched the Cochrane Library, MEDLINE, Embase, CINAHL, PEDro, Thesis and Dissertation Abstracts, AMED, WHO ICTRP, and ClinicalTrials.gov up to December 2016, unrestricted by language, to identify potentially relevant trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in adults with the diagnosis of fibromyalgia based on published criteria including a WBV intervention versus control or another intervention. Major outcomes were health-related quality of life (HRQL), pain intensity, stiffness, fatigue, physical function, withdrawals, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data, performed risk of bias assessments, and assessed the quality of evidence for major outcomes using the GRADE approach. We used a 15% threshold for calculation of clinically relevant differences.

MAIN RESULTS

We included four studies involving 150 middle-aged female participants from one country. Two studies had two treatment arms (71 participants) that compared WBV plus mixed exercise plus relaxation versus mixed exercise plus relaxation and placebo WBV versus control, and WBV plus mixed exercise versus mixed exercise and control; two studies had three treatment arms (79 participants) that compared WBV plus mixed exercise versus control and mixed relaxation placebo WBV. We judged the overall risk of bias as low for selection (random sequence generation), detection (objectively measured outcomes), attrition, and other biases; as unclear for selection bias (allocation concealment); and as high for performance, detection (self-report outcomes), and selective reporting biases.The WBV versus control comparison reported on three major outcomes assessed at 12 weeks post intervention based on the Fibromyalgia Impact Questionnaire (FIQ) (0 to 100 scale, lower score is better). Results for HRQL in the control group at end of treatment (59.13) showed a mean difference (MD) of -3.73 (95% confidence interval [CI] -10.81 to 3.35) for absolute HRQL, or improvement of 4% (11% better to 3% worse) and relative improvement of 6.7% (19.6% better to 6.1% worse). Results for withdrawals indicate that 14 per 100 and 10 per 100 in the intervention and control groups, respectively, withdrew from the intervention (RR 1.43, 95% CI 0.27 to 7.67; absolute change 4%, 95% CI 16% fewer to 24% more; relative change 43% more, 95% CI 73% fewer to 667% more). The only adverse event reported was acute pain in the legs, for which one participant dropped out of the program. We judged the quality of evidence for all outcomes as very low. This study did not measure pain intensity, fatigue, stiffness, or physical function. No outcomes in this comparison met the 15% threshold for clinical relevance.The WBV plus mixed exercise (aerobic, strength, flexibility, and relaxation) versus control study (N = 21) evaluated symptoms at six weeks post intervention using the FIQ. Results for HRQL at end of treatment (59.64) showed an MD of -16.02 (95% CI -31.57 to -0.47) for absolute HRQL, with improvement of 16% (0.5% to 32%) and relative change in HRQL of 24% (0.7% to 47%). Data showed a pain intensity MD of -28.22 (95% CI -43.26 to -13.18) for an absolute difference of 28% (13% to 43%) and a relative change of 39% improvement (18% to 60%); as well as a fatigue MD of -33 (95% CI -49 to -16) for an absolute difference of 33% (16% to 49%) and relative difference of 47% (95% CI 23% to 60%); and a stiffness MD of -26.27 (95% CI -42.96 to -9.58) for an absolute difference of 26% (10% to 43%) and a relative difference of 36.5% (23% to 60%). All-cause withdrawals occurred in 8 per 100 and 33 per 100 withdrawals in the intervention and control groups, respectively (two studies, N = 46; RR 0.25, 95% CI 0.06 to 1.12) for an absolute risk difference of 24% (3% to 51%). One participant exhibited a mild anxiety attack at the first session of WBV. No studies in this comparison reported on physical function. Several outcomes (based on the findings of one study) in this comparison met the 15% threshold for clinical relevance: HRQL, pain intensity, fatigue, and stiffness, which improved by 16%, 39%, 46%, and 36%, respectively. We found evidence of very low quality for all outcomes.The WBV plus mixed exercise versus other exercise provided very low quality evidence for all outcomes. Investigators evaluated outcomes on a 0 to 100 scale (lower score is better) for pain intensity (one study, N = 23; MD -16.36, 95% CI -29.49 to -3.23), HRQL (two studies, N = 49; MD -6.67, 95% CI -14.65 to 1.31), fatigue (one study, N = 23; MD -14.41, 95% CI -29.47 to 0.65), stiffness (one study, N = 23; MD -12.72, 95% CI -26.90 to 1.46), and all-cause withdrawal (three studies, N = 77; RR 0.72, 95% CI -0.17 to 3.11). Adverse events reported for the three studies included one anxiety attack at the first session of WBV and one dropout from the comparison group ("other exercise group") due to an injury that was not related to the program. No studies reported on physical function.

AUTHORS' CONCLUSIONS

Whether WBV or WBV in addition to mixed exercise is superior to control or another intervention for women with fibromyalgia remains uncertain. The quality of evidence is very low owing to imprecision (few study participants and wide confidence intervals) and issues related to risk of bias. These trials did not measure major outcomes such as pain intensity, stiffness, fatigue, and physical function. Overall, studies were few and were very small, which prevented meaningful estimates of harms and definitive conclusions about WBV safety.

Automated assessment of symptom severity changes during deep brain stimulation (DBS) therapy for Parkinson's disease

Deep brain stimulation (DBS) is currently being used as a treatment for symptoms of Parkinson's disease (PD). Tracking symptom severity progression and deciding the optimal stimulation parameters for people with PD is extremely difficult. This study presents a sensor system that can quantify the three cardinal motor symptoms of PD - rigidity, bradykinesia and tremor. The first phase of this study assesses whether data recorded from the system during physical examinations can be used to correlate to clinician's severity score using supervised machine learning (ML) models. The second phase concludes whether the sensor system can distinguish differences before and after DBS optimisation by a clinician when Unified Parkinson's Disease Rating Scale (UPDRS) scores did not change. An average accuracy of 90.9 % was achieved by the best ML models in the first phase, when correlating sensor data to clinician's scores. Adding on to this, in the second phase of the study, the sensor system was able to pick up discernible differences before and after DBS optimisation sessions in instances where UPDRS scores did not change.

The Phenomenology of Parkinson's Disease

The motor symptoms of Parkinson's disease are not limited to the cardinal symptoms of bradykinesia, rigidity, and resting tremor, but also include a variety of interrelated motor phenomena such as deficits in spatiotemporal planning and movement sequencing, scaling and timing of movements, and intermuscular coordination that can be clinically observed. Although many of these phenomena overlap, a review of the full breadth of the motor phenomenon can aid in the diagnosis and monitoring of disease progression.

Face-referenced measurement of perioral stiffness and speech kinematics in Parkinson's disease

PURPOSE

Perioral biomechanics, labial kinematics, and associated electromyographic signals were sampled and characterized in individuals with Parkinson's disease (PD) as a function of medication state.

METHOD

Passive perioral stiffness was sampled using the OroSTIFF system in 10 individuals with PD in a medication ON and a medication OFF state and compared to 10 matched controls. Perioral stiffness, derived as the quotient of resultant force and interoral angle span, was modeled with regression techniques. Labial movement amplitudes and integrated electromyograms from select lip muscles were evaluated during syllable production using a 4-D computerized motion capture system.

RESULTS

Multilevel regression modeling showed greater perioral stiffness in patients with PD, consistent with the clinical correlate of rigidity. In the medication-OFF state, individuals with PD manifested greater integrated electromyogram levels for the orbicularis oris inferior compared to controls, which increased further after consumption of levodopa.

CONCLUSIONS

This study illustrates the application of biomechanical, electrophysiological, and kinematic methods to better understand the pathophysiology of speech motor control in PD.

Associations between quantitative mobility measures derived from components of conventional mobility testing and Parkinsonian gait in older adults

Objective

To provide objective measures which characterize mobility in older adults assessed in the community setting and to examine the extent to which these measures are associated with parkinsonian gait.

Methods

During conventional mobility testing in the community-setting, 351 ambulatory non-demented Memory and Aging Project participants wore a belt with a whole body sensor that recorded both acceleration and angular velocity in 3 directions. We used measures derived from these recordings to quantify 5 subtasks including a) walking, b) transition from sit to stand, c) transition from stand to sit, d) turning and e) standing posture. Parkinsonian gait and other mild parkinsonian signs were assessed with a modified version of the original Unified Parkinson’s Disease Rating Scale (mUPDRS).

Results

In a series of separate regression models which adjusted for age and sex, all 5 mobility subtask measures were associated with parkinsonian gait and accounted for 2% to 32% of its variance. When all 5 subtask measures were considered in a single model, backward elimination showed that measures of walking sit to stand and turning showed independent associations with parkinsonian gait and together accounted for more than 35% of its variance. Cross-validation using data from a 2^nd group of 258 older adults showed similar results. In similar analyses, only walking was associated with bradykinesia and sway with tremor.

Interpretation

Quantitative mobility subtask measures vary in their associations with parkinsonian gait scores and other parkinsonian signs in older adults. Quantifying the different facets of mobility has the potential to facilitate the clinical characterization and understanding the biologic basis for impaired mobility in older adults.

Handedness and dominant side of symptoms in Parkinson's disease

BACKGROUND AND OBJECTIVE

To investigate the association between handedness and the side of symptom dominance in Parkinson's disease (PD).

PATIENTS AND METHODS

One hundred and forty-six PD patients with symmetric symptoms (92 males and 54 females), aged 64.3 ± 9.1 years old, from a series of 247 PD patients were assessed for handedness and clinical features. The severity of PD was scored by unified Parkinson's disease rating scale (UPDRS) and Hoehn-Yahr staging on the "ON" state.

RESULTS

Of 134 right-handed patients (91.8%), 83 (61.7%) had an initial onset on the right side (P=0.008), while of 12 left-handed patients (8.2%), 9 (75.0%) had an initial onset on the left side (P=0.013). Out of right-handed patients, 103 (76.9%) had the right-side dominance of PD symptoms (P<0.001). Among the left-handed subjects, 7 patients (58.3%) had left-sided and 5 patients (41.7%) had right-sided symptom dominance (P=0.564). In general, dominant side of symptoms was in accordance with handedness (P=0.008). In right-handed patients, rest tremor was the most common initial symptom (P<0.001), while rest tremor and rigidity-bradykinesia were initial symptoms in left-handed patients (P=0.366).

CONCLUSIONS

PD symptoms emerge more often on the dominant hand-side, and the dominant side of symptoms is in accordance with handedness.

[Arterial rigidity, a marker of cardiovascular diseases]

Rigidity of the arterial wall is a generally accepted marker of cardiovascular diseases. Many studies are designed to investigate arterial rigidity in patients with arterial hypertension, coronary heart disease, and diabetes mellitus. The authors consider pathophysiological mechanisms underlying the enhancement of vascular rigidlity and the respective contributing fiactors, such as extensibility compressibility elasticity modulus, pulse wave propagation velocity, and augmentation index. The main methods for measuring arterial rigidity are described with special reference to non-invasive techniques and fbctors responsible for this condition. Possibilities for medicamental modification of main arteries are discussed

Stiff-person syndrome (SPS) and anti-GAD-related CNS degenerations: protean additions to the autoimmune central neuropathies

Stiff Person Syndrome (SPS) is a rare autoimmune neurological disease attributable to autoantibodies to glutamic acid decarboxylase (anti-GAD) more usually associated with the islet beta cell destruction of autoimmune type 1 diabetes (T1D). SPS is characterized by interference in neurons with the synthesis/activity of the inhibitory neurotransmitter gamma amino butyric acid (GABA) resulting in the prototypic progressive spasmodic muscular rigidity of SPS, or diverse neurological syndromes, cerebellar ataxia, intractable epilepsy, myoclonus and several others. Remarkably, a single autoantibody, anti-GAD, can be common to widely different disease expressions, i.e. T1D and SPS. One explanation for these data is the differences in epitope engagement between the anti-GAD reactivity in SPS and T1D: in both diseases, anti-GAD antibody reactivity is predominantly to a conformational epitope region in the PLP- and C-terminal domains of the 65 kDa isoform but, additionally in SPS, there is reactivity to conformational epitope(s) on GAD67, and short linear epitopes in the C-terminal region and at the N-terminus of GAD65. Another explanation for disease expressions in SPS includes ready access of anti-GAD to antigen sites due to immune responsiveness within the CNS itself according to intrathecal anti-GAD-specific B cells and autoantibody. Closer study of the mysterious stiff-person syndrome should enhance the understanding of this disease itself, and autoimmunity in general.

Generalized tetanus in a Labrador retriever

A 10-week-old, intact female, Labrador retriever was presented for progressive extensor rigidity, facial swelling, and difficulty in walking. Generalized tetanus was diagnosed and treated successfully.

Dopa-responsive infantile hypokinetic rigid syndrome due to dominant guanosine triphosphate cyclohydrolase 1 deficiency

We report on a GTP cyclohydrolase 1 mutation-confirmed heterozygous case presenting with an infantile hypokinetic rigid syndrome and delay in attainment of motor milestones starting from the first year of life. He had a family history of dopa-responsive dystonia-parkinsonism. CSF neopterin, biopterin and HVA values were decreased. Molecular study of GCH-1 gene showed the Q89X mutation in exon 1. Treatment with l-dopa resulted in a complete remission of symptoms.

Acoustic Changes Related to Laryngeal Examination with a Rigid Telescope

The influence on voice quality of the insertion of endoscopic equipment with tongue anchoring and head position requirements during endoscopic evaluation has not been fully investigated. The present study attempted to examine the influence of: (1) the presence of a rigid endoscope and tongue anchoring, and (2) the angle of position technique (70-degree and 90-degree) on participants' vocal output during sustained production of the vowel /i/. Five acoustic measurements including fundamental frequency (F0) values, percent jitter values, relative average perturbation of F0 shimmer, and noise-to-harmonic ratios were used to represent participants' voice quality. Results indicated that F0 values were significantly influenced by the angle of sitting position, while percent jitter values, relative average perturbation of F0, shimmer, and noise- to-harmonic ratios were affected by the presence of a rigid endoscope and tongue anchoring.

Muscle stiffness and strength and their relation to hand function in children with hemiplegic cerebral palsy

This study compared the passive stiffness of wrist flexors and the strength of wrist flexors and extensors in three different wrist positions (30 degrees of flexion, neutral, and 30 degrees of extension) between children with cerebral palsy (CP) and typically developing (TD) comparison children. It also examined associations between these characteristics and manual function in children with CP. Eleven children with spastic hemiplegic CP (six females, five males; mean age 8y 5mo [SD 1y 8mo], range 6-11y) and 11 TD children, matched for age and sex, took part in this study. Passive stiffness of muscles was measured as the torque/angle relation during passive motion. Isometric strength tests were performed and the time needed to complete three tasks based on the Jebsen-Taylor Hand Function Test was recorded. Flexor stiffness was higher in the group with CP. Strength of flexors and extensors in the group with CP was lower with the wrist extended. No difference among test positions was found in the TD group. Moderate correlations were observed between manual function and variables related to strength and stiffness of wrist muscles in the group with CP. Children with CP showed muscle alterations coherent with the use of the wrist in flexion. Intervention on these characteristics could have a positive impact on manual function.

Substrate rigidity and force define form through tyrosine phosphatase and kinase pathways

Cell forces define cell morphology, alterations in which are caused by tyrosine kinase and phosphatase mutations, which implies a causal linkage. Recent studies have shown that phosphotyrosine signaling is involved in force sensing for cells on flat surfaces. Early force-dependent activation of Src family kinases by phosphatases or cytoskeleton stretch leads to the activation of downstream signaling. In addition, force generation by cells depends on a feedback mechanism between matrix rigidity or force generation and myosin contractility. Components of the force-sensing pathway are linked to the integrin-cytoskeleton complex at sites of force application and serve as scaffolds for signaling processes. Thus, early events in force detection are mechanically induced cytoskeletal changes that result in biochemical signals to mechanoresponsive pathways that then regulate cell form.

Estimation of early postmortem intervals by a multiple regression analysis using rectal temperature and non-temperature based postmortem changes

Five general methods based on rectal temperature and a multiple regression analysis using rectal temperature and non-temperature based postmortem changes were applied to 212 postmortem cases of within 24h postmortem (PM) intervals. Non-temperature based postmortem changes of rigidity, hypostasis and corneal turbidity were numerically categorized and used with rectal temperatures as four statistical variables in the multiple regression analysis. The correlation coefficient values between true and calculated postmortem intervals were 0.78-0.82 in the five general methods based on rectal temperature. The multiple regression analysis produced a multiple correlation coefficient value of 0.89 and according to the error ranges of the PM intervals, 72% of the cases were estimated within the error of +/-1.0 h and 92% within +/-5.0 h. Although assessments of non-temperature based PM changes are mostly subjective and have a wide variation, the present study demonstrated a usefulness of non-temperature based PM changes in the estimation of PM intervals.

Apparent life-threatening events in infants: high risk in the out-of-hospital environment

STUDY OBJECTIVE

The purpose of this study is to define the prevalence and significance of apparent life-threatening events among infants in the out-of-hospital setting.

METHODS

This was a retrospective, cohort, outcome study of infants for whom a caregiver activated the emergency medical services (EMS) system. For purposes of the study, an apparent life-threatening event was defined as an episode of apnea, skin color change, or change in muscle tone. Study data characteristics included initial physical appearance, work of breathing, circulation skin signs, pulse rate, respiratory rate, and overall concern for the chief complaint as interpreted by EMS personnel.

RESULTS

Sixty (7.5%) of 804 infants encountered by EMS during the study period met our criteria for apparent life-threatening event. Mean age was 3.1+/-3.3 months, and 55% were boys. Of the infants with apparent life-threatening event, 50 (83.3%) infants appeared to be in no distress, 8 (13.3%) infants were in mild distress, and 2 (3.3%) infants were in moderate distress. General physical appearance, work of breathing, circulatory signs, respiratory rate, and pulse rate were not clinically abnormal in the study group as a whole. Critical conditions associated with apparent life-threatening event included pneumonia or bronchiolitis (12%), seizure (8%), sepsis (7%), intracranial hemorrhage (3%), bacterial meningitis (2%), dehydration (2%), and severe anemia (2%). Limitations of the study included retrospective design and inability to follow up study patients beyond hospital discharge.

CONCLUSION

An apparent life-threatening event in an infant can present without signs of acute illness and is commonly encountered in the EMS setting. It is often associated with significant medical conditions, and EMS personnel should be aware of the clinical importance of an apparent life-threatening event. Infants meeting criteria for an apparent life-threatening event should receive a timely and thorough medical evaluation.

Mechanical factors of cardiovascular risk in systemic arterial hypertension. A new sign of arterial rigidity

ANTECEDENT: By means of sphygmokinetocardiography (SKCG) we developed and arterial rigidity index (ARI) which measure the pulse wave aortic carotid reflexion time over the left ventricular ejection time (LVET). This index, together with the pulse wave velocity (PWV) and the pulse pressure (PP) are indicators of arterial stiffness. In this paper we measured these index in 27 systemic artery hypertension. Cases (group A, GA), with and without left ventricular hypertrophy (subgroups: A1 SGA1, n = 13, and A2, SGA2, n = 14), respectively, and 28 normotensive cases (group B, GB).

PROTOCOL

In two occasions: after 3 minutes of sitting position (SP) and after 3 minute of logging in an upright position (UP), blood pressure, ARI, PP, PWV (aortic-hand finger distance/aorto-hand finger pulse time) and R-IV interval (electrocardiographic R wave-left early ventricular kinetocardiography deflexion) were measured.

RESULTS

Demography was similar in GA and GB. Systolic, diastolic and pulse pressure were significantly higher in GA vs GB. LVET (ms) was lower in GA vs GB in SP (268 +/- 42 vs 274 +/- 40, p < 0.001, respectively) and higher postexercise UP (280 +/- 42 vs 244 +/- 46, p < 0.001). PWV m/s were higher in SP in GA vs GB (9.8 +/- 2.8 vs 7.4 +/- 1.2, p < 0.001, respectively) and in UP (10.1 +/- 1.9 vs 7.9 +/- 9, p < 0.001, respectively). ARI was lower in UP in GA vs GB (0.48 +/- 0.3 vs 0.80 +/- 0.3, p < 0.003). Correlation index of PP vs SBP, vs DBP and vs PWV were significant in SP and in UP. Height had a significant correlation vs ARI in SP and UP (r = 0.60, p < 0.01, and r = 0.42, p < 0.05, respectively).

CONCLUSION

PWV is increased in GA vs GB patients. The ARI index is lower in GA vs GB cases in post exercise. PWV and PP showed a statistical significant correlation; height vs ARI had also a significant correlation: SKCG is a new method, that uses a not commercially instrument, which should have clinical application.

Rigor-force producing cross-bridges in skeletal muscle fibers activated by a substoichiometric amount of ATP

Isometric skinned muscle fibers were activated by the photogeneration of a substoichiometric amount of ATP and their cross-bridge configurations examined during the development of the rigor force by x-ray diffraction and electron microscopy. By the photogeneration of approximately 100 microM ATP, approximately 2/3 of the concentration of the myosin heads in a muscle fiber, muscle fibers originally in the rigor state showed a transient drop of the force and then produced a long-lasting rigor force (approximately 50% of the maximal active force), which gradually recovered to the original force level with a time constant of approximately 4 s. Associated with the photoactivation, muscle fibers revealed small but distinct changes in the equatorial x-ray diffraction that run ahead of the development of force. After reaching a plateau of force, long-lasting intensity changes in the x-ray diffraction pattern developed in parallel with the force decline. Two-dimensional x-ray diffraction patterns and electron micrographs of the sectioned muscle fibers taken during the period of 1-1.9 s after the photoactivation were basically similar to those from rigor preparations but also contained features characteristic of fully activated fibers. In photoactivated muscle fibers, some cross-bridges bound photogenerated ATP and underwent an ATP hydrolysis cycle whereas a significant population of the cross-bridges remained attached to the thin actin filaments with no available ATP to bind. Analysis of the results obtained indicates that, during the ATP hydrolysis reaction, the cross-bridges detached from actin filaments and reattached either to the same original actin monomers or to neighboring actin monomers. The latter cross-bridges contribute to produce the rigor force by interacting with the actin filaments, first producing the active force and then being locked in a noncycling state(s), transforming their configuration on the actin filaments to stably sustain the produced force as a passive rigor force.